About AirNow

The Air Quality Index

Every day the Air Quality Index (AQI) tells you how clean or polluted your outdoor air is, along with associated health effects that may be of concern. The AQI translates air quality data into numbers and colors that help people understand when to take action to protect their health.

You can get the AQI in different ways:

  1. At http://www.airnow.gov
  2. On Facebook and Twitter
  3. Through EnviroFlash email alerts
  4. With the free AirNow App for iPhones and Android
  5. With the customizable AirNow Widget for your organization

AirNow offers daily AQI conditions for over 400 cities:

Other AirNow Offerings

Flag Program: Schools, organizations, and the community know the daily air quality conditions by using colored flags.

AirNow Tech & API: Password-protected portals that allow state and local agencies and other researchers to submit and track air quality data.

AirNow International: A separate, international version of AirNow that allows interested countries to better manage their air quality data.

About the Data

Map and forecast data are collected using federal reference or equivalent monitoring techniques or techniques approved by the state, local or tribal monitoring agencies. To maintain "real-time" maps, the data are displayed after the end of each hour. Although preliminary data quality assessments are performed, the data in AirNow are not fully verified and validated through the quality assurance procedures monitoring organizations used to officially submit and certify data on the EPA Air Quality System (AQS).

This data sharing and centralization creates a one-stop source for real-time and forecast air quality data. The benefits include quality control, national reporting consistency, access to automated mapping methods, and data distribution to the public and other data systems.

The U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, National Park Service, tribal, state, and local agencies developed the AirNow system to provide the public with easy access to national air quality information. State and local agencies report the air quality index (AQI) for cities across the US and parts of Canada and Mexico.

AirNow data are used only to report the AQI, not to formulate or support regulation, guidance or any other EPA decision or position.

This page was last updated on Tuesday, March 29, 2016.