Airsheds in Nelson
Nelson's urban area has four airsheds defined for air quality management purposes. An airshed is a geographic area within which air pollutant concentrations tend to be similar and pollutants do not tend to mix with those in adjoining airsheds (except during windy periods).
Airsheds tend to be bounded by hills or by the coast forming basins which the pollutants sit in. They also tend to have a similar intensity of development and/or similar land use patterns.