中国66个县/区日温差对人群死亡影响的时间序列研究

目的 了解中国不同城市日温差对居民死亡风险的影响。方法 用时间序列方法分析中国66个县/区日温差与居民日死亡数的关系,利用Meta分析方法整合不同县/区的结果。在调整季节、年龄、性别和死亡地影响后,以累计超额危险度（CER）为指标,分析极端日温差对死亡的影响。结果 研究共收集1 260 913例死亡信息,北部、中部和南部县/区的日均死亡人数分别为6.1、9.7和10.7人,日温差均值为11.1、8.0及8.2℃。在全国范围内,日温差与居民死亡存在非线性关系,其暴露-反应曲线呈J形,即极高日温差存在显著死亡风险（最大CER=3.6%,95% CI：1.9%～5.3%）,而极低日温差的死亡效应差异无统计学意义;且极高日温差对人群的死亡风险有明显的时空异质性,对中部县/区人群的影响（CER=5.1%,95% CI：2.4%～7.9%）大于南部（CER=4.5%,95% CI：1.7%～7.3%）,在冬春季的效应高于夏秋季;老年人（≥75岁）为极高日温差的脆弱人群。结论 极端日温差对人群的死亡风险存在时空异质性,不同县/区的极高日温差均对居民死亡风险造成影响。对中部的影响高于南部和北部,冬春季的影响强于夏秋季,对老年人等脆弱人群影响最大,应因时因地制定政策保护脆弱人群。     

Air pollution and mortality in Madrid, Spain: a time-series analysis

To assess the relationship, if any, between air pollutant (sulfur dioxide and total suspended particulate) levels and mortality in the city of Madrid during the period 1986–1992, controlling for weather, season, and influenza epidemics. Methods: Daily death counts were obtained from the Regional Mortality Registry. Pollution data were supplied by the Municipal Monitoring Network. Time-series analysis methodology was used to assess the link between non-accidental as well as circulatory- and respiratory-disease mortality, on the one hand, and mean daily concentrations of SO₂ and total suspended particulate (TSP), on the other. Multivariate autoregressive integrated moving-average (ARIMA) models were used to adjust for season, temperature, relative humidity, and influenza. A␣sensitivity analysis was run to assess the robustness of the estimators. Results: Graphical analysis revealed a linear relationship between mortality and TSP. The relationship was logarithmic in the case of SO₂. TSP lagged 1 day and SO₂ lagged 3 days with an independent effect on mortality. This relationship was produced without the detection of a minimal threshold in emission values. Conclusions: These results support the hypothesis of an association between pollution levels and mortality between 1986–1992 in Madrid. Additional measures designed to reduce pollution levels without compromising thermal comfort should be implemented. Received: 28 January 1998 / Accepted: 6 July 1998     

Seasonal effect of PM10 concentrations on mortality and morbidity in Seoul, Korea: A temperature-matched case-crossover analysis

Background

Explorations of interactions between air pollution and seasonal changes have represented one approach in examining the consequences of global warming. However, only a few studies have focused on evaluating the effects of seasonal air pollution using data on both morbidity and mortality in Asia.

Method

We examined the associations between PM₁₀ concentrations and mortality and hospital admissions in Seoul, Korea for the periods 2000-2006 and 2001-2006. We employed a temperature-matched case-crossover design, where reference periods matched case days in regard to temperature (same rounded to degrees celsius (°C)), month, and year.

Results

A total of 238,826 deaths were identified, along with 98,570 and 93,553 inpatient admissions for cardiovascular and respiratory diseases, respectively. We found that the association with PM₁₀ and mortality/morbidity increased during the summer. During the study period, 10μg/m³ increase in PM₁₀ was associated with the increase in mortality by 0.28% (95% confidence interval: 0.12, 0.44), 0.51% (0.19, 0.83), and 0.59% (-0.08, 1.26) for non-accidental, cardiovascular, and respiratory causes. 10μg/m³ increase in PM₁₀ was also associated with increase in hospitalization from cardiovascular and respiratory causes by 0.77% (0.53, 1.01) and 1.19% (0.94, 1.44). In the summer, the increase in mortality and hospitalization was 0.57% (0.20, 0.93), 0.64% (-0.10, 1.38), 0.50% (-1.02, 2.05), 1.52% (0.89, 2.16), and 1.55% (0.87, 2.22).

