Patent Publication Number: US-11649977-B2

Title: Systems and methods for air remediation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of International Application Number PCT/US2019/050416, filed Sep. 10, 2019, which claims benefit of U.S. Provisional Application No. 62/783,718, filed Dec. 21, 2018, and claims benefit of U.S. Provisional Application No. 62/756,913, filed Nov. 7, 2018, and claims benefit of U.S. Provisional Application No. 62/731,535, filed Sep. 14, 2018, which are all hereby incorporated herein by reference in their entirety. This application also is a continuation-in part of International Application Number PCT/US2019/050339 filed Sep. 10, 2019, which claims benefit of U.S. Provisional Application No. 62/756,913, filed Nov. 7, 2018, and claims benefit of U.S. Provisional Application No. 62/731,535, filed Sep. 14, 2018, which are all hereby incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to assessing, monitoring, and improving the indoor air quality in a habitable environment and/or spaces therein. 
     BACKGROUND 
     Most people spend significant amounts of time in habitable environments such as enclosed indoor spaces associated with homes, apartments, condominium units, hotel suites or rooms, motel suites or rooms, spas, hospitals, and other public and private facilities. Sometimes these indoor spaces are controlled, or even owned by, the principal occupants, such as homes, apartments or condominium units. Other times these enclosed spaces are controlled by others, for example a facility owner or operator who may own and/or operate a hotel, motel, spa, hospital. 
     Significant time in these indoor spaces exposes the occupant to a wide range of environmental factors, any of which may have either adverse or beneficial effects on the occupant&#39;s health, well-being or sense of well-being. For example, poor indoor air quality has been linked to numerous short- and long-term health issues. Common indoor air pollutants include, for example, carbon dioxide (CO 2 ), carbon monoxide (CO), particulate matter (e.g., PM 2.5 , PM 10 ), volatile organic compounds (VOCs), radon, nitrogen dioxide, ozone (O), and noxygen (NOx), which may be produced or otherwise released by, for example, building materials, HVAC systems, fuel burning combustion appliances, cleaning products, smoking, etc. 
     Short-term effects of indoor air pollutants may include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue, while long-term effects may include respiratory diseases, heart disease, and even cancer. Sick Building Syndrome (SBS) is a condition associated with increased time spent in buildings, and the chemicals used in building materials are thought to be a major contributing factor. 
     New approaches for improving air quality in indoor spaces within habitable environments are desirable. 
     BRIEF SUMMARY 
     Most people spend significant amounts of time in habitable environments such as enclosed indoor spaces associated with homes, apartments, condominium units, hotel suites or rooms, motel suites or rooms, spas, hospitals, office spaces, meeting rooms, and other public and private facilities. Sometimes these indoor spaces are controlled, or even owned by, the principal occupants, such as homes, apartments or condominium units. Other times these enclosed spaces are controlled by others, for example a facility owner or operator who may own and/or operate a hotel, motel, spa, hospital, office building or office space, etc. 
     Products, methods and systems may be usable for improving air quality within a particular indoor space or other habitable environment. Such spaces may include, for example, an office building, building office, school, apartment building, dormitory, single family home, multi-family dwelling or building, townhouse, theatre, train or bus station, library, public lounge, store or market, bakery, restaurant, tavern, pub, resort, bar, hostel, lodge, hotel, motel, inn, guest house, mall, art gallery, art studio, craft studio, ship, boat, gym, spa, fitness center, sports facility, gas station, airplane, airport, automobile, train, bus, kiosk, hospital, doctor&#39;s office, dentist&#39;s office, police station, fire station, lighthouse, bank, coffee shop, dry cleaner, department store, pharmacy, hardware store, drug store, grocery store, institution, music studio, recording studio, concert hall, radio station or studio, television station or studio, post office, church, mosque, synagogue, chapel, mobile home, barn, farm house, silo, residence, assisted living center, hospice, dwelling, laundromat, museum, hair salon, parking structure or facility, greenhouse, nursery, nail salon, barbershop, trailer, warehouse, storage facility, rest home, day care facility, laboratory, military facility, and any other place or facility where one or more people may congregate, live, work, meet, engage, spend time, etc. Within such spaces, there may be one or more sub-spaces or habitable environments that may be used for single or multiple purposes, such as home or other offices, kitchens, galleys, pantries, cooking areas, eating areas, home or office libraries or studies, conference rooms, dining rooms, bathrooms, toilets, powder rooms, play rooms, bedrooms, foyers, reception areas, file rooms, pods, pet rooms, storage rooms, junk rooms, carports, dens, basements, attics, garages, closets, classrooms, cabins, cabooses, train cars, bunk rooms, media rooms, baths, auditoriums, locker rooms, changing rooms, engine rooms, cockpits, work rooms, stairwells, exhibition rooms, platforms, elevators, walk ways, hallways, pools, stock rooms, exercise rooms, break rooms, snack rooms, living or family rooms, dressing rooms, slumber rooms, meeting rooms, conference rooms, offices, game rooms, porches, patios, seating areas, clean rooms, common rooms, lunch rooms, sky boxes, stages, prop rooms, make up rooms, safes, vaults, reception areas, check-in areas, compartments, drafting rooms, drawing rooms, computer or information technology rooms, waiting rooms, operating rooms, examination rooms, therapy rooms, emergency rooms, recovery rooms, machine rooms, equipment rooms, control rooms, laboratory rooms, monitoring rooms, and enclosed or partially enclosed areas, among others. In some spaces, requirements in the design, operation or other aspect of the space may apply. For example, enclosed stairwells often may have a separate source of air, a separate air handling system, or be pressurized to make sure that the stairwells remain usable in a fire. 
     Various approaches described herein employ combinations of passive and active techniques for improving air quality in indoor spaces, to reduce or ameliorate adverse effects of various indoor air pollutants. These approaches may have application in occupational environments, for instance offices, retail locations, factories or warehouses. These approaches may have application in residential settings, for instance homes, apartments, porches, condominiums or other residences. These approaches may have application in other settings, for instance hospitals or clinics, waiting areas associated with transportation such as airports and train stations, and/or public areas such as theaters, arenas, stadiums, museums, hotels and other venues. The various combinations may advantageously produce synergistic results, which may not be otherwise achievable on an individual basis. 
     Occupants or other users of such spaces or sub-spaces (i.e., zones) may want to control or influence the indoor air quality or other parameters within a given space or sub-space, which may be, or may be part, of a habitable environment or other habitable, usable or occupiable area. 
     In one illustrative approach, a system for improving the air quality in an indoor space may be summarized as including a sensor array configured to measure at least one air parameter in an indoor space; an air handling unit comprising a control circuit; and a central control circuit that includes at least one processor and at least one non-transitory processor-readable medium that stores at least one of processor-executable instructions or data. The central controller is communicatively coupled to the sensor array and the air handling unit and is configured to receive from the sensor array a first signal indicative of a measurement of a first air parameter in the space; determine if the measurement of the first air parameter is above a first threshold value for a first duration; if the measurement of the first air parameter is above the first threshold value for the first duration, determine if air within the space is currently being remediated; and if the air within the space is not currently being remediated, cause the air handling unit to remediate the air within the space until a measurement of the first air parameter is lower than a second value for a second duration. In some embodiments, a sensor array may be or include one or more environmental parameter measuring devices or other sensors. 
     In some embodiments, the first and second threshold values may be substantially the same. In other embodiments, the second threshold value may be lower than the first threshold value. For example, the second threshold value may be about half of the first threshold value. 
     The sensor array may be configured to measure one or more air parameters at defined detection intervals. In addition, each of the first and second durations may comprise at least one, and sometimes, at least two sensor detection intervals. In some embodiments, the first and second durations are substantially similar. In other embodiments, the second duration is longer than the first duration. 
     The sensor array may include one or more sensors that are capable of detecting and/or measuring any detectable air pollutant or air quality parameter including, but not limited to, carbon dioxide, carbon monoxide, particulate matter, volatile organic compounds (VOCs), radon, nitrogen dioxide, ozone, noxygen (NOx), and combinations thereof. 
     The air handling unit may remediate the air within the indoor space using any suitable air remediation technique including, but not limited to fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, ultraviolet air purification, chemical sorbent filtration, catalyst sorbent filtration, and combinations thereof. In some embodiments, when the detected air quality parameter above the threshold is carbon dioxide, the air handling unit may remediate the air within the indoor space by fresh air exchange. For example, when the measurement of carbon dioxide in the indoor space is above the first threshold value for the first duration, the central control circuit causes a window or vent in the indoor space to open a predetermined amount to facilitate the fresh air exchange by the air handling unit. 
     In some embodiments, the central control circuit may receive from the sensor array a second signal indicative of a measurement of a second air pollutant or parameter in the space. In some embodiments, the central control circuit may then determine if the measurement of the second air parameter is above a third threshold value for a third duration, and if the measurement of the second air parameter is above the third threshold value for the third duration, the central control circuit may cause the air handling unit to remediate the air within the space until a measurement of the second air parameter is lower than a fourth threshold value for a fourth duration. In other embodiments, the central control circuit may determine that a combined measurement of the first and second air parameters in the indoor space is above a first combined threshold value for the first duration, and cause the air handling unit to remediate the air within the space until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration. When the first air parameter comprises carbon dioxide and a second air parameter comprises particulate matter, the air handling unit may remediate the air in the indoor space by at least fresh air exchange. 
     The system may further include one or more occupancy sensors or sensor arrays communicatively coupled to the central control circuit and configured to detect an occupancy in the indoor space or zones therein, and the system may automatically adjust the first and second threshold values and/or the first and second durations based on a detected occupancy in the indoor space or zones therein. 
     In some embodiments, the central control circuit may be further configured to initiate operation of the air handling unit at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter below a threshold value that is lower than each of the first and second threshold values. 
     The system may further comprise an outdoor air sensor communicatively coupled to the central control circuit, the outdoor air sensor located in an outdoor area outside of the indoor space and configured to measure at least one air outdoor parameter in the outdoor area. The central control circuit may receive from the outdoor sensor a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area and determine if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the central control circuit may cause the air handling unit to remediate the air within the indoor space without using fresh air exchange until the sooner of: a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration, or a measurement of the first air parameter in the indoor space is lower than the second threshold value for the second duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the control circuit may delay air remediation in the indoor space by the air handling unit until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is currently being remediated, the central control circuit may cause the air handling unit to cease air remediation in the indoor space until the measurement of the first outdoor air parameter is lower than a second outdoor threshold value for the second outdoor duration. 
     In another illustrative approach, a system for improving the air quality in an indoor space may be summarized as including a first sensor array located in a first zone of an indoor space and a second sensor array located in a second zone of the indoor space, the first and second sensors configured to measure at least one air parameter in the first and second zones of the indoor space, respectively; and an air handling unit associated with the first and second zones of the indoor space comprising a control circuit. The system further includes a central control circuit communicatively coupled to the sensor array and the air handling unit, the central control circuit configured to receive from the first sensor array a signal indicative of a measurement of a first air parameter in the first zone; determine if the measurement of the first air parameter is above a first threshold value for a first duration; if the measurement of the first air parameter is above the first threshold value for the first duration, determine if air within the first zone is currently being remediated; and if the air within the first zone is not currently being remediated, cause the air handling unit to remediate the air within the first and second zones until a measurement of the first air parameter is lower than a second value for a second duration. 
     In some embodiments, the air handling unit associated with the first and second zones may further comprise a first damper located in the first zone and a second damper located in the second zone, the first and second dampers configured to control airflow into the first and second zones, respectively. If the measurement of the first air parameter is above the first threshold value for the first duration, and if the air within the first zone is not currently being remediated, the air handling unit associated with the first and second zones may remediate the air within the first zone by reconfiguring positions of the first and second dampers to allow airflow into the first zone and to restrict airflow into the second zone. 
     The system may further may comprise a third sensor array located in a third zone of a of the indoor space and a fourth sensor array located in a fourth zone of the indoor space, the third and fourth sensor arrays communicatively coupled to the central control circuit and configured to measure at least one air parameter in the third and fourth zones of the indoor space, respectively. The system may further include an air handling unit associated with the third and fourth zones of the indoor space comprising a control circuit. The control circuit may be further configured to receive from the third sensor array a signal indicative of a measurement of a second air parameter in the third zone; determine if the measurement of the second air parameter in the third zone is above a third threshold value for a third duration; if the measurement of the second air parameter in the third zone is above the third threshold value for the third duration, determine if air within the third zone is currently being remediated; and if the air within the third zone is not currently being remediated, cause the air handling unit associated with the third and fourth zones to remediate the air within the third and fourth zones until a measurement of the second air parameter in the third zone is lower than a fourth threshold value for a fourth duration. 
     In some embodiments, the air handling unit associated with the third and fourth zones may further comprise a third damper located in the third zone and a fourth damper located in the fourth zone, the third and fourth dampers configured to control airflow into the third and fourth zones, respectively. If the measurement of the first air parameter in the third zone is above the first threshold value for the first duration, and if the air within the third zone is not currently being remediated, the air handling unit associated with the third and fourth zones may remediate the air within the third zone by reconfiguring positions of the third and fourth dampers to allow airflow into the third zone and to restrict airflow into the fourth zone. 
     In some embodiments, the first and second threshold values may be substantially the same. In other embodiments, the second threshold value may be lower than the first threshold value. For example, the second threshold value may be about half of the first threshold value. In some embodiments, the first, second, third, and fourth threshold values may be substantially the same. In other embodiments, the first and third threshold values may be substantially the same and the second and fourth values may be substantially the same. In some embodiments, the second and fourth threshold values may be lower than the first and third threshold values. For example, the second and fourth threshold values may be about half of the first and third thresholds values. 
     The sensor arrays are generally capable of detecting and/or measuring any detectable air quality parameter including, but not limited to, carbon dioxide, carbon monoxide, particulate matter, volatile organic compounds (VOCs), radon, nitrogen dioxide, ozone, noxygen (NOx), and combinations thereof. The sensor arrays may be configured to measure one or more air parameters at defined detection intervals. In addition, each of the first, second, third, and/or fourth durations may comprise at least one, and in some embodiments, at least two sensor detection intervals. In some embodiments, the first, second, third, and fourth durations maybe substantially similar. In other embodiments, the first and third durations may be substantially similar and the second and fourth durations may be substantially similar, and the second and fourth durations may be longer than the first and third durations. 
     The air handling unit associated with the first and second zones may remediate the air within the first and second zones using any suitable air remediation technique including, but not limited to fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, ultraviolet air purification, and combinations thereof. In some embodiments, when the detected air quality parameter above the threshold is carbon dioxide, the air handling unit associated with the first and second zones may remediate the air within the first and second zones by fresh air exchange. For example, when the measurement of carbon dioxide in the first and second zones is above the first threshold value for the first duration, the central control circuit causes a window or vent in the first and/or second zones to open a predetermined amount to facilitate the fresh air exchange by the air handling unit. 
     In some embodiments, the central control circuit may receive a signal from the first sensor array indicating that levels of two different air parameters in the first zone are above respective first and second thresholds for the first duration. The central control circuit may then cause the air handling unit associated with the first and second zones to remediate the air within the first and second zones until a measurement of the two air parameters in the first zone is lower than respective second predetermined threshold values for the second duration. In other embodiments, the central control circuit may determine that a combined measurement of first and second air parameters in the first zone is above a first combined threshold value for the first duration and cause the air handling unit to remediate the air within the first and second zones until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration. When the first air parameter comprises carbon dioxide and a second air parameter comprises particulate matter, the air handling unit associated with the first and second zones may remediate the air in the first and second zones by at least fresh air exchange. 
     The system may further include one or more occupancy sensors or sensor arrays communicatively coupled to the central control circuit and configured to detect an occupancy in the first zone, and the system may automatically adjust the first and second threshold values and/or the first and second durations based on a detected occupancy in the first zone 
     In some embodiments, the central control circuit may be further configured to initiate operation of the air handling unit associated with the first and second zones at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter in the first zone below a threshold value that is lower than each of the first and second threshold values. 
     The system may further comprise an outdoor air sensor communicatively coupled to the central control circuit, the outdoor air sensor located in an outdoor area outside of the indoor space and configured to measure at least one air outdoor parameter in the outdoor area. The central control circuit may receive from the outdoor sensor a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area and determine if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the first and second zones is not currently being remediated, the central control circuit may cause the air handling unit to remediate the air within the first and second zones without using fresh air exchange until the sooner of: a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration; or a measurement of the first air parameter in the first zone is lower than the second threshold value for the second duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the control circuit may delay air remediation in the first and second zones by the air handling unit until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the first and second zones is currently being remediated, the central control circuit may cause the air handling unit to cease air remediation in the first and second zones until the measurement of the first outdoor air parameter is lower than a second outdoor threshold value for the second outdoor duration. 
     In one illustrative approach, a method of improving air quality in an indoor space may be summarized as including receiving from a sensor array a first signal indicative of a measurement of a first air parameter in the space; determining if the measurement of the first air parameter is above a first threshold value for a first duration; if the measurement of the first air parameter is above the first threshold value for the first duration, determining if air within the space is currently being remediated; and if the air within the space is not currently being remediated, initiating air remediation in the space by an air handling unit and continuing air remediation within the space until a measurement of the first air parameter is lower than a second value for a second duration. The air handling unit may remediate the air within the space using at least one of fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, and ultraviolet air purification. The first air parameter may be selected from the group consisting of carbon dioxide, particulate matter, volatile organic compounds (VOCs), radon, carbon monoxide, nitrogen dioxide, ozone, noxygen (NOx), and combinations thereof. 
     In some embodiments, the method may further include receiving from a sensor array a second signal indicative of a measurement of a second air parameter in the space; determining if the measurement of the second air parameter is above a third threshold value for a third duration; and if the measurement of the second air parameter is above the third threshold value for the third duration, initiating air remediation in the indoor space by the air handling unit and continuing air remediation within the space until a measurement of the second air parameter is lower than a fourth threshold value for a fourth duration. In other embodiments, the method may further include receiving from the sensor array a second signal indicative of a measurement of a second air parameter in the space; determining that a combined measurement of the first and second air parameters in the indoor space is above a first combined threshold value for the first duration; initiating air remediation in the indoor space by the air handling unit; and continuing air remediation within the space until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration. 
     In some embodiments, the method may further include initiating operation of the air handling unit at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter below a threshold value that is lower than each of the first and second threshold values. 
     The method may further comprise receiving from an outdoor sensor a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area; and determining if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the method may further comprise initiating air remediation within the indoor space by the air handling unit without using fresh air exchange, and continuing air remediation until the sooner of: a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration; or a measurement of the first air parameter in the indoor space is lower than the second threshold value for the second duration. In other embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the method may further comprise delaying air remediation in the indoor space by the air handling unit until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is currently being remediated, the method may further comprise causing the air handling unit to cease air remediation in the indoor space until the measurement of the first outdoor air parameter is lower than a second outdoor threshold value for the second outdoor duration. 
     In another illustrative approach, a method of improving air quality in an indoor space may be summarized as including receiving from a first sensor array a signal indicative of a measurement of a first air parameter in a first zone; determining if the measurement of the first air parameter is above a first threshold value for a first duration; if the measurement of the first air parameter is above the first threshold value for the first duration, determining if air within the first zone is currently being remediated; if the air within the first zone is not currently being remediated, initiating air remediation in the first and second zones by an air handling unit associated with the first and second zones; and continuing air remediation within the first and second zones until a measurement of the first air parameter in the first zone is lower than a second value for a second duration. In some embodiments, the air handling unit associated with the first and second zones may remediate the air within the first zone by reconfiguring positions of first and second dampers located in the first and second zones, respectively, to allow airflow into the first zone and to restrict airflow into the second zone. 
     The method may further comprise receiving from a third sensor array a signal indicative of a measurement of a second air parameter in a third zone; determining if the measurement of the second air parameter in the third zone is above a third threshold value for a third duration; if the measurement of the second air parameter in the third zone is above the third threshold value for the third duration, determining if air within the third zone is currently being remediated; if the air within the third zone is not currently being remediated, initiating air remediation in the third and fourth zones by an air handling unit associated with the third and fourth zones; and continuing air remediation within the third and fourth zones a measurement of the second air parameter in the third zone is lower than a fourth threshold value for a fourth duration. In some embodiments, the air handling unit associated with the third and fourth zones may remediate the air within the third zone by reconfiguring positions of third and fourth dampers located in the third and fourth zones, respectively, to allow airflow into the third zone and to restrict airflow into the fourth zone. 
     The air handling units may remediate the air within the zones using at least one of fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, and ultraviolet air purification. The air parameters may be selected from the group consisting of carbon dioxide, particulate matter, volatile organic compounds (VOCs), radon, carbon monoxide, nitrogen dioxide, ozone, noxygen (NOx), and combinations thereof. 
     In some embodiments, the method may further include receiving a signal from the first sensor array indicating that levels of two air parameters in the first zone are above respective first threshold values for the first duration, initiating air remediation in the first and second zones by the air handling unit associated with the first and second zones, and continuing air remediation within the first and second zones until a measurement of the two air parameters in the first zone is lower than respective second predetermined threshold values for the second duration. In other embodiments, the method may further include receiving from the first sensor array a second signal indicative of a measurement of a second air parameter in the first zone, determining that a combined measurement of the first and second air parameters in the first zone is above a first combined threshold value for the first duration, initiating air remediation in the first and second zones by the air handling unit associated with the first and second zones, and continuing air remediation within the first and second zones until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration. 
     In some embodiments, the method may further include initiating operation of the air handling unit at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter below a threshold value that is lower than each of the first and second threshold values. 
     The method may further comprise receiving from an outdoor sensor a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area; and determining if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the first and second zones is not currently being remediated, the method may further comprise initiating air remediation within the first zone by the air handling unit associated with the first and second zones without using fresh air exchange, and continuing air remediation in the first zone until the sooner of: a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration; or a measurement of the first air parameter in the first zone is lower than the second threshold value for the second duration. In other embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the first and second zones is not currently being remediated, the method may further comprise delaying air remediation in the first zone by the air handling unit associated with the first and second zones until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the first and second zones is currently being remediated, the method may further comprise causing the air handling unit associated with the first and second zones to cease air remediation in the first and second zones until the measurement of the first outdoor air parameter is lower than a second outdoor threshold value for the second outdoor duration. 
     In another illustrative approach, a method of improving air quality in an indoor space may be summarized as including receiving from a first sensor array a signal indicative of a measurement of an air parameter in a first zone; receiving from a second sensor array a signal indicative of a measurement of an air parameter in a second zone; determining that the measurements of the air parameters in the first and second zones are above first respective threshold values for first respective durations; ranking the first and second zones as one of a highest ranked zone and a next highest ranked zone based on air remediation priority; initiating air remediation in the highest ranked zone by an air handling unit associated with the first and second zones; continuing air remediation in the highest ranked zone until a measurement of the respective air parameter in the highest ranked zone is lower than a respective second value for a respective second duration; initiating air remediation in the next highest ranked zone by the air handling unit; and continuing air remediation in the next highest ranked zone until a measurement of the respective air parameter in the next highest zone is lower than a respective second value for a respective second duration. 
     In some embodiments air remediation priority may be based on, for example, at least one of: (a) the type of elevated air parameter(s); (b) the respective measurements or scores of the air parameter(s); (c) comparison of which air parameter(s) exceeds its threshold value the most; (d) estimated, actual, or predicted occupancy of the zone (e.g., if one zone is occupied and the other is not, the occupied zone may be remediated first; the zone scheduled for occupancy first may be remediated first; etc.); (e) intended or expected use of the zone, the type of room/zone, etc. (e.g., a bedroom may be remediated before a kitchen, a child&#39;s bedroom may be remediated before an adult&#39;s bedroom, a meeting room may be remediated before a document storage room); (f) the zone that was remediated the longest time ago may be remediated first; (g) the zone that can be remediated the quickest may be remediated first; (h) time of day or year; (i) day of week; (j) the relative impacts of elevated air parameters on one or more people&#39;s health; (k) occupant or other user preference or need; (l) location; (m) external weather or other conditions (e.g., noise level); (n) group related preference or need; (o) power or energy availability; (p) noise level or other ramification created during remediation of a zone; (q) the length of time it might take to remediate a zone; or (r) one or more other factors (e.g., a room having food out in the open may be remediated before another room). 
     Occupants of an indoor space may want to continuously or otherwise regularly monitor indoor environmental quality parameters, including thermal and indoor air quality parameters, within the indoor space. Continuously or regularly monitoring an indoor environment allows for the environment to be more precisely and accurately controlled. 
     In one illustrative approach, an apparatus for sheltering occupants may summarized as including a built structure having an indoor environment; a sensor array configured to measure at least one of air quality, thermal quality, sound parameters, or lighting parameters; a central control circuit communicatively coupled to the sensor array. The central control circuit in the apparatus may be configured to delineate occupant zones based on an electronic floor plan; instruct allocation or installation of at least one sensor array for or in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identify overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; and instruct allocation or installation of at least one sensor array for or in the identified overlapping zones. If the sensor arrays available are less than a total of the combined delineated occupant zones and identified overlapping zones, then allocation or installation of thermal sensor arrays may occur on the basis of the following order of preference: combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones and allocation or installation of air quality sensor arrays occurs on the basis of the following order of preference: the combined boundary-occupant zone, the combined boundary-occupant-air handling zone, and then the combined air handling-occupant zone. 
     In another illustrative approach, a system for monitoring indoor environmental quality may be summarized as including a built structure having a plurality of environmentally-controllable zones; a sensor array configured to measure at least one indoor environmental quality parameters; an environmental control system associated with the built structure; at least one electronic user device associated with a user; and a control circuit that is communicatively coupled to the sensor array, the electronic device, and the environmental control system. In the system, the environmentally-controllable zones may be delineated into one or more occupant zones, air handling zones, and boundary zones. The control circuit may be configured to detect a particular occupant having an occupant profile in an environment database, locate the particular occupant in a particular occupant zone, compare the sensor readings in the particular occupant zone with parameters of the occupant profile associated with the particular occupant, and, upon detection that the sensor readings in the particular occupant zone are not within the parameters of the occupant profile, instruct the environmental control system to adjust the parameters pursuant to the occupant profile. 
     In one embodiment, the system for monitoring indoor environmental quality may include a sensor array configured to measure at least one of air quality, thermal quality, sound parameters, or lighting parameters. 
     In another illustrative approach, a method of monitoring indoor air quality may be summarized as including delineating a plurality of occupant zones in a built structure based on an electronic floor plan; allocating or installing at least one of a plurality of sensor arrays for or in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identifying overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; installing at least one of the plurality of sensor arrays in the identified overlapping zones; and operating an air handling system according to readings from the sensor arrays in the delineated occupant zones and the identified overlapping zones. If sensor arrays available for the identified occupant zones are less than the delineated occupant zones and the identified overlapping zones, then allocation or installation of thermal sensor arrays may occur on the basis of the following order of preference combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Disclosed herein are embodiments of systems, apparatus, and methods pertaining to assessing, monitoring, and improving the indoor air quality in a habitable environment and/or spaces therein. In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings. 
