Objective Using case-crossover design to explore the association between ambient air pollution and the hospital emergency room visits for respiratory diseases (International Classification of Diseases, tenth vision ICD-10: J00-J99) in Beijing, China. Methods Data regarding the daily hospital emergency room visits' of the respiratory diseases (ICD-10: J00-J99)were obtained in 2004.01.01-2005.12.31, from the Peking University Third Hospital and data on relevant air pollution and meteorological factors from the local municipal environmental monitoring center and meteorology bureau of Beijing, respectively. Time-stratified case-crossover technique was used to evaluate their relationships. Results from the bi-directional control sampling approach were compared with unidirectional approach. Results Using a unidirectional control sampling approach,the results obtained from a conditional logistic regression model (multi-pollutant model) after adjusting for meteorological variables, showed that the ORs of the hospital emergency room visits for the respiratory diseases associated with each 10 μg/m3 increment of PM10, SO2, NO2 were 1.010(95%CI: 1.005-1.014), 1.010(95%CI: 1.001-1.018) ,0.996(95%CI:0.983-1.009) respectively.In the bi-directional control sampling approach, the ORs were 1.002(95%CI:0.998-1.005)、 1.011 (95%CI:1.003-1.018)、 1.012(95%CI: 1.001-1.022). Conclusion Results from this study provided evidence that higher levels of ambient air pollutants increased the risk of hospital emergency room visits for respiratory diseases.

BACKGROUND: The growing public health concern caused by non-communicable diseases in urban surroundings cannot be solved by health care alone; therefore a multidisciplinary approach is mandatory. This study aimed to evaluate the airborne aerosol pollution level in primary schools as possible factor influencing origin and course of the diseases in children. METHODS: Seasonal aerosol particle number concentration (PNC) and mass concentration (PMC) were studied in the randomly selected eleven primary schools in the Lithuanian capital, Vilnius, as model of a middle-size Eastern European city. Total PNC in the size range from 0.01 to >1.0 μm in diameter was measured using a condensation particle counter. Using an optical particle sizer, PNC was measured and PMC estimated for particles from 0.3 to 10.0 μm. A descriptive statistics was used to estimate the aerosol pollution levels. RESULTS: During all seasons, local cafeterias in the absence of ventilation were the main sources of the elevated levels of indoor PMC and PNC (up to 97,500 particles/cm). The other sources of airborne particulates were the children's activity during the lesson breaks with PMC up to 586 μg/m. Soft furniture, carpets in the classrooms and corridors were responsible for PMC up to 200 μg/m. Outdoor aerosol pollution (up to 18,170 particles/cm) was higher for schools in city center. Elevated air pollution in classrooms also resulted from intermittent sources, such as construction work during classes (200-1000 μg/m) and petrol-powered lawn trimmers (up to 66,400 particles/cm). CONCLUSION The results of our survey show that even in a relatively low polluted region of Eastern Europe there are big differences in aerosol pollution within middle-sized city. Additional efforts are needed to improve air quality in schools: more frequent wet cleaning, monitoring the operation of ventilation systems, a ban on construction works during school year, on a use of sandblasting mechanisms in the neighborhood of schools.