white paper

CO2 measurement is only thefirst step to define indoor airquality
Learn how to protect your health – and not just fromCOVID-19
Olivier Martimort, CEO, NanoSense.

1. Indoor Air Quality (IAQ), a major concern not addressed often
enoughIndoor air quality is a largely neglected topic. On average we spend more than
90% of our time indoors, where air is 5 to 10 times more polluted than outdoors.
Today almost everybody recognizes the dangers of outdoor pollution, but few
people consider the risks of exposure to indoor pollutants.
Indoor air quality is affected by outdoor pollution plus indoor pollutant emissions
caused by human activity and building/furnishing materials. But more importantly,
it’s necessary to understand that pollutants tend to accumulate indoors.

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Whereas outdoor pollution is hard to avoid, improving indoor air quality is wellwithin our control. Measuring the pollutants is the first step towards improving
indoor air quality (IAQ), which is sadly poor in most cases.

2. Main indoor pollutants and environmental factors to beconsidered• Pollutants: CO2 (human exhalation), VOC (cleaning products, building
materials, furniture, odours, perfume, perspiration, etc.), ozone (laser printers,electric motors, etc.), particulate matter (mainly from outdoor combustion
sources i.e. heating, road traffic - plus indoor sources e.g. smoking, cooking...)• Environmental factors: temperature & humidity, noise & light levels, lighttemperature.
Light affects melatonin (sleep hormone) levels which impacts productivity, just like
temperature extremes and noise.

3. CO2 is not a universal indicator of indoor air quality
CO2 has long been regarded as the prime indicator of indoor air quality. However,today this parameter alone is insufficient to define air quality as a whole. When webreathe, CO2, VOC (Volatile Organic Compound) and PM (Particulate Matter)enter the bloodstream via the lungs, then reach the brain (accounting for 42% of
human energy consumption) affecting many cognitive functions.
It should be taken into account that the mix of these three pollutants is far
unhealthier than CO2 alone. Likewise, environmental factors play a huge role inworsening cognitive functions and productivity. According to a study conducted by
the Harvard Institute, productivity of the average employee increases by $6,500
per year just by increasing air renewal – at an additional cost of just $14 to $40 peryear/employee (depending upon the location’s climate).
The EnOcean Alliance is an international association of leading companies in thebuilding and IT industries founded in 2008. The open, non-profit organization iscommitted to enabling and promoting interoperable, maintenance-free and proveneco-systems based upon the wireless EnOcean radio standard (ISO/IEC 145433-10/11). With their decades of experience, EnOcean Alliance members strive toco-create a healthy, safe, and sustainable environment in smart homes, intelligent
buildings and smart spaces for the benefit of all.

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NanoSense, an EnOcean Alliance member specialized in air quality
management, has recently launched a new standardized EnOcean Equipment
Profile (EEP) related to physiological factors as mentioned above for productivity,
as well for the quality of sleep, building health (mold growth, condensation, particledeposition…) and more. Those factors take into account the combination (“cocktaileffect”) of various pollutants and environmental factors. They are used to express
AQ (Air Quality) in a more intuitive way but can also be used as set points for
remediation control (mainly through ventilation). For example, CO2 has no impact
on health.

CO2 VOCtPM

✓

✓

✓

✓

✓✓
✓

✓
✓
✓

Cognitivity /Productivity
HealthQuality of sleep
Asthma attacks
Olfactory
comfortFormaldehyde
Radon Noise OdorsBenzene✓✓✓

RHNOxLightLuxO3T°.

✓✓✓✓✓✓ ✓✓ ✓ ✓✓✓✓T°✓ ✓✓✓ ✓Thermal comfort✓

Sound comfort
Dry air comfort(skin, mucousmembranes)✓Respiratory tractirritation✓✓ ✓Building health(mold, sporesand mites)✓✓

The table above summarizes the cocktail effect for different physiological impacts.

4. Indoor Air Quality - impact on health
The impact of air quality upon human health is a major concern – 9 million people
worldwide die prematurely every year because of a harmful air exposure. To put
this into perspective, the total number of global deaths attributable to the COVID19 pandemic in 2020 is roughly 3 million (or 3 times less!), yet the subject of indoor
air quality receives much less attention. And this pandemic is also related to airquality, since air renewal based upon IAQ could have saved many lives. Therefore,indoor air quality is a global issue – long-term exposure to polluted indoor aircauses a broad range of health issues (i.e. respiratory illness, heart disease and© EnOcean Alliance, 2023

white papercancer). The fact that the dire consequences of exposure topolluted indoor air are not immediate doesn’t lessen the gravity of the problem.
In addition, certain populations are more vulnerable than others to indoor airquality. Pregnant women, children, the elderly and individuals with pre-existing
conditions (asthma, allergies…) are those who most need protection from air
pollution. Hence the importance of measuring and controlling air quality e.g. with
NanoSense’s multi-sensors, IAQ probes or equivalent systems.
Air Quality monitoring and control is also essential in professional and industrialsectors, helping to reduce absenteeism and improve employee productivity
through better health and comfort.
According to a study conducted by the National Institute of Health (NIH, Harvard)
the cost of lost workdays due to absenteeism resulting from a degraded IAQ is
estimated to average $480/employee/year!

5. Improving indoor air quality whilst reducing energy consumption
by 70%? Yes, we can!
We have learned from the pandemic that improving indoor air quality is not aluxury, but an absolute necessity. Now that an energy crisis directly follows thepandemic, the main question is: how best to balance the need for clean indoor air
with the need to save energy in buildings?
The answer is simple. First measure the pollutants, then control ventilationaccordingly. This is called On-Demand Ventilation.
The way to achieve sustainable IAQ according to NanoSense, expert in air quality
for more than 20 years, is by deploying IAQ probes throughout buildings in orderto monitor indoor air quality. These probes can then automatically control theventilation system. Instead of running the ventilation non-stop (24/7 as in mostbuildings), with On-Demand Ventilation the airflow rate is governed according toindoor air quality. This is how we control heating and cooling today, so why notventilation?
This process can save more than 70 % of HVAC energy
consumption. Additionally, the NanoSense IAQ probe
features an algorithm estimating the physiologicalimpact upon the building and its occupants. This allows
companies to control air quality based upon
productivity and health goals. It’s a multi-pollutant andmulti-protocol probe that provides an overall picture of
the impact of many pollutants, and it can be integrated
into many types of building ecosystems.

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ENERGY SAVING ESTIMATIONS BASED UPON VENTILATION CONTROL:

Type

Ventilationcontrol

Energysaving

IAQ

24/7

No

0%

Good

ON/OFF or speed

30-50%

Uncertain

Clock

ON/OFF

50%

Uncertain

Occupancy sensor

ON/OFF

54%

Good

Number of persons (CO2)

Proportional (PI)71%

Moderate

Multi-sensor IAQ probe with physio

Proportional (PI)

70%

Good

Multi-sensor IAQ probe with physio
and modes

Proportional (PI)

74%

Good

Manual control

Energy savings estimate based upon different methods sorted in ascending order - as per the EN 13779 standard•

The basic, less adequate solution is 24/7 (100% of the time) ventilation. On theone hand this ensures good air quality as the airflow is generally dimensioned
for worst-case occupancy (example: if a room can potentially welcome 20
people but is in reality occupied by 5 people, the airflow will be dimensioned for
20 people and over-ventilate most of the time).

•

Manual control is performed without intelligent feedback since air quality cannot
be perceived by our senses, we can only detect odours. IAQ result is totallyuncertain. An IAQ display would improve manual control efficiency.