         FIG.  1    is a block diagram of an air remediation system for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  2    is a block diagram of an air remediation system for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  3    is a schematic diagram of an indoor space in accordance with some embodiments. 
         FIG.  4    is a schematic diagram of a multi-zone indoor space in accordance with some embodiments. 
         FIG.  5    is a schematic diagram of a multi-zone indoor space in accordance with some embodiments. 
         FIG.  6    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  7    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  8    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  9    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  10    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  11    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  12    is a flow diagram of a method for improving air quality in an indoor space in accordance with some embodiments. 
         FIG.  13    is a block diagram of a system for monitoring indoor environmental quality. 
         FIG.  14 A  and  FIG.  14 B  are schematic diagrams of an exemplary indoor environment with multiple occupant zones. 
         FIG.  14 C  is a schematic diagram of the location of sensor packages in an exemplary indoor environment with multiple occupant zones. 
         FIG.  14 D  is a schematic diagram of boundary zones an exemplary indoor environment. 
         FIG.  14 E  is a schematic diagram of air handling zones an exemplary indoor environment. 
         FIG.  14 F  is a schematic diagram of overlapping areas an exemplary indoor environment. 
         FIG.  14 G  is a schematic diagram of outdoor zones adjacent to an exemplary indoor environment. 
         FIGS.  15 A and  15 B  are a flow diagrams of a method for monitoring indoor environmental quality in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with environmental control such as fans, blowers, heaters, coolers such as air conditioners or swamp coolers, compressors or other cooling systems, and control systems such as computing systems, as well as networks and other communications channels have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. 
     Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.” 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
       FIG.  1    illustrates an exemplary air remediation system  100  for improving air quality in a habitable environment or indoor space therein. In some approaches, the air remediation system  100  may be a standalone system for remediating air quality in a habitable environment. In other approaches, the air remediation system may form part of, or otherwise incorporate, one or more existing HVAC systems within a habitable environment. In some embodiments, the air remediation system  100  may form part of a home wellness and/or a “smart home” system in the habitable environment, which may also include other systems or components that contribute to a wellness or sense of wellness of the occupant of the habitable environment. For example, embodiments of the air remediation describe herein may be incorporated into systems for enhancing wellness in a habitable environment, and example of which is described in International Application No. PCT/US2017/048382, filed on Aug. 27, 2017, which published as WO/2018/039433 on May 1, 2018, the contents of which is hereby incorporated by reference. 
     As shown in  FIG.  1   , air remediation system  100  generally includes one or more indoor air quality (IAQ) sensor arrays  110 . The sensor arrays  110  may comprise one or more indoor air quality sensors configured to sense, detect, or otherwise measure air pollutants in the habitable space or one or more zones therein. Examples of air pollutants that may be detected by sensors comprising sensor array  110  may include, but are not limited to, carbon dioxide (CO 2 ), carbon monoxide (CO), particulate matter (e.g., PM 2.5 , PM 10 ), volatile organic compounds (VOCs), radon, nitrogen dioxide, ozone, and noxygen (NOx). 
     The air remediation system  100  may optionally include one or more outdoor air quality (OAQ) sensor arrays  150  to measure outdoor air pollutants. The outdoor air quality sensor arrays may include air quality standalone sensors located outside of the habitable environment and configured to send signals to the air remediation system  100 , and may also include sensors associated with weather stations, which may broadcast air quality data, weather predictions or forecasts, or other information for public use. The system may also include one or more occupancy sensors, motion detectors, face or other visual recognition technologies, or other technology or devices located in the indoor space or zones therein  160  to sense, detect, or otherwise measure the occupancy of an indoor space of the habitable environment or zones therein. 
     The air remediation system  100  further may include one or more air handling units  130  communicatively coupled to a central control circuit  120 , directly or indirectly. The one or more air handling systems  130  may form part of an existing HVAC system in the habitable environment and may include a variety of components to ensure that air supplied to one or more zones in the habitable environment is healthy and comfortable for the occupant(s). It should be noted that although air handling unit  130  as depicted in  FIG.  1    may include a variety of components, as discussed below in further detail, it is not necessary for the air handling unit to include each and every component discussed below. Some components may be optional, depending on the geographical location of the habitable environment, the configuration of the habitable space, the number of rooms or other zones within the habitable space, the needs and/or desires of occupants, cost, external conditions, availability, etc. Various air pollutants and techniques for partial or complete remediation of them which may be utilized by air remediation system  100  are discussed in more detail below. 
     Good air quality is one of the most important features of a healthy environment. Stationary adults typically inhale 6 to 10 liters of air each minute. This amount may double with moderate activity and may double again with vigorous exercise. Approximately 15 cubic meters of air pass through the lungs of a moderately active adult each day. 
     Minute quantities of gaseous pollutants and particulates may be present in the air from both natural and anthropogenic sources, which can cause serious health problems. Reducing the sources of gases and particulates in the home will decrease their negative effects. Airborne contaminants generated by materials, and the presence of individuals in the home, require expulsion through ventilation to the outdoors, and filtration to ensure that they do not return to the indoor air supply. 
     The major health effects of poor air quality include lung cancer and cardio-pulmonary disease. Often a significantly greater number of deaths from these ailments can be attributed to periods of higher levels of particulate matter. Other effects of air quality are asthma attacks, emphysema, and interference with the immune system. 
     At the microscopic scale, natural laws concerning fluid dynamics and gravity work differently, allowing solids and liquids to float in the air almost indefinitely. Put broadly, this microscopic particulate matter can be divided into two categories: fine particles, smaller than 2.5 μm (PM 2.5 ); and coarse particles larger than 2.5 μm and smaller than 10 μm (PM 10 -PM 2.5 ). Fine particles are inhalable particles that can lead to a number of health issues. Due to physical processes that govern their formation, fine particles are inherently more acidic and mutagenic than their larger counterparts. Fine particles are drawn deep into the lungs, maximizing damage. Most cases of mortality from inhalation of coarse particulate matter and larger contaminants arise from toxic chemicals they contain rather than the particles themselves. 
     Coarse particles usually do not penetrate as deeply into the lungs as fine particles, and therefore are the less dangerous of the two. However, many coarse particles are allergens. For example, dust mites are microscopic arachnids that feed on pet dander, dead human skin cells, and other biological matter. They thrive in carpets, mattresses, and curtains, and tend to dwell in synthetic fibers rather than natural materials. Mites are not inherently dangerous, but their droppings contain chemicals that trigger an immune response in some individuals. The resulting symptoms often include itchy eyes, runny nose, and wheezing, a reaction that can be particularly debilitating for asthmatics. Nearly one quarter of American homes have dust mite levels associated with symptomatic asthma, and almost half of them contain enough dust mites to cause allergic reactions in susceptible individuals. 
     Air constantly flows into homes and is subject to a wide range of pollutants both from outdoor air pollution and source contaminants within the home. Indoor air pollution is among the top five environmental health risks and has been shown to be 2-5 times higher than the pollution of outdoor spaces—up to 100 times higher in extreme cases. Therefore, effectively managing indoor air quality through the filtration of air drawn from outdoors and the circulation of indoor air can help reduce the concentration of contaminants in the home. To that end, air handling unit  130  may include one or more mechanical air filters (e.g., mesh, screen, woven, or piled material)  131 , through which air passes to remove larger particulate. Suitable mechanical air filters may include an activated carbon air filter, high efficiency particulate (HEPA) air filter (i.e., MERV equivalent 17+), MERV 13-16 air filter, a quantity of Zeolite, or a porous material. 
     The air handling unit  130  may include one or more electrostatic filters or precipitators  132  to remove fine particulate in one or more zones. In particular, electrostatic filter(s)  132  trap particles that could contain allergens, toxins, and pathogens. In addition, the electrostatic filter(s)  132  are installed to reduce dust mites, pollen, carpet fibers, mold spores, bacteria, smoke, and diesel particulate matter from the air. The electrostatic filter(s)  132  attracts particles using an electrostatic charge and extracts them from the air into a wire mesh. 
     The electrostatic filters  132  may take a variety of forms, for instance ones which place a charge on particles and an opposite charge on a screen or other electrode element to attract the charged particles. An example of such is a corona discharge type of electrostatic filter. The electrostatic filter  132  may be supplied charge via an electrical power supply  139 . 
     Various airborne pathogens may present problems, particular in enclosed spaces or habitable environments. This may be of particular concern with newer construction techniques which are employed to reduce the exchange of air with the exterior environment, for instance to reduce heat loss and thereby increase thermal efficiency. Although most airborne microbes are pervasive and generally harmless, some can be dangerous pathogens easily spread throughout a home&#39;s ventilation system. 
     Mold spores can induce skin, nose, throat, and eye irritation, and trigger asthma attacks. These fungi release volatile organic compounds that produce the characteristic “moldy” odor and have been linked to dizziness and nausea. Humidity control has been proven effective in reducing mold, and insulated windows reduce condensation so as to prevent mold from growing in nearby joints. 
     Individual microbes are very small and often can evade some filters if they are not attached to other particles. In order to reduce the probability of airborne pathogens from traveling through the indoor space or habitable environment, UVGI can be used to provide additional protection. UVGI is based on a specific frequency of UV light that specifically targets the DNA of microbes and viruses passing through the ventilation system. The growth and spread of health-threatening biotic agents is a primary concern for moisture buildup in HVAC systems. The use of ultraviolet germicidal irradiation (UVGI) lights installed on the upstream side of the coil in HVAC systems has been associated with a significant reduction in microorganism concentrations on irradiated cooling coils and drip pans. According to a study conducted with office workers, significantly fewer work-related respiratory, mucosal, and overall health symptoms were reported when a UVGI system was used; the use of UVGI also resulted in a 99% reduction in the concentrations of bacteria, fungi, and endotoxins on irradiated surfaces in the HVAC system. 
     The air handling unit  130  may include a UV air sanitizer designed to disinfect air via UV light within one or more components (e.g., ducts) of a ventilation system. The aim is to sterilize airborne bacteria, viruses, dust mites, and mold spores that may have escaped filtration. 
     Thus, the air handling unit  130  may include one or more UV illumination sources  133 . The UV illumination source(s)  133  is positioned to illuminate air with UV illumination of a sufficient intensity for a sufficient time as to render pathogens non-harmful. 
     Various gaseous pollutants may produce harmful effects in humans, particularly where allowed to accumulate in habitable enclosed spaces. Volatile Organic Compounds (VOCs) are carbon-based chemicals that evaporate into gases at room temperature. Many paints, varnishes, cleaning products, and pest control chemicals emit VOCs, whose presence in buildings can be 2 to 5 times as high as outside levels. Wet applied products, such as paints, coatings, varnishes, adhesives, and sealants, can often be a significant source of VOCs if they are not low-VOC materials, especially when they are drying, but also after drying. Composite wood products, which may be included in some furniture, millwork, etc. typically contain high levels of formaldehyde, which, can emit significant off-gas following their production/installation. Vinyl, or polyvinyl chloride (PVC) is another chemical that is commonly found in gasketing, carpet backing, furniture and in the household, shower curtains, etc. Depending on the product, significant off-gas may be emitted specifically as a result of the PVC. In the short term, exposure can cause dizziness, nausea, headaches, throat irritation, and fatigue, while chronic effects include damage to the liver, kidneys, and central nervous system. 
     Nitrogen dioxide is a product of combustion and mainly found near burning sources. Indoor areas that contain gas stoves, fireplaces, and cigarette smoke often have a much higher concentration of nitrogen dioxide. Epidemiological studies have suggested that excessive nitrogen dioxide inhalation may decrease lung function, particularly in children. In the short term, it can also trigger allergic responses from the immune system, resulting in irritation of the eyes, nose, and throat. 
     Ozone is created by reactions between molecular oxygen, nitrogen oxides, and sunlight. It is the major catalyst in the formation of smog. Ozone impedes cellular respiration, resulting in reduced cell activity. High concentrations of inhaled ozone can result in an itchy throat and chest tightness; chronic exposure scars the lung tissue, which can lead to emphysema. In addition, ozone interferes with the body&#39;s immune system, which compounds the danger from air or water-borne pathogens. Under current standards, the U.S. Environmental Protection Agency expects ozone to cause more than 110,000 lost work days and 1,100,000 lost school days between 2008 and 2020. Thus, the air handling unit  130  may include one or more activated carbon air filters  134  in the flow path to reduce VOC/TVOC, nitrogen dioxide, and ozone that pass through activated carbon media filters designed to intercept gas molecules. Activated carbon air filters  134  can be very beneficial in zones or other areas with sources of fumes or odors. 
     Additionally, or alternatively, the electrostatic filter  132  or some other element may optionally include one or more catalysts selected to catalyze certain impurities in the air. For instance, the electrostatic filter  132  may include one or more catalysts (e.g., non-metal catalysts for instance: titanium dioxide, chromium oxide or aluminum oxide, or metal catalysts for instance: Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt and Au, as well as combinations or alloys thereof, such as an alloy of Pt and Rh) to catalyze species of VOCs into more acceptable or less harmful forms. 
     The air handling unit  130  may include one or more heaters or heating systems  135  to heat air or provided heated air in one or more zones. The heaters  135  may take any of a large variety of forms. Heaters  135  may take the form of various electric heaters, which employ a resistive radiant element to heat air. Heaters  135  may take the form of forced air heaters which typically include burners that burn a fuel such as natural gas or propane. Heaters  135  may alternatively take the form of oil furnaces, gas furnaces, or the like. In some embodiments, hot water supplied from a boiler or other hot water source also may be included. 
     The air handling unit  130  may include one or more compressors or other cooling systems  136  which may form part of an air conditioner cooling unit. The cooling systems  136  may be fluidly coupled to control pressure of a fluid, coupled with one or more coils or other heat exchangers, and may operate in a similar fashion to standard air conditioner units to remove heat from the air. In some embodiments, chilled water supplied from a cooling system or other chilled water source also may be included. 
     Relative humidity is the measure of water vapor in the air compared to the total amount that can be held at a given temperature. In the spring and summer months, humidity levels can be high enough to cause discomfort. When cool air flows through central air systems, humidity in the air often is reduced, since cooler air holds less water vapor. However, as dry air is drawn in and heated within a building in the winter, relative humidity may fall, so the air feels may feel dry. 
     To maintain comfort, and prevent the establishment and growth of mold, dust mites, and bacteria, relative humidity in the habitable environment preferably is kept between 30% and 500%. Using high-temperature water within the ventilation system of the home suppresses bacteria growth. Humidity towards the bottom of this range usually is better in terms of air quality, but extremely low moisture levels may lead to dry skin and respiratory irritation. 
     Thus, the air handling unit may include a humidifier and/or dehumidifier  137  which may be used to control humidity in one or more zones or throughout the indoor habitable environment. This is particularly important when moisture levels in the air fall in winter, thus the air handling unit  130  may increase the moisture (i.e., humidify) during dry periods. Conversely, the air handling unit may lower moisture (i.e., dehumidifies) during humid periods. The humidifier and/or dehumidifier  137  may include a reservoir (not shown) that retains water to either be added to the air in a humidification mode or removed from the air in a dehumidification mode. The humidifier and/or dehumidifier  137  may include a compressor or other cooling system (not shown) used to, for example cool air as part of removing moisture from the air. The humidifier and/or dehumidifier  137  may optionally include a heating element to heat air as part of adding moisture to the air. 
     The air handling unit  130  may include one or more fans and/or blowers  138  coupled to one or more ducts and/or vents to facilitate air circulation and/or fresh air exchange in one or more zones. The fans and/or blowers  138  may circulate air within the air handling unit  130  and/or within the indoor habitable environment or zones therein. The fans and/or blowers  138  may expel air to an exterior environment and/or draw fresh air from the exterior environment, prior to treating the fresh air. In particular, a high flow ventilation system may expel indoor air to reduce the buildup of internally generated air impurities such as volatile organic compounds, dust mites, and pet dander. A heat exchanger may advantageously be employed to recover energy from the outgoing air. 
     The air handling unit  130  may further include a control circuit  141 . Control circuit  141  may be communicatively coupled directly or indirectly to the air handling unit  130  and configured to control one or more components of the air handling unit  130 . 
     The air remediation system  100  also may include a central control circuit  200 . The central control circuit  200  may take the form of a programmed computer or other processor-based system or device. For example, the central control circuit  200  may take the form of a conventional mainframe computer, mini-computer, workstation computer, personal computer (desktop or laptop), or handheld computer. 
     The central control circuit  200  may include one or more processing units  220  (one illustrated), non-transitory system memories  222   a - 222   b  (collectively  222 ) and a system bus  224  that couples various system components including the system memory  222  to the processing unit(s)  220 . The processing unit(s)  220  may be any logic processing unit, such as one or more central processing units (CPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic controllers (PLCs), etc. Non-limiting examples of commercially available computer systems include, but are not limited to, an 80x86, Pentium, or i7 series microprocessor from Intel Corporation, U.S.A., a PowerPC microprocessor from IBM, a Sparc microprocessor from Sun Microsystems, Inc., a PA-RISC series microprocessor from Hewlett-Packard Company, or a 68xxx series microprocessor from Motorola Corporation. The system bus  224  can employ any known bus structures or architectures, including a memory bus with memory controller, a peripheral bus, and a local bus. The system memory  222  includes non-transitory Flash or read-only memory (“ROM”)  222   a  and non-transitory random-access memory (“RAM”)  222   b . A basic input/output system (“BIOS”)  226   a , which can form part of the ROM  222   a  or RAM  222   b , contains basic routines that help transfer information between elements within the controller  200 , such as during start-up. 
     The controller  200  may include a hard disk drive  228   a  for reading from and writing to a hard disk  228   b , an optical disk drive  230   a  for reading from and writing to removable optical disks  230   b , and/or a magnetic disk drive  232   a  for reading from and writing to magnetic disks  232   b . The optical disk  230   b  can be a CD/DVD-ROM, while the magnetic disk  232   b  can be a magnetic floppy disk or diskette. The hard disk drive  228   a , optical disk drive  230   a  and magnetic disk drive  232   a  may communicate with the processing unit  220  via the system bus  224 . The hard disk drive  230   a , optical disk drive  230   a  and magnetic disk drive  232   a  may include interfaces or controllers (not shown) coupled between such drives and the system bus  224 , as is known by those skilled in the relevant art. The drives  228   a ,  230   a  and  232   a , and their associated computer-readable storage media  228   b ,  230   b ,  232   b , may provide non-volatile and non-transitory storage of computer readable instructions, data structures, program engines and other data for the air remediation system  100 . Although controller  200  is illustrated employing a hard disk  228   a , optical disk  230   a  and magnetic disk  232   a , those skilled in the relevant art will appreciate that other types of computer- or processor-readable storage media that can store data accessible by a computer may be employed, such as magnetic cassettes, flash memory, digital video disks (“DVD”), Bernoulli cartridges, RAMs, ROMs, smart cards, etc. The hard disk  228   a  may, for example, store instructions and data for controlling the air remediation system  100 , as well as other for components of a home wellness and/or home automation system, for example based on specific aspects or characteristics detected in one or more indoor spaces or zones therein in the habitable environment, inputs by an occupant or user of the habitable environment, or events expected or occurring in the habitable environment, to improve indoor air quality in one more indoor spaces or zones therein to promote the wellness or wellbeing of the occupant(s). 
     Program engines can be stored in the system memory  222   b , such as an operating system  236 , one or more application programs  238 , other programs or engines and program data. Application programs  238  may include instructions that cause the processor(s)  220  to automatically generate signals to control various of the other subsystems to achieve various environmental characteristics or scenes in the habitable environment, for example based on one or more aspects, characteristics or attributes of an occupant thereof. Application programs  238  may include instructions that cause the processor(s)  220  to automatically receive input and/or display output via various user operable input/output (I/O) devices  170  such as, for example, panels installed in the habitable environment, handheld mobile devices, kiosks, and the like. 
     Other program engines (not specifically shown) may include instructions for handling security such as password or other access protection and communications encryption. The system memory  220  may also include communications programs  240 , for example, a server for permitting the central control circuit  200  to provide services and exchange data with the air remediation system  100  and, optionally, other subsystems or computer systems or devices via the Internet, corporate intranets, extranets, or other networks (e.g., LANs, WANs), as well as other server applications on server computing systems such as those discussed further herein. The server in the depicted embodiment may be markup language based, such as Hypertext Markup Language (HTML), Extensible Markup Language (XML) or Wireless Markup Language (WML), and operates with markup languages that use syntactically delimited characters added to the data of a document to represent the structure of the document. A number of servers are commercially available such as those from Microsoft, Oracle, IBM and Apple. 
     While shown in  FIG.  1    as being stored in the system memory  222   b , the operating system  236 , application programs  238 , other programs/engines, program data and communications applications (e.g., server, browser)  240  can be stored on the hard disk  228   b  of the hard disk drive  228   a , the optical disk  230   b  of the optical disk drive  230   a  and/or the magnetic disk  232   b  of the magnetic disk drive  232   a.    
     An operator can enter commands and information (e.g., configuration information, data or specifications) via various user operable input/output (I/O) devices, such as, for example, panels installed in the habitable environment, handheld mobile devices, kiosks, and the like, or through other input devices such as a dedicated touch screen or keyboard and/or a pointing device such as a mouse and/or via a graphical user interface. Other input devices can include a microphone, joystick, game pad, tablet, scanner, touch pad, etc. These and other input devices may be connected to one or more of the processing units  220  through an interface such as a serial port interface  242  that couples to the system bus  224 , although other interfaces such as a parallel port, a game port or a wireless interface or a universal serial bus (“USB”) can be used. A monitor or other display device may be coupled to the system bus  224  via a video interface, such as a video adapter (not shown). The central control circuit can include other output devices, such as speakers, printers, etc. Alternatively, or in addition, these and other input devices may be connected directly to the air handling unit  130 , allowing a user to directly communicate with and/or control the air handling unit  130 . 
     The central control circuit  200  can operate in a networked environment using logical connections to one or more remote computers and/or devices as described above with reference to  FIG.  1   . For example, the central control circuit  200  can operate in a networked environment using logical connections to one or more other subsystems  204 - 214 , one or more server computer systems  244  and associated non-transitory data storage device  246 . The server computer systems  244  and associated non-transitory data storage device  246  may, for example, be controlled and operated by a facility (e.g., hotel, spa, apartment building, condominium building, hospital) in which the habitable environment is located. Communications may be via wired and/or wireless network architectures ( 190  in  FIG.  2   ), for instance, wired and wireless enterprise-wide computer networks, intranets, extranets, and the Internet. Thus, the central control circuit  200  may include wireless communications components, for example one or more transceivers or radios  248  and associated antenna(s)  250  for wireless (e.g., radio or microwave frequency communications, collected referred to herein as RF communications). Other embodiments may include other types of communication networks including telecommunications networks, cellular networks, paging networks, and other mobile networks. 
     The air remediation system  100  may further include one or more windows and/or vents  180  communicatively coupled, directly or indirectly, to central control circuit  200  such that the central control circuit  200  may control the opening and closing of the windows and/or vents in response to detected levels of various indoor and outdoor air pollutants. 
     As described above, the air remediation system  100  may include one or more wired or wireless user input/display devices  170  communicatively coupled to the central control circuit  200  and/or to air handling unit  130  directly, which allows a user to view and/or control functions of the air remediation system  100 , as well as the air handling system  130  directly. The user input/display device  170  may include user actuatable controls (e.g., user selectable icons displayed on touch screen, keys, buttons) manipulation of which allows a user, for instance an occupant of the habitable environment, to select parameters or programs to control one or more components of the air remediation system  100  and/or the air handling unit  130 . In some approaches, a mobile or handheld device may serve as the user input/display device  170  and may include a display (e.g., LCD) to display information and user actuatable controls (e.g., user selectable icons, keys, buttons) manipulation of which allows a user, for instance an occupant of the habitable environment, to select parameters or programs to execute to control one or more components of the air remediation system  100 . The mobile or handheld device may execute a downloaded customized application or “APP” that communicatively interfaces via a wireless protocol (e.g., IEEE 802.11, BLUETOOTH®, WI-FI®, Zigbee, Z-Wave, LTE). 
       FIGS.  3  to  5    illustrates various scenarios in which air remediation system  100  may be utilized to improve the air quality of an indoor space  10  in a habitable environment.  FIG.  3    illustrates a single-zone indoor space  10  (i.e., the space only has one conditioned zone), with one air handling unit  130 . The indoor space  10  may be, for example, studio apartment, a small home, a small office space, a hotel room, or any other habitable environment in which a single air handling unit may be used. 
     The air remediation system utilized in the single-zone scenario illustrated in  FIG.  3    may include some or all of the components described above with reference to  FIG.  1   . For example, the air remediation system may include one or more sensor arrays  110  comprising one or more sensors configured to measure at least one air parameter in the indoor space  10 , including, but not limited to carbon dioxide, particulate matter, volatile organic compounds (VOCs), radon, carbon monoxide, nitrogen dioxide, ozone, noxygen (NOx), and combinations thereof. The sensors in the sensor array  110  may be positioned throughout indoor space  10  in any suitable location. In one approach, one or more sensors that form the sensor array may be positioned at the expected typical breathing level(s) and/or height(s) of an average adult. For example, in some approaches, one or more sensors that form the sensor array may be positioned at, for example, from about 3 to about 7 feet from the floor, or even more specifically from about 4 to about 6 feet above the floor where one or more people may be expected to be standing in the indoor space  10 ; from about 2 to about 5.5 feet, or even more specifically from about 2 to about 4.5 feet above the floor where one or more people may be expected to be sitting in the indoor space  10 ; and/or from about 1.5 to about 4.5 feet, or even more specifically about 1.5 to about 3.5 feet above the floor where one or more people may be expected to be laying down on a bed or a couch in the indoor space  10 . One or more sensors may also be placed or otherwise adjusted to be positioned to accommodate spaces where children are expected to occupy. In some embodiments, two or more sensor arrays configured to measure the same or different air quality parameters, or multiple air quality parameters, may be placed at different heights within the indoor space  10 . For example, if a person is using a desk that can raise and lower to enable the person to stand or sit while using the desk, one sensor may be placed at a lower height from the floor to measure one or more air quality parameters at a sitting height for the person and another sensor may be placed at a higher height from the floor to measure one or more air quality factors at a standing height for the person. 
     A sensor used in the sensor array  110  may be configured to measure one or more air parameters at defined detection intervals, for example, every set number of milliseconds, seconds, minutes, etc. In some approaches, the sensor detection interval for one or more of the sensor arrays may be 1 minute, in some approaches two minutes, in some approaches three minutes, in some approaches four minutes, etc. In some approaches, the sensor detection interval may be between 1 and 5 minutes or even longer (e.g., ten minutes, twenty minutes, thirty minutes, sixty minutes, four hours, twelve hours, twenty-four hours). 
     Air handling unit  130  is configured to remediate or otherwise improve the air quality in indoor space  10  using any suitable air remediation technique, including but not limited to fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, and ultraviolet air purification. In the single-zone scenario illustrated in  FIG.  3   , setting points regarding thermal comfort may be achieved with indoor air quality remediation simultaneously, and particulate matter can be reduced in default mode for most of the time, even without a heating/cooling load. 
     Sensor array  110  and air handling unit  130  are communicatively coupled, directly or indirectly, to a central control circuit, which may comprise central control circuit  200  described above with reference to  FIG.  1   . The central control circuit  200  is configured to receive from the sensor array  110  signals indicative one or more air parameter measurements in indoor space  10  and communicate with air handling unit  130  to cause air handling unit  130  to initiate air remediation when certain conditions are met. For example, when the central control circuit  200  receives a first signal indicative of a measurement of a first air parameter in indoor space  10 , the central control circuit determines if the measurement of the first air parameter is above a first threshold value for a first duration. 
     In some approaches, the threshold values for various air pollutants may correspond to threshold values recommended by experts in the field. In some approaches, threshold values may be dependent and/or may otherwise change based on, for example, geographic region, season, location, user preference, month, day, and even time of day. Threshold values, detection intervals, and durations may be dependent on, or may otherwise change, based on intended or expected use of the space or an internal event such as, for example, when the occupant count in the space exceeds a normal range, the space has been unoccupied for a period of time, a window is opened, a person known to have severe allergies enters or leaves the indoor space, etc. In other approaches, threshold values, detection intervals, and durations may change based on an external event such as, for example, a local increase or decrease in local pollen count, external air pollution, etc. In some approaches, threshold values, detection intervals, and durations may change (e.g., may decrease) after air remediation is triggered a first time. In some approaches, thresholds, detection intervals, and durations may increase if air remediation is not triggered for a certain period of time, or may decrease if air remediation is being triggered with only short variations in between. 
     As one example, in one approach, a first threshold value for PM 2.5  may be 12 ug/m 3 , a first threshold value for PM 10  may be 50 ug/m 3 , and a first threshold value for CO 2  may be 800 ppm. In some approaches, the first duration may comprise at least one sensor detection interval, and in some approaches at least two detection intervals, in order to confirm the high measurement of the air parameter. For example, if a detection interval for a given sensor measuring a given air parameter is 2 minutes, the first and/or second duration may be 4 minutes. 
     If the measurement of the first air parameter is above the first threshold value for the first duration (e.g., two detection intervals), the central control circuit  200  determines if air within the indoor space  10  is currently being remediated. If the air within the indoor space  10  is not currently being remediated, the central control circuit  200  sends a signal to air handling unit, directly or indirectly, to cause the air handling unit  130  to remediate the air within the indoor space  10  until a measurement of the first air parameter is lower than a second threshold value for a second duration. Exemplary default threshold values, threshold value ranges, detection intervals, and durations for common air pollutants/air quality indicators are listed in Table 1 below. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 Detection 
                   
