Environmental researchers say that harmful chemicals and biological agents in the air inside buildings could play a large role in people’s lifetime exposure to dangerous substances.
“What I’ve learned about the indoor environment is that it is a major location for exposure to chemicals in part because Americans spend almost 90% of their time indoors,” environmental sciences professor Barbara Turpin said Wednesday during a panel discussion at the Rayburn House Office Building.
“Indoors people are exposed to chemicals that are brought in from the outside environment and chemicals that are emitted from people’s activities, from consumer products, from building materials and furniture. They are also exposed to chemicals formed through indoor chemistry, for example, the oxidation of cigarette smoke,” said Ms. Turpin, chair of the environmental sciences and engineering department at the University of North Carolina at Chapel Hill.
When chemicals are emitted indoors, their concentration levels are much higher than outdoor levels, she said. She suspects there are more chemicals in indoor air than what is currently known, noting that an Environmental Protection Agency database lists more than 75,000 chemicals in 15,000 consumer products, most of which don’t have toxicology or exposure data.
Other environmental scientists and engineers at the panel event have conducted studies to better understand indoor air quality and chemistry in home spaces.
Marina Vance, an environmental engineer at the University of Colorado at Boulder, and her team carried out a study in a manufactured house in Austin, Texas, that examined particulate matter, volatile organic compounds, microbes and other materials. The researchers looked at how cooking, cleaning, human occupancy and use of personal care products affected air quality.
From preliminary data analysis, the team uncovered higher emissions of particulate matter or aerosols indoors, especially during cooking, Ms. Vance said, noting that interesting chemical reactions that took place during cleaning.
She said there is a need to study indoor air quality and chemistry, pointing out how construction has evolved to develop more airtight buildings, which contributes to exposure to indoor pollutants.
Third-hand smoke — the tobacco residue that sits on surfaces and dust for months after someone smokes — is another point to consider with indoor pollution, said Hugo Destaillats, staff scientist at the Lawrence Berkeley National Laboratory.
Mr. Destaillats said the burning of nicotine can produce carcinogenic substances and increase asthma hazards, adding that questions about third-hand exposure to vaping also arise.
Richard Corsi, dean of the Maseeh College of Engineering and Computer Science at Portland State University, stressed how particles land on indoor materials such as wood, vinyl, carpet and polyurethane foam in pillows and create chemical reactions.
Mr. Corsi and his researchers learned that materials such as polyurethane foam and carpet are reservoirs for chemicals. They also found that higher humidity levels lead to “gushes of chemicals” coming off of indoor materials and floor dust contaminated with a chemical that disrupts the endocrine system in the test house in Austin.
Ms. Turpin suggested establishing a regulatory agency to help address indoor pollution, commenting on how the EPA oversees outdoor pollution and on improvements in cleaning outside air over the years.
To lower indoor exposure, Mr. Corsi recommended trying to avoid sources of pollutants such as scented candles, using vents when cooking and cleaning, being on guard against any materials that contain flame retardants or plasticizers and opening windows to ventilate buildings.
Common indoor air pollutants include lead, asbestos, pesticides, nitrogen dioxide, formaldehyde (pressed wood products), radon, indoor particulate matter, volatile organic compounds and stoves, heaters, fireplaces and chimneys, according to the EPA.