Research
Effects of particulate air pollution on blood pressure in a highly exposed population in Beijing, China: a repeated-measure study
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* Corresponding author: Chang Dou changdou2004@sohu.com
1 Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
2 Department of Occupational and Environmental Health, University of Milan and Fondazione IRCCS Ca' Granda Policlinico, Milan, Italy
3 Deptartment of Safety Engineering, China Institute of Industrial Health No.45 Zengguang Rd., Haidian District, Beijing 100048, China
4 Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
5 Center for Health Studies, Universidad del Valle de Guatemala, Guatemala City, Guatemala
6 Department of Occupational and Environmental Health, Peking University Health Science Center, Beijing, China
Environmental Health 2011, 10:108 doi:10.1186/1476-069X-10-108
Published: 21 December 2011Abstract
Background
Particulate Matter (PM) exposure is critical in Beijing due to high population density and rapid increase in vehicular traffic. PM effects on blood pressure (BP) have been investigated as a mechanism mediating cardiovascular risks, but results are still inconsistent. The purpose of our study is to determine the effects of ambient and personal PM exposure on BP.
Methods
Before the 2008 Olympic Games (June 15-July 27), we examined 60 truck drivers and 60 office workers on two days, 1-2 weeks apart (n = 240). We obtained standardized measures of post-work BP. Exposure assessment included personal PM2.5 and Elemental Carbon (EC, a tracer of traffic particles) measured using portable monitors during work hours; and ambient PM10 averaged over 1-8 days pre-examination. We examined associations of exposures (exposure group, personal PM2.5/EC, ambient PM10) with BP controlling for multiple covariates.
Results
Mean personal PM2.5 was 94.6 μg/m3 (SD = 64.9) in office workers and 126.8 (SD = 68.8) in truck drivers (p-value < 0.001). In all participants combined, a 10 μg/m3 increase in 8-day ambient PM10 was associated with BP increments of 0.98 (95%CI 0.34; 1.61; p-value = 0.003), 0.71 (95%CI 0.18; 1.24; p-value = 0.01), and 0.81 (95%CI 0.31; 1.30; p-value = 0.002) mmHg for systolic, diastolic, and mean BP, respectively. BP was not significantly different between the two groups (p-value > 0.14). Personal PM2.5 and EC during work hours were not associated with increased BP.
Conclusions
Our results indicate delayed effects of ambient PM10 on BP. Lack of associations with exposure groups and personal PM2.5/EC indicates that PM effects are related to background levels of pollution in Beijing, and not specifically to work-related exposure.