               
               
                 Pollutant 
                 Default threshold value 
                 Value range 
                 interval 
                 Duration 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 CO 2   
                 800 
                 ppm 
                 600-1000 
                 ppm 
                 1-5 min 
                 2 intervals 
               
               
                 PM 2.5   
                 15 
                 ug/m 3   
                 12-35 
                 ug/m 3   
                 1-5 min 
                 2 intervals 
               
               
                 PM 10   
                 50 
                 ug/m 3   
                 20-150 
                 ug/m 3   
                 1-5 min 
                 2 intervals 
               
               
                 CO 
                 9 
                 ppm 
                 6-30 
                 ppm 
                 1-5 min 
                 2 intervals 
               
               
                 TVOC 
                 500 
                 ug/m 3   
                 200-1000 
                 ug/m 3   
                 1-5 min 
                 2 intervals 
               
               
                 Radon 
                 4 
                 pCi/L 
                 2-8 
                 pCi/L 
                 1-5 min 
                 2 intervals 
               
               
                 NO 2   
                 21 
                 ppb 
                 15-100 
                 ppb 
                 1-5 min 
                 2 intervals 
               
               
                 O 3   
                 51 
                 ppb 
                 25-70 
                 ppb 
                 1-5 min 
                 2 intervals 
               
               
                   
               
            
           
         
       
     
     As discussed above, any suitable air remediation technique may be used to remediate the air in the indoor space, and may often depend on the particular air pollutant detected. For example, when the system determines a measurement of CO 2  that is above, for example, 800 ppm for at least one detection interval, and in some approaches at least two detection intervals, the air remediation technique employed by the system to improve air quality in indoor space  10  may include fresh air exchange. When the system determines a measurement of PM 10  is above, for example, 150 ug/m 3 , the, the air remediation technique employed by the system to improve air quality in indoor space  10  may include mechanical air filtration and/or fresh air exchange. As discussed below, fresh air exchange may not be a suitable air remediation technique in scenarios where outdoor air quality may be poorer than the air quality in indoor space  10 . 
     Regardless of the air parameter being measured, air remediation by the air handling unit  130  may not begin with an instant concentration peak. Generally, only a high level of the detected air parameter which lasts more than at least one detection interval, and in some approaches at least two detection intervals, may trigger remediation (a delay loop may be included to execute this feature before sending a command to the air handling unit). Even if the detected air parameter is above a set threshold value for a set duration, in some approaches air remediation may not begin unless or until the system determines that no remediation is occurring in any other areas or zones of the indoor space. In some approaches, air remediation may be triggered by the occurrence of an external event such as, for example, an increase in local pollen count, external air pollution, etc. In other approaches, air remediation may be triggered by the occurrence of an internal event such, as for example, within a designated time period after a fire is started in a fireplace or a stove is started in a kitchen, even if the threshold has not been met in the room containing the fireplace or the stove. As another example, air remediation may be triggered by a sudden increase in room occupancy. 
     Additionally, the remediation process will not cease instantly when the concentration drops below the second threshold. In some approaches, the same delay loop mentioned above may be applied when the concentration drops below the second threshold. For example, the detected air parameter should be below the threshold value for more than at least one detection interval for air remediation to cease. 
     In some approaches, the first and second threshold values for a given air parameter are substantially the same. In other words, air remediation might be triggered when a detected level of an air parameter is above a particular threshold value and then may cease when the detected level of the air parameter falls below the same threshold value. In other approaches, the second threshold value for ceasing air remediation may be lower than the first threshold value for a given air parameter. For example, the second threshold value may be about half of the first threshold value. 
     In some approaches, each of the first and second durations comprise at least one sensor detection interval. In some approaches, the first and second durations may be substantially similar. In other words, air remediation might be triggered when a detected level of an air parameter is above a particular threshold for a set duration (e.g., at least one detection interval) and then may cease when the detected level of the air parameter falls below the threshold value for at least the same set duration. In other approaches, the second duration may be longer than the first duration. 
     In some embodiments, the sensor array  110  may be configured to measure at least two different air parameters at defined detection intervals. For example, the sensor array  110  may be configured to measure both PM 2.5  and CO 2  using on or more sensors. In this approach, the central control circuit  200  may be further configured to receive from the sensor array  110  both the first and second signals indicative measurements of a first and second air parameter in the space  10 . The central control circuit  200  may then determine if the measurement of one or both of the first and second air parameters are above set threshold values for a set duration for each air parameter, and if one or both measurements are above the set threshold value(s) for the set duration(s), the central control circuit may cause the air handling unit  130  to remediate the air within the space  10  until a measurement of both the first and second the second air parameters are lower than respective second thresholds for second durations for each given air parameter. In other embodiments, the central control circuit may calculate a combined measurement (e.g., an air quality score) of at least two air parameters and determine that the combined measurement of the first and second air parameters in the indoor space  10  is above a first combined threshold value for the first duration. The central control circuit may then send a signal to air handling unit  130 , directly or indirectly, to cause the air handling unit  130  to remediate the air within the space  10  until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration. 
     The combined measurement, which may also be referred to as an air quality score, may be represented by S(i) to indicate the contamination level, where i is the type of contaminant. The higher the score, the more polluted the air. The score may be calculated per the following equation: Most pollutants found indoors have the minimum concentration at  0  or instrument detect limit (like PM, NOx) 
     
       
         
           
             
               
                 
                   { 
                   
                     
                       
                         
                           
                             
                               S 
                               ⁡ 
                               
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                                 ⁡ 
                                 
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                                   ) 
                                 
                               
                               
                                 t 
                                 ⁡ 
                                 
                                   ( 
                                   i 
                                   ) 
                                 
                               
                             
                           
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                             t 
                             ⁡ 
                             
                               ( 
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                               S 
                               ⁡ 
                               
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                               ( 
                               i 
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             Where: 
             S(i) is the score of the contamination level of pollutant i, which is a real number in 0˜1; 
             t(i) is the health threshold of the pollutant i. The value of thresholds can be referred to WELL Building Standard. 
             C(i) is the concentration of pollutant i. 
             For pollutants that the minimum concentration in the indoor environment is not 0 (like CO 2 ): 
           
         
       
    
     
       
         
           
             
               
                 
                   { 
                   
                     
                       
                         
                           
                             
                               S 
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                               C 
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                             ⁡ 
                             
                               ( 
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                             = 
                             
                               
                                 
                                   C 
                                   ⁡ 
                                   
                                     ( 
                                     i 
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                                 - 
                                 
                                   
                                     C 
                                     min 
                                   
                                   ⁡ 
                                   
                                     ( 
                                     i 
                                     ) 
                                   
                                 
                               
                               
                                 
                                   t 
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                                     ( 
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                                     ( 
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                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             
                               
                                 C 
                                 min 
                               
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                           &lt; 
                           
                             t 
                             ⁡ 
                             
                               ( 
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                               S 
                               ⁡ 
                               
                                 ( 
                                 i 
                                 ) 
                               
                             
                             = 
                             1 
                           
                           , 
                         
                       
                       
                         
                           
                             if 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             
                               C 
                               ⁡ 
                               
                                 ( 
                                 i 
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                             t 
                             ⁡ 
                             
                               ( 
                               i 
                               ) 
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                     
                 
               
             
           
         
       
         
         
           
             Where: 
             C min (i) is the minimum concentration of pollutant i that can be achieved in the normal environment. The typical value of C min (i) is 350-450 ppm 
             The overall score of the air quality is determined by the highest score of different pollutants: 
           
         
       
    
     
       
         
           
             
               
                 
                   
                     S 
                     IAQ 
                   
                   = 
                   
                     
                       max 
                       i 
                     
                     ⁢ 
                     
                       ( 
                       
                         S 
                         ⁡ 
                         
                           ( 
                           i 
                           ) 
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                     
                 
               
             
           
         
       
         
         
           
             The threshold of S IAQ  is 1 in normal scenario. The threshold of S IAQ  can be adjusted according to, but not limited to, the following reasons: 
             Season: In summer, the relative humidity may relatively higher than it in winter. The higher humidity will reduce the efficiency and effectiveness of the filtration system. As a result, to ensure the performance of the air remediation system, the threshold for S IAQ  will be adjusted to a, 0.8≤a&lt;1. 
             Space type of the system: Different spaces have different functionalities. The threshold of S IAQ  will be adjusted according to these designated functionalities to avoid potential air pollution. For example, in a kitchen area, the most common activity often is cooking. Most of cooking operation will generate much more combustion related pollutant than the other activities that happens in the residential homes. Thus, to ensure the performance of the system, the threshold for S IAQ  will be reduced from the value in the building standard by multiplying a factor, b. Some example values for b is listed below: 
           
         
       
    
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Type of spaces 
                 Value of b 
               
               
                   
                   
               
             
            
               
                   
                 Kitchen 
                 0.75-1  
               
               
                   
                 Garage (when 
                 0.8-1 
               
               
                   
                 people occupied) 
               
               
                   
                 Printing/copying 
                 0.8-1 
               
               
                   
                 room 
               
               
                   
                   
               
            
           
         
       
         
         
           
             Occupancy: Human beings are the dominant source of CO 2  and major source of PM in the indoor space. The CO 2  and PM level may increase rapidly when a space has been squeezed in many people. To address the potential pollution issue, the practical threshold for S IAQ  will be reduced when the room is over-occupied. 
             Sensor Array Location: Sensor array location will influence the measurement of the level of pollutants. If a sensor array is installed in a place that always has a lower reading compared with the real concentration of the pollutant in the breathing zone, e.g., ceiling mount, the threshold of S IAQ  can be reduced to ensure the performance of air remediation. 
           
         
       
