News, Culture & Society

Air pollution has lowered US life expectancy, study finds

Air pollution may be a factor in thousands of deaths every year in the US and has shortened life expectancy, a new study finds.

Researchers say that being exposed to high levels of particles from power plants, exhaust systems and dust storms has caused 30,000 deaths between 1999 and 2015, mostly from secondary conditions such as asthma and heart attacks.

Exposure to these emissions has also shortened life expectancy by 0.15 years for women and 0.13 years for men  

The joint team, from Imperial College London and Carnegie Mellon University in Pennsylvania, says that even at levels deemed safe, these tiny particles can cause mortality rates to soar.

A new study led by Imperial College London has found that emissions from tiny PM2.5 particles has lowered life expectancy in the US by 0.15 years for women and 0.13 years for men. Pictured: High-rise buildings in downtown Los Angeles, California, surrounded by smog in September 2018

For the study, published in PLOS Medicine, the team looked at outdoor air pollution from PM2.5 across the continental US (not including Alaska and Hawaii) between 1999 and 2015.

PM2.5 are tiny particles that come from various sources including power plants, exhaust systems, airplanes, forest fires and dust storms.

Because of how small they are, PM2.5 particles stay in the air longer than heavy particles, increasing the risk of us inhaling them.

Additionally, due to their size, they can get deep into the lungs and potentially enter the circulatory system.

Studies have shown that exposure to fine particles can increase our risk of lung disease and heart disease as well as worsen chronic conditions including asthma and bronchitis.

Currently, the World Health Organization estimates that, worldwide, seven million people die every year from exposure to such pollution with most deaths occurring in low- and middle-income countries, chiefly in Africa and Asia.

Researchers used data from 750 air quality monitory stations across the country, satellite images and death counts from the National Center for Health Statistics.

The current US standard is at 12 microgram per cubic meter of air (ug/m3), but researchers suggest this level may still be too high. 

Despite PM2.5 levels falling since 1999, the team found that 30,300 people died between 1999 and 2015 when levels were as low as 2.8ug/m3

This was broken down to more than 15,600 deaths among women and more than 14,700 deaths among men – all from conditions such as asthma or heart attacks linked to air pollution. 

Researchers also found that these deaths caused the national life expectancy to lower by 0.15 years for women and 0.13 years for men.

Morality associated with PM2.5 was highest in Los Angeles, California, and southern states, including Alabama, Arkansas and Oklahoma.   

‘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,’ said lead author Dr Majid Ezzati from Imperial’s School of Public Health.

‘Lowering the PM2.5 standard below the current level is likely to improve the health of the US nation, and reduce health inequality.’

This comes as President Trump’s administration enacts several environmental policy changes including repealing Obama’s Clean Power Plan and repealing the emission requirements for certain vehicles.

Also air quality has improved overall since 2000, but slightly worsened since Trump’s inauguration. 

The Environmental Protection Agency’s Air Quality Index shows that the number of  days with air deemed ‘unhealthy for sensitive groups’ rose from 721 days in 2017 to 799 days in 2018.