Another invisible enemy indoors: COVID-19, human health, the home, and United States indoor air policy.

After the emergence of the respiratory virus SARS-CoV-2 (COVID-19), many exposure and environmental health scientists promptly recognized the potentially catastrophic public health ramifications of concurrent infectious and air pollution-mediated disease. Nevertheless, much of this attention has been focused on outdoor interactions. Each year, 3.8 million people worldwide prematurely die from illnesses attributable to indoor air. Hence, poor household indoor air quality is a long-standing public health issue with even greater relevance now that many individuals are spending more time at home. At present, the Environmental Protection Agency does not regulate indoor air, and state-level legislation has resulted in a patchwork of national coverage. Here, we describe common sources of indoor air pollution, the health impacts of indoor pollutants, and populations disparately impacted by COVID-19 and poor indoor air quality. Furthermore, we detail the need for better legislation that promotes the integrity of the indoor air environment, and what individuals can do to personally protect themselves as we await more comprehensive indoor air legislation.