Effects of air pollution on children's respiratory health in three Chinese cities.

During the winter of 1988-1989, parents of 2,789 elementary-school students completed standardized questionnaires. The students were 5-14 y of age and were from three urban districts and one suburban district of three large Chinese cities. The 4-y average ambient levels of total suspended particles in the three cities differed greatly during the period 1985-1988: Lanzhou, 1,067 microg/m3; urban Wuhan, 406 microg/m3; Guangzhou, 296 microg/m3; and suburban Wuhan, 191 microg/m3. The authors constructed unconditional logistic-regression models to calculate odds ratios and 95% confidence intervals for prevalences of several respiratory symptoms and illnesses, adjusted for district, use of coal in the home, and parental smoking status. There was a positive and significant association between total suspended particle levels and the adjusted odds ratios for cough, phlegm, hospitalization for diseases, and pneumonia. This association was derived from only the 1,784 urban children and, therefore, the authors were unable to extrapolate it to the suburban children. The results also indicated that parental smoking status was associated with cough and phlegm, and use of coal in the home was associated only with cough prevalence (alpha = 0.05).