NEW YORK, July 25 ― New research has found that air pollution could be a factor in over 30,000 deaths in the US and is associated with a reduction in life expectancy.

Carried out by researchers from Imperial College London, UK, and the Centre for Air, Climate and Energy Solutions at Carnegie Mellon University, US, the new study analysed data from more than 750 air quality monitoring stations across the US, and combined the information with other sources of air pollution data, such as satellite images.

The researchers focused on a type of pollution called fine particle matter, or PM2.5, which are particles smaller than 2.5 microns in diameter mainly produced by burning fossil fuels from car and other vehicle exhausts, power plants and industrial emissions.

The particles are around 30 times smaller than the width of a human hair and can penetrate deeply into the respiratory tract. They have already been linked with a range of conditions including heart attacks and various forms of lung disease.

The researchers also looked at information on mortality rates from the National Centre for Health Statistics, and took into account various factors which could influence the results, such as age, education, poverty and smoking rates.

The findings, published in the journal PLOS Medicine, showed that PM2.5 levels between 2.8ug/m3 (microgramme per cubic metre of air) and 13.2ug/m3, were associated with an estimated 15,612 deaths in females and 14,757 deaths in men.

The deaths were caused by cardiorespiratory conditions, which refers to heart and lung problems such as heart attack and asthma. The researchers noted that there is already strong evidence of an association between cardiorespiratory diseases and air pollution.

They also estimate that these deaths would lower national life expectancy by 0.15 years for women, and 0.13 years for men.

The levels of PM2.5 associated with the deaths were also mostly below the current standard of 12 (ug/m3). The highest concentration of PM2.5 during the study period was 22.1ug/m3, in 1999, Fresno County, California.

Professor Majid Ezzati, lead author of the research, commented on the findings saying, "We’ve known for some time that these particles can be deadly. This study suggests even at seemingly low concentrations ―mostly below current limits ― they still cause tens of thousands of deaths. Lowering the PM2.5 standard below the current level is likely to improve the health of the US nation, and reduce health inequality.”

"US PM2.5 concentrations are generally lower than those in many Europe cities ― which suggests there may also be a substantial number of deaths in Europe associated with air pollution,” he added. — AFP-Relaxnews