Airshed

An airshed is a geographic area that shares a common volume of air. The boundaries of an airshed are typically defined by topographic features such as mountains or valleys, weather patterns, and prevailing winds, which tend to trap and concentrate pollutants within the defined space. Because of these characteristics, airsheds function somewhat independently in terms of air quality.

The concept of an airshed is crucial for understanding and managing air pollution. Pollutants released into an airshed can accumulate and affect the air quality throughout the entire area. Air quality management often focuses on airsheds as a unit, implementing regulations and strategies designed to reduce emissions and improve air quality within the defined boundaries. Understanding airshed dynamics is essential for developing effective policies aimed at protecting public health and the environment from the harmful effects of air pollution.

The size of an airshed can vary greatly, from a small valley to a large metropolitan area. Factors such as topography, meteorology, and emission sources influence the specific characteristics of each airshed. Monitoring air quality within an airshed involves measuring the concentrations of various pollutants, tracking their movement, and analyzing their impact on human health and ecosystems.