DOI: 10.7941/d1zs7x
title: Data from: Indoor air quality in California homes with code-required mechanical ventilation

description: Data were collected in 70 detached houses built in 2011-2017 in compliance
 with the mechanical ventilation requirements of California’s building
 energy efficiency standards. Each home was monitored for a one-week period
 with windows closed and the central mechanical ventilation system
 operating. Pollutant measurements included time-resolved fine particulate
 matter (PM2.5) indoors and outdoors and formaldehyde and carbon dioxide
 (CO2) indoors. Time-integrated measurements were made for formaldehyde,
 NO2 and nitrogen oxides (NOX) indoors and outdoors. Operation of the
 cooktop, range hood and other exhaust fans was continuously recorded
 during the monitoring period. One-time diagnostic measurements included
 mechanical airflows and envelope and duct system air leakage. All homes
 met or were very close to meeting the ventilation requirements. On average
 the dwelling unit ventilation fan moved 50% more airflow than the minimum
 requirement. Pollutant concentrations were similar or lower than those
 reported in a 2006-2007 study of California new homes built in 2002-2005.
 Mean and median indoor concentrations were lower by 44% and 38% for
 formaldehyde and 44% and 54% for PM2.5. Ventilation fans were operating in
 only 26% of homes when first visited and the control switches in many
 homes did not have informative labels as required by building standards.
description: Overview of HENGH
 Study The HENGH study was
 conceived, designed and implemented for the purpose of evaluating impacts
 of residential mechanical ventilation equipment requirements that have
 been part of the California’s Building Energy Efficiency Standards since
 2008. Starting in 2009, these standards have required bath and kitchen
 exhaust fans and dwelling unit mechanical ventilation with sizing and
 performance levels based on the residential ventilation standard (62.2) of
 the ASHRAE organization. The ventilation standards are intended to help
 maintain indoor air quality as homes are constructed with tighter shells
 to reduce uncontrolled outdoor air infiltration for energy
 efficiency. The study was led by
 Lawrence Berkeley National Laboratory (LBNL). All study protocols
 involving interactions and collection of data from private individuals and
 monitoring in occupied homes were reviewed and approved by the LBNL Human
 Subjects Committee. Research Funding and technical contributions of
 collaborators are noted below in the acknowledgements.  The field study included the following data
 collection elements: 
 Homeowner survey about household demographics, ventilation
 practices, activities that can impact indoor air quality, and satisfaction
 with environmental conditions in the home.
 Compilation of basic data about the houses (location, size,
 number of bedrooms, etc.) and gas appliances and mechanical ventilation
 equipment (technology type, make, model, etc.)
 Measurements of air leakiness of the building envelope and
 forced air system ductwork. Measurements of the
 following parameters over a weeklong monitoring period: 
 Airflows of all mechanical ventilation equipment;
 Air pollutants and environmental parameters indoors and
 outdoors; Cooktop and oven surface temperatures to
 identify burner use. 
 Participants were expected to complete a daily activity
 log.<b> </b> What is contained in this
 dataset? The dataset
 contains the most relevant information collected about the 70 houses and
 their mechanical equipment, results of the participant survey, results of
 air leakage and airflow measurements at the homes, pollutant
 concentrations measured by time-integrated passive samplers inside and
 outside of the home, usage of cooktop and oven, external door open state,
 and time-series or air pollutants and environmental indicators measured
 within and outside of the houses.  Organization of
 Dataset  
 Airflow This folder contains time series
 data of monitored mechanical ventilation equipment, estimates of air
 infiltration rate, and overall air exchange rate.  There is one csv file
 for each home. See HENGH_Airflow_ReadMe for more details. 
 Ambient_PM This
 folder contains a summary of PM2.5 data reported by one or more ambient
 air monitoring stations nearest to each study home. There is one EXCEL
 file containing PM2.5 data reported from up to three closest regulatory
 monitoring sites. A composite estimate of ambient PM2.5 was calculated for
 each home using an inverse distance weighing method.  
 Home_Equipment_Data 
 This folder contains data about the house, including basic
 characteristics, air leakage test results, and measured airflow rates of
 mechanical ventilation equipment. There is one EXCEL file containing the
 data for all homes. The EXCEL file has ReadMe information about the data
 provided and a note about data quality issue concerning exhaust airflow
 measurements of over-the-range microwaves.    
