ARB Research Seminar
This page updated June 19, 2013
Ventilation and Indoor Air Quality in New Homes
Francis (Bud) J. Offermann, President, Indoor Environmental Engineering, San Francisco, California
May 06, 2008
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA
Mr. Offermann will present the results of the first major study of ventilation and indoor air quality (IAQ) in new homes in California. Concerns have been raised regarding whether households in new California homes use windows, doors, exhaust fans, and other mechanical ventilation devices enough to remove indoor air pollutants and excess moisture. However, few measurements of ventilation and indoor pollutant levels have been made in California homes of recent vintage.
The goals of this field study were to measure, and analyze the relationships between, ventilation characteristics and IAQ in new, single-family detached homes in California. Information was obtained from 24-hour measurements in 108 homes in multiple seasons and regions of the state to help characterize the full range of exposure to indoor pollutants in such homes. A subset of homes with outdoor air mechanical ventilation systems was also studied.
The study results indicate that all of the homes had indoor levels of formaldehyde that exceeded the Proposition 65 "No Significant Risk Level" for lifetime cancer risk, and most of the homes also exceeded the Proposition 65 level for acetaldehyde. In addition 59% of the homes had indoor levels of formaldehyde that exceeded ARB's IAQ Guideline of 33 µg/m3 (27 ppb) for preventing acute (irritant) health effects. Two-thirds of the homes did not meet the proposed state minimum for outdoor air exchange rates of 0.35 air changes per hour. Over 80% of the homes with the direct outdoor air type of mechanical ventilation system did not meet the proposed state standard for outdoor air exchange, apparently due to short ventilation times and low air flow rates.
Mr. Offermann will discuss these and other results of the study, and their implications for building product selection, home design, and home operation. The California Energy Commission was the primary funding source for this study; they are using the results to help revise ventilation requirements and compliance programs for the state's building energy efficiency standards. The ARB will use the results to update its assessments of Californians' exposures to toxic air contaminants and other pollutants, and to recommend effective strategies for reducing indoor air pollution.
Francis (Bud) J. Offermann, is founder and President of Indoor Environmental Engineering (IEE), a San Francisco based building science research and consulting firm. Mr. Offermann directs an interdisciplinary team of environmental scientists, chemists, and mechanical engineers in IAQ building investigations, healthy building design projects, and laboratory chamber measurements of material and consumer product contaminant emission rates and air cleaner performance.
Mr. Offermann has received various State and Federal research grants regarding IAQ and ventilation field studies, tracer gas techniques, in situ contaminant emission rate measurements, and the development of IAQ measurement instrumentation. He has published 63 scientific papers on the measurement and mitigation of indoor air pollution. He served for many years on national committees for building ventilation standards and materials emissions testing. He currently serves on the ASHRAE Environmental Health Committee, the ACGIH Bioaerosols Committee, the U.S. Green Building Council Indoor Environmental Quality Technical Advisory Group, and the ASTM D22 IAQ Subcommittee. Previously, Mr. Offermann was a Staff Scientist with the Building Ventilation and IAQ Program, Energy and Environment Division, Lawrence Berkeley National Laboratory, Berkeley, California.
Mr. Offermann received his B.S. in Mechanical Engineering from Rensselaer Polytechnic Institute in 1976 and his M.S. in Mechanical Engineering from Stanford University in 1985.