People with pre-existing heart or lung conditions, with an exposure to high levels of traffic-related air pollutants is associated with lowered heart rate variability (HRV).

HRV is supposedly the cause or a risk factor for sudden cardiac death.

Through an observational study which included 30 Atlanta-area residents with lung disease (chronic obstructive pulmonary disease) or heart disease (previous myocardial infarction) it was surveyed for the ambient levels of air pollutants in the areas where the patients lived were unrelated to HRV.

However, in case of traffic exposure with air pollutant exposure like elemental carbon and nitrogen dioxide, the exposure levels were vitally seemed to be associated with HRV.

It was stated that the recent evidences pertaining to the short term, personal exposure to traffic-related pollution is associated to decreased HRV and increased cardiac risk.

These findings have found place the Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM).