Zhengmin Qian

Public Health and Air Pollution in Asia (PAPA): A Multicity Study of Short-Term Effects of Air Pollution on Mortality

Background and objectives Although the deleterious effects of air pollution from fossil fuel combustion have been demonstrated in many Western nations, fewer studies have been conducted in Asia. The Public Health and Air Pollution in Asia (PAPA) project assessed the effects of short-term exposure to air pollution on daily mortality in Bangkok, Thailand, and in three cities in China: Hong Kong, Shanghai, and Wuhan. Methods Poisson regression models incorporating natural spline smoothing functions were used to adjust for seasonality and other time-varying covariates that might confound the association between air pollution and mortality. Effect estimates were determined for each city and then for the cities combined using a random effects method. Results In individual cities, associations were detected between most of the pollutants [nitrogen dioxide, sulfur dioxide, particulate matter ≤ 10 μm in aerodynamic diameter (PM10), and ozone] and most health outcomes under study (i.e., all natural-cause, cardiovascular, and respiratory mortality). The city-combined effects of the four pollutants tended to be equal or greater than those identified in studies conducted in Western industrial nations. In addition, residents of Asian cities are likely to have higher exposures to air pollution than those in Western industrial nations because they spend more time outdoors and less time in air conditioning. Conclusions Although the social and environmental conditions may be quite different, it is reasonable to apply estimates derived from previous health effect of air pollution studies in the West to Asia.

High Temperatures Enhanced Acute Mortality Effects of Ambient Particle Pollution in the “Oven” City of Wuhan, China

Background We investigated whether the effect of air pollution on daily mortality is enhanced by high temperatures in Wuhan, China, using data from 2001 to 2004. Wuhan has been called an “oven” city because of its hot summers. Approximately 4.5 million permanent residents live in the 201-km2 core area of the city. Method We used a generalized additive model to analyze pollution, mortality, and covariate data. The estimates of the interaction between high temperature and air pollution were obtained from the main effects and pollutant–temperature interaction models. Results We observed effects of consistently and statistically significant interactions between particulate matter ≤ 10 μm (PM10) and temperature on daily nonaccidental (p = 0.014), cardiovascular (p = 0.007), and cardiopulmonary (p = 0.014) mortality. The PM10 effects were strongest on extremely high-temperature days (daily average temperature, 33.1°C), less strong on extremely low-temperature days (2.2°C), and weakest on normal-temperature days (18.0°C). The estimates of the mean percentage of change in daily mortality per 10-μg/m3 increase in PM10 concentrations at the average of lags 0 and 1 day during hot temperature were 2.20% (95% confidence interval), 0.74–3.68) for nonaccidental, 3.28% (1.24–5.37) for cardiovascular, 2.35% (−0.03 to 4.78) for stroke, 3.31% (−0.22 to 6.97) for cardiac, 1.15% (−3.54% to 6.07) for respiratory, and 3.02% (1.03–5.04) for cardiopulmonary mortality. Conclusions We found synergistic effects of PM10 and high temperatures on daily nonaccidental, cardiovascular, and cardiopulmonary mortality in Wuhan.

Short-term association between sulfur dioxide and daily mortality: the Public Health and Air Pollution in Asia (PAPA) study.

Sulfur dioxide (SO(2)) has been associated with increased mortality and morbidity, but only few studies were conducted in Asian countries. Previous studies suggest that SO(2) may have adverse health effects independent of other pollutants. In the Public Health and Air Pollution in Asia (PAPA) project, the short-term associations between ambient sulfur dioxide (SO(2)) and daily mortality were examined in Bangkok, Thailand, and three Chinese cities: Hong Kong, Shanghai, and Wuhan. Poisson regression models incorporating natural spline smoothing functions were used to adjust for seasonality and other time-varying covariates. Effect estimates were obtained for each city and then for the cities combined. The impact of alternative model specifications, such as lag structure of pollutants and degree of freedom (df) for time trend, on the estimated effects of SO(2) were also examined. In both individual-city and combined analysis, significant effects of SO(2) on total non-accidental and cardiopulmonary mortality were observed. An increase of 10 microg/m(3) of 2-day moving average concentrations of SO(2) corresponded to 1.00% [95% confidence interval (CI), 0.75-1.24], 1.09% (95% CI, 0.71-1.47), and 1.47% (95% CI, 0.85-2.08) increase of total, cardiovascular and respiratory mortality, respectively, in the combined analysis. Sensitivity analyzes suggested that these findings were generally insensitive to alternative model specifications. After adjustment for PM(10) or O(3), the effect of SO(2) remained significant in three Chinese cities. However, adjustment for NO(2) diminished the associations and rendered them statistically insignificant in all four cities. In conclusion, ambient SO(2) concentration was associated with daily mortality in these four Asian cities. These associations may be attributable to SO(2) serving as a surrogate of other substances. Our findings suggest that the role of outdoor exposure to SO(2) should be investigated further in this region.

