AIRNow-International: The Future of the United States Real-time Air Quality Reporting and Forecasting Program with GEOSS participation

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Figure 1. Number of people living in areas with poor air quality in the United States in 2007.

John E. White

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711, USA


The goal of AIRNow-International is to strengthen relationships among governments and international organizations by sharing the technology to transform air quality data into vital information. AIRNow-International is poised to become the centerpiece of the United States Environmental Protection Agency‘s (EPA) real-time air quality reporting and forecasting program. The system is a redesign of the AIRNow information technology infrastructure that distributes current air quality information for the United States and Canada. The AIRNow-International software suite is being built to support and embrace the Global Earth Observation System of Systems (GEOSS) concept.

AIRNow-International is more than just an information technology system, however. Establishing partnerships with other organizations and governments will facilitate the broader sharing of air quality information around the globe. Multi-language capability and other improvements to the software suite will permit Shanghai, China to pilot the first AIRNow-International system for the public reporting of current air quality at the 2010 World Expo.

Keywords: EPA AIRNow Air Quality Data Forecasts GEOSS


Air quality is a worldwide problem. Emission sources such as motor vehicles, power plants, industry, along with individual actions all contribute to air pollution. Figure 1 illustrates that over 150 million people in the United States alone live in areas designated as nonattainment for the National Ambient Air Quality Standards (EPA, 2008).

Providing people with timely air quality information and educating them about the links between pollution sources, air quality, and health, can lead to a healthier and better-informed society. The ability to provide real-time data and air quality information and forecasts is critical to protecting public health. For many individuals—children, outdoor workers, and those who suffer from respiratory problems or cardiac conditions—knowing the quality of the air they breathe affects the quality of their lives and how they plan their daily activities. EPA’s AIRNow program has fulfilled this need for the past decade in the United States.

Developing countries are installing air quality monitoring networks and beginning to forecast air pollution levels to provide information to government officials and citizens. Effectively communicating information, educating the public about air quality conditions, and exchanging data with other organizations and systems will be critical next steps.

These communication efforts are consistent with the World Health Organization’s Guidelines for Air Quality (WHO, 2005), which state that public information systems are increasingly important to raise awareness, warn of pollution episodes, and advise susceptible populations. Such efforts are also consistent with the Group on Earth Observations (GEO) goals of building GEOSS (GEOSS, 2009) to provide comprehensive, coordinated Earth observations from countries, transforming the data they collect into vital information for society. Attaining these goals will require clearing a number of hurdles, both in developed and emerging countries. These include a lack of software systems and knowledge about how to effectively communicate and exchange air quality information to the public. Several countries have expressed interest in obtaining EPA’s U.S. AIRNow system; however, in its current configuration, the system is not easily distributable. The new AIRNow-International system, leveraging 10 years of working knowledge, experience, and technology, is being built to address this challenge.

This paper describes the AIRNow program in the United States and the transition to newer technology, the Shanghai pilot project, the technology and services of the updated software system, the building of future relationships with AIRNow partners and the sharing of environmental information globally within AIRNow and GEOSS.

The EPA AIRNow Program

AIRNow has proven to be a successful model for communicating air quality conditions and forecasts to the U.S. public (Wayland et al., 2002). It has become a national resource used by decision makers, the media, and the public to access real-time air quality information (see In addition to EPA, AIRNow is supported by state, local and other federal agencies, all of which voluntarily submit air quality data each hour. AIRNow displays air quality conditions using animated maps with colors that correspond to the Air Quality Index (EPA, 1999), official next-day forecasts for U.S. cities, and news stories and special air quality episodes coverage.

Figure 2. The United States EPA Air Quality Index.

The United States Air Quality Index

The Clean Air Act required EPA to establish a uniform index for reporting air quality data to the public. The agency’s Air Quality Index (AQI), issued in 1999, provides a simple, uniform system to report levels of five of the pollutants for which EPA sets national air quality standards. The AQI converts a measured pollutant concentration to a number on a scale of 0 to 500 as shown in Figure 2. An AQI above 100 indicates that the air may be unhealthy and poses a health concern for some people. The AIRNow program provides a majority of air quality products using the AQI.

Having a daily or sub-daily AQI for several pollutants requires having a real-time reporting system. Real-time and forecast air quality information plays an important role in informing the public about potentially harmful conditions and fostering successful voluntary emission reduction programs. Many U.S. cities use air quality forecasts to declare air quality action days. Some cities offer incentives such as free mass transit on such days to reduce the number of cars on the highway during poor air quality days (True North Research, 2004)

Figure 3. EPA AIRNow Program Overview.