Conclusions

This study provides evidence that the effect of PM₁₀ on mortality and morbidity varies with season and increases during the summer season.     

Seasonal variation of chemical species associated with short-term mortality effects of PM(2.5) in Xi'an, a Central City in China

The authors conducted a time-series analysis to examine seasonal variation of mortality risk in association with particulate matter less than 2.5 μm in aerodynamic diameter (PM(2.5)) and chemical species in Xi'an, China, using daily air pollution and all-cause and cause-specific mortality data (2004-2008). Poisson regression incorporating natural splines was used to estimate mortality risks of PM(2.5) and its chemical components, adjusting for day of the week, time trend, and meteorologic effects. Increases of 2.29% (95% confidence interval: 0.83, 3.76) for all-cause mortality and 3.08% (95% confidence interval: 0.94, 5.26) for cardiovascular mortality were associated with an interquartile range increase of 103.0 μg/m(3) in lagged 1-2 day PM(2.5) exposure. Stronger effects were observed for the elderly (≥65 years), males, and cardiovascular diseases groups. Secondary components (sulfate and ammonium), combustion species (elemental carbon, sulfur, chlorine), and transition metals (chromium, lead, nickel, and zinc) appeared most responsible for increased risk, particularly in the cold months. The authors concluded that differential association patterns observed across species and seasons indicated that PM(2.5)-related effects might not be sufficiently explained by PM(2.5) mass alone. Future research is needed to examine spatial and temporal varying factors that might play important roles in modifying the PM(2.5)-mortality association.     

天津市空气污染物对脑卒中死亡影响的时间序列分析

目的 探讨天津市大气污染对居民脑卒中死亡率的影响,为脑卒中的预防控制提供依据.方法 采用天津市疾病预防控制中心收集的居民全死因监测数据,气象资料和大气污染资料来源于天津市气象局和天津市环境监测中心.采用时间序列的泊松回归广义可加模型进行天津市每日大气污染与居民脑卒中死亡危险度分析,同时控制气象因素、长期趋势、星期几效应以及人口数等混杂因素的影响,进行单污染物和多污染物分析.结果 2001至2009年天津市脑卒中粗死亡率为136.67～160.01/10万,有逐年上升趋势(P=0.000),但天津市脑卒中世界标化死亡率为138.36～99.14/10万,呈逐年下降趋势(P=0.000);大气中SO2、NO2、PM10日均浓度每升高10μg/m3,脑卒中死亡的风险RR值分别为1.0105(95％CI:1.0060～1.0153),1.0197(95％CI:1.0149～1.0246)和1.0064(95％CI:1.0052～1.0077).SO2效应在1日后达到最大,NO2、PM10效应在当日达到最大.结论 天津市大气污染能增加人群脑卒中死亡风险,可能对脑卒中急性发作起到诱导作用.     

