Lee Rannals for redOrbit.com – Your Universe Online
Researchers have shown that around 2.1 million deaths are caused each year by a human-caused increase in fine particulate matter (PM2.5). These are tiny particles suspended in the air that can penetrate deep into the lungs, causing cancer and other respiratory diseases. The team also found that around 470,000 die each year as a result of increases in ozone.
“Our estimates make outdoor air pollution among the most important environmental risk factors for health,” said Jason West, from the University of North Carolina and co-author of the study. “Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe.”
Climate change can affect air pollution because temperature and humidity can change the reaction rates which determine the formation or lifetime of a pollutant, while rainfall determines the time that pollutants can accumulate. Higher temperatures 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,” said West.
The researchers used several climate models for the study to help simulate the concentrations of ozone and PM2.5 in the years 2000 and 1850. They used 14 models that simulated levels of ozone and six that simulated levels of PM2.5. The team also used past studies to assess how the specific concentrations of air pollution from the climate models related to current global mortality rates.
The study’s findings fell in line with previous studies that have analyzed air pollution and mortality. However, the latest study had variation depending upon which climate model was used.
“We have also found that there is significant uncertainty based on the spread among different atmospheric models. This would caution against using a single model in the future, as some studies have done,” added West.