New Report Offers Policy Strategies for Reducing Indoor Exposure to Outdoor Pollutants

February 2020

(Washington, D.C.): Particulate matter (PM) remains one of the most significant air pollutants in terms of public health impact. PM exposure affects the cardiovascular, respiratory, and nervous systems, causing illness and premature death. And recent research has shown that health effects are associated with PM levels below current federal air quality standards. While the health risks from particle pollution have been understood for some time, it is less widely recognized that most of our exposure occurs indoors.

Because particles in outdoor air enter buildings through cracks and gaps in the building and through natural or mechanical ventilation, people are exposed to particle pollution from outdoor sources while they are inside their homes, schools, and workplaces—the same locations where people spend the majority of their time. “Fortunately, building science provides solutions that can help reduce indoor exposure to outdoor pollutants,” noted Tobie Bernstein, Director of the Environmental Law Institute’s Indoor Environments and Green Buildings Program.

A new ELI report, Reducing Indoor Exposure to Particle Pollution from Outdoor Sources: Policies and Programs to Improve Air Quality in Homes, offers a range of policy and program opportunities for reducing exposures in homes and also highlights strategies for addressing school environments. 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,” added Bernstein, lead author of the new report.

The report is organized into three chapters:

  • Introduction: Chapter One provides background on the health effects of particulate matter, the current particle pollution problem in the United States, and technical solutions for reducing indoor exposures.
  • New Construction:  Chapter Two 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.
  • Existing Homes: Chapter Three discusses policies and programs for reducing PM exposures in existing homes, including financial assistance programs that could be made available to assist vulnerable households. This discussion is relevant to indoor PM exposures generally and to extreme PM events, such as wildfires.

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 requirements for wood-burning devices – are also important and will be addressed in future reports from ELI.

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