Patients with cardiovascular diseases who are exposed to air pollution in traffic have a greater risk of suffering from stroke or cardiac arrest, a new study conducted by researchers from the Harvard School of Public Health reveals.

The researchers observed 30 residents living in Atlanta who were suffering from either a lung disease or a heart disease and found that high levels of pollutants like carbon monoxide led to a decrease heart rate variability (HRV) and thereby increasing the risk of heart attack.

But the researchers did not find any link between reduced heart rate variability and ambient levels of air pollutants in the area where the subjects resided.