京津两地不同温度水平下大气PM_(10)与居民每日死亡关系的时间序列研究

目的探讨北京市和天津市不同温度水平下大气可吸入颗粒物(PM_(10))与居民每日死亡的定量关系。方法收集北京市和天津市2007年1月1日至2009年12月31日的每日大气PM_(10)、每日平均温度、每日平均相对湿度、每日居民不同病因别死亡人数,建立时间序列数据库。将每日温度分成低(P_(50))、中(P_(50)~P_(75))、高(P_(75))3个层次,采用广义相加模型,分析两城市大气PM_(10)与居民每日不同病因别死亡的相关性。结果对于总死亡,北京市和天津市高、中温水平下大气PM_(10)的超额危险度(excess risk,ER)明显高于低温水平,且中温水平下效应值最大,两城市的ER分别为0.46%(95%CI:0.18%~0.75%)和0.87%(95%CI:0.34%~1.41%);对于循环系统死亡,北京市和天津市高、中温水平下大气PM_(10)的超额危险度明显高于低温水平,且高温水平下的超额危险度值更大,两城市的ER分别为0.52%(95%CI:0.07%~0.98%)和1.13%(95%CI:0.43%~1.83%);对于呼吸系统死亡,北京和天津市中温水平下大气PM_(10)的超额危险度最大,两城市的ER分别为0.99%(95%CI:0.16%~1.74%)和1.48%(95%CI:0.25%~1.95%)。结论不同温度水平下,北京市和天津市大气PM_(10)污染致居民死亡的急性效应不同,中高温水平下,大气PM_(10)的健康效应值更大。制定人群大气污染健康效应公共政策时,需考虑温度对其影响的修饰作用。     

Race, gender, and social status as modifiers of the effects of PM10 on mortality

Interest has recently been focused on which populations are most at risk of premature mortality induced by air pollution. This coincides with greater concern about environmental justice. We analyzed total mortality in the four largest US cities with daily measurements of particulate matter less than 10 microns (PM10) and combined the results to determine whether race, sex, and education are potential modifiers of the effects of PM10 on mortality. We computed daily counts of deaths stratified by sex, race, and education in each city and investigated their associations with PM10 in a Poisson regression model. We combined the results by using inverse variance weighted averages. We found evidence of effect modification by sex, with the slope in female deaths one third larger than in male deaths, whereas for social factors and race we found only weak evidence of effect modification. In general, the effect modification appeared modest compared with other reports of substantial effect modification by medical conditions.     

Outdoor air pollution and infant mortality: analysis of daily time-series data in 10 English cities

BACKGROUND: There is growing concern that moderate levels of outdoor air pollution may be associated with infant mortality, representing substantial loss of life-years. To date, there has been no investigation of the effects of outdoor pollution on infant mortality in the UK. METHODS: Daily time-series data of air pollution and all infant deaths between 1990 and 2000 in 10 major cities of England: Birmingham, Bristol, Leeds, Liverpool, London, Manchester, Middlesbrough, Newcastle, Nottingham and Sheffield, were analysed. City-specific estimates were pooled across cities in a fixed-effects meta-regression to provide a mean estimate. RESULTS: Few associations were observed between infant deaths and most pollutants studied. The exception was sulphur dioxide (SO2), of which a 10 mug/m(3) increase was associated with a RR of 1.02 (95% CI 1.01 to 1.04) in all infant deaths. The effect was present in both neonatal and postneonatal deaths. CONCLUSIONS: Continuing reductions in SO2 levels in the UK may yield additional health benefits for infants.     

上海市A城区大气PM_(10)、PM_(2.5)污染与居民日死亡数的相关分析

目的　探讨大气颗粒物污染对人群健康的影响。方法　采用Poisson广义相加模型对上海市A城区大气PM1 0 、PM2 5的日平均污染浓度与居民日死亡数进行相关回归分析 ,并控制了时间长期趋势、气象、季节、一周日效应混杂因素的影响。结果　当大气PM1 0 、PM2 5浓度上升 10 μg m3时 ,总死亡数分别上升 0 5 3%(0 2 2 %～ 0 85 % )、0 85 % (0 32 %～ 1 39% )。结论　大气粗细颗粒物污染具有潜在的急性人群健康危害。     

Air pollution and mortality in the Canary Islands: a time-series analysis

Background  

The island factor of the cities of Las Palmas de Gran Canaria and Santa Cruz de Tenerife, along with their proximity to Africa and their meteorology, create a particular setting that influences the air quality of these cities and provides researchers an opportunity to analyze the acute effects of air-pollutants on daily mortality.     

