The researchers looked at a specific kind of pollution known as fine particulate matter, or PM2.5 – microscopic particulates that are composed of both solids and liquid droplets. Some come from burning fuel and others form in the atmosphere as a result of complex reactions of chemicals such as sulphur dioxide and nitrogen oxides from power plants, industries and automobiles.
Long-term exposure to the particles can lead to respiratory and cardiovascular problems, which has led to many cities introducing measures such as London’s ULEZ zone in the most congested areas.
The study compared seven datasets, including both on-the-ground and satellite measurements, to analyse trends in PM2.5 levels across New York State.
It found that PM2.5 levels dropped by 28 to 37 per cent between 2002 and 2012. They calculated that this drop cut the air pollution mortality burden for New York State residents by 67 per cent, or from 8,410 premature deaths in 2002 to 2,750 deaths in 2012.
“What’s novel about this study is that we use seven different PM2.5 exposure estimates to analyse the long-term change in mortality burden and they all show a consistent decrease in mortality burden,” said Xiaomeng Jin, who led the study.
The study looked at four ailments triggered by long-term exposure to fine particulate matter: chronic obstructive pulmonary diseases; ischemic heart disease; lung cancer, and cerebrovascular and ischemic stroke.
The researchers said their study provides evidence that emission controls on air pollutants, initiated by the Clean Air Act of 1970 and further expanded under amendments passed in 1990, have improved public health across New York State.
“Those reviews have sometimes resulted in stricter standards being set, which in turn set in motion the process of emission controls to meet those standards,” said study co-author Arlene Fiore.
Other factors that have improved air quality in New York include continued progress in cleaner vehicles, additional programs to reduce air pollution, including programs targeting diesel fuel, a source of sulphur dioxide, and the reduction of high sulphur dioxide-emitting coal-burning power plants.
Earlier this year, London’s mayor described the capital’s poor air quality as a “public health emergency” and a research project suggested that cyclists should travel different routes in peak hours to avoid the worst of the smog.