Researchers at the University of Pittsburgh School of Public Health found that combining affordable air filtration with community-based environmental health education improved indoor air quality in homes in Pittsburgh’s Homewood neighborhood.
The findings demonstrate how practical interventions can help communities reduce exposure to harmful air pollutants.
Published in May in the Journal of Environmental Health, the pilot study combined indoor and outdoor air pollution monitoring, environmental health literacy training, clinical asthma tracking and in-home air filtration interventions among adults with asthma living in or near Homewood.
“Air pollution is heavily associated with adverse respiratory and cardiovascular outcomes,” said Nesta Bortey-Sam, PhD, associate professor of environmental and occupational health. “We wanted to analyze local air pollution trends within Homewood because the community experiences significantly higher rates of these illnesses and asthma-related emergency department visits and hospitalization than many other neighborhoods in the Pittsburgh area.”
The researchers selected Homewood based on data from the CDC Environmental Justice Index showing the neighborhood has disproportionately high prevalence of pre-existing chronic disease burden, including asthma and coronary heart disease. While outdoor air pollution has been widely studied, less is known about the air people breathe inside their homes, where the U.S. Environmental Protection Agency estimates people spend about 90% of their time.
To better understand indoor exposures, air quality monitors were installed inside participants’ homes for four weeks. After collecting two weeks of baseline data, the team installed either high-efficiency MERV 13 HVAC filters or portable HEPA air purifiers, depending on each home’s heating and cooling system. Participants also received environmental health literacy training and tracked their asthma symptoms and lung function.
The researchers focused primarily on fine particulate matter, or PM2.5—tiny airborne particles measuring 2.5 micrometers or smaller that can penetrate deep into the lungs and even enter the bloodstream. Common outdoor sources include vehicle emissions, industrial pollution, wildfire smoke and tobacco smoke, while common indoor sources include cooking, burning candles and using air fresheners.
Following the interventions, indoor PM2.5 concentrations declined by an average of 21% across participating homes. Although the overall reduction was not significant because of the study’s small sample size, six of the eight homes experienced improved air quality, and three showed statistically significant reductions.
“We found that the homes starting with the highest baseline pollution levels experienced the greatest overall benefit from the interventions,” said Miranda Aman, MPH, a Public Health Practice PhD student. “At the same time, one home experienced increased pollution, reinforcing that environmental interventions are heavily behavior-dependent. Factors like pets, household activities and airflow patterns can all influence indoor air quality.”
“We know improving indoor air quality is only one piece of the solution, but we're encouraged that it's a controllable and relatively affordable option that can lead to measurable respiratory health improvements.” said Tina Ndoh, PhD, associate professor of environmental and occupational health and director of the Center for Public Health Practice at Pitt Public Health.
In future research, the team plans to expand the study by recruiting more participants, extending the monitoring period and strengthening partnerships with the Homewood Community Engagement Center.
“This should not be a ‘one-and-done’ study where we extract data and leave the community,” Bortey-Sam said. “We want to drive sustainable public health changes.”
Other authors of the study include Sally Wenzel, James Fabisiak and Allison Koller, all of the University of Pittsburgh School of Public Health
-Ava Dzurenda