History of the EPA AIRNow Program

The Maryland Department of the Environment began mapping ozone air quality in 1994. A larger regional effort followed, coordinated by EPA’s New England office (Boston). In 1997 U.S. EPA AIRNow was able to build upon these earlier concepts and create a national-scale program for reporting real-time air quality information to the public using the AQI. Currently AIRNow ingests real-time ozone and particle pollution data delivered from more than 2,000 monitors from all the states and Canadian provinces on an hourly basis and receives next-day air quality forecasts for more than 325 cities in the United States. Prior to the development of the AIRNow program, a central repository for the real-time air quality data in the U.S. did not exist.

As shown in Figure 3, the core of the AIRNow community consists of more than 120 stakeholders (local, state, federal, tribal, and provincial agencies) that deliver local data and provide local air quality forecasts to the AIRNow Data Management Center (DMC).

The AIRNow DMC serves as the centralized hub for acquiring, processing, quality controlling, and distributing the data and information. AIRNow information and data are distributed to media outlets, health organizations, and ultimately to the public. Data flow from the agencies to the public is quick and highly automated; air quality readings are delivered to the AIRNow DMC in the first 20 minutes of each hour. Software automatically processes and quality-controls the data in real-time, generates maps and other data files, sends status e-mails to the stakeholder agencies, and distributes the products to media outlets and the public.

Air quality forecasts are issued by the state or local air quality agencies who predict maximum AQI levels for the current-day and next-day periods. The forecasts are consolidated at the DMC and redistributed. The AIRNow program has developed relationships with media companies, commercial weather service providers, and public communication organizations to get AIRNow information to the broader public. Commercial weather service providers redistribute the real-time AQI maps and AQI forecasts to hundreds of television stations, newspapers, and Web sites across the United States, such as the example shown below in Figure 4.

Figure 4. Local TV station (WDBJ) in Richmond, VA using AIRNow AQI maps as part of the evening news weathercast.


The current AIRNow infrastructure was developed in 2001. Given the recent technological advances and proliferation of Web 2.0 applications, improvements to the AIRNow system have become necessary to meet these demands and take advantage of new developments in information dissemination. Overhauling the system also provides the opportunity to create a software package that interested countries and organizations could readily implement. While the system is geared toward air quality observations, the fundamental nature of the package is real-time environmental data reporting.

The new U.S. EPA AIRNow system, which became operational in Spring 2009, is based on the AIRNow-International system software but with an added forecasting module to store the forecast information provided by U.S. air agencies. EPA’s AIRNow program will use the AIRNow-International software to help ensure the sustainability of the system. The software can be made available to organizations that are interested in distributing data to the public, as well as exchanging data with other organizations. The heart of the system is real-time data reporting, so agencies could leverage the technology for communicating data about other environmental media. The software is critical to reaching the larger AIRNow International Program goal of developing a community of organizations that collect, process, exchange, and communicate air quality observations and forecasts. Collaboration helps all organizations and countries learn from each other about methods, challenges, and approaches in collecting, processing, analyzing, and communicating environmental observations and forecasts. An overview of this concept is displayed in Figure 5.

Shanghai ‰ÛÒ Initial Partner of AIRNow-International

The Shanghai Environmental Protection Bureau (EPB) and Environmental Monitoring Center (EMC) will be the first AIRNow partners to install and operate the AIRNow-International system. Shanghai approached EPA in 2004 for assistance in implementing a real-time reporting and forecasting system. However, until AIRNow-International applied for funding through EPA’s Office of Research and Development as a GEO project in 2007, technical assistance to Shanghai was limited to air quality forecasting training and meetings.

Figure 5. AIRNow-International Concept.

Shanghai was a logical choice for a pilot, due to its existing monitoring network, capability in analyzing and reporting data, and determination to improve its air quality forecasting and modeling expertise. As the first AIRNow-International partner, Shanghai assisted in the programming and testing efforts, and provided crucial input into the design phase. The beta install took place in Shanghai in Spring 2009. The AIRNow-International project will enable Shanghai to communicate air quality information when the city hosts the 2010 World Expo. Extensive testing will take place up to the start of the Expo.

AIRNow-International Specifications

The AIRNow-International software consists of a suite of modules (software programs and schedulers) centered around a relational database that stores data, site information, metadata, program settings, and status and event log information. The system performs data processing, quality control, system diagnostic monitoring, GIS mapping, and distribution. AIRNow-International is based upon the Microsoft .NET 2.0 framework, using ESRI software and Microsoft SQL Server databases to support the system. AIRNow-International initially will have some multi-language capability (English, Chinese, Portuguese, and Spanish.).

The components of AIRNow-International, illustrated below in Figure 6, includes a SQL database, Data Management System (DMS) to process and quality control data, mapping service to generate GIS-based maps, and an information module to distribute and share information. The Administration module allows for full control of data ingests, processing, quality control, mapping, and data sharing.

