Guohai Chen

Season, Sex, Age, and Education as Modifiers of the Effects of Outdoor Air Pollution on Daily Mortality in Shanghai, China: The Public Health and Air Pollution in Asia (PAPA) Study

Background Various factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries. Objectives We conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants [particulate matter < 10 μm in aerodynamic diameter (PM10), sulfur dioxide, nitrogen dioxide, and ozone] and daily mortality in Shanghai, China, using 4 years of daily data (2001–2004). Methods Using a natural spline model to analyze the data, we examined effects of air pollution for the warm season (April–September) and cool season (October–March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality. Results Outdoor air pollution was associated with mortality from all causes and from cardiorespiratory diseases in Shanghai. An increase of 10 μg/m3 in a 2-day average concentration of PM10, SO2, NO2, and O3 corresponds to increases in all-cause mortality of 0.25% [95% confidence interval (CI), 0.14–0.37), 0.95% (95% CI, 0.62–1.28), 0.97% (95% CI, 0.66–1.27), and 0.31% (95% CI, 0.04–0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above). Conclusions Season, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.

Ozone and daily mortality in Shanghai, China

Background Controversy remains regarding the relationship between ambient ozone and mortality worldwide. In mainland China, the largest developing country, there has been no prior study investigating the acute effect of O3 on death risk. Given the changes in types of air pollution from conventional coal combustion to the mixed coal combustion/motor vehicle emissions in China’s large cities, it is worthwhile to investigate the acute effect of O3 on mortality outcomes in the country. Objectives We conducted a time-series study to investigate the relation between O3 and daily mortality in Shanghai using 4 years of daily data (2001–2004). Methods We used the generalized additive model with penalized splines to analyze mortality, O3 pollution, and covariate data in warm and cold seasons. We considered daily counts of all-cause mortality and several cause-specific subcategories (respiratory and cardiovascular). We also examined these associations among several subpopulations based on age and sex. Results O3 was significantly associated with total and cardiovascular mortality in the cold season but not in the warm season. In the whole-year analysis, an increase of 10 μg/m3 of 2-day average (lag01) O3 corresponds to 0.45% [95% confidence interval (CI), 0.16–0.73%], 0.53% (95% CI, 0.10–0.96%), and 0.35% (95% CI, −0.40 to 1.09%) increase of total nonaccidental, cardiovascular, and respiratory mortality, respectively. In the cold season, the estimates increased to 1.38% (95% CI, 0.68–2.07%), 1.53% (95% CI, 0.54–2.52%), and 0.95% (95% CI, −0.71 to 2.60%), respectively. In the warm season, we did not observe significant associations for both total and cause-specific mortality. The results were generally insensitive to model specifications such as lag structure of O3 concentrations and degree of freedom for time trend. Multipollutant models indicate that the effect of O3 was not confounded by particulate matter ≤ 10 μm in diameter (PM10) or by sulfur dioxide; however, after adding nitrogen dioxide into the model, the association of O3 with total and cardiovascular mortality became statistically insignificant. Conclusions O3 pollution has stronger health effects in the cold than in the warm season in Shanghai. Our analyses also strengthen the rationale for further limiting levels of O3 pollution in outdoor air in the city.

Visibility, air quality and daily mortality in Shanghai, China.

This study was designed to assess the association between visibility and air quality, and to determine whether the variations in daily mortality were associated with fluctuations in visibility levels in Shanghai, China. Mortality data were extracted from the death certificates, provided by Shanghai Municipal Center of Disease Control and Prevention, and visibility data were obtained from Shanghai Municipal Bureau of Meteorology. Air quality data (PM(10), PM(2.5), PM(10-2.5), SO(2), NO(2) and O(3)) were obtained from Shanghai Environmental Monitoring Center. Generalized additive model (GAM) with penalized splines was used to analyze the mortality, visibility, air pollution, and covariate data. Among various pollutants, PM(2.5) showed strongest correlation with visibility. Visibility, together with humidity, was found appropriate in predicting PM(2.5) (R-squared: 0.64) and PM(10) (R-squared: 0.62). Decreased visibility was significantly associated with elevated death rates from all causes and from cardiovascular disease in Shanghai; one inter-quartile range (8 km) decrease in visibility corresponded to 2.17% (95%CI: 0.46%, 3.85%), 3.36% (95%CI: 0.96%, 5.70%), and 3.02% (95%CI: -1.32%, 7.17%) increase of total, cardiovascular and respiratory mortality, respectively. The effect estimates using predicted PM(2.5) and PM(10) concentrations were similar to those assessed using actual concentrations. This is the first study in Mainland China assessing the association between visibility and adverse health outcomes. Our findings suggest the possibility of using visibility as a surrogate of air quality in health research in developing countries where air pollution data might be scarce and not routinely monitored.

Diurnal temperature range as a novel risk factor for COPD death

Background and objective:  Although the relationship between day‐to‐day temperature changes and COPD mortality is well established, it is not known whether temperature variation within one day, that is diurnal temperature range (DTR), is a risk factor for acute COPD death, independent of the absolute temperature level.

Short-term Effects of Ambient Gaseous Pollutants and Particulate Matter on Daily Mortality in Shanghai, China

Short‐term Effects of Ambient Gaseous Pollutants and Particulate Matter on Daily Mortality in Shanghai, China: Guohai Chen, et al. Shanghai Environmental Monitoring Center, China—Identification of the specific pollutants contributing most to the health hazard of the air pollution mixture may have important implications for environmental and social policies. In the current study, we conducted a time‐series analysis to examine the specific effects of major air pollutants [particulate matter less than 10 microns in diameter (PM10), sulfur dioxide (SO2), and nitrogen dioxides (NO2)] on daily mortality in Shanghai, China, using both single‐pollutant and multiple‐pollutant models. In the single‐pollutant models, PM10, SO2, and NO2 were found to be associated with mortality from both all non‐accidental causes and from cardiopulmonary diseases. Unlike some prior studies in North America, we found a significant effect of gaseous pollutants (SO2 and NO2) on daily mortality even after adjustment for PM10 in the multiple‐pollutant models. Our findings, combined with previous Chinese studies showing a consistent, significant effect of gaseous pollutants on mortality, suggest that the role of outdoor exposure to SO2 and NO2 should be investigated further in China.