Nature’s Anti-Pollution Powerhouse

While trees' pollution removal equated to an average air quality improvement of less than 1%, the impacts of that improvement are substantial. David J. Nowak, from the United States Department of Agriculture (USDA) Forest Service (New York, USA), and colleagues have completed a  first broad-scale estimate of air pollution removal by trees nationwide.  The study considered four pollutants for which the US Environmental Protection Agency (EPA) has established air quality standards: nitrogen dioxide, ozone, sulfur dioxide, and particulate matter less than 2.5 microns (PM2.5) in aerodynamic diameter. Health effects related to air pollution include impacts on pulmonary, cardiac, vascular, and neurological systems. In the United States, approximately 130,000 PM2.5-related deaths and 4,700 ozone-related deaths in 2005 were attributed to air pollution.  The data revealed that air pollution removal is substantially higher in rural areas than urban areas, however the effects on human health are substantially greater in urban areas than rural areas. Importantly, the study authors report that: “Health impacts included the avoidance of more than 850 incidences of human mortality and 670,000 incidences of acute respiratory symptoms.”