New research published today (July 12) in IOP Publishing’s Environmental Research Letters adds to the growing body of evidence showing that human-caused air pollution is directly responsible for an increased number of deaths. According to the study, more than two million people worldwide die each year as a direct result of breathing in the fine particulates spewed into the air by factories, automobiles, and the like.
“Our estimates make outdoor air pollution among the most important health risk factors for health. Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and pollution is severe,” said co-author Jason West of the University of North Carolina in a journal press release. West and his colleagues estimate that roughly 470,000 people die each year because of increases in ozone due to human activity.
Interestingly, the researchers found that climate change since the industrial revolution contributed little to increased mortality. Although climate–temperature, humidity, and rainfall–can affect air pollution, they estimate that global warming resulted in only 1500 deaths due to ozone and 2200 deaths related to fine particulate matter. According to West, few studies have tried to calculate 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.
To reach their conclusions, the researchers used 14 different climate models to simulate the concentrations of ozone and fine particulate matter in the years 1850 and 2000. Then, they used the results of previous epidemiological studies to evaluate the relationship between specific concentrations of air pollution from the climate models and global mortality rates. West noted the advantage of using multiple climate models to assess the impact of air pollution on health:
“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,” he stated.
The study by West and his colleagues comes on the heels of another recently published study finding a strong correlation between air pollution caused by burning coal and a significant reduction in life expectancy. In that study, published in the Proceedings of the National Academy of Sciences, researchers compared populations living in northern and southern China and found that people in the north, who generally depend on coal for their heating requirements, are likely to die more than five years sooner than those living in the less polluted south. Researchers also concluded that every additional 100 micrograms of particulate matter per cubic meter in the atmosphere reduces an infant’s life expectancy by three years.
It remains to be seen whether the proliferation of evidence showing the negative impact of human-driven air pollution on mortality rates will lead to meaningful changes in either global energy policies or human behavior.