    
     As discussed above, when one of the air quality parameters includes CO 2 , the air handling unit  130  may remediate the air within the space  10  by fresh air exchange. For example, wherein when the measurement of CO 2  in the indoor space  10  is above a first threshold value (e.g., 800 ppm) for a first duration (e.g., two detection cycles), the central control circuit  200  may initiate fresh air exchange. However, some habitable environments might not have fresh air intake capability. In such scenarios, the central control circuit  200  may be configured to communicate with one or more windows  180 , which are communicatively coupled to the central control circuit, to cause the one or more windows  180  in the indoor space  10  to open a predetermined amount to facilitate fresh air exchange by the air handling unit  130 . Alternatively, or in addition, the central control circuit  200  may be configured to provide an alert to occupants, for example a sound alert or and alert to the occupant&#39;s or another person&#39;s handheld mobile device, to open one or more windows to facilitate fresh air exchange, or to take another action. 
     The indoor space  10  may further include one or more occupancy sensor arrays  160  communicatively coupled to the central control circuit  200  and configured to detect an occupancy in the indoor space  10  or zones therein. The one or more occupancy sensor arrays  160  may be positioned throughout the indoor space  10  and configured to send signals to the central control circuit  200  indicative of an occupancy in one or more areas of the indoor space  10 . In some approaches, the central control circuit  200  may be configured to receive occupancy data from the occupancy sensor array(s)  160  and to adjust one or more threshold values and/or durations for various air parameters based on a detected occupancy in the indoor space  10 . For example, the central control circuit may reduce the thresholds for CO 2  and/or particulate matter (PM) when indoor space  10  is over-occupied. In some approaches, the central control circuit may automatically reduce the threshold(s) of one or more air parameters when detected occupancy is above a set threshold and/or when occupancy increases at a faster rate than expected. 
     The central control circuit  200  may be further configured to initiate operation of the air handling unit  110  at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter below a threshold value that is lower than each of the first and second threshold values. In other words, the system may be configured to pre-remediate an indoor space or zones therein. For example, if indoor space  10  is a bedroom within a house, and the bedroom belongs to a child suffering from asthma, the central control circuit  200  may be configured to begin remediating the air within the child&#39;s bedroom to a lower threshold than in the rest of the house on hour before the child&#39;s expected bedtime. 
     The air remediation system  100  may further include one or more outdoor air sensor arrays communicatively coupled to the central control circuit, such as the outdoor air sensor arrays  150  described above with reference to  FIG.  1   . The outdoor air sensor(s)  150  are located in an outdoor area outside of the indoor space  10  and are configured to measure at least one air outdoor parameter in the outdoor area. The central control circuit  200  may receive from the outdoor sensor array  150  a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area and determine if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. The outdoor air sensor measurement may be used to determine if the air quality outside the indoor space is poorer than the air quality inside the indoor space (e.g., in polluted cities), in which case the system may determine that fresh air exchange should not be used for air remediation until certain conditions are met. 
     For example, in some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration (indicative of high external air pollution), and if the air within the space is not currently being remediated, the central control circuit may cause the air handling unit  110  to remediate the air within the indoor space  10  without using fresh air exchange until the sooner of (1) a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration; or (2) a measurement of the first air parameter in the indoor space  10  is lower than the second threshold value for the second duration. In this example, the system remediates air in the indoor space without using fresh air exchange until levels of one or more outdoor air pollutants fall below a set threshold. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is not currently being remediated, the central control circuit may delay air remediation in the indoor space by the air handling unit  130  until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In this example, the system delays air remediation in the indoor space until levels of one or more outdoor air pollutants fall below a set threshold. Such a scenario may occur in an apartment or condo where fresh air exchange is the only air remediation technique available for reducing certain air pollutants in the indoor space. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within the space is currently being remediated, the central control circuit may cause the air handling unit  130  to cease air remediation in the indoor space  10  until the measurement of the first outdoor air parameter is lower than a second outdoor threshold value for the second outdoor duration. Indoor space  10  may also include one or more networked or remote user input/display devices  170 , described above with reference to  FIG.  1   , which may allow a user or occupant to view and/or control functions of the air remediation system governing indoor space  10 . 
     As discussed above, the air remediation system  100  may be configured to provide various alerts or notifications based on certain conditions. For example, in some approaches, the system may provide an alert or notification when a determination is made that the measurement of the first air parameter is above the first threshold value for the first duration, a determination is made that the measurement of the first air parameter is lower than the second threshold value for the second duration, air remediation in the indoor space is initiated due to the first parameter being above the first threshold for the first duration and the air within the space is not currently being remediated, air remediation in the indoor space has ceased, and/or a change to at least one of the first air parameter, the first threshold value, the first duration, the second threshold value, the second duration is made, requested, or approved. In some approaches, the system may provide an alert or notification when, for example, a determination is made that the measurement of the first air parameter is above the first threshold value for the first duration and the system determines that the room currently is occupied and/or a determination is made that the measurement of the first air parameter is above the first threshold value for the first duration and the system determines that the room currently is not occupied. 
     In another approach, the system may provide an alert or notification when at least one error in or damage to the sensor array or the air handling system is detected, when the sensor array is out of calibration, when the sensor or air handling unit have exceeded their expected lifespan, the sensor is no longer positioned at the best place within a zone or room, when maintenance to the air handling system is scheduled or overdue, or when relocation of the sensor is scheduled or overdue. 
     In yet another approach, the system may provide an alert or notification when activation of air remediation in the indoor space due to a measurement of the first parameter exceeds a designated number of times during a designated time period. For example, the system may provide an alert or notification if air remediation is triggered in the space more than twice in an hour, more than ten times during a twenty-four hour period, etc., due to the measurement of the first air parameter in the space exceeding the first threshold value for the first duration. 
     Any suitable alert or notification technology may be used. For example, alerts or notifications may include, but are not limited to, text or SMS messages, MMS messages, email messages, radio signals, automated voice messages, sound notifications, or any other audio or visual alert or signal, which may be sent to (or emitted by) one or more components, electronic devices, or displays associated with the indoor space, the occupant(s), or selected persons associated with the space. In some approaches, the alert or notification may be sent to one or more persons associated with the indoor space (e.g., someone who lives in an apartment or house but who is not there at the apartment or house), someone who is responsible for the space (e.g., a landlord, a maintenance person, an owner), a current occupant of the space who is not in the specific space, a database that stores information relevant to the operation of the space, an automation control device or application, or a parent or caregiver (e.g., if a child or other family member is in the space). 
     In some approaches, air remediation may not necessarily begin automatically when the first air parameter is determined to be above the first threshold value for the first duration. Instead, in some approaches, the system may send an alert, notification, or other signal to a device or a person who must approve initiation of the remediation by, for example, sending a designated approval message back to the system, selecting a designated button or icon on a device communicatively coupled to the system, etc. In some approaches, if an approval signal is not received by the system within a certain period of time (e.g., 60 seconds, 10 minutes, one hour), air remediation may begin automatically. In other approaches, remediation in a particular area or zone of the indoor space may not begin unless or until the central control circuit  200  determines that no remediation is occurring in any other areas or zones of the indoor space. 
     For an indoor space that has more than one conditioned zone, the flexibility of remediation is further enhanced by employing multiple air handling units in the indoor space, as illustrated in  FIG.  4   . In a multi-zone multi-AHU scenario, as described below, some rooms or other zones may be bundled together as a single area or zone for remediation, which can address the problem of crossover of air pollutants from one zone to another due to pressure. The air handling unit associated with each area or zone will generally, but not necessarily, be triggered by the worst detection reading in the room or space associated with that area or zone. Spatially close rooms may be bundled together as one area for remediation, and if any room in this bundled area has confirmed contamination, all the rooms or other zones near the contaminated room may be cleaned as well. In this scenario, setting points regarding thermal comfort may be achieved with indoor air quality remediation simultaneously, and particulate matter and CO 2  can be reduced in default mode for most of the time, even without a heating/cooling load. 
     In some embodiments a zone may include one or more rooms or other spaces that are largely or completely walled off or otherwise separated from each other, or which may be otherwise isolatable from each other by doors, windows, partitions, walls, etc., that can be opened, closed, moved, etc. For example, one zone may encompass multiple bedrooms in a house, while another zone may encompass the kitchen and dining room. In other embodiments, a zone may include one or more rooms or other spaces that are not completely walled off or otherwise separated from each other, as is common in homes, offices, and other indoor environments using open plan design. In some embodiments, a zone may include one or more rooms bundled together based on the type of room (e.g., bedrooms), the expected use(s) of the room (e.g., cooking), the expected occupancy of the room, thermal aspects, air handling system configuration, sizes of the room, materials used in the room, furniture used in the room, etc. In some embodiments, a single room may comprise more than one zone. For example, a large open space that includes a kitchen area, a dining room area and a living room area may be considered a single room having multiple distinct zones. 
     In scenarios involving multiple zones (as described in more detail below), each zone may include a plurality of indoor air quality sensor arrays located in each zone (in some cases in each room of the zone). The sensor arrays in each zone may be configured to detect one or more air quality parameters in their respective zone. The sensor arrays in the multiple zones and/or rooms within the multiple zones may be configured to detect the same or different parameters and may have the same or different detection intervals, durations, and/or threshold values, and may be located at the same or different heights relative to the floor. 
     In one example, a first zone in a house may comprise bedrooms, a second zone may comprise a kitchen, and a third zone may comprise a home office. Sensor arrays located in the bedrooms may be located at a sleeping height and may be configured to measure particulate matter, sensor arrays in the kitchen may be located at a standing height of an adult and may be configured to measure particulate matter and CO, and sensor arrays in the home office may be located at a seated height of an adult and may be configured to measure particulate matter and VOCs. The detection intervals, durations, and/or threshold values for particulate matter in the bedrooms may be the same or different than in the kitchen and home office, while the detection intervals and durations for CO and VOCs in the kitchen and home office, respectively, may be the same of different than those for particulate matter in those areas. 
     In another example, in a bedroom used by a person who suffers from asthma or other allergies the threshold value for particulate matter may be lower and the duration and the detection interval may be shorter compared to a bedroom used by a person who does not suffer from asthma or other allergies. In rooms that are less frequently used, such as a formal dining room, threshold values may be higher, and durations and detection intervals may be longer compared to more frequently used rooms, such as a family room. 
       FIG.  4    illustrates an air remediation system utilized in an indoor space  10  that is divided into multiple zones bundled into remediation areas. Zones  1  and  2  are bundled together as bundled area A and are served by air handling unit  130 A. Zones  1  and  2  may comprise, for example, bedrooms in a house or apartment. Zones  3  and  4  are bundled together as bundled area B and are served by air handling unit  130 B. Zones  3  and  4  may comprise, for example, a living room and kitchen in a house or apartment. Air handling units  130 A and  130 B may comprise air handling unit  130  described above with reference to  FIGS.  1  to  3   . 
     Each of zones  1 ,  2 ,  3 , and  4  may include an indoor air quality sensor arrays  110   a ,  110   b ,  110   c , and  110   d , respectively, configured to sense, detect, or otherwise measure air pollutants such as, for example, carbon dioxide (CO 2 ), carbon monoxide (CO), particulate matter (e.g., PM 2.5 , PM 10 ), volatile organic compounds (VOCs), radon, nitrogen dioxide, ozone, and noxygen (NOx) in zones  1 ,  2 ,  3 , and  4 , respectively. Air sensor arrays  110   a ,  110   b ,  110   c , and  110   d  may comprise air sensor array  110  described above with reference to  FIGS.  1  to  3   . Although  FIG.  4    shows only one sensor array  110  in each of the four zones, each of the zones may include a plurality of indoor air quality sensor arrays. 
     In the scenario illustrated in  FIG.  4   , air handling unit  130 A will generally be triggered by the worst indoor air quality reading from sensor arrays  110   a  and  110   b  in bundled area A (zones  1  and  2 ), while air handling unit  110 B will generally be triggered by the worst indoor air quality reading from sensor arrays  110   c  and  110   c  in bundled area B (zones  3  and  4 ). One or more of the threshold values, durations, and detection intervals for bundled area A may be the same as or different from the threshold values, durations, and detection intervals for bundled area B. One or more of the threshold values, durations, and detection intervals for zone  1  in bundled area A may be the same as or different from the threshold values, durations, and detection intervals for zone  2  in bundled area A or the zones  3  and  4  in bundled area B. Similarly, one or more of the threshold values, durations, and detection intervals for zone  3  in bundled area B may be the same as or different from the threshold values, durations, and detection intervals for zone  4  in bundled area B or the zones  1  and  2  in bundled area A. 
     For example, the central control circuit communicatively coupled to sensor arrays  110   a ,  110   b ,  110   c , and  110   d  and air handling units  130 A and  130 B receive a signal from sensor arrays  110   a  and  110   b  indicative measurements of an air parameter in zones  1  and  2 , respectively, and determines if at least one of those measurements is above a first threshold value for a first duration for that given air parameter. Threshold values and durations may correspond to the threshold values and durations described above with reference to  FIG.  3   . If the measurement of the air parameter in zone  1  is above the first threshold value for the first duration for that given air parameter, the central control circuit determines if air within bundled area A is currently being remediated. If the air within bundled area A is not currently being remediated, the central control circuit  200  sends a signal to air handling unit  130 A, directly or indirectly, to cause air handling unit  130 A to remediate the air within the positive zone (e.g., zone  1 ) and its adjacent zone (zone  2 ) in bundled area A until a measurement of the air parameter is lower than a second value for a second duration in the positive zone (zone  1 ) and the adjacent zone (zone  2 ) in bundled area A. 
     An example of the above scenario may occur in a home comprising two bedrooms (zone  1 ) adjacent to a home office and a den (zone  2 ), these four rooms forming bundled area A, with each room having at least one air quality sensor. If a sensor in one of the bedrooms of zone  1  detects an air quality parameter above a set threshold for longer than a set duration, the system initiates air remediation in the two bedrooms (zone  1 ) and the adjacent home office and den (zone  2 ) forming bundled are A until the level of the air parameter falls below a set threshold for a set duration in both zones of bundled area A (the threshold and duration may be the same or different than the threshold and duration used to initiate air remediation). 
     The central control circuit  200  also may be further configured to receive from sensor arrays  110   c  and  110   d  signals indicative of measurements of one or more air parameters in bundled area B. The central circuit may determine that an air parameter in zone  3  is above a first threshold value for a first duration for that given air parameter. If the measurement of the air parameter is above the first threshold value for the first duration for that given air parameter, the central control circuit determines if air within bundled area B is currently being remediated. If the air bundled area B is not currently being remediated, the central control circuit sends a signal, directly or indirectly, to air handling unit  130 B to cause air handling unit  130 B to remediate the air within the positive zone (e.g., zone  3 ) and its adjacent zone (zone  4 ) in bundled area B until a measurement of the air parameter is lower than a second value for a second duration in the positive zone (zone  3 ) and the adjacent zone (zone  4 ) in bundled area B. 
     Continuing with the home example discussed above, the home may further comprise a kitchen and a dining room (zone  3 ) adjacent to a living room and a play room (zone  4 ), the four rooms forming bundled area B, with each room having at least one air quality sensor. If a sensor in the kitchen of zone  3  detects an air quality parameter above a set threshold for longer than a set duration, the system initiates air remediation in the kitchen and dining room (zone  3 ) and the adjacent family room and play room (zone  4 ) forming bundled are B until the level of the air parameter falls below a set threshold for a set duration in both zones of bundled area B (the threshold and duration may be the same or different than the threshold and duration used to initiate air remediation). 
     As discussed above, air remediation by the air handling units  130 A and  130 B might not begin with an instant concentration peak. Generally, only a high level of the detected air parameter which lasts more than at least one detection interval (for example, at least two detection intervals) may trigger remediation (a delay loop may be included to execute this feature before sending a command to the air handling unit). Additionally, the remediation status might not cease instantly when the concentration drops below the second threshold. In some approaches, the same delay loop mentioned above may be applied when the concentration drops below the second threshold. 
     In some embodiments, sensor arrays  110   a ,  110   b ,  110   c , and  110   d  may be configured to measure at least two different air parameters at defined detection intervals in their respective zones. For example, the sensor arrays may be configured to measure both PM 2.5  and CO 2 . In this approach, the central control circuit  200  may determine if the measurement of one or both of the first and second air parameters are above set threshold values for a set duration for each air parameter, and if one or both measurements are above the set threshold value(s) for the set duration(s), the central control circuit  200  may cause the air handling unit associated with the bundled area to remediate the air within the bundled area until a measurement of the first and second air parameters are lower than a set threshold value for a set duration for each air parameter. In other embodiments, the central control circuit  200  may calculate a combined measurement (e.g., an air quality score) of two air parameters in the bundled area and determine that the combined measurement of the first and second air parameters in the bundled area is above a first combined threshold value for the first duration. The central control circuit  200  may then cause the air handling unit associated with that bundled area to remediate the air within the bundled area until a combined measurement of the first and second air parameters is lower than a second combined threshold value for the second duration in the bundled area. The combined measurement, which may also be referred to as an air quality score, may be represented by S(i) to indicate the contamination level, and may be calculated as described above. 
     In some embodiments, the sensor arrays associated with one zone or bundled area of zones may measure one or more different air parameters than the sensor arrays associated with another zone or bundled area of zones. For example, one or more sensor arrays located in a bedroom might measure CO level, CO 2  level, PM 2.5  particles, PM 10  particles and the presence of one or more VOCs, while one or more sensor arrays in a kitchen might measure only the presence of smoke and PM 2.5  and PM 10  particles. The bedroom and the kitchen may be in the same or different zones or the same or different bundled areas. 
     When one of the air quality parameters includes CO 2 , the air handling unit associated with a bundled area may remediate the air within the bundled area by fresh air exchange. For example, with reference to  FIG.  4   , when the measurement of CO 2  in zones  1  or  2  of bundled area A is above the first threshold value (e.g., 800 ppm) for the first duration (e.g., two detection cycles), the central control circuit  200  may cause one or more windows or vents  180  in bundled area A to open a predetermined amount to facilitate fresh air exchange by air handling unit  130 A. Similarly, when the measurement of CO 2  in zones  3  or  4  of area B is above the first threshold value (e.g., 800 ppm) for the first duration (e.g., two detection cycles), the central control circuit  200  may cause one or more windows or vents  180  in bundled area B to open a predetermined amount to facilitate fresh air exchange by air handling unit  130 B. Alternatively, or in addition, the central control circuit  200  may be configured to provide an alert to occupants, for example a sound alert or and alert to the occupant&#39;s handheld mobile device or to another person&#39;s mobile device, to open one or more windows to facilitate fresh air exchange. 
     The indoor space may further include one or more occupancy sensor arrays  160  in one or more zones of the bundled areas. For example, with reference to  FIG.  4   , zones  1  and  2  in bundled area A and at zones  3  and  4  in bundled area B may include one or more occupancy sensor arrays  160  communicatively coupled to a central control circuit and configured to detect an occupancy in the zones in which the occupancy sensor arrays are located. The central control circuit may be configured to receive occupancy data from the occupancy sensor(s)  160  and to adjust one or more of the first and second threshold values and the first and second durations based on a detected occupancy in one or more zones and/or bundled areas. For example, the central control circuit may reduce the thresholds for CO 2  and/or particulate matter (PM) in bundled area A if zones  1  and/or  2  are over-occupied or are more frequently occupied. In some approaches, the central control circuit may automatically reduce the threshold(s) of one or more air parameters in on or more zones and/or bundled areas when detected occupancy is above a set threshold and/or when occupancy increases at a faster rate than expected for that zone and/or bundled area. 
