Association of short-term exposure to fine particulate matter and nitrogen dioxide with acute cardiovascular effects

This study evaluated whether exposure to fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) is associated with cardiovascular effects by examining a panel of 89 healthy subjects in Taipei, Taiwan. The subjects received two health examinations approximately 8 months apart in 2013. Brachial–ankle pulse wave velocity (baPWV), a physiological indicator of arterial stiffness, and high-sensitivity C-reactive protein (hsCRP), a biomarker of vascular inflammations, were measured during each examination. Two exposure assessment methods were used for estimating the subjects' exposure to PM_2.5 and NO₂. The first method involved constructing daily land use regression (LUR) models according to measurements collected at ambient air quality monitoring stations. The second method required combining the LUR estimates with indoor monitoring data at the workplace of the subjects. Linear mixed models were used to examine the association between the exposure estimates and health outcomes. The results showed that a 10-μg/m³ increase in PM_2.5 concentration at a 1-day lag was associated with 2.1% (95% confidence interval: 0.7%–3.6%) and 2.4% (0.8%–4.0%) increases in baPWV based on the two exposure assessment methods, whereas no significant association was observed for NO₂. The significant effects of PM_2.5 remained in the two-pollutant models. By contrast, NO₂, but not PM_2.5, was significantly associated with increased hsCRP levels (16.0%–37.3% in single-pollutant models and 26.4%–44.6% in two-pollutant models, per 10-ppb increase in NO₂). In conclusion, arterial stiffness might be more sensitive to short-term PM_2.5 exposure than is inflammation.