A spatially disaggregated time-series analysis of the short-term effects of particulate matter exposure on mortality in Chennai, India

The global burden of disease due to air pollution is concentrated in the rapidly developing counties of Asia, but a recent meta-analysis found that relatively few studies on short-term exposure to air pollution and mortality have been performed in these countries, including India. Local evidence on the effects of short-term exposures to air pollutants on mortality and cardio-respiratory morbidity in Asia would reduce the uncertainties in current impact estimations and facilitate effective public policy responses to a deteriorating air pollution situation in South Asia. Here, we report the results from one of the first of such studies in metropolitan Chennai, India, conducted as part of a co-ordinated multi-city time-series initiative in India aimed at estimating the effect of short-term exposure to particulate matter ≤10 μm in aerodynamic diameter (PM₁₀) on all-cause mortality. The studies in Indian cities (Chennai, Delhi and Ludhiana) were part of a larger multi-city effort in Asia, co-ordinated by The Health Effects Institute (Boston, MA, USA) under their program for Public health and Air Pollution in Asia (PAPA). An important study output included the development of methodological refinements to overcome the limitations of routinely collected data in terms of missing measurements, small footprints of air pollution monitors and incomplete address information on death records. We used data on ambient air quality and all-cause mortality collected over the period 2002–2004. Exposures and health outcomes were disaggregated at the level of individual city zones and subsequently used in quasi-Poisson generalized additive models with smooth functions of time, temperature and relative humidity. Our model estimated a 0.44% (95% confidence interval?0.17–0.71) increase in mortality per 10 μg/m³ increase in daily average concentrations of PM₁₀, which is comparable to estimates from other PAPA cities and previous studies in North America and Europe. The results from PAPA studies in India, while preliminary, serve to strengthen the local evidence base for air pollution-related health effects that is imminently needed for better air quality management, while adding valuable information from India to the global repository of evidence.     

Relationships of mortality with the fine and coarse fractions of long-term ambient PM10 concentrations in nonsmokers

In a cohort of 6338 California Seventh-day Adventists, we previously observed for males associations between long-term concentrations of particulate matter (PM) with an aerodynamic diameter less than 10 microm (PM10) and 15-year mortality due to all natural causes (ANC) and lung cancer (LC) listed as underlying causes of death and due to nonmalignant respiratory disease listed as either the underlying or a contributing (CRC) cause of death. The purpose of this analysis was to determine whether these outcomes were more strongly associated with the fine (PM2.5) or the coarse (PM2.5-10) fractions of PM10. For participants who lived near an airport (n=3769), daily PM2.5 concentrations were estimated from airport visibility, and on a monthly basis, PM2.5-10 concentrations were calculated as the differences between PM10 and PM2.5. Associations between ANC, CRC, and LC mortality (1977-1992) and mean PM10, PM2.5, and PM2.5-10 concentrations at study baseline (1973-1977) were assessed using Cox proportional hazards models. Magnitudes of the PM10 associations for the males of this subgroup were similar to those for the males in the entire cohort although not statistically significant due to the smaller numbers. In single-pollutant models, for an interquartile range (IQR) increase in PM10 (29.5 microg/m3), the rate ratios (RRs) and 95% confidence intervals (CI) were 1.15 (0.94, 1.41) for ANC, 1.48 (0.93, 2.34) for CRC, and 1.84 (0.59, 5.67) for LC. For an IQR increase in PM2.5 (24.3 microg/m3), corresponding RRs (95% CI) were 1.22 (0.95, 1.58), 1.64 (0.93, 2.90), and 2.23 (0.56, 8.94), and for an IQR increase in PM2.5-10 (9.7 microg/m3), corresponding RRs (95% CI) were 1.05 (0.92, 1.20), 1.19 (0.88, 1.62), and 1.25 (0.63, 2.49), respectively. When both PM25 and PM2.5-10 were entered into the same model, the PM2.5 estimates remained stable while those of PM2.5-10 decreased. We concluded that previously observed associations of long-term ambient PM10 concentration with mortality for males were best explained by a relationship of mortality with the fine fraction of PM10 rather than with the coarse fraction of PM10.     