     The central control circuit may be further configured to initiate operation of one or more air handling units associated with a bundled area at a specific time of day or for a period prior to a predetermined time of day to reduce a measurement of the first air parameter in a zone of the bundled area below a threshold value that is lower than each of the first and second threshold values. For example, in a bedroom belonging to a child suffering from asthma (e.g., zone  1  in  FIG.  4   ), the central control circuit may be configured to begin remediating the air within the child&#39;s bedroom and one or more rooms adjacent to the child&#39;s bedroom (e.g., zone  2  in  FIG.  4   .) to a lower threshold than in the rest of the house one hour before the child&#39;s expected bedtime. 
     One or more outdoor air sensor arrays  150  may also be associated with at least one of the bundled areas or zones in the indoor area  10  and may be communicatively coupled to the central control circuit. As shown in  FIG.  4   , each of bundled area A and B may include an associated occupancy sensor array  150  located in an outdoor area outside of the indoor space  10  and configured to measure at least one air outdoor parameter in the outdoor area adjacent to bundled areas A and B. The outdoor air sensor arrays may comprise outdoor air sensors described above with reference to  FIG.  1   . The central control circuit may receive from, for example, outdoor sensor array  150  associated with bundled area A, a first outdoor signal indicative of a measurement of a first outdoor air parameter in the outdoor area and determine if the measurement of the first outdoor air parameter is above a first outdoor threshold value for a first outdoor duration. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within bundled area A is not currently being remediated, the central control circuit may cause air handling unit  130 A to remediate the air within the bundled area A without using fresh air exchange until the sooner of (1) a measurement of the first outdoor air parameter is lower than a second outdoor threshold value for a second outdoor duration; or (2) a measurement of the first air parameter in one or both bundled areas A and B or zones therein is lower than the second threshold value for the second duration. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within bundled area A is not currently being remediated, the central control circuit may delay air remediation in bundled area A until a measurement of the first outdoor air parameter is lower than the second threshold value for the second outdoor duration. In this example, the system remediates air in bundled area A without using fresh air exchange until levels of one or more outdoor air pollutants fall below a set threshold. 
     In some embodiments, if the measurement of the first outdoor air parameter is above the first outdoor threshold value for the first outdoor duration, and if the air within bundled area A is currently being remediated, the central control circuit may cause air handling unit  130 A to cease air remediation until the measurement of the first outdoor air parameter is lower than the second outdoor threshold value for the second outdoor duration. In this example, the system delays air remediation in bundled area A until levels of one or more outdoor air pollutants fall below a set threshold. 
     Each bundled area may also include one or more networked or remote user input/display devices  170 , described above with reference to  FIG.  1   , which may allow a user or occupant to view and/or control functions of the air remediation system governing one or both bundled areas. 
       FIG.  5    illustrates a multi-zone scenario with one air handling unit  130  and a plurality of dampers  180   a  and  180   b . In this scenario, zoning is achieved by controlling the flow rate introduced to each of zones  1  and  2  zone through PID damper systems. For example, the flow rate may be set or controlled to be within 200-800 cubic feet per minute (CFM), but in some settings the CFM may depend on the room size, room type, or other factors. Thus, in some settings the CFM may be set to be 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or other level, or to be within a range of levels. 
     During remediation, the central control circuit sends commands to the air handling unit requiring a higher flow rate to clean the polluted room, while the dampers in the other rooms are closed so the flow rate will not be weakened. In this scenario, particulate matter and CO 2  can be reduced with default mode for most of the time, even without heating/cooling load. 
     A control circuit communicatively coupled to sensor arrays  110   a  and  110   b  and air handling unit  130  receives from a first sensor array (e.g., sensor array  110   a  in zone  1 ) a first signal indicative of a measurement of a first air parameter in the first zone. The central control circuit then determines if the measurement of the first air parameter in the first zone is above a first threshold value for a first duration, as described above with reference to  FIG.  4   . If the measurement of the first air parameter is above the first threshold value for the first duration, the control circuit determines if air within the first zone (zone  1 ) is currently being remediated. If the air within the first zone is not currently being remediated, the central control circuit causes the air handling unit to remediate the air within the first zone by determining the relative configurations of the dampers communicatively coupled to the central control circuit and reconfiguring positions of the first damper (damper  180   a ) and the second damper (damper  180   b ) to allow airflow into the first zone (zone  1 ) and to restrict airflow into the second zone (zone  2 ). For example, central control circuit may (re)configure the dampers so that the damper in the polluted zone (e.g., damper  180   a  in zone  1 ) may be open a sufficient amount and the other dampers (e.g., damper  180   b  in zone  2 ) closed a sufficient amount to achieve at least a 20% fresh air exchange. In some embodiments, the central control circuit may (re)configure the dampers so that the damper in the polluted zone (e.g., damper  180   a  in zone  1 ) may be fully open, while the other dampers (e.g., damper  180   b  in zone  2 ) may be fully or partially closed. 
     In this scenario, indoor air quality remediation may result in an increase of the total enthalpy introduced to the target zone, which may result in a transient deviation from thermal comfort status. However, the thermal comfort level can recover quickly after remediation, and the heating/cooling coil temperature should compensate the heating/cooling load. 
     The multi-zone scenario with one air handling unit illustrated in  FIG.  5    may also include one or more occupancy sensor arrays ( 160   a ,  160   b ), outdoor air sensor arrays ( 150 ), user display/output devices ( 170 ) and windows ( 180   b ,  180   c ) described above with reference to  FIGS.  1  to  4   . 
     It should be understood that the multi-zone scenario with one air handling unit described above with reference to  FIG.  5    may be incorporated into a habitable environment having a plurality of bundled areas. For example, the scenario described above with reference to  FIG.  5    can be incorporated into the scenario described above with reference to  FIG.  4   , where each bundled area in  FIG.  4    may be considered a separate multi-zone indoor space serviced by one air handling unit. 
       FIG.  6    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method begins at start step  300 . In step  301 , one or more indoor air quality (IAQ) parameters are measured by a sensor array having one or more sensors located in an indoor space. In step  302 , the system determines if a first air parameter is above a first threshold for a first duration. If the first air parameter is not above a first threshold for a first duration, the system may then proceed back to start step  300 . 
     If the first air parameter is above the first threshold for the first duration, in step  303  the system determines if the air within the indoor space is currently being remediated. If the air is not currently being remediated, in step  304  the system initiates air remediation by an air handling unit (AHU) and in step  305  the system continues air remediation until the first air parameter is lower than a second threshold for a second duration. If at step  303  the system determines that the air within the space is currently being remediated, the system proceeds to step  305  and continues to remediate the air within the space until the first air parameter is lower than a second threshold for a second duration. Once the first air parameter is lower than the second threshold for the second duration at step  305 , the system may then proceed back to start step  300 . 
       FIG.  7    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method begins at start step  400 . In step  401 , first and second indoor air quality (IAQ) parameters are measured by a sensor array located in an indoor space. In step  402  the system determines if the first and second measured air parameters are above set thresholds for set durations for that given air parameter. If at least one of the first and second air parameters is above a set threshold for a set duration, in step  403  the system determines if the air is currently being remediated in the indoor space. If the air is not currently being remediated, in step  404  the system initiates air remediation by an air handling unit (AHU) and in step  405  the system continues air remediation until both the first and second air parameters are lower than set thresholds for set durations. If at step  403  the system determines that the air within the space is currently being remediated, the system proceeds to step  405  and continues air remediation until both the first and second air parameters are lower than set thresholds for set durations. Once the first and second air parameters are lower than the set thresholds for the set durations at step  405 , the system may then proceed back to start step  400 . 
       FIG.  8    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method begins at start step  500 . In step  501 , first and second indoor air quality (IAQ) parameters are measured by a sensor array located in an indoor space. In step  502  the system determines a combined value for the first and second air parameters. In step  503 , the system determines if a combined value for the first and second air parameters is above a set threshold for a set duration. If the combined value for the first and second measured air parameters is not above a set threshold for a set duration, the system may then proceed back to start step  500 . 
     If the combined value for the first and second measured air parameters is above a set threshold for a set duration, in step  504  the system determines if the air is currently being remediated in the indoor space. If the air is not currently being remediated, in step  505  the system initiates air remediation by an air handling unit (AHU) and in step  506  the system continues air remediation until the combined value for the first and second measured air parameter is lower than a set threshold for a set duration. If at step  504  the system determines that the air within the space is currently being remediated, the system proceeds to step  506  and continues air remediation until the combined value for the first and second measured air parameter is lower than a set threshold for a set duration. Once the combined value for the first and second measured air parameter is lower than the set threshold for the set duration step  506 , the system may then proceed back to start step  500 . 
       FIG.  9    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method begins at start step  600 . In step  601 , one or more indoor air quality (IAQ) parameters are measured by a sensor array located in an indoor space. In step  602 , the system determines if a first air parameter is above a first threshold for a first duration. If a first air parameter is above a first threshold for a first duration, in step  603  the system determines if the air within the indoor space is currently being remediated. If the air is not currently being remediated, in step  604  the system initiates air remediation by an air handling unit (AHU) and in step  605  the system continues air remediation until the first air parameter is lower than a second threshold for a second duration. If at step  603  the system determines that the air within the space is currently being remediated, the system proceeds to step  605  and continues to remediate the air within the space until the first air parameter is lower than a second threshold for a second duration. Once the first air parameter is lower than the second threshold for the second duration at step  605 , the system may then proceed back to start step  600 . 
     At step  606 , which may or may not occur concurrently with step  601 , the system determines the current time of day. In step  607 , the system determines whether the current time of day matches a target time of day and/or is within a set duration of a target time of day. If not, the system may proceed to step  602 . If so, in step  608  the system determines if the air within the indoor space is currently being remediated. If the air is not currently being remediated, in step  609  the system initiates air remediation by an air handling unit (AHU) and in step  610  the system continues air remediation until the first air parameter is below a threshold that is lower than the first and second thresholds for a second threshold. Once the first air parameter is lower than the second threshold for the second duration at step  605 , the system may then proceed back to start step  600 . 
       FIG.  10    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method described with reference to  FIG.  10    may be especially useful in multi-zone scenarios, such as those described above with reference to  FIGS.  4  and  5   . The method begins at start step  700 . In step  701 , a first indoor air quality (IAQ) parameter is measured by a sensor array located in a first zone in an indoor space and a first indoor air quality (IAQ) parameter is measured by a sensor array located in a second zone in an indoor space, the first and second zones being adjacent. In step  702  the system determines if at least one of the first air parameters from the first or second zones is above a first threshold for a first duration. If at least one of the first air parameters from the first or second zones is not above a first threshold for a first duration, the system may then proceed back to start step  700 . 
     If at least one of the first air parameters from the first or second zones is above a first threshold for a first duration, in step  703  the system determines if the air is currently being remediated in the first and second zones. If the air is not currently being remediated in the first and second zones, in step  804  the system initiates air remediation by an air handling unit (AHU) in the first and second zones and in step  705  the system continues air remediation in the first and second zones until the first air parameter in both the first and second zones are lower than a second threshold for a second duration. If at step  703  the system determines that the air within the space is currently being remediated, the system proceeds to step  705  and continues air remediation in the first and second zones until the first air parameter in both the first and second zones are lower than a second threshold for a second duration. Once the first air parameter in both the first and second zones are lower than the second threshold for the second duration at step  705 , the system may then proceed back to start step  700 . 
       FIG.  11    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method described with reference to  FIG.  11    may be especially useful in multi-zone scenarios, such as those described above with reference to  FIGS.  4  and  5   . The method begins at start step  800 . In step  801 , a first indoor air quality (IAQ) parameter is measured by a sensor array located in a first zone in an indoor space and a first indoor air quality (IAQ) parameter is measured by a sensor array located in a second zone in an indoor space, the first and second zones being adjacent. In step  802  the system determines if at least one of the first air parameters from the first or second zones is above a first threshold for a first duration. If at least one of the first air parameters from the first or second zones is not above a first threshold for a first duration, the system may then proceed back to start step  800 . 
     If at least one of the first air parameters from the first or second zones is above a first threshold for a first duration, in step  803  the system determines if the air is currently being remediated in the first and second zones. If the air is not currently being remediated in the first and second zones, in step  804  the system initiates air remediation by an air handling unit (AHU) in the first and second zones by reconfiguring positions of dampers in the first and second zones to allow air into the first zone and restrict air into the second zone. In step  805  the system continues air remediation in the first and second zones until the first air parameter in both the first and second zones are lower than a second threshold for a second duration. If at step  803  the system determines that the air within the space is currently being remediated, the system proceeds to step  805  and continues air remediation in the first and second zones until the first air parameter in both the first and second zones are lower than a second threshold for a second duration. Once the first air parameter in both the first and second zones are lower than a second threshold for a second duration at step  805 , the system may then proceed back to start step  800 . 
       FIG.  12    illustrates a method for improving air quality in an indoor space in accordance with some embodiments, which may be executed by air remediation system  100  described above with reference to  FIGS.  1  to  5   . The method described with reference to  FIG.  12    may be especially useful in multi-zone scenarios, such as those described above with reference to  FIGS.  4  and  5   , and especially in scenarios where poor indoor air quality may create a need for remediation in more than one zone. The method begins at start step  900 . In step  901 , a first indoor air quality (IAQ) parameter is measured by a sensor array located in a first zone in an indoor space and a first indoor air quality (IAQ) parameter is measured by a sensor array located in a second zone in an indoor space, the first and second zones being adjacent. While  FIG.  12    describes the indoor air sensor arrays in both zones measuring a “1st IAQ [indoor air quality] parameter,” it should be understood that the indoor air quality parameter(s) measured by sensor arrays in the first and second zones do not necessarily have to be the same parameter. Indeed, the measured indoor air quality parameters in the different zones can be the same or different indoor air quality parameters, which may have the same or different threshold values, durations, and detection intervals. For example, an air sensor array in the first zone may measure carbon dioxide, while an air sensor array in the second zone may measure volatile organic compounds. In such a scenario, the threshold values would likely differ, but the detection intervals and/or durations for the two zones may be the same or different. 
     In another example, the air sensor arrays in the first and second zones may both be configured to measure carbon dioxide levels. In such a scenario, the threshold values, durations, and detection intervals for the first zone may be the same or different from those for the second zone. Threshold values, durations, and detection intervals, may be determined based on, for example, one or more of: location(s) of the zone(s), intended or expected use of the zone(s), estimated, actual, or predicted occupancy of the zone(s), time of day or year, user preference or need, location, elevation, etc. 
     In step  902  the system determines if the first air parameter in the first zone is above a first threshold for a first duration. If the first air parameter in the first zone is not above the first threshold for a first duration, in step  903  the system determines if the first air parameter in the second zone is above a first threshold for a first duration. If the first air parameter in the second zone is not above the first threshold for a first duration, the system may then proceed back to start step  900 . 
     If the first air parameter in the second zone is above the first threshold for a first duration, in step  904  the system determines if the air is currently being remediated in the second zone. If the air is not currently being remediated in the second zone, in step  905  the system initiates air remediation by an air handling unit (AHU) in the second zone by reconfiguring positions of dampers in the first and second zones to allow air into the second zone and restrict air into the first zone. In step  906  the system continues air remediation in the second zone until the first air parameter in the second zone is lower than a second threshold for a second duration. If at step  904  the system determines that the air within the second zone is currently being remediated, the system proceeds to step  906  and continues air remediation in second zone until the first air parameter in the second zone is lower than a second threshold for a second duration. Once the first air parameter in the second zone is lower than the second threshold for the second duration in step  906 , the system may then proceed back to start step  900 . 
     If at step  902  the system determines that the first air parameter in the first zone is above a first threshold for a first duration, in step  907  the system determines if the first air parameter in the second zone is above a first threshold for a first duration. If the first air parameter in the second zone is not above the first threshold for a first duration, in step  908  the system determines if the air is currently being remediated in the first zone. If the air is not currently being remediated in the first zone, in step  909  the system initiates air remediation by an air handling unit (AHU) in the first zone by reconfiguring positions of dampers in the first and second zones to allow air into the first zone and restrict air into the second zone. In step  910  the system continues air remediation in the first zone until the first air parameter in the first zone is lower than a second threshold for a second duration. If at step  908  the system determines that the air within the first zone is currently being remediated, the system proceeds to step  910  and continues air remediation in first zone until the first air parameter in the first zone is lower than a second threshold for a second duration. Once the first air parameter in the first zone is lower than the second threshold for the second duration in step  910 , the system may then proceed back to start step  900 . 
     The steps described above with reference to  FIG.  12    relate to scenarios where either the first zone or second zone (but not both) experiences an above-threshold indoor air quality measurement that triggers air remediation in zone with the above-threshold measurement. The steps described below with reference to  FIG.  12    encompass scenarios where both the first and second zones experience above-threshold indoor air quality measurements, triggering either concurrent or consecutive air remediation in the first and second zones. 
     If at step  902  the system determines that the first air parameter in the first zone is above a first threshold for a first duration, and if at step  907  the system determines that the first air parameter in the second zone is above a first threshold for a first duration, the system determines whether the first and second zones can or otherwise should be remediated concurrently. This determination may be made based on, for example, at least one of the type of elevated air parameter(s), the measurement(s) of the air parameter(s), configurations of the zones, efficiency, locations of the zones, intended or expected use of the zones, estimated, actual, or predicted occupancy of the zones, time of day or year, day of week, location, elevation, user preference or need, etc. 
     If at step  911  the system determines that the first and second zones can or otherwise should be remediated concurrently, at step  912  the system initiates air remediation by an air handling unit (AHU) in the first and second zones. For example, if two bedrooms are occupied and each has a different elevated air quality parameter needing remediation, the system may initiate air remediation concurrently in both rooms. In some approaches, the air handling unit may remediate the air in both zones by reconfiguring positions of dampers in the first and second zones to allow sufficient airflow into both zones. Additionally, or alternatively, in some approaches the air handling unit may remediate air in one or both zones using fresh air exchange, particulate filtration, ionic filtration, activated carbon filtration, ultraviolet air purification, and combinations thereof. In step  913  the system continues air remediation in the first and second zones until the first air parameter in both the first and second zones are lower than a second threshold for a second duration. Once the first air parameter in both the first and second zones are lower than the second threshold for the second duration in step  913 , the system may then proceed back to start step  900 . 
