July 14, 2008
Gauging the Quality of Indoor Air
Contact: Allan Chen
The quality of the air we breathe indoors significantly impacts our health, but most of us take our indoor environment for granted most of the time. There are exceptions — for example, people with asthma, or who have allergies to indoor pollutants, are often very much aware of indoor air quality (IAQ), as are those who suffer from building related symptoms, sometimes called "sick building syndrome." These are sets of symptoms that include respiratory problems, coughs, irritation of the eyes and nose, and headaches – which disappear when the sufferer leaves the building where the symptoms began.
Researchers at Berkeley Lab's Environmental Energy Technologies Division (EETD) have developed a new website that provides state-of-the-science information on the effects of indoor air quality on human health and work performance. The site, called the Indoor Air Quality Scientific Findings Resource Bank (see Additional Information, below) brings together summaries of current, peer-reviewed scientific thinking on such issues as the impacts of the indoor environment on human health, the health and economic impacts of building ventilation, and the impact of indoor dampness and mold on human health. Development of the website was sponsored by the U.S. Environmental Protection Agency's Office of Radiation and Indoor Air, Indoor Environments Division. EPA researchers work closely with those in EETD to advance the science of indoor air quality.
In the industrial world, most people spend 90 percent of their time indoors in homes, workplaces, shops, or elsewhere. Yet almost of the research conducted on air quality has been focused on the outdoors. Within the U.S., neither the general public nor the architectural and engineering community are broadly aware of IAQ-health science connection, because there has been no simple, central source of information, and no single agency guiding research in this area.
At Berkeley Lab, the Indoor Environment Department has been conducting research on indoor air quality and health since the 1970s. Although numerous scientists in universities, hospitals, and government labs throughout the country conduct research on IAQ, there are very few U.S. departments or institutes with a mission focus on the indoor environment and fewer still with the scale and multidisciplinary scope of EETD's Indoor Environment Department.
Thanks to its position as part of a U.S. Department of Energy national laboratory with close ties to the University of California at Berkeley, the Indoor Environment Department has a unique opportunity to serve as a source of sound scientific research on IAQ, as well as a center for summarizing and distributing research information conducted throughout the U.S. and the rest of the world to those who can use it: builders and building design engineers, public health officials, facilities managers, and the like.
When the media takes note
While indoor air quality research does not always have a high public and media profile, a number of headline stories in recent years fall squarely within the field of indoor air or environmental quality. Some examples in which Berkeley Lab has been involved:
- In 2008 the Centers for Disease Control and Prevention, with the help of Berkeley Lab scientists, conducted a study of gaseous chemical emissions inside trailers supplied by the Federal Emergency Management Agency to people left homeless by Hurricane Katrina.
- The first evidence of a link between levels of outdoor ozone, an air pollutant regulated by the EPA, and levels of building-related symptoms was reported jointly by Berkeley Lab and EPA scientists in 2008.
- A study of the gaseous emissions of common household cleaners and other consumer chemicals, conducted by University of California at Berkeley and Berkeley Lab scientists, made headlines in 2005.
- A study summarizing the knowledge linking building dampness and mold with allergies, released by the Institute of Medicine of the National Academy of Sciences, attracted media attention in 2004. A Berkeley Lab scientist was a member of the committee that wrote this report. Two research papers in 2007 by that scientist and his colleagues at the EPA quantified the large economic impact of respiratory symptoms and asthma and found a strong association among dampness, mold growth, and asthma.
- When a study conducted in Australia on emissions of fine particles from laser printers and their possible health impacts made the news, the media turned to Berkeley Lab scientists for technical comment on the science.
- From time to time news reports surface of newly built office buildings in which occupants suffer from building related symptoms so severe that contractors have to radically change the building or sometimes even tear it down. Berkeley Lab scientists have long studied the relationship between these symptoms and indoor factors.
What is IAQ?
Indoor air quality, broadly interpreted, refers to the environmental characteristics inside buildings that may affect human health, comfort, or work performance. IAQ characteristics include concentrations of pollutants in indoor air as well as air temperature and humidity.
People living and working indoors can be exposed to pollutants generated directly from the indoor environment, such as tobacco smoke, particles and gases released by mold, and volatile organic compounds emitted by building materials, furnishings, and consumer products. Outdoor pollutants can also enter indoor spaces, where they may behave differently — sometimes reacting with chemicals and materials found indoors to produce new pollutants.
The IAQ scientific findings resource bank offers an overview of indoor air quality issues, plus four sections that address major areas of indoor environmental quality research. The first two of these sections are detailed reviews; the third and fourth are overviews which will expand as more research becomes available.
- Health and Economic Impacts of Building Ventilation. The first section addresses current scientific knowledge of how proper or improper ventilation can affect health and work performance in different kinds of buildings such as offices, schools, and homes. It summarizes current research on best ventilation rates to minimize health impacts like respiratory problems for different types of structures.
- Impacts of Indoor Environments on Human Performance and Productivity. This section summarizes research on the effects of temperature and ventilation and other IAQ factors on performance at work and in school.
- Indoor Dampness, Mold, and Health. The relationship of building dampness and mold to health, such as the exacerbation of asthma, is reviewed and quantified. The associated economic impacts of asthma attributable to dampness is estimated.
- Indoor Volatile Organic Compounds and Human Health. This section summarizes the state of science on the relationship between indoor volatile organic compounds — the hundreds of carbon-containing chemicals that are gases at room temperature — and irritation symptoms, allergies and asthma, and cancer risks.
All sections have downloadable scientific papers and much longer lists of references on current science. Berkeley Lab will continue to expand and update the site as the scientific consensus advances and new research moves the state of knowledge forward.
Pioneering the indoor air-quality field
The study of the indoor environment is a relatively recent area of science. The scientific community did not address this area or study how to optimize the energy efficiency of buildings in a systematic way until the 1970s. At Berkeley Lab, the division now known as the Environmental Energy Technologies Division came into existence in 1973, and indoor environment research started just a few years later.
Included in the division's broad early research portfolio were efforts to reduce building energy use by applying physics and engineering toward better lighting, windows, and envelope technologies like insulation. But the scientists of the era also recognized that if they improved energy efficiency by sealing buildings to reduce hot and cold air leaks, there might be implications for health in the indoor environment. Researchers including public health scientists, mechanical engineers, chemists, and others began the serious study of these issues.
In the 1980s and 1990s, the Indoor Environment Department had a leading program of research on indoor radon, a radioactive gas that increases the risk of lung cancer. Department scientists conducted key research showing that the pressure-driven flow of gas into buildings from radon-laden soil was the main source of indoor radon in houses with elevated concentrations. This research provided the foundation of knowledge needed to devise effective and energy-efficient radon mitigation technologies; the Department conducted pioneering research on these technologies. Berkeley Lab scientists and partner Columbia University also developed a high radon website to help homeowners estimate risks from radon exposure.
The Department has also maintained a long standing program of research on indoor volatile organic compounds, or VOCs, a family of chemicals released from building materials, furnishings, consumer products, and unvented combustion including tobacco smoke. VOCs can be an odorous source of irritation, and some are known or suspected carcinogens. Indoor concentrations of VOCs were quantified, methods were developed for quantifying VOC emissions from sources, important sources were identified, and control methods were evaluated. Current research is investigating how ozone-initiated reactions affect indoor VOCs. A recent paper reviewed the linkage of VOCs with allergies and asthma.
The Department, in partnership with UC Berkeley, has been a leader of research on indoor particles. Many studies have investigated the transport of particles from outdoors to indoors and between the indoor air and surfaces, including recent research on indoor particle resuspension from surfaces — a potentially important mechanism for human exposure. Improved methods for measuring particles were developed and current research is evaluating the particle emissions from office equipment.
Because ventilation — the replacement of indoor air with outdoor air — has such an strong impact on indoor air quality, the Department has maintained a broad portfolio of research on building ventilation. Elements include investigations of how ventilation affects people's health and work performance and the development of improved ventilation technologies and practices.
In the late 1990s, Berkeley Lab's IAQ researchers began studying the possible deliberate release of chemical and biological agents in buildings, including ways of reducing casualties from such attacks — research that predated 9/11 by several years. Afterward research in this area increased and resulted in specific tools for building managers, airport managers, and others. The Secure Buildings website (see Additional Information, below) provides advice for safeguarding buildings from these kinds of attacks, and makes software called BVAMP available to help building staff assess the security of their own structures. In partnership with Sandia National Laboratory, Berkeley Lab researchers have also developed airport protection guidelines.
Research on detecting and minimizing casualties from chem-bio attacks continues. One ongoing project focuses on developing very fast sensor networks and software that can detect and localize an attack in a building within tens of seconds, providing authorities with crucial time to evacuate and take other steps to slow the spread of airborne toxins.
With the threat of climate change, IAQ research has become even more important. In the U.S., buildings consume about 40 percent of all energy. Dramatic reductions in building energy use are essential to minimize future climate change. Building energy use and indoor air quality are strongly linked. Future research must help us learn how to provide acceptable IAQ in the increasingly energy efficient buildings of the future.
- Indoor Air Quality Scientific Findings Resource Bank
- EETD's Indoor Environment Department
- Ozone and building-related symptoms