Isolated and synergistic effects of PM10 and average temperature on cardiovascular and respiratory mortality

OBJECTIVE

To analyze the effect of air pollution and temperature on mortality due to cardiovascular and respiratory diseases.

METHODS

We evaluated the isolated and synergistic effects of temperature and particulate matter with aerodynamic diameter < 10 µm (PM₁₀) on the mortality of individuals > 40 years old due to cardiovascular disease and that of individuals > 60 years old due to respiratory diseases in Sao Paulo, SP, Southeastern Brazil, between 1998 and 2008. Three methodologies were used to evaluate the isolated association: time-series analysis using Poisson regression model, bidirectional case-crossover analysis matched by period, and case-crossover analysis matched by the confounding factor, i.e., average temperature or pollutant concentration. The graphical representation of the response surface, generated by the interaction term between these factors added to the Poisson regression model, was interpreted to evaluate the synergistic effect of the risk factors.

RESULTS

No differences were observed between the results of the case-crossover and time-series analyses. The percentage change in the relative risk of cardiovascular and respiratory mortality was 0.85% (0.45;1.25) and 1.60% (0.74;2.46), respectively, due to an increase of 10 μg/m³ in the PM₁₀ concentration. The pattern of correlation of the temperature with cardiovascular mortality was U-shaped and that with respiratory mortality was J-shaped, indicating an increased relative risk at high temperatures. The values for the interaction term indicated a higher relative risk for cardiovascular and respiratory mortalities at low temperatures and high temperatures, respectively, when the pollution levels reached approximately 60 μg/m³.

CONCLUSIONS

The positive association standardized in the Poisson regression model for pollutant concentration is not confounded by temperature, and the effect of temperature is not confounded by the pollutant levels in the time-series analysis. The simultaneous exposure to different levels of environmental factors can create synergistic effects that are as disturbing as those caused by extreme concentrations.     

An ecologic analysis of county-level PM2.5 concentrations and lung cancer incidence and mortality

Few studies have explored the relationship between PM2.5 and lung cancer incidence. Although results are mixed, some studies have demonstrated a positive relationship between PM2.5 and lung cancer mortality. Using an ecologic study design, we examined the county-level associations between PM2.5 concentrations (2002-2005) and lung cancer incidence and mortality in North Carolina (2002-2006). Positive trends were observed between PM2.5 concentrations and lung cancer incidence and mortality; however, the R2 for both were <0.10. The slopes for the relationship between PM2.5 and lung cancer incidence and mortality were 1.26 (95% CI 0.31, 2.21, p-value 0.01) and 0.73 (95% CI 0.09, 1.36, p-value 0.03) per 1 μg/m3 PM2.5, respectively. These associations were slightly strengthened with the inclusion of variables representing socioeconomic status and smoking. Although variability is high, thus reflecting the importance of tobacco smoking and other etiologic agents that influence lung cancer incidence and mortality besides PM2.5, a positive trend is observed between PM2.5 and lung cancer incidence and mortality. This suggests the possibility of an association between PM2.5 concentrations and lung cancer incidence and mortality.     