     If at step  911  the system determines that the first and second zones cannot or otherwise should not be remediated concurrently, at step  914  the system ranks the zones based on air remediation priority. Air remediation priority or other ranking may be based on, for example, at least one of: (a) the type of elevated air parameter(s); (b) the respective measurements or scores of the air parameter(s); (c) comparison of which air parameter(s) exceeds its threshold value the most or by the highest percentage; (d) estimated, actual, expected, or predicted occupancy of the zone (e.g., if one zone is occupied and the other is not, the occupied zone may be remediated first; the zone scheduled for occupancy first may be remediated first; the zone having or expected to have the highest occupancy level may be remediated first etc.); (e) current, intended or expected use of the zone, the type of room/zone, etc. (e.g., a bedroom may be remediated before a kitchen, a sick person&#39;s bedroom may be remediated before another room, an office for a person with asthma may be remediated before another office, a meeting room may be remediated before a storage room); (f) the zone that was remediated the longest time ago may be remediated first; (g) the zone that can be remediated the quickest may be remediated first; (h) time of day, time of year, or day of week; (i) location; (j) external weather or other conditions: (k) the relative impacts of elevated air parameters on one or more people&#39;s health: (l) occupant or other user preference or need; (m) group related preference or need; (n) power or energy availability; (o) noise level or other ramification created during remediation of a zone; (p) the length of time it might take to remediate a zone; or (q) other factor(s). 
     In step  915 , the system initiates air remediation by an air handling unit (AHU) in the highest ranked zone. In step  916  the system continues air remediation in the highest ranked zone until the first air parameter in this zone is lower than a second threshold for a second duration. In step  917  the system then initiates air remediation by the air handling unit (AHU) in the next highest ranked zone. In step  918  the system continues air remediation in the next highest ranked zone until the first air parameter in this zone is lower than a second threshold for a second duration. The system may then proceed back to start step  900 . 
       FIG.  13    illustrates a system for monitoring indoor air quality in accordance with some embodiments. A lack of adequate data on an indoor environment makes it difficult for occupants to understand and improve their indoor environmental conditions. Implementing an indoor air quality monitoring system provides occupants of a built structure more information on their indoor environment such that the environment may be more precisely and accurately tailored to occupants. Installing or otherwise using a system that obtains accurate information on indoor environment quality parameters improves the ability of an environmental control system to control the indoor environment and improve occupant health and comfort. For example, the air quality monitoring system can provide information on the thermal environment or indoor air quality parameters in the built structure. Information on the thermal environment and indoor air quality parameters may instruct occupants how to effectively control those parameters. 
     Furthermore, with a system installation that provides access to precise and accurate real-time data on indoor environmental quality parameters, occupants may reliably evaluate their indoor environment and intervene to control indoor environmental parameters as necessary. Spatial and temporal variation of parameters related to indoor environmental quality, especially thermal and indoor air quality parameters, may impact the quality of data collected by sensor arrays in an indoor air quality monitoring system. As such, sensor array placement impacts the performance of an indoor air quality monitoring system. Installing an indoor air quality monitoring system with optimal sensor array placement ensures that system operates more precisely and accurately. In order to enhance performance of the indoor air quality monitoring system  1000 , the delineation of zones within an indoor environment may help to determine optimal sensor array placement. 
     As shown in  FIG.  13   , the indoor air quality monitoring system  1000  may include, be associated with, or be part of a built structure  1010 . In one embodiment, the built structure is an office space. The indoor air quality monitoring system  1000  may further include an environmental control system  1030 , at least one sensor array  1040 , a control circuit  1050 , and an electronic user device  1090 . 
     The control circuit  1050  is communicatively coupled to the sensor arrays  1040 , the electronic device  1090 , the environmental control system  1030 , and the environment database  1080 . The central control circuit  1050  may take the form of a programmed computer or other processor-based system or device. For example, the central control circuit  1050  may take the form of a conventional mainframe computer, mini-computer, workstation computer, personal computer (desktop or laptop), or handheld computer. The control circuit  1050  may be similar to the central control circuit  120  that is described above with reference to  FIG.  1   . 
     The control circuit  1050  can operate in a networked environment using logical connections to one or more remote computers and/or devices as described above with reference to  FIG.  13   . For example, the control circuit  1050  can operate in a networked environment using logical connections to one or more other subsystems, one or more server computer systems and associated non-transitory data storage device. The server computer systems and associated non-transitory data storage device may, for example, be controlled and operated in full or in part by a facility (e.g., hotel, spa, apartment building, condominium building, hospital) in which the habitable environment is located. In some embodiments, the server computer systems and associated non-transitory data storage device also may provide one or more other functions, services, or support for all or part of a facility such as, for example, accounting, security, energy expenditure management, scheduling, resource management, inventory management, etc. 
     Communications may be via wired and/or wireless network architectures, for instance, wired and wireless enterprise-wide computer networks, intranets, extranets, and the Internet. Thus, the control circuit  1050  may include wireless communications components, for example one or more transceivers or radios  1061  and associated antenna(s) for wireless (e.g., radio or microwave frequency communications, collected referred to herein as RF communications). Other embodiments may include other types of communication networks including telecommunications networks, cellular networks, paging networks, and other mobile networks. 
     In operation, in one embodiment the control circuit  1050  may delineate occupant zones based on an electronic floor plan. The control circuit may then instruct installation of at least one sensor array  1040  in each delineated occupant zone. After delineating occupant zones, the control circuit  1050  delineates at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan. Once occupant zones, boundary zones, and air handling zones have been delineated, the control circuit identifies overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone. The control circuit then instructs the installation of at least one sensor array  1040  in the identified overlapping zones. If the number of sensor arrays available are less than a total of the combined delineated occupant zones and identified overlapping zones, then installation of thermal sensor arrays may occur on the basis of the following order of preference: combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones and installation of air quality sensor arrays occurs on the basis of the following order of preference: the combined boundary-occupant zone, the combined boundary-occupant-air handling zone, and then the combined air handling-occupant zone. 
     An environment database  1080  may be in communication with the control circuit  1050  and the electronic user device  1090 . The environment database  1080  may be stored, for example, on a server. The environment database  1080  may include a profile associated with an occupant of the built structure. In the environment database  1080 , temperature parameter data, light parameter data, sound parameter data, and environmental air quality data may be associated with an occupant in the user profile. 
     In operation, the environment database  1080  may store occupant profiles associated with particular occupants within the built structure. In one embodiment, the control circuit  1050  detects a particular occupant within an occupant zone, the occupant having an occupant profile in the environment database  1080 . By another approach, the control circuit may be configured to detect multiple occupants within the occupant zones and in some configurations may identify the particular occupant. The control circuit then locates the particular occupant in an occupant zone within the built structure and analyzes sensor array readings in the occupant zone. Next, the control circuit compares sensor readings with the thermal and indoor air quality parameters stored in the occupant profile. Upon detection that the sensor readings in the particular occupant zone are not within the parameters of the occupant profile, the control circuit  1050  instructs the environmental control system to adjust the parameters pursuant to the occupant profile. Upon detecting that sensor readings in a particular occupant zone are not within the parameters of the occupant profile, the control circuit may also send a notification to a user via an electronic user device regarding the reading and adjustment of parameters pursuant to the occupant profile. 
     In some embodiments, the environment database  1080  also may include information related to one or more occupants such as, for example, allergies or other health conditions that occupants may have, schedule of occupancy by hour, day, week, etc. for one or more zones, preferred air temperatures, etc. 
     In one embodiment, the system  1000  and the control circuit  1050  may be employed with the method of  FIGS.  15 A and  15 B . 
     The electronic user device  1090  may be configured to receive one or more instructions regarding the allocation of or the installation location of one or more sensor arrays  1040  which may be allocated or installed pursuant to the following methodology: delineate occupant zones based on an electronic floor plan; instruct installation of at least one sensor array in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identify overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; and instruct installation of at least one sensor in the identified overlapping zones. If the sensor arrays available are less than a total of the combined delineated occupant zones and identified overlapping zones, then allocation or installation of thermal sensor arrays occurs on the basis of the following order of preference: combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones and allocation or installation of air quality sensor arrays occurs on the basis of the following order of preference: the combined boundary-occupant zone, the combined boundary-occupant-air handling zone, and then the combined air handling-occupant zone. Additionally, the electronic user device  1090  may be configured to send allocation or installation configuration information, HVAC plans, and floor plan updates for the built structure to the control circuit  1050 . 
     In addition to having an installer receive instructions on a user device, the device  1090  also may be employed to gather information about the space, such as for example, capturing electronic images of a space, portion thereof, or one or more of the environmental control systems. Obtaining accurate information in the space during sensor array installation can help account for late changes to the building design 
     During operation, the control circuit  1050  may send notifications to the user of the electronic device  1090  upon detection of particular measurements by the sensor arrays  1040  in the built structure. For example, the control circuit may send a user of an electronic user device a notification the user has not been exposed to natural light within a predetermined period of time. In another example, the control circuit may send a user of an electronic user device a notification that the user has been exposed to certain indoor air pollutants. 
     The built structure  1010  generally includes environmentally-controllable zones  1020 . The environmentally-controllable zones may include, for example, occupant zones  1022 , air handling zones  1024 , boundary zones  1026 , and outdoor zones  1028 . The occupant zones  1022  designate the areas in the built structure  1010  where occupants spend the greatest fraction of their time in the built structure. See  FIG.  14 A  and  FIG.  14 B  for further description of occupant zones. If two occupant zones are of similar size, share boundaries, and are adjacent then the two occupant zones may be combined in to a single occupant zone. Air handling zones  1024  designate the area in the built structure  1010  that is easily affected by the components of the environmental control system  1030 , including the air outlets  1032  and indoor heating devices  1034 . See  FIG.  14 E  for further description of air handling zones  1024 . Boundary zones  1026  designate the area in the built structure  1010  that is directly impacted by potential factors that affect the thermal environment and indoor air quality within the built structure, excluding the areas impacted by components of the indoor environmental control system  1030 . See  FIG.  14 D  for further illustration of boundary zones  1026 . See  FIG.  14 G  for further illustration of outdoor zones  1028  designate the are in the built structure  1010  that is not in direct contact with the occupant zones  1022  but can still influence the indoor air quality of the occupant zones and the comfort of occupants in the built structure. Occupant zones, air handling zones, and boundary zones may overlap with each other. 
     Air quality monitoring system  1000  generally includes at least one sensor array  1040 . The sensor arrays  1040  may comprise one or more indoor air quality sensors configured to sense, detect, or otherwise measure air quality, thermal quality, sound quality, or lighting parameters. For example, with respect to thermal quality, the sensor arrays may be configured to measure ambient temperature levels, air humidity, and relative humidity. With respect to air quality, parameters that may be monitored by the sensor array  1040  include, for example, carbon dioxide, particulate matter, total volatile organic compounds, and ozone. 
     Choosing optimal or near optimal installation type for sensor arrays  1040  within the indoor space of a built structure may be important for delivering reliable data and constructive feedback for occupants. Due to the spatial heterogeneity of indoor environments, the installation type for sensor arrays  1040  may affect measurement results. Possible sensor array installation types include work-station mounted, wall-mounted, ceiling-mounted, self-mounted, and wearable configurations. 
     In one exemplary configuration, workstation-mounted sensor arrays are installed on the work surface of a workstation within a built structure or similar location. For example, a workstation-mounted sensor array may be installed on a desk. In one approach, a workstation-mounted sensor array may be positioned in a location where the sensor array is unlikely to be affected by occupants, indoor air pollutant sources, or heating or cooling sources. For example, a workstation-mounted sensor array may be positioned so that air exhaled by an occupant does not affect the reading. In another example, a workstation-mounted sensor array may be positioned to avoid indoor air pollutant sources such as computers, monitors, printers, or air humidifiers. By one approach, a workstation-mounted sensor array is not installed in an area that receives direct exposure to sunlight. In some embodiments, workstation-mounted sensor arrays are used because the can directly monitor the indoor environment around occupants. Other sensor array installation types present drawbacks to monitoring of the thermal environment and indoor air quality. 
     Wall-mounted sensor arrays may be installed on the walls or partitions in a built structure. By one approach, a wall-mounted sensor array may be installed at the height of seated occupants. By one approach, a wall-mounted sensor array is installed between 3-6 feet above the floor. More specifically, a wall-mounted sensor array may be installed between about 4 feet and 5 feet above the floor on interior walls or partitions. By another approach, wall-mounted sensor arrays may be installed to avoid direct sunlight, open windows, air intakes or exhausts, and areas where air could be exhaled directly onto the sensor array by occupants. If there is displacement ventilation or floor heating within the indoor space, an additional temperature sensor may be installed in an area between 8 inches and 1 foot 8 inches above the floor on an interior wall or partition. Wall-mounted sensor arrays may be inaccurate at measuring the thermal environment in built structure due to the influence of the building envelope. For example, in the summer the temperature of the interior surface of an exterior wall of the built structure will be higher than the indoor air temperature. Therefore, the temperature measured by a wall-mounted sensor array will be higher than the perceived indoor air temperature. The opposite effect occurs during the winter. Wall-mounted sensor arrays can also be affected by air infiltration from the building envelope, which may result in underestimation of the concentration of indoor air pollutants. By one approach, a wall-mounted sensor array may be positioned about 2 to 5 feet away from indoor air pollutant sources such as photocopiers or printers. In another approach, such installation is about 3.25 feet from indoor air pollutant sources. 
     Ceiling-mounted sensor arrays face similar drawbacks to wall-mounted sensor delays. Ceiling-mounted sensor arrays do not capture pollutant levels that occupants are exposed to at lower levels of an indoor space. By one approach, ceiling-mounted sensor arrays are not used to measure indoor air quality parameters or temperature. Additionally, the accuracy of ceiling-mounted sensor arrays is dependent on the air distribution equipment within the built-structure. For example, when a displacement ventilation system or under floor air distribution system is installed, the air in an indoor space tends to become stratified. When air within an indoor space becomes stratified, the air temperature measured by a ceiling-mounted sensor array may be higher than the air temperature perceived by occupants. In another example, if an indoor space has a ceiling air distribution device, such as a ceiling diffuser, the indoor environment measured by a ceiling-mounted sensor array may be strongly affected by the intensive turbulence of air. As a result, the measurements from ceiling mounted sensor arrays may have a larger variation than that of, for example, a workstation-mounted sensor array. 
     In one illustrative configuration, self-mounted sensor arrays mount a connection part of one sensor of a sensor array directly on the ceiling with a portion of the sensor array extending into an occupant breathing zone. A connection part for a sensor array may be, for example, a hanger. A self-mounted sensor array may avoid impeding daily office work but may also affect the overall appearance of the indoor space and arrangement. By one approach, the location of hangers may be positioned to minimize interference with daily office work and the impact to the appearance of the indoor space. By one approach, the self-mounted sensor array has a consistent power supply. Wearable sensor arrays may be positioned on an occupant or associated with an occupant of a built structure. Wearable sensor arrays are accurate in measuring certain parameters for which the human body is not a major influencing factor, like total volatile organic compounds. However, for some parameters that are highly affected by the human body in the indoor environment, like carbon dioxide and temperature, the position of the sensor array on the occupant may affect the measurements. For example, if a wearable sensor array is in contact with an occupant&#39;s skin or is very close to the skin of the occupant, the measured temperature may be higher than the indoor air temperature since the surface of a human body is usually higher than the surrounding air temperature. Similarly, if the wearable sensor array is located at a position in the breathing zone of an occupant, the measured relative humidity and the concentration of carbon dioxide may be higher due to the impact of exhalation. A wearable sensor array may, like self-mounted sensor arrays, avoid impeding daily office work. However, if a wearable sensor array cannot be connected via a cable power supply, a durable battery may be useful. 
       FIG.  14 A  and  FIG.  14 B  illustrate an exemplary layout of an indoor environment  1001  with multiple occupant zones. By one approach, the indoor environment  1001  is an office space and occupant zones  1022  designate the area where occupants spend a majority of their time during working hours.  FIG.  14 A  illustrates the layout of an office space with vertical segmental partitions  1012  and workstations  1014  positioned within the indoor environment.  FIG.  14 B  illustrates the corresponding occupant zones  1022  within the indoor environment of  FIG.  14 A . 
     An occupant zone  1022  is delineated by vertical segmental partitions  1012  within the office space and by the horizontal layout of the indoor environment  1001 . Vertical segmental partitions  1012  may include, for example, interior decorative partitions and partitions attached to workspaces. Vertical segmental partitions  1012  may delineate occupant zones since partitions impact air motion in office areas. Certain office spaces may have high segmental partitions to separate working areas and provide visual and acoustic privacy. When the height of a vertical segmental partition is higher than about 1.9 meters (6 feet 3 inches), air distribution in the indoor environment  1001  forms a unique pattern. If the height of a vertical segmental partition  1012  is greater than about 1.9 meters (6 feet 3 inches), the vertical segmental partitions  1012  are considered “effective” and the vertical segmental partition  1012  may be used to divide occupant zones. However, when the vertical segmental partition  1012  is lower than about 1.9 meters (6 feet 3 inches) it is not considered to be an “effective” barrier and cannot fully separate occupant zones. 
     In the horizontal layout of the indoor environment  1001 , the boundary of occupant zones  1022  may be delineated based on the offset from the edges of workstations  1014 . More specifically, the boundary of an occupant zone  1022  may be delineated by a about 1.5 meter (4 foot 11 inch) offset from the edge of a workstation  1014 . When two occupant zones overlap, they can be merged into a single occupant zone. For example, two workstations with a about 2.0 meter (6 foot 7 inch) gap between each other are considered a single occupant zone because there are overlaps between the occupant zones delineated by each workstation in one embodiment. However, four occupant zones delineated by workstations with a about 4.0 meter (13 foot 1 inch) horizontal distance are considered to be four separate occupant zones. 
     In  FIG.  14 B , occupant zones  1022   a  to  1022   e  designate each occupant zone in the exemplary indoor environment  1001 . The environment within each occupant zone ( 1022   a - 1022 ) can be assumed to be uniform if there is no overlap with other zones. 
       FIG.  14 C  illustrates an exemplary layout of sensor packages in an indoor environment with multiple occupant zones. In one approach, at least one sensor array  1040  is installed in each of the occupant zones  1022 . A method for sensor installation is further detailed in  FIGS.  15 A and  15 B . 
       FIG.  14 D  illustrates an exemplary layout of a boundary zone in an indoor environment. Boundary zones are the area of the indoor environment that is directly impacted by potential factors that affect thermal environment and indoor air quality, excluding the air handling zones. Potential factors that affect thermal environment and indoor air quality include envelope-related factors and interior environment-related factors. Envelope-related factors may include fenestrations such as windows or doors and the opaque envelope of the built structure. The opaque envelope of the built structure includes, for example, external building walls. Interior environment-related factors include indoor pollutant sources, kitchen appliances, water heaters, coffee machines, and other major indoor heating sources. Indoor pollutant sources may include, for example, printers, copy machines, gas stoves, space heaters, fireplaces, and woodstoves. Further, the environment within a boundary zone typically varies due to the temporal characteristics of potential factors. The area influenced by potential factors is determined by the influencing distance from those factors. Table 2 provides examples of the influencing distance associate with potential factors that may be present in a typical office space. Determining the area impacted by potential factors calls for detailed information on the built structure and its interior spaces. By one approach, an accurate delineation of the boundary zones may be determined by the integrated utilization of floor plans and on-site examinations. 
     
