The field data collection of an air pollution epidemiologic study was carried out from 1993 to 1996 in four Chinese cities of Lanzhou, Chongqing, Wuhan, and Guangzhou. In each city, an urban district and a suburban district were selected. Ambient concentrations of total suspended particles (TSP), size-fractionated particulate matter including PM2.5, PM2.5-10, and PM10, sulfur dioxide (SO2), and oxides of nitrogen (NOx) were measured in these districts. The results indicate the presence of wide inter-city and intra-city gradients in long-term ambient levels of these measured pollutants. Across the eight districts, the 1993-1996 4-year means of TSP, SO2, and NOx ranged from 198 to 659 microg/m3, from 14.6 to 331 microg/m3, and from 31.5 to 239 microg/m3, respectively, and the 1995-1996 2-year means of PM2.5, PM2.5-10, and PM10 ranged from 51.5 to 142 microg/m3, from 29.2 to 107 microg/m3, and from 80.7 to 232 microg/m3, respectively. These pollution ranges substantially extended the upper end of the pollution ranges of previous air pollution epidemiologic studies conducted in North America and Europe. In each district, significant correlations among the measured pollutants were observed for daily concentrations. However, the gradient patterns in long-term means of different pollutants were different across the eight districts. (e.g., PM2.5-10 and TSP were highest in the Lanzhou urban district, PM2.5 and PM10 were highest in the Guangzhou urban district, SO2 was highest in the Chongqing urban district, and NOx was highest in the Guangzhou urban district). In general, seasonal variations were present in the ambient concentrations with high levels often occurring in winter months. The eight districts may be classified into four district clusters based on integrated levels of all measured pollutants. These features of the ambient air pollution have important implications for epidemiological studies and may provide unique opportunities to study exposure-effects relationships in the four Chinese cities.

Air Pollutants↗

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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).

Adolescent↗

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The epidemiology of lung cancer in Xuan Wei, China: current progress, issues, and research strategies.

In Xuan Wei, a rural Chinese county of about one million people, females' annual lung cancer mortality is China's highest, and males' is among China's highest. Xuan Wei's very high indoor air pollution levels (sometimes exceeding 20 mg/m3), residentially stable population, relatively uncomplicated lifestyle, and wide geographic variation in lung cancer mortality render it highly amenable to quantitative, interdisciplinary investigation of chemical carcinogens due to indoor air pollution. To date, epidemiologic findings reveal a closer association of lung cancer with the indoor burning of "smoky" coal (as opposed to "smokeless" coal or wood) than with tobacco use or occupation. Current aerometric, chemical, and toxicologic findings tend to confirm this association, though the specific carcinogenic constituents of Xuan Wei indoor air pollution have not yet been determined. Chinese and American investigators are conducting interdisciplinary field and laboratory investigations to quantify the lung cancer risk attendant on indoor air pollution relative to other factors, to measure and compare the characteristics of pollution from different Xuan Wei fuels, to determine the relative etiologic importance of pollution composition and concentration, and to develop quantitative relationships between air pollution dose and lung cancer risk.

Adult↗

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Effects of air pollution on children's pulmonary function in urban and suburban areas of Wuhan, People's Republic of China.

In May and June of 1988, the spirometric lung function of 604 children, who were aged 7-13 y and who were free of chronic respiratory conditions, was measured in the urban core and a suburb of Wuhan, China. During 1981-1988, ambient total suspended particulate (TSP) levels averaged 481 micrograms/m3 in the urban core and 167 micrograms/m3 in the suburb. In 1988, TSP levels, measured within 500 m of the children's homes, averaged 251 micrograms/m3 in the urban core and 110 micrograms/m3 in the suburb. Levels of sulfur dioxide and nitrogen oxides were also higher in the urban core. Proportions of families who burned coal and gas domestically were similar in both areas. In linear and logarithmic regression models, height was a stronger determinant of forced vital capacity and forced expiratory volume in 1 s than was age or weight. In linear models, the proportion of variance explained by height (R-squared) ranged from 0.54 for urban females' forced expiratory volume in 1 s to 0.77 for suburban males and females. Both forced vital capacity and forced expiratory volume in 1 s were consistently lower in urban than suburban children. The average forced vital capacity and forced expiratory volume in 1 s in children 132-144 cm tall were 6.7% and 3.8% lower, respectively, in the urban core than the suburb; suburban-urban differences increased with height. Suburban-urban differences in slopes of lung function growth curves were statistically significant for forced vital capacity but not for forced expiratory volume in 1 s. Rates of clinical upper respiratory irritation were also generally elevated in urban children. These results strongly suggest that urban ambient air pollution exposure in China contributes to retardation in the growth of children's lung function. Confirmatory longitudinal studies are in progress in Wuhan and three other Chinese cities.

Adolescent↗

PubMedDate not supplied

Effects of air pollution on respiratory health of adults in three Chinese cities.

The authors examined potential associations between air-pollution exposures and respiratory symptoms and illnesses of 4,108 adults who resided in 4 districts of 3 large, distinct Chinese cities. Data on respiratory health outcomes and relevant risk factors for parents and children were obtained via standardized questionnaires in the winter of 1988. (The effects in children were described previously.) The yearly averages of ambient levels of total suspended particles in the 4 districts for the years 1985-1988 differed greatly. The authors constructed logistic-regression models to assess the respiratory health parameters of parents of the children. The results revealed significant and strong effects, by district, on prevalence rates of cough, phlegm, persistent cough and phlegm, and wheeze for both the mothers and the fathers. In addition, the odds ratios increased as ambient total suspended particle concentration increased across the 3 urban districts. Other local within-city risk factors, however, may have confounded the total suspended particles-effects association, especially for asthma prevalence. Findings for adults were similar to those found for their children. A strong adverse effect of active tobacco smoking on the fathers' respiratory health was observed. The children appeared to be more strongly affected by passive smoking exposure received in their homes than their mothers.

Adult↗

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Child Language↗