Reducing Indoor Exposure to Particle Pollution from Outdoor Sources: Policies and Programs to Improve Air Quality in Homes

January 2020

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Particulate matter (PM) is one of the most significant air pollutants in terms of public health impacts. Exposure to particle pollution is associated with a range of respiratory and cardiovascular symptoms and diseases, as well as premature death. While the U.S. has achieved notable progress in reducing ambient air pollution over the past several decades, communities throughout the country still experience levels of particle pollution that put people at risk.

Most exposure to outdoor particle pollution occurs inside buildings, where people spend the large majority of their time. Particles in outdoor air enter buildings through cracks and gaps in the building envelope and through natural or mechanical ventilation. Fortunately, building science provides solutions that can help reduce indoor exposure to outdoor pollutants. States, tribes, and local governments can improve public health by strengthening building design, construction, operation, and maintenance practices to reduce indoor exposures, especially for people who are most vulnerable to the health effects of particle pollution. By taking action now, policymakers and agency officials can increase the resilience and adaptive capacity of individuals and buildings in the years ahead.

This report supports such efforts by discussing a range of policy and program opportunities for reducing indoor PM exposure in residential buildings and, to a more limited extent, school buildings. While the report is focused on particulate matter generated outdoors, people are also exposed to particles emitted indoors. Policy and program strategies tailored to specific indoor sources – e.g., enhanced exhaust ventilation in kitchens or restrictions on wood-burning devices – are also important and will be addressed in future ELI reports.

This report is organized into three chapters:

  • Chapter One (Introduction) – provides background on the health effects of particulate matter, the current particle pollution problem in the U.S., and technical solutions for reducing indoor exposures.
  • Two (New Construction) – discusses building codes and other policies that can advance key technical practices for reducing indoor exposure to outdoor PM in new homes, highlighting California's recent adoption of building code requirements for high-efficiency air filtration. The chapter addresses new construction generally, as well as the construction of new homes near local pollution sources such as major roadways.
  • Chapter Three (Existing Homes) – discusses policies and programs for reducing PM exposures in existing homes, including financial assistance programs that could be made available to assist vulnerable households. The chapter focuses on reducing indoor PM exposures generally and addressing extreme PM events, such as wildfires. 

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