       
         
           
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Approximate 
               
               
                   
                 Influencing Distance 
               
               
                 Factor Type 
                 from Factors 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Envelope-related 
                 Fenestrations: windows, doors 
                 0.5-1 m 
                 (1′8″-3′3″) 
               
               
                   
                 Opaque envelope 
                 0.5 m 
                 (1′8″) 
               
               
                 Interior 
                 Kitchen, including water 
                 1.5 m 
                 (4′11″) 
               
               
                 environment-related 
                 heater, coffee machines, etc. 
               
               
                   
                 Printer, copying machines 
                 1.5 m 
                 (4′11″) 
               
               
                   
                 Other major indoor heating 
                 1.5 m 
                 (4′11″) 
               
               
                   
                 sources 
               
               
                   
               
            
           
         
       
     
     Based on the exemplary building structure  1010  from  FIG.  14 A ,  FIG.  14 D  illustrates the position of boundary zone  1026  for the indoor environment  1001 . Boundary zone  1026  is defined based on the location of potential factors within building structure  1010 . The potential factors in building structure  1010  includes a printer  1002 , a door  1004 , a stairway  1006 , and multiple windows  1008 . Accordingly, boundary zone  1026  designates the area influenced by those potential factors. 
       FIG.  14 E  illustrates the layout of air handling zones an indoor space with multiple occupant zones. Air handling zones designate the areas within an indoor environment that are easily affected by components of an air handling system. In an indoor environment, components of an air handling system can significantly affect thermal environment and indoor air quality. The effect of the air handling system may be taken into consideration when determining the location of sensor arrays for measuring them and indoor air quality parameters. For further description of how to determine the location of sensor arrays, see.  FIG.  15   . Components of an air handling system include, for example, air outlets, air diffusers, radiators, portable heating or cooling sources, and vents. Table 3 provides example instructions for delineating air handling zones based on various components of an air handling system. The area impacted by components of the air handling system is determined by both the location and the properties of the components. By one approach, an accurate delineation of the air handling zone may be determined by an integrated utilization of floor plans and on-site examination, which may include capturing the space via electronic image via the electronic user device. 
     
       
         
           
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Types 
                 Suggested Air Handling Zone 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Air Outlet 
                 Group A1*: Outlets mounted on or near 
                 360° horizontal diffusers: 
               
               
                   
                 the ceiling that discharge air 
                 1.0 m (3′3″) around the 
               
               
                   
                 horizontally. 
                 diffuser. 
               
               
                   
                   
                 Four-way diffusers, little 
               
               
                   
                   
                 spread: 3.0 m (9′10″) around 
               
               
                   
                   
                 the diffuser. 
               
               
                   
                 Group A2*: Outlets discharging 
                 Side wall grills, no 
               
               
                   
                 horizontally that are not influenced by 
                 deflection: a rectangle space 
               
               
                   
                 an adjacent surface (free jet). 
                 staring from the grill length: 
               
               
                   
                   
                 4.0 m (13′1″), width: twice the 
               
               
                   
                   
                 horizontal length of the grill. 
               
               
                   
                   
                 Side wall grills, wide 
               
               
                   
                   
                 deflection: a rectangle space 
               
               
                   
                   
                 starting from the grill, length: 
               
               
                   
                   
                 3.0 m (9′10″), width: twice the 
               
               
                   
                   
                 horizontal length of the grill. 
               
               
                   
                 Group B*: Outlets mounted on or near 
                 3.0 m (9′10″) around the outlet. 
               
               
                   
                 the floor that discharge air vertically in a 
               
               
                   
                 linear jet. 
               
               
                   
                 Group C*: Outlets mounted on or near 
                 3.0 m (9′10″) around the outlet. 
               
               
                   
                 the floor that discharge air vertically in a 
               
               
                   
                 spreading jet. 
               
               
                   
                 Group D*: Outlets mounted on or near 
                 Low sidewall, no spread: a 
               
               
                   
                 the floor that discharge air horizontally. 
                 rectangle space starting at the 
               
               
                   
                 When used in fully stratified systems, 
                 outlet, length: 4.0 m, width: 
               
               
                   
                 these outlets use low discharge 
                 twice the horizontal length of 
               
               
                   
                 velocities; in mixed systems, they use 
                 the outlet. 
               
               
                   
                 higher discharge velocities. 
                 Low sidewall, wide spread: a 
               
               
                   
                   
                 rectangle space starting at the 
               
               
                   
                   
                 outlet, length: 3.0 m (9′10″), 
               
               
                   
                   
                 width: twice the horizontal 
               
               
                   
                   
                 length of the outlet. 
               
               
                   
                 Group E*: Outlets that project supply air 
                 Air curtain: 3.0 m (9′10″) 
               
               
                   
                 vertically downward. When used in 
                 around the outlet. 
               
               
                   
                 partially satisfied systems, these outlets 
               
               
                   
                 use low discharge velocities; in mixed 
               
               
                   
                 systems, they use higher discharge 
               
               
                   
                 velocities. 
               
               
                   
                 Underfloor air distribution system. 
                 All areas. 
               
               
                 Return Air Outlet 
                 Return air diffuser. 
                 3.0 m (9′10″) around the 
               
               
                   
                   
                 diffuser. 
               
               
                 Indoor 
                 Portable heating/cooling source. 
                 Electric heater: 1.5 m (4′11″). 
               
               
                 Heating/Cooling 
                 Heating/cooling surface integrated with 
                 Chilled ceiling, radiant heating 
               
               
                 Sources 
                 the air handling system. 
                 floor: All areas. 
               
               
                   
               
               
                 *The group number is based on the grouping in Section 20 of the ASHRAE handbook-Fundamentals. 
               
            
           
         
       
     
     Based on the exemplary building structure  1010  from  FIG.  14 A ,  FIG.  14 E  illustrates the position of air handling zone  1024  for the indoor environment  1001 . The air handling system in indoor environment  1001  includes air outlet  1032  and indoor heating device  1034 . 
       FIG.  14 F  illustrates the layout of overlapping areas in an indoor space with multiple occupant zones. Overlapping areas represent occupant zones that overlap with other zones, including boundary zones and/or air handling zones. The overlapping area defines the portion of the indoor environment which interacts with occupants and is also directly affected by other factors such as air handling components and envelope-related aspects of the built structure. The overlapping areas are the most complicated with respect to achieving thermal comfort for occupants and acceptable indoor air quality parameters. Overlapping areas may be areas where an occupant and boundary zones overlap.  FIG.  14 F  shows an exemplary indoor environment with three overlapping occupant and boundary zones (O+B). Specifically, with reference to  FIG.  14 F , overlapping occupant and boundary zones are designated by O+B  1 , O+B  2 , and O+B  3 . As shown in  FIG.  14 D , the indoor environment includes three occupant zones 
     Overlapping areas may also be areas where occupant and air handling zones overlap.  FIG.  14 F  shows an exemplary indoor environment with three overlapping occupant and air handling (O+A) zones. Specifically, with reference to  FIG.  14 F , overlapping air handling and occupant zones are designated by O+A  1 , O+A  2 , and O+A  3 . 
       FIG.  14 G  illustrates a schematic diagram of outdoor zones near a built structure. Outdoor zones delineate the area that may not be in direct contact with the occupant zones but can still influence the comfort of occupants and the indoor environmental quality in the occupant zones. The outdoor zone includes spaces such as stairways, elevator areas, and outdoor environments. Table 4 provides examples of spaces in an outdoor zone and impacted environmental variables. 
     
