AirNow-International Hub >> AirNow-I Basics


AirNow in the USA

  • Year round 24/7 coverage delivers real-time data (ozone & particle pollution) for 50 states, 6 Canadian provinces and 24 U.S. national parks
  • Next-day Air Quality Index (AQI) forecasts for over 400 cities in the summer and 300 cities year-round
  • State-of-the-science information about air pollution health effects
  • Distributes air quality forecasts and data with The Weather Channel, USA Today, CNN, weather service providers, NOAA National Weather Service
  • iPhone and Android app to access air quality information right where you are
  • Enviroflash a subscription service that delivers air quality notifications to your phone or email

What is AirNow?

The U.S. EPA AirNow program is the national repository of real time air quality data and forecasts for the United States. AirNow is the vehicle for providing timely Air Quality Index (AQI) information to the public, media outlets, other federal agencies and their applications, and to the research community. The system is managed by the U.S. EPA’s Office of Air Quality Planning and Standards Outreach and Information Division, Information Transfer Group in Research Triangle Park (RTP), North Carolina. AirNow is currently hosted and operated at a contractor facility, known as the AirNow Data Management Center (DMC), which currently resides outside of RTP.


The primary purpose of AirNow is to support the U.S. EPA’s AQI Program as well as the real-time reporting and forecasting by state, local, tribal and international governments by hosting and distributing outdoor (ambient) air quality monitoring data and forecasts.

System Components

AirNow contains outdoor air quality measurements from thousands of monitoring stations across the US, Canada, and Mexico. AirNow is an interactive system, allowing government agencies to submit the data and forecasts they collect. The flow of data and information from these agencies is critical to the success of EPA’s strategic goal for maintaining and improving outdoor air quality. The AirNow multi-tiered Microsoft SQL database application is coupled with a complex web-based decision support system (AirNow-Tech) and an Application Programming Interface (API). The core AirNow infrastructure (Data Management System (DMS) and Information Management System (IMS)) is also known and marketed within EPA as AirNow-International. EPA has provided other foreign governments (including several provinces in China and Monterrey, Mexico) with the same core software operated at the AirNow DMC to assist other countries in managing air quality and promote the sharing of information.

How it works

The AirNow DMC receives, manages, and distributes real time air quality and meteorological data on an hourly basis year-round from thousands of air quality monitors from over 130 separate air agencies. The AirNow DMC allows air quality agencies to submit air quality data and forecast information to the agency for AQI product development and the sharing and dissemination of data on a national scale. The AirNow DMC converts air quality data to the AQI and shows hourly formation and movement of ground level ozone and PM2.5 with the AQI colors on EPA’s AirNow website ( The entire process, from initial data collection by air agencies to publicly available maps and information on the Internet, should occur in less than one hour. The AirNow DMC also receives 400+ current and next-day air quality forecasts from State, Local and Tribal agencies for distribution to the public: web, mobile applications, AirNow web services, email notification (via the AirNow EnviroFlash service), and other forecast products produced for and by the media.

The AirNow DMC also takes in other air quality information and data, such as meteorological, fire data, air parcel trajectories, smoke plumes and model guidance from the National Oceanic and Atmospheric Administration (NOAA) for decision support and analyses using the AirNow-Tech web application. AirNow also works with NOAA to take in a specialized satellite Aerosol Optical Depth (AOD) product initially provided by the National Aeronautic and Space Administration (NASA) to estimate fine particle pollution (PM2.5) concentrations and fuses that data layer with actual PM2.5 observations. This application, called the AirNow Satellite Data Processor, was designed to fuse other gridded datasets as well.

Reaching out to the public

The essence of AirNow is to provide members of the public with current and relevant AQI information to help them protect their health. The AirNow program has partnered with Weather Service Providers and companies that supply weather data to print, television, and online media outlets. These private companies then disseminate these data via satellite, telephone, and Internet data links to their media clients, which in turn, can show their viewers and readers current air quality conditions or forecasts.


In addition to state, local and tribal air agencies, the U.S. EPA AirNow program has partnerships with NOAA, NASA, the National Park Service (NPS), the U.S. Forest Service (USFS), other EPA offices and programs, Environment Canada, regional planning organizations, and numerous university/non-governmental institutions to further the science of air quality forecasting and public awareness through new and innovative products and data sharing.

AirNow future

Air quality information provided by the participating AirNow partner governments enables EPA and air agencies to inform the public of possible health impacts and voluntary participation in emission reduction programs such as air quality action days. The AirNow program has demonstrated over the past decade to be a dynamic and nimble program. AirNow is expected to continue to expand to include new air quality parameters, forecasts, partner agencies, innovative AQI products, tools and services. EPA also anticipates additional activity in the AirNow-International program as more countries become interested in sharing air quality information and data.

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About the AirNow Data

Map and forecast data are collected using U.S. EPA federal reference or equivalent monitoring techniques or techniques approved by state, local or tribal monitoring agencies. To maintain "real-time" maps, the data are displayed after the end of each hour.

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. They are not used to formulate or support regulations or guidance.

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).

Air Quality Notifications Subscription Services

In the U.S. you may subscribe to receive AQI information so you don’t have to go searching for it. Here you will find information on Air Quality Notifications online subscriptions and links to EnviroFlash on Twitter, AirNow RSS Feeds, and AirNow iPhone & Android Apps.

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This page was last updated on Friday, September 23, 2016