Promoted Relationship of Cardiovascular Morbidity with Air Pollutants in a Typical Chinese Urban Area

BACKGROUND A large number of studies about effects of air pollutants on cardiovascular mortality have been conducted; however, those investigating association between air pollutants and cardiovascular morbidity are limited, especially in developing countries. METHODS A time-series analysis on the short-term association between outdoor air pollutants including particulate matter (PM) with diameters of 10 µm or less (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2) and cardiovascular morbidity was conducted in Tianjin, China based on 4 years of daily data (2008-2011). The morbidity data were stratified by sex and age. The effects of air pollutants during the warm season and the cool season were also analyzed separately. RESULTS Each increase in PM10, SO2, and NO2 by increments of 10 µg/m3 in a 2-day average concentration was associated with increases in the cardiovascular morbidity of 0.19% with 95 percent confidence interval (95% CI) of 0.08-0.31, 0.43% with 95% CI of 0.03-0.84, and 0.52% with 95% CI of -0.09-1.13, respectively. The effects of air pollutants were more evident in the cool season than those in the warm season, females and the elderly were more vulnerable to outdoor air pollution. CONCLUSIONS All estimated coefficients of PM10, SO2 and NO2 are positive but only the effect of SO2 implied statistical significance at the 5% level. Moreover, season, sex and age might modify health effects of outdoor air pollutants. This work may bring inspirations for formulating local air pollutant standards and social policy regarding cardiovascular health of residents.