OBJECTIVETo systematically review and assess the relationship between particulate matter (PM(10) and PM(2.5)) and children's hospital admissions for asthma, using both time-series and case-crossover analyses.

METHODThe PubMed, Ebsco, Ovid and four Chinese periodical databases were screened for studies related to short-term effects of particulate matter on pediatric asthma hospital admissions published from 1 January 1990 to 31 December 2013.Sixteen studies on PM(10) and 10 studies on PM(2.5) were selected finally for meta-analysis. Relative risk (RR) or odds ratio (OR) and 95% confidence intervals (CI) of asthma hospital admissions per 10 µg/m³ increase of daily particulate matter were obtained from each study. RevMan 5.2.11 was used to test the heterogeneity of the results among the different studies and amalgamat the effect size by fixed or random effect model.

RESULTAs the concentration of PM(10) increased per 10 µg/m³, the children's hospital admissions for asthma increased by 1.75%; for PM(2.5), a 3.45% increase for asthma hospital admissions as the concentration increased per 10 µg/m³. By subgroup analysis based on study design, the effect size on both PM(10) and PM(2.5) of case-crossover study's results were higher than time-series analysis.

CONCLUSIONThe short-term increase of the concentration of PM(10) and PM(2.5) may led to the increase of Children's hospital admissions for asthma, and PM(2.5) will present a higher risk contribution.