Indoor Air Quality

A public health, housing, and equity issue in Los Angeles County

Indoor air quality affects health, safety, and quality of life. Although people spend a significant amount of their time indoors, indoor air pollution has received far less attention than outdoor air pollution in policy, regulation, monitoring, and public health planning.

Indoor air quality can be affected by everyday activities, household appliances, building materials, mold, poor ventilation, wildfire smoke, freeway pollution, industrial emissions, and other outdoor contaminants that move indoors. These conditions can increase exposure to pollutants such as nitrogen dioxide, carbon monoxide, particulate matter, volatile organic compounds, and biological contaminants, which may worsen respiratory, cardiovascular, and other health conditions. The health risks associated with indoor air contamination are not experienced equally. Health conditions, age, housing quality, income, access to care, and neighborhood pollution burdens all shape who is most likely to be impacted.

Los Angeles County is working to better understand these overlapping risks, including pollutant exposure, health sensitivity, housing conditions, and the ability to reduce or avoid exposure. This work supports healthier indoor environments, especially in communities where indoor air concerns intersect with public health, housing, climate, and environmental justice challenges.

Why Indoor Air Quality Is Overlooked

Indoor air quality is often overlooked because it is harder to see, harder to measure at scale, and split across multiple areas of responsibility. Unlike outdoor air pollution, which is addressed through clearer regulatory frameworks, Protections that can improve indoor air quality are scattered across multiple systems, including housing standards for mold, lead, pests, and habitability; building and ventilation codes; appliance safety requirements; energy efficiency programs; public health guidance on asthma and environmental health risks; and tenant protections.

This fragmentation of responsibility creates a policy blind spot. Different systems may address pieces of the issue, such as mold, lead, ventilation, appliance safety, energy upgrades, respiratory health, public education, or outdoor pollution that moves indoors, but they are not always coordinated around indoor air quality as a whole.

The impacts of indoor air contamination are also uneven. Communities with higher rates of asthma, cardiovascular disease, chronic illness, poverty, housing instability, or limited access to health care may face more serious health consequences when indoor contaminants are present.

Natural Gas and Indoor Air Concerns

Natural gas appliances, including stoves, ovens, and some heating systems, can contribute to indoor air pollution. Combustion can release nitrogen dioxide, carbon monoxide, fine particulate matter, ultrafine particles, and other pollutants that may worsen respiratory and cardiovascular conditions.

Natural gas is not the only source of indoor air pollution, but it is an important concern because it connects indoor air quality with public health, housing quality, building decarbonization, and climate resilience. These risks may be harder to reduce in older, smaller, overcrowded, or rental housing where residents have limited control over appliances, ventilation, repairs, or building upgrades.

Indoor Air Quality Sensitivity Index Overview

A tool to support equity-informed planning

The Indoor Air Quality Sensitivity Index (IAQS) was developed by the County of Los Angeles Chief Executive Office’s Anti-Racism, Diversity, and Inclusion (ARDI) Initiative in response to the Board motion Ensuring Equitable Distribution of Climate Equity Account Funds. The motion directed the Chief Executive Office, in consultation with ARDI, the Chief Sustainability Office, and the Department of Public Works, to report back with recommendations for distributing $5 million anticipated from Southern California Gas Company into a new County Climate Equity Account, as well as eligibility criteria, guidelines, and procedures for using those funds.

The IAQS was created to help the County make equity-informed decisions about where indoor air quality, public health, and decarbonization investments may be most needed. ARDI added the IAQS to the County’s Equity Explorer to make this information accessible through an existing equity data platform and to help users connect indoor air quality sensitivity with broader patterns of community need. The tool complements ARDI’s broader equity data work by applying a focused lens to indoor air quality sensitivity. It helps identify communities that may be more sensitive and vulnerable to indoor air pollution impacts, including potential exposure related to natural gas combustion when natural gas is present in the home.

The IAQS uses public health, environmental, socioeconomic, and housing data to show patterns and disparities across Los Angeles County down to the census tract level. It does not measure indoor air quality inside individual homes or determine whether a specific residence has natural gas appliances or other indoor contaminants. Instead, the tool helps County departments, local jurisdictions, community-based organizations, health systems, schools, utilities, and other partners identify where interventions can reduce cumulative burdens and improve health outcomes.

How the IAQS Works

The IAQS combines multiple factors to create a score:

Higher IAQS scores indicate greater potential sensitivity and vulnerability to indoor air pollution impacts.

Stay Informed and Engaged

Los Angeles County is continuing to refine the IAQS and welcomes feedback from community partners, public agencies, health systems, local jurisdictions, schools, researchers, and residents.

For more information about indoor air quality, the IAQS, or opportunities to provide feedback, contact Benjamin Russak at BRussak@ceo.lacounty.gov.