Data and Statistics

The California Air Resources Board (ARB) gathers air quality data for the State of California, ensures the quality of this data, designs and implements air models, and sets ambient air quality standards for the state. ARB compiles the state's emissions inventory and performs air quality and emissions inventory special studies.

The Air Quality Data page provides access to ambient air quality data, maps of areas that violate the national and state air quality standards, and maps of the ambient air quality monitoring network.

The ARB uses the Emissions Inventory and Air Quality Models to evaluate air quality and reduce emissions in each of the 35 local air districts.

Air Quality Data

The main page for data, statistics and other information on California’s air quality.

Today's Air Quality

The AQMIS2 web page provides access to near real time air quality data for California. This page provides links to other products including week-at-a-glance statistics and hourly air quality data.

Air Quality Data Statistics

The iADAM web page lets you see historical summaries indicating how good or bad the air quality is throughout California for a number of pollutants. For example, you can view the number of days per year that air quality is deemed to be unhealthy, and how this has changed over the years. Toxics data summaries are also available.

Air Quality Monitoring Network

Here you will find a listing of the air quality monitoring sites in California and what pollutants are monitored at each site. Tables indicate how many years of data are available for each site. Includes maps of the site locations.

Standards and Designations

The ARB designates areas of California for each criteria pollutant based on recent ambient air quality data. The Area Designations provides information regarding the designation areas in California with respect to the State Ambient Air Quality Standards. Areas can be designated as attainment, nonattainement, or unclassified.

Current Air Quality Standards

This page describes California’s ambient air quality standards currently in effect.

Standards Under Review

This page provides information about the current review of California ambient air quality standards mandated by the Children's Environmental Health Protection Act (CEHPA, Senate Bill 25, Escutia, 1999).

Air Quality Index (AQI)

The U.S. EPA's Air Quality Index (AQI) provides accurate, timely and easily understandable information about daily levels of air pollution.

Emission Inventory

An emission inventory is an estimation of air pollution that helps us answer questions about what pollutants are being emitted, how much is being emitted, and where they are coming from.

Air Quality Models

Air quality modeling software and associated documentation.

Southern California Studies

Air quality modeling studies in Southern California.

Central California Studies

Air quality modeling studies in Central California.

Frequently Asked Questions

Easy to understand information for commonly asked questions about ambient air quality in California. Learn how air quality varies statewide. Learn how to tell how polluted the air is where you live and work.

Transport

This web area describes the State's triennial transport assessment program including the identification of transport couples and the associated mitigation regulations.

Demographic Data

California Demographic and financial data from the Department of Finance.

ARB Programs