 IAQ_Monitoring This folder
 contains time-resolved air quality data, including estimated PM2.5 as
 measured by photometry (PM), carbon dioxide (CO2), nitrogen dioxide (NO2),
 formaldehyde (FRM), temperature (T), and relative humidity (RH). There is
 one csv file of 1-minute time-series data for each home. See
 HENGH_IAQ_Monitoring_ReadMe for data header definitions and data
 issues.  IAQ_Sample
 This folder contains the results of time-integrated
 air quality samples, including passive measurements of formaldehyde,
 nitrogen dioxide and nitrogen oxides, and PM2.5 gravimetric filter
 measurements. There is one EXCEL file containing all data. Detail
 information about chemical analysis of air samples are provided elsewhere
 in the journal paper and report.  
 Occupant_Activity This folder contains
 tabulated information provided by study participants from their daily
 activity logs. There is one EXCEL file containing data transcribed by a
 staff member, which was independently spot checked by another staff to
 confirm accuracy. The PDF file is the daily activity log used. 
 Occupant_Survey 
 This folder contains results of a survey about the occupants,
 their general activities related to ventilation and IAQ
 satisfaction, completed by study participants. There is one EXCEL file
 containing data transcribed by a staff member. Two homes did not complete
 surveys; these homes have "No survey" in each data file.
 Questions for the occupant surveys are provided in MS Word and PDF
 formats.  State_Monitoring
 This folder contains time series data of cooking
 burners monitored with iButton temperature sensors and open/close status
 of external (mostly patio) doors monitored with state sensors. There is
 one csv file for each home. See HENGH_State_Monitoring_ReadMe for more
 details. 
description: Time Series Data Handling and
 Quality Assurance Review Most instruments had internal logging and special
 software to download data from the field instruments as binary files or
 ascii/csv files. The instruments for which files downloaded as binary
 provide software to view the data or export the data to csv
 files.  One-minute resolution
 time-series data files were created for each house using an R script that
 pulled data from the csv files, aligned data by time, executed unit
 conversions, and translated from instruments with longer or different data
 intervals (e.g. 30 min formaldehyde data and 1.5 min for anemometer data).
 Visual review was conducted on the compiled files (and primary csv or
 binary files were consulted as needed) to check for translation or writing
 errors (especially from terminal emulator), indications of instrument
 malfunction, mislabeled units or unit conversion errors, mislabeled
 location, and time stamp errors.  The draft final set of time-series data were
 visually reviewed by a second researcher by creating multi-panel,
 time-series plots by monitoring period. Panel combinations included (1)
 indoor CO2 and indoor and outdoor PM, T, and RH; (2) indoor PM, NO2, and
 formaldehyde along with cooktop and oven temperatures, and range hood
 operation (focused on checking formaldehyde and NO2). The time series data
 were visually reviewed to search again for examples of possible instrument
 malfunction or errors introduced via data transfer. More detail
 information about data issues identified are explained in the ReadMe
 information provided in each data folder.  Acknowledgements In addition to research funding noted below, the
 Southern California Gas Company (SoCalGas) provided direct financial
 support to the Gas Technology Institute (GTI) to purchase equipment and to
 conduct field data collection. Staff support was contributed by the
 Pacific Gas & Electric Company (PG&E) which funded Misti
 Bruceri & Associates (MBA) to provide a staff person to support
 the study, and by SoCalGas, which allocated engineering and technical
 staff to contribute to the field work in SoCalGas service territory under
 GTI direction. SoCalGas and PG&E also supported the project by
 allocating Gas Service Technicians to conduct gas appliance safety
 inspections in study homes. The
 dataset presented here would not exist without the committed work of the
 field research teams in PG&E and SoCalGas service territories; the
 authors are deeply appreciative of their efforts. The field work for this
 project was conducted by Luke Bingham, Erin Case, and Shawn Scott of GTI;
 Guy Lawrence of MBA; and Eric Barba, Mary Nones, Ara Arouthinounian, and
 Ricardo Torres of SoCalGas; and Randy Maddalena, Marion Russell, and
 student interns of LBNL. Rick Chitwood also assisted with field data
 collection and provided guidance on measuring airflow rates in supply
 ventilation systems.