Impact of particulate matter and heat stress on cardiovascular health during traffic exposure

Abstract

This study investigates the combined effects of particulate matter (PM) and heat stress on cardiovascular health during vehicle commutes. It addresses limitations in previous research that often examined PM or heat stress in isolation. A four-day field study was conducted among healthy female students to assess cardiovascular health indices (CHI)—heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP)—under varying ventilation conditions: open windows without air conditioning, closed windows with air conditioning and recirculating air, closed windows with air conditioning drawing in outside air, and open windows with air conditioning. Previous studies often overlooked the interaction between PM size fractions and heat stress or ignored the impact of different ventilation scenarios. Data were analyzed using multiple linear regression and ANOVA, with statistical significance set at p ≤ 0.05. PM concentrations and heat stress indices revealed significant associations between specific PM sizes (PM_0.5–0.7 μm, PM_0.7–1.0 μm, PM_1.0–2.0 μm, and PM ≥ _5.0 μm) and increased HR. PM_0.7–1.0 μm significantly influenced SBP, while larger PM sizes (PM_2.0–5.0 μm and PM ≥ _5.0 μm) affected both SBP and DBP. Heat stress indices were associated with changes in blood pressure but did not significantly affect HR. The interaction between PM and heat stress highlighted complex relationships influencing CHI. This study underscores the need for targeted public health strategies to mitigate cardiovascular risks associated with traffic-related exposures.