Green Housing Boasts Clean Indoor Air

Green architecture aims to lower the energy consumption of buildings and promote sustainable building materials, saving operating costs and natural resources in the process. But this green movement also may mean better health for the people living inside the buildings. Researchers found that public housing built to green standards had lower levels of airborne pollutants than conventional dwellings (Environ. Sci. Technol. 2014, DOI: 10.1021/es501489u).

In the past, architects made buildings energy efficient by tightening them up, limiting the transfer of air from the inside to the outside and vice versa. “There’s an energy cost of moving more air in an apartment,” says Gary Adamkiewicz of the Harvard School of Public Health, who led the new study. However, one consequence of reducing air flow is that pollutants generated in the home, such as cigarette smoke and cooking by-products, tend to linger in the air. Poor indoor air quality is linked to a variety of health conditions, particularly among people living in low-income housing. Adamkiewicz points out that asthma rates are significantly higher among people living in public housing compared to the general population.

Green building designs try to get around this problem by implementing ventilation systems that circulate air efficiently. “But there hasn’t been data to demonstrate tangible improvements in air quality,” Adamkiewicz says. Luckily for his team, recent changes to low-income housing in Boston offered an ideal natural experiment where they could test the effects of green housing on air quality and health outcomes.

In 2011, the Boston Housing Authority began redeveloping large public housing developments in the South Boston neighborhood. Today, there is a mix of the original buildings, dating back to the 1940s, and newer ones certified by the U.S. Green Building Council’s Leadership in Energy & Environmental Design (LEED) program. These certified green buildings have features such as advanced ventilation systems that protect against heat loss, electric stoves instead of gas ones, and a smoke-free policy.

The researchers identified 13 families living in conventional buildings and 18 families who had recently moved from conventional housing into green housing. The team asked the inhabitants about their health and then sampled the indoor air of the participants’ homes for seven days. Those living in green buildings reported less fatigue and fewer symptoms related to poor respiratory health. Plus, the researchers found significantly lower levels of air pollutants in green versus conventional homes: 57% less particulate matter measuring less than 2.5 μm in diameter, 65% less nitric dioxide, and 93% lower levels of nicotine. But levels of formaldehyde and carbon dioxide did not differ between the two types of housing.

Patrick N. Breysse, a public health researcher at Johns Hopkins University, calls the study important because it shows that green housing clearly contributes to reductions in indoor air pollutants and to associated improvements in residents’ health. He adds that the results suggest the need for larger studies that can look at, for example, whether green housing can improve the health of people with asthma.

Brendan Owens of the U.S. Green Building Council says the study provides helpful feedback for his organization, suggesting ways to improve their standards. In particular, the similarity in formaldehyde levels between the green and conventional housing is an area Owens wants to see improved. “A lower threshold of formaldehyde in products may be in order,” he says.