16 Jul 2013 07:53
WASHINGTON, July 13 (Bernama) -- U.S. researchers say air pollution may be responsible for over two million deaths worldwide every year, Xinhua news agency reported. The study published in the journal Environmental Research Letters estimated that around 470,000 people die annually due to human-caused increases in ozone. It also said around 2.1 million deaths are caused each year by human-caused increases in fine particulate matter, tiny particles suspended in the air that can penetrate deep into the lungs, causing cancer and other respiratory disease. "Our estimates make outdoor air pollution among the most important environmental risk factors for health," said Jason West, co-author of the study from the University of North Carolina. "Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe." The number of deaths attributable to changes in climate since the industrial era in the year 1850 is, however, relatively small. A changing climate results in 1,500 deaths due to ozone and 2,200 deaths related to fine particulate matter each year, the study finds. Climate change affects air quality in many ways, possibly leading to local increases or decreases in air pollution. For instance, temperature and humidity can change the reaction rates which determine the formation or lifetime of a pollutant, and rainfall can determine the time that pollutants can accumulate. Higher temperatures can also increase the emissions of organic compounds from trees, which can then react in the atmosphere to form ozone and particulate matter. "Very few studies have attempted to estimate the effects of past climate change on air quality and health. We found that the effects of past climate change are likely to be a very small component of the overall effect of air pollution," West said. --BERNAMA EE