Air Pollution Damages

Air pollution damages more than just your lungs — it can break your heart too.

A new study has revealed that microscopic particles in polluted air can adversely affect the heart’s functioning by obstructing its ability to conduct electrical signals. Researchers at Harvard University have based their findings on an analysis of 48 patients living in Boston, all of whom had coronary artery disease.

They used 24-hour Holter monitors to examine electrocardiograms for the conductivity change called an ST-segment depression, which indicates inadequate blood flow to the heart or inflamed heart muscle. The average 24-hours levels for all pollutants included in the analysis were below accepted or proposed National Air Quality standard thresholds, meaning patients were breathing air considered healthy. “We found that an elevation in fine particles, from non-traffic as well as traffic sources, and black carbon, a marker for traffic, predicted ST-segment depression.

“Effects were greatest within the first month after hospitalisation, and for patients who were hospitalised for a heart attack or had diabetes,” the study’s senior author Diane R Gold said. Previous studies documented that exposure to road traffic can trigger heart attacks and that particulate air pollution can raise the rise for a heart attack.

“When coal sales were banned in Dublin, Ireland, and black smoke concentrations declined by 70 per cent within the next 72 months, cardiovascular deaths fell by ten per cent,” said Gold. The ST-segment changes Gold observed were not associated with symptoms in the patients, all of whom had undergone in-hospital procedures to examine or open up their coronary arteries. Nevertheless, the findings expand the evidence that air pollution can affect heart health, either through inflaming the heart muscle or through reducing blow flow to the heart.

“The study suggests the need for greater vigilance by physicians and heart patients in the weeks after discharge from the hospital,” the researchers said.