CMAQ is an acronym for the Community Multiscale Air Quality Model, a sophisticated three-dimensional Eulerian grid chemical transport model developed by the

US EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

for studying air pollution from local to hemispheric scales. EPA and state environmental agencies use CMAQ to develop and assess implementation actions needed to attain National Ambient Air Quality Standards (NAAQS) defined under the Clean Air Act. CMAQ simulates air pollutants of concern—including

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

, particulate matter (PM), and a variety of air toxics — to optimize air quality management. Deposition values from CMAQ are used to assess ecosystem impacts such as

eutrophication Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...

and

acidification Acidification may refer to: * Ocean acidification, decrease in the pH of the Earth's oceans * Freshwater acidification, atmospheric depositions and soil leaching of SOx and NOx * Soil acidification, buildup of hydrogen cations, which reduces the ...

from air pollutants. In addition, the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

uses CMAQ to produce twice-daily forecast guidance for ozone air quality across the U.S. CMAQ unites the modeling of meteorology, emissions, and chemistry to simulate the fate of air pollutants under varying atmospheric conditions. Other kinds of models—including crop management and hydrology models— can be linked with the CMAQ simulations, as needed, to simulate pollution more holistically across environmental media. CMAQ is developed and maintained by scientists in EPA’s Office of Research and Development, and new versions of the software are made publicly available through regular public releases. CMAQ may also refer to the Congestion Mitigation and Air Quality Improvement Program, a program of the

United States Department of Transportation The United States Department of Transportation (USDOT or DOT) is one of the executive departments of the U.S. federal government. It is headed by the secretary of transportation, who reports directly to the President of the United States and ...

References

Atmospheric dispersion modeling Air pollution Environmental engineering Industrial emissions control {{ecology-stub