       
         
           
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                 Example Impacted Environmental 
               
               
                 Spaces 
                 Variables 
               
               
                   
               
             
            
               
                 Outdoor Environment 
                 Temperature, Relative Humidity, Ozone, PM 2.5   
               
               
                 Elevator 
                 PM 2.5 , CO 2   
               
               
                 Stairway/Stairwell 
                 Temperature, Relative Humidity, PM 2.5   
               
               
                   
               
            
           
         
       
     
       FIGS.  15 A and  15 B  illustrate a method for monitoring indoor environmental quality in accordance with some embodiments. The method of  FIGS.  15 A and  15 B  may be deployed by the indoor air quality monitoring system  1000  or portions thereof as described above with reference to  FIG.  13   . The method includes steps for sensor installation within the indoor environment. Spatial and temporal variation of parameters related to indoor environmental quality, especially in the thermal environment and air quality, impact the quality of data collected by sensor arrays. In order to enhance performance of the indoor air quality monitoring system  1000 , the method also includes zoning of the indoor environment to determine optimal sensor placement. By one approach, the method is primarily executed by the control circuit  1050  of indoor air quality monitoring system  1000 . 
     The method begins at step  1102 . In step  1102 , the system defines occupant zones (OZs). Occupant zones may be delineated as illustrated in  FIGS.  14 A and  14 B . By one approach, the floor plan detailing the layout of the indoor space and drawings of the interior layout of the indoor space may be used for this step. Onsite examination of the indoor space may also be used to delineate occupant zones in step  1102 . For example, the arrangement of the indoor space may be modified during the process and onsite examination of the indoor space may detect changes to the arrangement. In the exemplary indoor environment in  FIG.  14 A , five occupant zones may be delineated based on the office layout, locations of workstations, and types and height of partitions.  FIG.  14 B  illustrates the boundaries of the five occupant zones in this exemplary indoor environment. 
     In some embodiments, the number of delineated occupant zones is less than or equal to the total number of sensor arrays. In step  1104 , the system determines whether the number of available or usable sensor arrays is greater than or equal to the number of occupant zones. If the total number of sensor arrays is less than the number of occupant zones, then the system proceeds to step  1106 . At step  1106 , the system instructs the installation of sensor arrays based on the priority of occupant zones. 
     Criteria for determining the priority of occupant zones may include the current, expected, intended, or predicted number of occupants in occupant zones and the similarity of occupant zones with respect to size, boundaries, and position. By one approach, more sensor arrays may be allocated to or installed in occupant zones which have more occupants. If two occupant zones are of similar size, share boundaries, and are adjacent then the two occupant zones may be combined in to a single zone which includes a single sensor array. If the total number of sensor arrays is greater than the number of occupant zones, then the system proceeds to step  1108 . At step  1108 , the system instructs the allocation or installation of one sensor package for or in each occupant zone. For example, considering the exemplary layout of occupant zones in  FIG.  14 B , the total number of sensor arrays is 9 and the number of occupant zones is 5. Because the total number of sensor arrays (9) is greater than the total number of occupant zones (5), the system may instruct the allocation or installation of one sensor array for or in each occupant zone as shown in  FIG.  14 C . 
     After the system has instructed the allocation or installation of sensor arrays, the system proceeds to step  1110 . At step  1110  the system determines whether there are any sensor arrays left (i.e., sensor arrays that have not yet been allocated or installed). The system may determine whether there are sensor arrays left by subtracting the number of sensor arrays installed at step  1108  from the total number of sensor arrays. If there are no sensor arrays left, the process stops. If there are sensor arrays left, which have not been yet installed, the system proceeds to step  1112 . 
     At step  1112 , the system defines boundary zones, air handling zones, and their overlapping areas (OAs). Boundary zones may be delineated as described in  FIGS.  14 D and  14 E . By one approach the floor plan and air handling system drawings may be used to delineate boundary zones and air handling zones. Onsite examination of the indoor space may also be used to delineate boundary zones and air handling zones in step  1112 . For example, onsite examination of the indoor space may assist in determining the areas affected by indoor air pollutant sources, heating sources, and cooling sources. At step  1112 , the system may delineate the overlapping areas of boundary zones, air handling zones, and occupant zones as described in  FIG.  14 F . 
     After defining overlapping areas at step  1112 , the system proceeds to step  1114 . At step  1114 , the system determines whether the number of sensor arrays left is greater than or equal to the number of overlapping areas (OAs). If the number of overlapping areas is greater than or equal to the number of sensor arrays left, then the system proceeds to step  1116 . At step  1116 , the system instructs the installation of one sensor array in each overlapping area. If the number of overlapping areas is less than the number of sensor arrays left, then the system proceeds to the method described in  FIG.  15 B , staring with step  1128 . By one approach, if there are no occupants in an overlapping area the system may skip step  1116 . For example, if there are not seats in an overlapping area in an office space, step  1116  may be skipped. 
     After sensor arrays have been installed according to step  1116 , the system proceeds to step  1118 . At step  1118  the system determines whether there are any sensor arrays left (i.e., sensor arrays that have not yet been installed). The system may determine whether there are sensor arrays left by subtracting the number of sensor arrays allocated or installed at step  1108  and the total number of sensor arrays installed at step  116  from the total number of sensor arrays. If there are no sensor arrays left, the process stops. If there are sensor arrays left, which have not been yet installed, the system proceeds to step  1120 . 
     At step  1120 , the system defines extending zones, outdoor zones, and non-overlapping boundary zones. The system may delineate outdoor zones as described in  FIG.  14 G . Non-overlapping boundary zones designate the area of boundary zones that do not overlap with occupant zones. The system may delineate non-overlapping boundary zones based on the area remaining in the boundary zone after defining overlapping areas at step  1112 . Outdoor zones and boundary zones that are not overlapping with occupant zones are less important for sensor installation because occupants are not present in these areas for a substantial amount of time. Therefore, outdoor zones and non-boundary zones are only considered for sensor array installation after sensor arrays have been installed in occupant zones and overlapping areas. 
     After defining the outdoor zones and non-overlapping boundary zones at step  1120 , the system continues to step  1122 . At step  1122 , the system determines whether the number of sensor arrays left (i.e., sensor arrays that have not yet been allocated or installed) is greater than or equal to the number of outdoor zones and non-overlapping boundary zones. The system may determine the number of sensor arrays left based on the calculation at step  1118 . The system may determine the number of outdoor zones and non-overlapping boundary zones by counting the number of zones defined at step  1120 . If the number of sensor arrays left is less than the number of outdoor zones and boundary zones, the system proceeds to step  1124 . If the number of sensor arrays left is greater than or equal to the number of outdoor zones and non-overlapping boundary zones, the system proceeds to step  1126 . 
     At step  1124 , the system instructs the installation of the remaining sensor arrays based on priority considerations with respect to the outdoor zones and non-overlapping boundary zones. Outdoor zones may impact the thermal and indoor air quality parameters in the indoor environment. Thus, installing sensor arrays in outdoor zones to measure outdoor environmental parameters may serve as an indicator of the relationship between the indoor and outdoor environment. Additionally, non-overlapping boundary zones have an impact on indoor air quality parameters. For example, areas near indoor air pollution sources, such as printers, have an impact on indoor air quality parameters. Installing sensor arrays in non-overlapping boundary zones may establish the impact of indoor air pollution sources on indoor environmental quality. More specifically, installing sensor arrays in indoor air pollution related areas may help determine potential risks to indoor environmental quality. 
     At step  1126 , the system instructs the installation of one sensor array in each outdoor zone and each non-overlapping boundary zone. After instructing the installation of the remaining sensor arrays at step  1126 , the process stops. 
     The method of  FIG.  15 B  begins with step  1128 . At step  1128 , the system determines whether indoor air quality (IAQ) or thermal parameters should be given priority. The system selects either a thermal path or an IAQ path depending on which parameters should be given priority. By one approach, the control circuit  1050  may be configured to select either the thermal path or IAQ path depending on a preset for the particular indoor environment. By another approach, an occupant may select a thermal path using an electronic user device  1090  that is in communication with the control circuit  1050 . For the thermal path and IAQ path, areas for sensor installation are prioritizes as follows:
         Thermal Path: O+A+B&gt;O+A&gt;O+B   IAQ Path: O+B&gt;O+A+B&gt;O+A   Where:   O+B represents the overlapping area resulted from an occupant zone and a boundary zone.   O+A represents the overlapping area resulted from an occupant zone and an air handling zone.   O+A+B represents the overlapping area resulted from an occupant zone, a boundary zone, and an air handling zone.       

     For the IAQ path, after step  1128 , the system proceeds to step  1130 . At step  1130 , the system determines whether the number of sensor arrays left is greater than or equal to the number of overlapping occupant and boundary (O+B) zones. If the number of sensor arrays is less than or equal to the number of O+B zones, then the system proceeds to step  1138 . At step  1138 , the system prioritizes sensor installation based on the occupant density within each O+B zone and instructs the installation of sensor arrays starting with the highest priority O+B zones first. By one approach, the system instructs sensor arrays to be installed in O+B zones with the highest number of occupants first. If the number of sensor arrays is greater than or equal to the number of O+B zones, the system instructs the installation of one sensor array in each O+B zones at step  1142 . Next, at step  1146 , the system determines whether there are sensor arrays left. To determine the number of arrays left, the system may subtract the number of sensor arrays installed in occupant zones and the number of sensor arrays installed in O+B zones from the total number of sensor arrays. If there are no sensor arrays left, the process stops. 
     If the system determines that there are sensor arrays left at step  1146 , the system proceeds to step  1150 . At step  1150 , the system determines whether the number of sensor arrays left is greater than or equal to the number of overlapping occupant and air handling and boundary (O+A+B) zones. The system may determine the number of sensor arrays left from the calculation at step  1146 . The system may determine the number of O+A+B zones from the process described at step  1112 . If the number of sensor arrays is less than or equal to the number of O+A+B zones, then the system proceeds to step  1154 . At step  1154 , the system prioritizes sensor installation based on the occupant density within each O+A+B zone and instructs the installation of sensor arrays starting with the highest priority O+A+B zones first. By one approach, the system instructs sensor arrays to be allocated or installed in O+A+B zones with the highest number of occupants first. If the number of sensor arrays is greater than or equal to the number of O+A+B zones, then the system instructs the installation of one sensor array in each O+A+B zone at step  1158 . Next, at step  1162 , the system determines whether there are sensor arrays left. To determine the number of sensor arrays left, the system may subtract the number of sensor arrays installed in occupant zones and the number of sensor arrays installed in O+B and O+A+B zones from the total number of sensor arrays. If there are sensor arrays left, the system instructs the installation of remaining sensor arrays in overlapping occupant and air handling (O+A) zones at step  1166 . At step  1166 , the system prioritizes installation of sensor arrays based on the occupant density in each O+A zone and instructs installation of sensor arrays starting with the highest priority O+A zones. By one approach, the system instructs sensor arrays to be installed in O+A zones with the highest number of occupants first. If there are no sensor arrays left, the process stops. 
     For the thermal path, after step  1128 , the system proceeds to step  1132 . At step  1132  the system determines whether the number of sensor arrays left is greater than or equal to the number of overlapping occupant and air handling and boundary (O+A+B) zones. If the number of sensor arrays is less than or equal to the number of O+A+B zones, then the system proceeds to step  1140 . At step  1140 , the system prioritizes sensor installation based on the occupant density within each O+A+B zone and instructs the installation of sensor arrays starting with the highest priority O+A+B zones first. By one approach, the system instructs sensor arrays to be allocated to or installed in O+A+B zones with the highest number of occupants first. If the number of sensor arrays is greater than or equal to the number of O+A+B zones, the system instructs the installation of one sensor array in each O+A+B zone at step  1144 . Next, at step  1148 , the system determines whether there are sensor arrays left. To determine the number of sensor arrays left, the system may subtract the number of sensor arrays installed in occupant zones and the number of sensor arrays installed in O+A+B zones from the total number of sensor arrays. If there are no sensor arrays left, the process stops. 
     If the system determines that there are sensor arrays left at step  1148 , the system proceeds to step  1152 . At step  1152 , the system determines whether the number of sensor arrays left is greater than or equal to the number of overlapping occupant and air handling (O+A) zones. The system may determine the number of sensor arrays left from the calculation at step  1148 . The system may determine the number of O+A zones from the process described at step  1112 . If the number of sensor arrays is less than or equal to the number of O+A zones, the system proceeds to step  1156 . At step  1156 , the system prioritizes sensor installation based on the occupant density within each O+A zone and instructs the installation of sensor arrays starting with the highest priority O+A zones first. By one approach, the system instructs sensor arrays to be allocated to or installed in O+A zones with the highest number of occupants first. If the number of sensor arrays is greater than or equal to the number of O+A zones, then the system instructs the installation of one sensor array in each O+A zone at step  1160 . Next, at step  1164 , the system determines whether there are sensor arrays left. To determine the number of sensor arrays left, the system may subtract the number of sensor arrays installed in occupant zones and the number of sensor arrays installed in O+A zones and O+A+B zones from the total number of sensor arrays. If there are sensor arrays left, the system instructs the installation of remaining sensor arrays in overlapping occupant and boundary (O+B) zones at step  1168 . At step  1168 , the system prioritizes installation of sensor arrays based on the occupant density in each O+B zone and instructs installation of sensor arrays starting with the highest priority O+B zones. By one approach, the system instructs sensor arrays to be installed in O+B zones with the highest number of occupants first. If there are no sensor arrays left, the process stops. 
     The method of  FIGS.  15 A and  15 B  may also further include sampling intervals for the measurement of indoor environmental quality parameters by installed sensor arrays. In addition to spatial considerations for sensor installation, temporal considerations for sensor measurements are also important for the accuracy of an environmental monitoring system. Temporal variations occur for example in air temperature and in the concentration of air pollutants. By one approach, the sampling interval for parameters for the thermal environment and indoor air quality may be a 5-minute frequency. A 5-minute frequency allows the environmental monitoring system to sufficiently capture transient changes in the thermal environment and indoor air quality. 
     In one illustrative approach, an apparatus for sheltering occupants may summarized as including a built structure having an indoor environment; a sensor array configured to measure at least one of air quality, thermal quality, sound parameters, or lighting parameters; a central control circuit communicatively coupled to the sensor array. The central control circuit in the apparatus may be configured to delineate occupant zones based on an electronic floor plan; instruct installation of at least one sensor in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identify overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; and instruct installation of at least one sensor in the identified overlapping zones. If the sensor arrays available are less than a total of the combined delineated occupant zones and identified overlapping zones, then allocation or installation of thermal sensor arrays occurs on the basis of the following order of preference: combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones and allocation or installation of air quality sensor arrays occurs on the basis of the following order of preference: the combined boundary-occupant zone, the combined boundary-occupant-air handling zone, and then the combined air handling-occupant zone. 
     In another illustrative approach, a system for monitoring indoor environmental quality may be summarized as including a built structure having a plurality of environmentally-controllable zones; a sensor array configured to measure at least one indoor environmental quality parameters; an environmental control system associated with the built structure; at least one electronic user device associated with a user; and a control circuit that is communicatively coupled to the sensor array, the electronic device, and the environmental control system. In the system, the environmentally-controllable zones may be delineated into one or more occupant zones, air handling zones, and boundary zones. The control circuit may be configured to detect a particular occupant having an occupant profile in an environment database, locate the particular occupant in a particular occupant zone, compare the sensor readings in the particular occupant zone with parameters of the occupant profile associated with the particular occupant, and, upon detection that the sensor readings in the particular occupant zone are not within the parameters of the occupant profile, instruct the environmental control system to adjust the parameters pursuant to the occupant profile. In one embodiment, the system for monitoring indoor environmental quality may include a sensor array configured to measure at least one of air quality, thermal quality, sound parameters, or lighting parameters. 
     In another illustrative approach, a method of monitoring indoor air quality may be summarized as including delineating a plurality of occupant zones in a built structure based on an electronic floor plan; installing at least one of a plurality of sensor arrays in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identifying overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; allocating or installing at least one of the plurality of sensor arrays in the identified overlapping zones; and operating an air handling system according to readings from the sensor arrays in the delineated occupant zones and the identified overlapping zones. If sensor arrays available for the identified occupant zones are less than the delineated occupant zones and the identified overlapping zones, then allocation or installation of thermal sensor arrays occurs on the basis of the following order of preference combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones. 
     In another illustrative approach, a method for monitoring indoor air quality may be summarized as receiving data from a plurality of sensor arrays in a space and operating an environmental system. In this illustrative approach, the space includes a plurality of zones and wherein the plurality of sensor arrays were positioned within the space by delineating a plurality of occupant zones in a built structure based on an electronic floor plan; installing at least one of a plurality of sensor arrays in each delineated occupant zone; after delineation of the occupant zones, delineating at least one boundary zone and at least one air handling zone based on the electronic floor plan and an electronic HVAC plan; identifying overlapping zones including at least one combined boundary-occupant zone, combined air handling-occupant zone, or combined boundary-occupant-air handling zone; allocating or installing at least one of the plurality of sensor arrays in the identified overlapping zones; and operating an air handling system according to readings from the sensor arrays in the delineated occupant zones and the identified overlapping zones. If sensor arrays available for the identified occupant zones are less than the delineated occupant zones and the identified overlapping zones, then installation of thermal sensor arrays occurs on the basis of the following order of preference combined boundary-occupant-air handling zone first, then the combined air handling-occupant combined zones, and then the combined boundary-occupant combined zones. 
     The above installation guidelines for sensor arrays in a system for monitoring indoor air quality may be considered before operating an environmental control system or remediating air in an indoor space. The data obtained from the system for monitoring indoor air quality may also be used to determine whether air within or remediating air in an indoor space needs remediation. 
     The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary or desirable to provide yet further embodiments. 
     These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.