Association between source-specific particulate matter air pollution and hs-CRP – role of fresh local traffic and industrial emissions

Abstract

Background Long-term exposure to fine particulate matter (PM2.5 and PM10) air pollution and high traffic load at residence have been shown to induce systemic inflammation. So far epidemiological investigations on inflammatory markers have concentrated on effects of total PM2.5 and PM10, a mixture of pollutants originating from different sources. Little is known about source-specific PM and inflammation. Aims To investigate the association of source-specific (local traffic and industry) fine PM and hs-CRP, a widely used marker for systemic inflammation and an independent predictor of cardiovascular disease. Methods We used longitudinal data from the Heinz Nixdorf Recall study,a prospective population-based German cohort of 4814 participants aged 45 to 75 years at baseline (2000-2003).We estimated individual 365-day mean exposure to local traffic- and industry-specific fine PM at participant’s residence by suppression of sources within a chemistry transport model. A linear mixed model with a random participant intercept was used to estimate associations of source-specific PM and log-transformed hs-CRP, controlling for age, sex, education, BMI, LDL/HDL, smoking habits, season and humidity. Results Analyzing 8,215 observations in 4,672 participants we observed positive associations between total PM2.5 and hs-CRP with a 2.83 % (95%-CI: 1.41 to 4.27 %) increase in hs-CRP level per 1 µg/m3 increase in total PM2.5. For traffic-specific PM2.5 we saw a 20.00 % (95%-CI: 9.36 to 31.34 %) increase, while the effect of industry-specific PM2.5 could not be separated from total PM due to high correlation (0.9). Results for PM10 were similar. Conclusions Our results suggest that local traffic-specific PM is more closely associated with systemic inflammation than total PM. Further investigations are needed to distinguish properly between total and industry-specific PM. Grant information: This study was funded by the German Research Council (DFG; JO 170/8-1, HO 3314/2-1).