Long-term ambient air pollution levels in four Chinese cities: inter-city and intra-city concentration gradients for epidemiological studies.

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 μg/m3, from 14.6 to 331 μg/m3, and from 31.5 to 239 μg/m3, respectively, and the 1995–1996 2-year means of PM2.5, PM2.5–10, and PM10 ranged from 51.5 to 142 μg/m3, from 29.2 to 107 μg/m3, and from 80.7 to 232 μg/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.

Effects of Air Pollution on Children's Respiratory Health in Three Chinese Cities

Abstract 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 μmlg/m3; urban Wuhan, 406 μmlg/m3; Guangzhou, 296 μmlg/m3; and suburban Wuhan, 191 μmlg/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 (α = 0.05).

Seasonal Pattern of the Acute Mortality Effects of Air Pollution

Abstract Evidence of seasonal variation of acute mortality effects of air pollution is inconsistent. The seasonal patterns of associations between daily mortality and daily mean concentrations of particulate matter 10 µm or less in aerodynamic diameter (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2) were examined using 4 yr of data (2001–2004) in Wuhan, China. Four distinct seasons occur in Wuhan, where approximately 4.5 million residents live in the city core area of 201 km2. Air pollution levels are higher and pollution ranges are wider in Wuhan than in most cities. Quasi-likelihood estimation within the context of the generalized additive models (natural spline [NS] models in R) was used to model the natural logarithm of the expected daily death counts as a function of the predictor variables. The estimates of the interaction between seasons and pollution were obtained from the main effects and pollutant season interaction models. It was found that the interactions between three pollutants and cause-specific mortality were statistically significant (P < 0.05). The strongest effects occurred consistently in winter for all-natural, cardiovascular, stroke, and respiratory mortality. Every 10-µg/m3 increase in PM10 daily concentration at lag 0–1 days was associated with an increase in all-natural mortality of 0.69% (95% confidence interval [CI]: 0.44–0.94%) for winter, 0.34% (95% CI: 0.00–0.69%) for spring, 0.45% (95% CI: –0.13 to 1.04%) for summer, and –0.21% (95% CI: –0.54 to 0.12%) for fall. The results show a clear seasonal pattern of acute mortality effects of ambient air pollution and the strongest effects occurred during winter in the study city.

Short-term effects of gaseous pollutants on cause-specific mortality in Wuhan, China

Abstract In Asia, limited studies have been published on the association between daily mortality and gaseous pollutants of nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2). Our previous studies in Wuhan, China, demonstrated long-term air pollution effects. However, no study has been conducted to determine mortality effects of air pollution in this region. This study was to determine the acute mortality effects of the gaseous pollutants in Wuhan, a city with 7.5 million permanent residents during the period from 2000 to 2004. There are approximately 4.5 million residents in Wuhan who live in the city’s core area of 201 km2, where air pollution levels are highest, and pollution ranges are wider than the majority of the cities in the published literature. We used the generalized additive model to analyze pollution, mortality, and covariate data. We found consistent NO2effects on mortality with the strongest effects on the same day. Every 10-μg/m3increase in NO2daily concentration on the same day was associated with an increase in nonaccidental (1.43%; 95% confidence interval [CI]: 0.87–1.99%), cardiovascular (1.65%; 95% CI: 0.87–2.45%), stroke (1.49%; 95% CI: 0.56–2.43%), cardiac (1.77%; 95% CI: 0.44–3.12%), respiratory (2.23%; 95% CI: 0.52–3.96%), and cardiopulmonary mortality (1.60%; 95% CI: 0.85– 2.35%). These effects were stronger among the elderly than among the young. Formal examination of exposure-response curves suggests no-threshold linear relationships between daily mortality and NO2, where the NO2concentrations ranged from 19.2 to 127.4 μg/m3. SO2and O3were not associated with daily mortality. The exposure-response relationships demonstrated heterogeneity, with some curves showing nonlinear relationships for SO2and O3. We conclude that there is consistent evidence of acute effects of NO2on mortality and suggest that a no-threshold linear relationship exists between NO2and mortality.

