Ambient particulate matter and lung function growth in Chinese children.

Background: Exposure to particulate matter (PM) has been associated with deficits in lung function growth among children in Western countries. However, few studies have explored this association in developing countries, where PM levels are often substantially higher. Methods: Children (n = 3273) 6-12 years of age were recruited from 8 schools in 4 Chinese cities. The lung function parameters of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV 1) were measured using computerized spirometers twice a year for up to 3 years (1993-1996). Dichotomous samplers placed in each schoolyard were used to measure PM2.5 and PM10 (PM with diameter <= 2.5 mu m and <= 10 mu m, respectively). Multivariable generalized estimating equations were used to examine the association between the quarterly average PM levels and lung function growth during the period of follow-up. Results: Annual average PM2.5 and PM10 levels in the 4 cities ranged from 57 to 158 mu g/m(3) and 95 to 268 mu g/m(3), respectively. In multivariable models, an increase of 10 mu g/m(3) of PM2.5 was associated with decreases of 2.7 mL FEV1 (95% confidence interval = -3.5 to -2.0), 3.5 mL FVC (-4.3 to -2.7), 1.4 mL/year FEV1 growth (-1.8 to -0.9), and 1.5 mL/year FVC growth (-2.0 to -1.0). Similar results were seen with PM10 exposure. Conclusions: Exposure to ambient particulate matter was associated with decreased growth in lung function among Chinese children.