The Need for US Indoor Air Quality Guidelines

This report by RMI argues for the establishment of comprehensive indoor air quality (IAQ) guidelines in the United States to protect public health and inform building decarbonization. It examines the health risks of indoor pollutants, compares indoor and outdoor air regulation, reviews international and domestic examples of IAQ guidelines, and outlines how such guidelines can be applied to product safety, building codes, and certifications.

• Indoor air quality is a critical public health issue because people spend nearly 90% of their time indoors, where pollutant concentrations can be two to five times higher than outdoors. Vulnerable populations, including children, the elderly, and low-socioeconomic households, face disproportionately higher risks. Specifically, homes with gas stoves may have nitrogen dioxide (NO2) levels 50 to 400 times higher than those with electric stoves.
• The United States lacks comprehensive federal IAQ guidelines, though the EPA has set a voluntary consensus standard for radon at 4 picocuries per liter (pCi/L). While the Clean Air Act (CAA) regulates outdoor 'ambient air,' it is not precise for indoor environments. The report notes that CAA pollutant controls from 1970 to 2020 reduced the six most common ambient pollutants by 78%, resulting in over $2 trillion in avoided health costs in 2020.
• The EPA has authority under Title IV, Section 403 of the Superfund Amendments and Reauthorization Act (SARA) to gather information, coordinate research, and disseminate information on indoor air. The report suggests this authority, along with the model provided by the Indoor Radon Abatement Act of 1988, could be used to establish broader IAQ guidelines.
• Various US states have implemented fragmented IAQ guidelines. California's Air Resources Board (CARB) published limits in 2005 and is updating NO2 guidelines as of May 2023. Illinois has voluntary guidelines under the Indoor Air Quality Act of 1994, and Texas established voluntary guidelines for government buildings and public schools in 2002. Other states, such as Indiana and Ohio, have set maximum exposure limits only for CO2 in specific settings.
• International models for IAQ guidelines exist in over 38 countries. The World Health Organization (WHO) provides non-binding guidelines to inform policy, though the report notes that some recent WHO reviews omitted indoor-specific pollutant exposures. Health Canada has provided residential guidelines since 1987, including a 2021 guideline for carbon dioxide (CO2) and action-based guidance for fine particulate matter (PM2.5) because no safe indoor level was found.
• IAQ guidelines can be applied across multiple sectors to improve health and safety: product safety agencies (like the CPSC) can set emission benchmarks for appliances; building codes can incorporate ventilation and efficiency requirements; and voluntary certification programs (such as LEED or WELL) could shift from ambient air standards to indoor-specific guidelines.
• Consumer interest in indoor air quality has risen since the COVID-19 pandemic, with over 53% of US consumers stating it is a greater concern than before. This is evidenced by increased sales of low-cost monitors and a reported interest by 76% of consumers in an IAQ 'rating system' for buildings.

APA

Prescott, N. (2023). The Need for US Indoor Air Quality Guidelines. RMI. https://rmi.org/resources/the-need-for-us-indoor-air-quality-guidelines/

Chicago

Prescott, Nina. The Need for US Indoor Air Quality Guidelines. RMI, 2023. https://rmi.org/resources/the-need-for-us-indoor-air-quality-guidelines/.

Wikipedia

{{cite report |last1=Prescott |first1=Nina |title=The Need for US Indoor Air Quality Guidelines |publisher=RMI |date=11 October 2023 |url=https://rmi.org/resources/the-need-for-us-indoor-air-quality-guidelines/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{prescott2023need, author = {Prescott, Nina}, title = {{The Need for US Indoor Air Quality Guidelines}}, institution = {RMI}, year = {2023}, month = oct, url = {https://rmi.org/resources/the-need-for-us-indoor-air-quality-guidelines/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }