This study aims to examine the effect of short-term changes in the concentration of particulate matter of diameter ≤2.5 µm (PM 2.5 ) and ≤10 µm (PM 10 ) on pediatric hospital admissions for pneumonia in Jinan, China. It explores confoundings factors of weather, season, and chemical pollutants. Information on pediatric hospital admissions for pneumonia in 2014 was extracted from the database of Jinan Qilu Hospital. The relative risk of pediatric hospital admissions for pneumonia was assessed using a case-crossover approach, controlling weather variables, day of the week, and seasonality. The single-pollutant model demonstrated that increased risk of pediatric hospital admissions for pneumonia was significantly associated with elevated PM 2.5 concentrations the day before hospital admission and elevated PM 10 concentrations 2 days before hospital admission. An increment of 10 μg/m 3 in PM 2.5 and PM 10 was correlated with a 6% (95% CI 1.02--1.10) and 4% (95% CI 1.00-1.08) rise in number of admissions for pneumonia, respectively.