Assessment of trends and present ambient concentrations of PM2.2 and PM10 in Dhaka, Bangladesh

The present air quality has been studied at two air quality monitoring stations in Dhaka, the capital of Bangladesh. One site at the Farm Gate area is a particulate matter (PM) hot spot (HSD) with very high pollutant concentrations because of its proximity to major roadways. The other site is in a semi-residential area (SR) located at the Atomic Energy Centre, Dhaka Campus with relatively less traffic. The samples were collected using a ‘Gent’ stacked filter unit in two fractions of 0–2.2 and 10–2.2 μm sizes. Samples of fine (PM_2.2) and coarse (PM_10–2.2) airborne particulate matter collected between 2000 and 2005 were studied. It has been observed that fine particulate matter concentrations at the HSD have decreased from over this period to less than half of the initial value even with an increasing number of vehicles. This decrease is likely the result of governmental policy interventions such as the requirement of vehicle maintenance, training of repair workers, and phase-wise removal of two-stroke three wheelers from the roads in Dhaka with a complete ban of their commercial use beginning on January 1, 2003. Other policy interventions were banning of old buses and trucks from operating in Dhaka, promotion of the compressed natural gas, introduction of pollution control devices on vehicles, control of emissions from industries, etc. It was found that both local (mostly from vehicular emissions and seasonal brick kilns) are responsible for the high PM_2.2 and black carbon concentrations in Dhaka. PM_2.2, PM_10–2.2, and black carbon concentration levels depend on the season, wind direction, and wind speed. PM_10–2.2 has not been the focus of policy decisions, and the decrease in concentrations has been much smaller than were observed for the PM_2.2. There is also some indication of the role of transport of PM_2.2 from regional sources.     

Air pollution and mortality in the elderly in Rio de Janeiro: a time-series analysis

This study investigates the association between particulate air pollution and mortality from cardiovascular and respiratory diseases among the elderly in the city of Rio de Janeiro. Death counts, levels of total suspended particles (TSP), and meteorological data were obtained from secondary databases. Daily counts of deaths and daily TSP levels from 1990 to 1993 were analyzed in Poisson regression models adjusted for long-term temporal trends, seasonality, weekdays, temperature, and humidity. For an increase in TSP levels from the 10th to the 90th percentile (104.7 microg/m3), the relative risks for mortality in elderly people from cardiovascular and respiratory diseases were 1.04 (95%CI: 0.96-1.13) and 1.10 (95%CI: 0.97-1.26) respectively. Although an upward trend in risk was observed, the associations were not statistically significant, which could be explained partially by the small number of pollution measures available for the period analyzed.     

Ambient endotoxin concentrations in PM10 from Southern California

Concentrations of endotoxin in urban air pollution have not previously been extensively characterized. We measured 24-hr levels of PM10 (particulate matter < 10 microm in aerodynamic diameter) and the associated endotoxin component once every 6 weeks for 1 year in 13 communities in Southern California. All the samples collected had detectable PM10 and endotoxin levels. The geometric mean PM10 was 34.6 microg/m3 [geometric SD (GSD), 2.1; range, 3.0-135]. By volume, the endotoxin geometric mean was 0.44 endotoxin units (EU)/m3 (GSD, 3.1; range, 0.03-5.44). Per unit material collected, the geometric mean of endotoxin collected was 13.6 EU/mg (GSD, 3.2; range, 0.7-96.8). No correlation was found between endotoxin concentrations and other ambient pollutants concurrently measured [ozone, nitrogen dioxide, total acids, or PM2.5 (particulate matter < 2.5 micro m in aerodynamic diameter]. PM10 and endotoxin concentrations were significantly correlated, most strongly in summer. Samples collected in more rural and agricultural areas had lower PM10 and mid-range endotoxin levels. The high desert and mountain communities had lower PM10 levels but endotoxin levels comparable with or higher than the rural agricultural sites. By volume, endotoxin levels were highest at sites downwind of Los Angeles, California, which were also the locations of highest PM10. Endotoxin concentrations measured in this study were all < 5.5 EU/m3, which is lower than recognized thresholds for acute adverse health effects for occupational exposures but in the same range as indoor household concentrations. This study provides the first extensive characterization of endotoxin concentration across a large metropolitan area in relation to PM10 and other pollutant monitoring, and supports the need for studies of the role of endotoxin in childhood asthma in urban settings.