Evolution of lower respiratory symptoms in New York police officers after 9/11: a prospective longitudinal study.

Objective: We studied the evolution of lower respiratory symptoms at 1 month (initial) and 19 months (follow-up) after the collapse of the World Trade Center on September 11, 2001 (9/11). Methods: A total of 1588 New York police officers completed initial self-administered questionnaires. The level of 9/11 exposure and pre-9/11 health was available in 1373. Of those, 471 (426 with no pre-9/11 chronic respiratory disease) completed a follow-up telephone survey. Results: Prevalence of cough was 43.5% at both initial and follow-up assessments, but increased were the prevalence of phlegm (14.4% to 30.7%, P < 0.001), shortness of breath (18.9% to 43.6%, P < 0.001), and wheeze (13.1% to 25.9%, P < 0.001). Rates of delayed-onset (present on follow-up assessment only) cough, phlegm, shortness of breath, and wheeze were 21%, 21.9%, 31.7%, and 17.3%, respectively. Conclusions: Most of the lower respiratory symptoms increased between 1 month and 19 months after 9/11.

Exposure-response relationships between lifetime exposure to residential coal smoke and respiratory symptoms and illnesses in Chinese children

Data collected in a large epidemiologic study were analyzed to examine respiratory health effects of residential coal use in 7058 school children living in the four Chinese cities of Chongqing, Guangzhou, Lanzhou, and Wuhan. A Scenario Evaluation Approach was used to develop two exposure variables, heating coal smoke and cooking coal smoke. Estimated lifetime exposures to heating coal smoke and cooking coal smoke were both classified into four-level ordinal scales, as follows: no reported exposure (control); lightly exposed; moderately exposed; and heavily exposed. Zero–one dummy variables were constructed for each exposure level other than the control level (total six variables). These variables were entered into the analytical model. We tested for exposure–response relationships using logistic regression models, while controlling for other relevant covariates, including an indicator variable of ambient air pollution levels. We observed monotonic and positive exposure–response relationships of exposure to heating coal smoke with modeled odds ratios (ORs) of phlegm, cough with phlegm, and bronchitis. Other health outcomes were not associated with such exposure in a monotonic exposure–response pattern. However, ORs for cough, wheeze, and asthma were all higher in the exposed groups than in the control group. We observed no consistent associations between cooking coal smoke and the examined health outcomes. We conclude that exposure to heating coal smoke could have adverse effects on childrens respiratory symptoms and illnesses in these four Chinese cities.

Associations Between Air Pollution and Peak Expiratory Flow Among Patients with Persistent Asthma

Responses of patients with persistent asthma to ambient air pollution may be different from those of general populations. For example, asthma medications may modify the effects of ambient air pollutants on peak expiratory flow (PEF). Few studies examined the association between air pollution and PEF in patients with persistent asthma on well-defined medication regimens using asthma clinical trial data. Airway obstruction effects of ambient air pollutants, using 14,919 person-days of daily self-measured peak expiratory flow (PEF), were assessed from 154 patients with persistent asthma during the 16 wk of active treatment in the Salmeterol Off Corticosteroids Study trial. The three therapies were an inhaled corticosteroid, an inhaled long-acting β-agonist, and placebo. The participants were nonsmokers aged 12 through 63 yr, recruited from 6 university-based ambulatory care centers from February 1997 to January 1999. Air pollution data were derived from the U.S. Environmental Protection Agency Aerometric Information Retrieval System. An increase of 10 ppb of ambient daily mean concentrations of NO2 was associated with a decrease in PEF of 1.53 L/min (95% confidence interval [CI] –2.93 to –0.14) in models adjusted for age, gender, race/ethnicity, asthma clinical center, season, week, daily average temperature, and daily average relative humidity. The strongest association between NO2 and PEF was observed among the patients treated with salmeterol. Negative associations were also found between PEF and SO2 and between PEF and PM10, respectively. The results show that the two medication regimens protected against the effects of PM10. However, salmeterol increased the sensitivity to NO2 and triamcinalone enhanced the sensitivity to SO2.