In addition to plotting surface air quality data, the mapping module could incorporate other data sources in regions with limited air quality monitoring coverage. U.S. EPA is collaborating with the NASA SERVIR project in Panama. SERVIR is a regional visualization and monitoring system that integrates Earth observations (e.g. satellite imagery) and forecast models together with in-situ data for decision makers. AIRNow-International and SERVIR collaboration could permit greater insights into the intensity and spatial coverage of air pollution by integrating data satellite sources (aerosol optical depth, fire hot spots, and visible imagery) with air quality observations.

Figure 6. AIRNow-International Functional Design.

The Informational Service module will distribute data in the following file formats and Web services: 1) Comma Separated Value (CSV), NetCDF, ESRI files (in ESRI Raster and Shapefile formats), OGC Web services (Web Mapping Service, Web Feature Service, Web Coverage Service), and Google Earth (KML) files.

Specific design details and elements of the system can be found in the AIRNow-International Draft Specifications Document, which can be obtained by contacting the author.

GEOSS Participation

The Group on Earth Observations (GEO) is a voluntary partnership of governments and international organizations leading an international effort to build a Global Earth Observation System of Systems to support environmental decision making. GEO is bridging international efforts to assemble the GEOSS. This emerging public infrastructure is interconnecting a diverse and growing array of instruments and systems for monitoring and forecasting changes in the global environment, including air quality. The intention of this ‰ÛÏsystem of systems‰Û is to provide data support for policymakers, resource managers, researchers, decision makers and the public.

AIRNow-International addresses the key GEO societal benefit of understanding environmental factors affecting human health and well-being. After AIRNow-International implementation in the United States, GEOSS will be supplied with robust information via service-oriented software and data components and services. The GEOSS framework can be leveraged by air quality agencies around the world to provide the necessary tools for countries around the globe to measure, evaluate, and distribute air quality information not only to further research, but more importantly to protect public health. Analysts worldwide will then be able to fuse models and disparate observations to arrive at improved estimates of current air quality conditions, forecasts, and historical trends accessed through GEOSS.

In addition, the AIRNow-International program will support the GEO initiative of the Common Alerting Protocol (CAP) to integrate air quality alerts into CAP’s all-hazards, all-media approach. CAP is a standardized format for exchanging public warnings, which can be consistently disseminated simultaneously over various warning systems and applications.

The International Air Quality Community and Future Partners

Air quality, meteorological, and health researchers are key participants within the U.S. AIRNow community, providing new methods and techniques for improving real-time data collection, new forecasting methods, and new insights and studies into the health impacts of air pollution. One of the goals for AIRNow International is to help set the stage for an international dialogue on real-time data ‰ÛÒ standards, methods, applications, and more.

AIRNow-International and established European and other systems can be the catalysts for world-wide integration and standardization of real-time air quality data. With agreed upon standards for the sharing of data, these air quality reporting systems could interface seamlessly with each other and therefore allow for worldwide sharing of air quality data. This availability of data will be beneficial for researchers and give citizens across the globe access to an important health resource.

AIRNow-International will depend on broad international support and GEOSS participation. To encourage participation in this community, AIRNow-International will largely utilize an open-source software development methodology. Partner nations will have access to source code and have the ability to share system modifications and new features with the AIRNow-International community. Partners are expected to participate in the community by sharing data and expertise, including add-on products or modules that are developed. Partners will have input into future development and access to new science and technologies. EPA is establishing criteria for selecting future AIRNow partners.

EPA will develop a Web site to provide manuals, detailed installation and configuration instructions and examples, Web tutorials that show the features and functions of the system, and a portal for sharing information. The GEO community of practice will be able to use the Web site to share experiences about data processing, mapping, and public communication, to answer questions and to resolve issues to help encourage collaboration and build capacity to facilitate a sustainable system.


Enabling and promoting environmental data sharing through efforts such as GEOSS, AIRNow, and other related reporting systems could lead to an improved understanding of pollution globally. As nations grow in their monitoring and data reporting expertise, forecasting programs can be implemented, and this valuable information can be more readily accessed and shared to benefit all. Explicit data exchange protocols and guidelines with standards and conventions and a willingness to share is needed to be successful in this endeavor.

Once the AIRNow-International pilot in Shanghai is completed, the system will be available to other interested organizations.


Environmental Protection Agency, Air Quality Index Reporting: Final Rule 40 CFR Part 58, United States Federal Register Vol. 64, no. 149. August 1999.

Environmental Protection Agency, Report on National Air Quality – Status and Trends through 2007, EPA-454/R-08-006. November 2008.

GEOSS, the Group on Earth Observations Work Plan. 2009. and

True North Research, Spare the Air Study Summer 2004 Ozone Season, pp74. November 2004.

Wayland R.A., J.E. White, P.G. Dickerson, and T. Dye, ‰ÛÏCommunicating real-time and forecasted air quality to the public: current state and future plans,‰Û EM, 28-36.December 2002.

WHO Regional Publications, European Series, 2005. Report on Air quality guidelines.