OBJECTIVEThe aim of this study was to investigate the impact of air pollution on the number of pediatric outpatient and emergency room visits in January 2013.

METHODSHealth-related data was from a major hospital in Haidian,Beijing while related data on air pollution was from the Chinese Research Academy of Environmental Sciences. Data on weather was from the China Weather Website. Number of hospital outpatient visits per day during the haze period was compared to those from the previous year to get the increase of percentage. Concentration-response functions were estimated using generalized additive modeling with natural log link function, while multiple structural change test was used to determine the changing point in CRFs. Constrained piecewise linear function was used to estimate the risks for different segments of CRFs.

RESULTSThe peak of NO(X), SO₂, PM(2.5) and PM(10) reached 672.63 µ g/m³, 146.20 µ g/m³, 312.19 µ g/m³ and 995.00 µ g/m³, around 28 December 2012 and 10 January 2013. The peaks of visits to the pediatric department were observed at the some days, showing 47.75% and 34.14% of increase in the visits to the pediatric department. In the low or intermediate ranges of concentration, all the four air pollutants were significantly associated with pediatric outpatient visits, in the form of C- and S- shape of concentration-response function. However, in the range of high concentration, only PM(10) and SO₂were significantly associated with the number of visits to the pediatric emergency room, appeared as the J-shape form. Discernable thresholds were found in S- and J- shapes which were located at 200 µg/m³, 20 µg/m³, 40 µg/m³ and 100 µ g/m³ for NO(X), SO₂, PM(2.5) and PM(10), respectively.

CONCLUSIONAir pollution during the haze period was associated with the increase of pediatric outpatient and emergency room visits. There were different sensitive groups within the pediatric cases. Their susceptibility showed a decreasing trend from C-, S-, to J- shape related group.