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An airshed is a part of the atmosphere that behaves in a coherent way with respect to the dispersion of emissions. It typically forms an analytical or management unit. Also: a geographic boundary for air-quality standards.

Alternatively - an airshed is a geographical area where local topography and meteorology limit the dispersion of pollutants away from the area. [1]

Topography The study of the shape and features of the surface of the Earth and other observable astronomical objects

Topography is the study of the shape and features of land surfaces. The topography of an area could refer to the surface shapes and features themselves, or a description.

Meteorology Interdisciplinary scientific study of the atmosphere focusing on weather forecasting

Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics and more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved.

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Environmental engineering is the branch of engineering which applies scientific and engineering principles to:

Environmental science The integrated, quantitative, and interdisciplinary approach to the study of environmental systems.

Environmental science is an interdisciplinary academic field that integrates physical, biological and information sciences to the study of the environment, and the solution of environmental problems. Environmental science emerged from the fields of natural history and medicine during the Enlightenment. Today it provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems.

Air pollution in British Columbia

Air pollution is a concern in British Columbia, Canada because of its effects on health and visibility. Air quality is influenced in British Columbia (BC) by numerous mountain ranges and valleys, which complicate atmospheric pollution dispersion and can lead to high concentrations of pollutants such as particulate matter from wood smoke.

Finnish Meteorological Institute government agency responsible for gathering and reporting weather data and forecasts in Finland

The Finnish Meteorological Institute is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport and Communications but it operates semi-autonomously.

Norwegian Institute for Air Research foundation

The Norwegian Institute for Air Research or NILU is one of the leading specialized scientific laboratories in Europe researching issues related to air pollution, climate change and health. NILU has a staff of scientists, engineers and technicians with specialized expertise for working on air pollution problems. The staff do more than two hundred projects annually for research councils, industries, international banks and local, national and international authorities and organizations. Its director since 2009 is Kari Nygaard.

Atmospheric dispersion modeling

Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that include algorithms to solve the mathematical equations that govern the pollutant dispersion. The dispersion models are used to estimate the downwind ambient concentration of air pollutants or toxins emitted from sources such as industrial plants, vehicular traffic or accidental chemical releases. They can also be used to predict future concentrations under specific scenarios. Therefore, they are the dominant type of model used in air quality policy making. They are most useful for pollutants that are dispersed over large distances and that may react in the atmosphere. For pollutants that have a very high spatio-temporal variability and for epidemiological studies statistical land-use regression models are also used.

Swedish Meteorological and Hydrological Institute Swedish administrative authority

The Swedish Meteorological and Hydrological Institute is a Government agency in Sweden and operates under the Ministry of the Environment. SMHI has expertise within the areas of meteorology, hydrology and oceanography, and has extensive service and business operations within these areas.

Royal Netherlands Meteorological Institute research institute

The Royal Netherlands Meteorological Institute is the Dutch national weather forecasting service, which has its headquarters in De Bilt, in the province of Utrecht, Netherlands.

The UK Dispersion Modelling Bureau is part of the Met Office which is the UK's national weather and meteorological service. The meteorologists in the bureau are among the UK's leading experts in areas such:

The Atmospheric Dispersion Modelling Liaison Committee (ADMLC) is composed of representatives from government departments, agencies and private consultancies. The ADMLC's main aim is to review current understanding of atmospheric dispersion and related phenomena for application primarily in the authorization or licensing of pollutant emissions to the atmosphere from industrial, commercial or institutional sites.

The National Atmospheric Release Advisory Center (NARAC) is located at the University of California's Lawrence Livermore National Laboratory. It is a national support and resource center for planning, real-time assessment, emergency response, and detailed studies of incidents involving a wide variety of hazards, including nuclear, radiological, chemical, biological, and natural emissions.

CALPUFF is an advanced, integrated Lagrangian puff modeling system for the simulation of atmospheric pollution dispersion distributed by the Atmospheric Studies Group at TRC Solutions.

DISPERSION21 is a local scale atmospheric pollution dispersion model developed by the air quality research unit at Swedish Meteorological and Hydrological Institute (SMHI), located in Norrköping.

The Czech Hydrometeorological Institute (CHMI) is within the Environmental Ministry of the Czech Republic. The head office and centralized workplaces of the CHMI, including the data processing, telecommunication and technical services, are located at the Institute's own campus in Prague. The CHMI has five major divisions:

The South Coast Air Quality Management District, also using the acronym SCAQMD, formed in 1976, is the air pollution agency responsible for regulating stationary sources of air pollution in the South Coast Air Basin, in Southern California. The separate California Air Resources Board is responsible for regulating mobile sources in the air basin.

The MEMO model is a Eulerian non-hydrostatic prognostic mesoscale model for wind-flow simulation. It was developed by the Aristotle University of Thessaloniki in collaboration with the Universität Karlsruhe. The MEMO Model together with the photochemical dispersion model MARS are the two core models of the European zooming model (EZM). This model belongs to the family of models designed for describing atmospheric transport phenomena in the local-to-regional scale, frequently referred to as mesoscale air pollution models.

The Journal of Environmental Engineering is a monthly engineering journal published by the American Society of Civil Engineers. The journal covers interdisciplinary aspects of the research and practice in environmental engineering, systems engineering, and sanitation. Papers focus on design, development of engineering methods, management, governmental policies, and societal impacts of wastewater collection and treatment; the fate and transport of contaminants on watersheds, in surface waters, in groundwater, in soil, and in the atmosphere; environmental biology, microbiology, chemistry, fluid mechanics, and physical processes that control natural concentrations and dispersion of wastes in air, water, and soil; nonpoint-source pollution on watersheds, in streams, in groundwater, in lakes, and in estuaries and coastal areas; treatment, management, and control of hazardous wastes; control and monitoring of air pollution and acid deposition; airshed management; and design and management of solid waste facilities. A balanced contribution from consultants, practicing engineers, and researchers is sought on engineering solutions, and professional obligations and responsibilities.

Air quality law

Air quality laws govern the emission of air pollutants into the atmosphere. A specialized subset of air quality laws regulate the quality of air inside buildings. Air quality laws are often designed specifically to protect human health by limiting or eliminating airborne pollutant concentrations. Other initiatives are designed to address broader ecological problems, such as limitations on chemicals that affect the ozone layer, and emissions trading programs to address acid rain or climate change. Regulatory efforts include identifying and categorizing air pollutants, setting limits on acceptable emissions levels, and dictating necessary or appropriate mitigation technologies.

Chehalis Gap

The Chehalis Gap is a gap in the Coast Range of Washington State between the southernmost foothills of the Olympic Mountains called the Satsop Hills, and the Willapa Hills.


  1. Okrainetz, Glen. "Air Quality Management in British Columbia" (PDF). BC Lung Ass'n. Archived from the original (PDF) on January 16, 2014. Retrieved July 6, 2013.