ARB Research Seminar

This page updated July 25, 2013

Indoor Residential Chemical Emissions as Risk Factors for Children's Respiratory Health

Mark Mendell, Ph.D., Indoor Environment Department, Lawrence Berkeley National Laboratory, California

August 03, 2006
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA



Most research into the effects of residential indoor air exposures on asthma and allergies has focused on exposures to biologic allergens, moisture and mold, endotoxin, or combustion byproducts. A growing body of research from outside the U.S., however, suggests that chemical emissions from common indoor materials and finishes have a variety of adverse effects, including increased risk of asthma, allergies, and pulmonary infections The identified risk factors include specific organic compounds such as formaldehyde, benzene, and phthalates, as well as indoor materials or finishes such as vinyl flooring, carpet, paint, and plastics. This presentation presents a brief review of studies published on this topic in the scientific, peer-reviewed literature. For selected compounds, it also compares reported risk levels to observed indoor concentrations. The review was funded by the Indoor Environments Division, Office of Radiation and Indoor Air, Office of Air and Radiation, of the U.S. Environmental Protection Agency.

Associations, some strong, were reported between many risk factors and respiratory or allergic effects in infants or children. Reported odds ratios (ORs) ranged to high levels (even excluding ORs up to 22.3 related to changes in T cell subpopulations): for formaldehyde, to 8.2; for aromatic chemicals, to 11.2; for aliphatic chemicals, to 8.1; for plastics and plasticizers, to 3.4 (and with low ventilation, to 12.6); and for painting, to 5.6. Elevated risks were also reported for renovation and cleaning activities, new furniture or particleboard, and carpets or textile wallpaper. Risk factors identified most frequently included formaldehyde or particleboard, phthalates or plastic materials, and recent painting. Findings for other risk factors, such as aromatic and aliphatic compounds, were limited but suggestive. Various forms of bias are likely to have influenced all these studies, but seem unlikely to explain the overall findings. The primary weakness of these studies is that the specific risk factors identified (with the likely exception of formaldehyde) may be not directly causal factors, but indicators of other truly causal factors associated with the same indoor materials or processes.

This body of literature, although entirely observational and of limited size and quality, overall suggests the occurrence of adverse respiratory and allergic effects from at least some common indoor materials in residences, including formaldehyde-emitting materials, flexible plastics, and painted surfaces. Findings are also consistent with additional risks from other indoor materials that emit various chemical compounds. All these indoor materials are nearly ubiquitous in modern homes, and their use seems likely to increase, leading to increased emissions. Available findings thus suggest the possible large-scale occurrence, and future increase, of important yet preventable adverse respiratory and allergic effects in infants and children worldwide, related to modern residential building materials and coatings and exacerbated by decreased ventilation.

It is important to confirm or disprove these environmental risks, identify specific causal exposures, and quantify any increased risks, in order to motivate and guide any necessary preventive actions. In particular, current findings relating formaldehyde, plasticizers, and new paint to respiratory and allergic effects in infants and children warrant substantially increased research and, especially for formaldehyde, consideration of preventive actions.

Speaker Biography

Mark Mendell, Ph.D., is currently a Staff Scientist/Epidemiologist in the Indoor Environment Department at Lawrence Berkeley National Laboratory in California. Dr. Mendell was formerly at the Centers for Disease Control/National Institute for Occupational Safety and Health, where he was head of the National Occupational Research Agenda Team on Indoor Environments. Dr. Mendell is on the editorial board of the journal Indoor Air and a member of the International Academy of Indoor Air Sciences. He holds a BA from Cornell University in Science, Technology, and Society, a Bachelor of Landscape Architecture from the University of Oregon, and a PhD in epidemiology from the University of California at Berkeley, School of Public Health. Dr. Mendell conducts research in the field of environmental epidemiology, focused on health effects related to indoor environments in buildings. His research interests include the causes and prevention of building-related symptoms (also called sick building syndrome); health risks associated with buildings, ventilation systems, moisture, and microbial growth; effects of indoor environments in schools on health and performance of students, and effects of indoor chemical exposures in residences on asthma and allergies.

For a complete listing of the ARB Research Seminars and the related documentation
for the seminars please view the Main Seminars web page