Particulate Matter Exposure in Cars Is Associated with Cardiovascular Effects in Healthy Young Men

TLDR

Fine airborne particulate matter (PM2.5) is linked to cardiovascular events and mortality in older adults and cardiac patients. The study examined whether in‑vehicle, roadside, and ambient PM2.5 affect cardiovascular physiology in young, healthy, nonsmoking male troopers. Nine healthy male troopers (age 23‑30) were monitored over four consecutive 3‑p.m. to midnight shifts, with each patrol car equipped with air‑quality monitors, blood drawn 14 h after shifts, and ambulatory ECG recorded, and the data were analyzed using mixed models.

Abstract

Exposure to fine airborne particulate matter (PM2.5) is associated with cardiovascular events and mortality in older and cardiac patients. Potential physiologic effects of in-vehicle, roadside, and ambient PM2.5 were investigated in young, healthy, nonsmoking, male North Carolina Highway Patrol troopers. Nine troopers (age 23 to 30) were monitored on 4 successive days while working a 3 P.M. to midnight shift. Each patrol car was equipped with air-quality monitors. Blood was drawn 14 hours after each shift, and ambulatory monitors recorded the electrocardiogram throughout the shift and until the next morning. Data were analyzed using mixed models. In-vehicle PM2.5 (average of 24 μg/m3) was associated with decreased lymphocytes (−11% per 10 μg/m3) and increased red blood cell indices (1% mean corpuscular volume), neutrophils (6%), C-reactive protein (32%), von Willebrand factor (12%), next-morning heart beat cycle length (6%), next-morning heart rate variability parameters, and ectopic beats throughout the recording (20%). Controlling for potential confounders had little impact on the effect estimates. The associations of these health endpoints with ambient and roadside PM2.5 were smaller and less significant. The observations in these healthy young men suggest that in-vehicle exposure to PM2.5 may cause pathophysiologic changes that involve inflammation, coagulation, and cardiac rhythm.