[Short-time effects of inhalable particles and fine particles on children's lung function in a district in Beijing]

To study short-term effects of PM10 (particulate matter of aerodynamic diameter <10 microm) and PM2.5 (particulate matter of aerodynamic diameter <2.5 microm) on children's lung function in one district in Beijing.

Two hundred and sixteen healthy students aged between 7 and 11 year-old were selected from two primary schools in Beijing in October 2008, and every subject was tested with eight lung function parameters. Levels of PM2.5 in the schoolyards were monitored. Temperature and relative humidity were also recorded. PM10 data was collected from the nearby monitoring sites. The association between children's lung function and PM10 and PM2.5 were analyzed by using ridge regression model.

The decrements found in indicators reflecting large airway characteristics including slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1.0), and in indicators reflecting small airway characteristics including forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), forced expiratory flow after 25% of vital capacity has been expelled (FEF25), forced expiratory flow after 50% of vital capacity has been expelled (FEF50), were associated with accumulated 1-day lagged and 2-day lagged PM2.5 and PM10, while FVC and FEV1.0 decreased more significantly, and the declines of SVC, FVC and FEV1.0 in girls were slightly greater than that in boys.

PM2.5 and PM10 had short-term adverse health effects on children's lung function. The effects on parameters reflecting large airway characteristics such as FVC and FEV1.0 were even more obvious. The large airways of girls might be more susceptible to ambient particulate matter.