In addition to producing clean air for us to breathe, trees also removepollutants from the air that could otherwise contribute to healthproblems for residents. Gaseous pollutants such as ozone, carbonmonoxide, nitrogen dioxide, and sulfur dioxide are absorbed into a treethrough tiny openings in leaves, "stomata", and then are broken downwithin the tree. The largest pollutant type consists of particulatematter that is less than 2.5 microns in size. According to theInternational Society of Arboriculture, “particulates are solid ratherthan gaseous, generated by combustion of fossil fuels, construction anddemolition, industrial processes, soil tillage and erosion, and complexreactions between sunlight and gaseous pollutants. Particulates havebeen associated with respiratory (asthma) and cardiopulmonary (heart andlung) diseases, and cancer.” These particulates are not absorbed bytrees the way that gaseous pollutants are, but they do collect on thesurfaces of leaves and are removed from the atmosphere in that way.
Overall, trees growing in Edmond’s residential areas remove 1,630 tonsof air pollution per year. See Table 1 for each pollutant removed byEdmond’s residential trees each year and the number of vehicles orsingle family homes with annual emissions equivalent to the amount ofthe pollutant removed from the air by trees. The air qualityimprovements from these trees result in savings of approximately $7.68million. This quantity is based on the estimated local incidence ofadverse health effects, such as costs associated with respiratory healthissues linked to air quality.