•By using a timer and completely cutting off ventilation during unoccupied times(typically at night, on the weekends in office spaces and during the day inresidential properties) we can estimate running the ventilation 40% - 46% of thetime (8 am to 7 pm in offices = 11 hours out of 24). This represents a saving of
100 - 46 = 54% based upon a level of supposed occupancy that has nothing todo with air quality. IAQ result is uncertain if the timer is not set properly (65% ofthe case after a few years).

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An occupancy sensor is better than a timer (as the timer
mechanism is frequently badly set after a certain length of time). Like a timer,
sensor switching is only ON/OFF and the energy saving is poor. As ventilation
is running at 100% during occupancy, the energy consumed is probably
excessive but the IAQ result is good (over-ventilation).

•Control based upon CO2 levels is the most basic form of On-Demand ventilation
adjustment as it is simply based upon an estimated number of occupants thathas nothing to do with air quality. This is still more efficient than control using
occupancy sensors as it governs proportional airflow. We can estimate an
average flow rate of 50% during the presence period, so a gain of half of the
54% of the version with occupancy sensor (i.e. 27%), which would make a totalof 54 + 27 = 81%. However, a regulated version ensures a minimum ventilation(never a 0% flow) for the health of the building (mold...) that consumes
intrinsically 10% more energy, that is to say a saving of 71%. Some go further
by sacrificing this minimum ventilation for the sake of building health, but it’s notrecommended. As ventilation is not based upon IAQ but only upon CO2 levels,
the IAQ result is uncertain.

•For a multi-sensor probe with a proportional integral control loop (PI) based on
physiological indexes, like the IAQ EP5000, the gain may not be higher than aventilation based upon CO2. This is the most sophisticated On-Demandventilation control. However, when necessary it may require more ventilation
than the CO2-based control (due to taking other pollutants into consideration).
It can also take extreme ambient temperature, bad lighting and noise intoconsideration. This extra energy consumption is the price to pay for ensuring
good air quality with beneficial associated productivity and health-related returnon investment.

•When modes are used (Comfort, Eco, Night…) setpoints are adapted to thesituation and additional savings can be expected (particularly for the nightmode). This gain obviously depends upon the adjustment of the requirements
during non-occupancy periods and at night. A lump-sum gain of 4% has been
estimated.

6. Energy consumption related to type of ventilation
According to a study conducted by the French BBC Effinergie labeling body, theenergy consumption of HVAC depends on the type of ventilation and its
geographical location.
Simple-flow (not filtered) HVAC consumes more energy by emitting hot air in winterand cool air in Summer. So the balance between simple-flow and double-flow
really depends on average weather conditions and geographical location.

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Dual-flow has two motors (supply andexhaust) that consume more electricity
than two simple-flow motors because of
the filter pressure drop as filtering is
mandatory to maintain the efficiency ofthe heat exchanger over time.
In any case, it is important to use OnDemand ventilation in order to save up to70% of energy. Other savings should also
be considered, like the cost reduction on
filters (replaced less often) and lesser
associated manpower requirements.

Please note that this illustration shows simple-flow consumption in a moderate
climate, with no air conditioning. With simple-low in hot regions like the Middle
East, we would see similar consumption to central Europe due to air conditioning.

7. Natural ventilation! Is it a good idea?
During the warm seasons, we used to ventilate by
opening windows. Is it a good idea? No. Generally,
the HVAC will continue running for nothing and burnunnecessary energy. In order to cut off ventilation
automatically, EnOcean open-window sensors canbe used and paired with the IAQ probe. This canbring a huge energy saving and should always be
considered.
But is window opening really safe? Outdoor air may
be polluted and worse than indoor air. Traffic noise can add to the problem. Under
such circumstances, the NanoSense IAQ probe can receive air-quality EnOcean
telegrams from outdoor air-quality sensors (one per facade) and compare thephysiological effects to issue dedicated visual warnings. This warning can also bebased on Well V2 outdoor pollution level depending on the setting.

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