Air pollution controls 'lower respiratory illness death rates'

The number of deaths caused by asthma, emphysema and pneumonia throughout North Carolina, US, has declined since air pollution controls were implemented in 1990. A new study, led by researchers from Duke University, has suggested that national and state air pollution controls that were put in place 24 years ago could be related to the decrease in deaths caused by respiratory illnesses.

Researchers used monthly air quality measurements taken from North Carolina air-monitoring stations between 1993 and 2010, comparing them to public health data showing mortality trends in the state. It was found that decreased levels of air pollution coincide with declining rates of respiratory illness-related deaths.

Dr Kim Lyerly, professor of surgery, associate professor of pathology and assistant professor of immunology at Duke University, said the research shows that environmental policies work. Not only do these policies have a benefit on the overall environment - helping with air quality in the state and aiding the fight against climate change - they also help to improve health.

"While a few studies have analyzed the associations of both air quality and health over a long period, they were typically limited to analyses of a specific air pollutant or a couple of pollutants. In contrast, we leveraged access to multiple disparate databases containing either environmental or health data, and we were able to study longitudinally a number of air contaminants, including both particulate matter and noxious gases over almost two decades."

The research team looked at a 17-year period following the implementation of several federal air pollution measures. These included reducing emissions from power plants and vehicle engines, as well as targeting certain emissions that contribute to damage to the ozone layer and acid rain. 

Researchers were able to calculate how a reduction of one unit worth of air pollution coincided with a decline in deaths from asthma, pneumonia and emphysema. This was done using the environmental and public health data, while adjusting figures to account for controlling factors - such as fluctuations in air quality and a reduction in smoking rates.

It was found that as well as gaseous pollutants, a decline in sulphur dioxide levels related to a significant fall in death rates for all three diseases, while falling carbon monoxide levels correlated with fewer deaths from emphysema and asthma.