Ambient Air Pollution In China Research Articles

Air pollution is associated with abnormal left ventricular diastolic function: a nationwide population-based study

BackgroundAir pollution is a growing public health concern of global significance. Till date, few studies have explored the associations between air pollutants and cardiac imaging phenotypes. In this study, we aim to explore the association of ambient air pollution and abnormal left ventricular diastolic function (ALVDF) among a large-scale free-living population.MethodsThe participants were from a national representative large-scale cross-sectional study, i.e., the China Hypertension Survey (CHS), 2012–15. After exclusion, 25,983 participants from 14 provinces and 30 districts in China were included for the final analysis. The annual average ambient PM2.5, PM10 and NO2 concentrations were obtained from the chemical data assimilation system (ChemDAS). The clinical evaluation of left ventricular function was conducted in the survey field which was based on echocardiography. Grading diastolic dysfunction was based on Recommendations for the evaluation of left ventricular diastolic function by echocardiography (2009).ResultsThe mean age of 25,983 participants was 56.8 years, 46.5% were male, and the crude prevalence of GradeI-III ALVDF were 48.1%, 1.6% and 1.1%, respectively. The ORs (95% CI) for ALVDF in the fully adjusted model were 1.31 (1.11–1.56), 1.11 (1.01–1.21) and 1.18 (0.90–1.54) for an increase of 10 μg/m3 of PM2.5, PM10 and NO2, respectively. And for different grades of ALVDF, elevated concentration of PM2.5 and PM10 exposures significantly increased the risk of gradeIinstead of gradeII ~ III ALVDF. There was a positive linear and “J” shape concentration–response association between annual average ambient PM2.5 and NO2 and the ALVDF risk assessed by the restricted cubic spline. The exposure level of most participants to PM10 was less than 130 μg/m3, and the risk of ALVDF increased significantly with the concentration rise.ConclusionsThis large-scale nationwide population study demonstrated a significantly positive association between ambient PM2.5, PM10 and NO2 with ALVDF, especially for mild ALVDF. The functional abnormality may partially explain the enhanced cardiovascular morbidity and mortality associated with air pollution, which highlights the importance of appropriate interventions to reduce ambient air pollution in China.

Ethnic disparities in the association between ambient air pollution and risk for cardiometabolic abnormalities in China.

Long-term exposure to ambient air pollution has been associated with cardiometabolic abnormalities (CAs), which, however, may be stronger in vulnerable populations, such as minorities. The variation of the association between ambient air pollution and CAs between the majority (Han) and minority populations in China have been poorly studied. We aimed to estimate and compare the Hans' and minorities' risks for CAs associated with long-term exposure to ambient air pollution in Southwest China. A cross-sectional study was conducted on the basis of the China Multi-Ethnic Cohort. CAs were defined by the presence of at least three pre-defined metabolic dysfunctions (central obesity, elevated triglycerides, reduced high-density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose). The concentrations of ambient air pollutants, including particulate matters (PM1, PM2.5, and PM10) and nitrogen dioxide (NO2), were generated from random forest models on the basis of multi-source data. One- and two-pollutant regression models were fit to assess associations between air pollutant exposure and CA risks. Sensitivity analyses were performed to examine the robustness of the associations. The final sample included 51,037 Hans and 28,702 minority participants. The prevalence of CAs was 25.0%, slightly higher in the minorities (25.5%) than the Hans (24.4%). The higher risks for CAs in the overall population were associated with each 10 μg/m3 increase in the exposure to PM1 (OR = 1.07 [1.05-1.09]), PM2.5 (OR = 1.11 [1.06-1.17]), PM10 (OR = 1.04 [1.03-1.06]), and NO2 (OR = 1.04 [1.03-1.07]). Compared to the Hans, the higher risks for CAs were observed in the minorities for PM1 (OR = 1.35 [1.18-1.53]), PM2.5 (OR = 1.61 [1.34-1.93]), and PM10 (OR = 1.15 [1.07-1.23]). The associations of metabolic dysfunctions (CA components) with ambient air pollution also varied between the Han and minority populations. The associations between exposure to ambient air pollution and CA risks were stronger in the minorities than Hans. Our findings provide a better understanding of ethnic disparities in CA risks when being exposed to ambient air pollution in China, which also have important implications for other low- and middle-income countries where less health resources (e.g., cohort populations) are available to conduct such studies.

Associations of pregnancy complications with ambient air pollution in China

BackgroundGestational hypertension (GH), preeclampsia (PE), and gestational diabetes mellitus (GDM) are common pregnancy complications and can result in maternal and prenatal morbidity and mortality. Air pollution exposure could adversely impact pregnancy complications; however, evidence remains limited in China, where ambient air pollution is relatively severe. ObjectiveThis study aims to examine the associations of GH, PE, and GDM with exposure to six air pollutants (PM2.5, PM10, SO2, NO2, O3, and CO) during pregnancy. MethodsLeveraging a multicenter birth cohort study among pregnant women in 24 hospitals from 15 provinces in China, we obtained data for maternal characteristics and pregnancy outcomes. We generated ambient concentrations of the six air pollutants using a combination of chemical transport model simulations with monitoring data. We used multivariable logistic regression models to estimate the effects on pregnancy complications from exposure to six air pollutants in each trimester and the entire pregnancy. ResultsAmong the total 3754 pregnant women in this study, the prevalences of GH, GDM, and PE were 2.6 %, 11.2 %, and 0.7 %, respectively. GH risk increased 11.9 % (95 % CI, −8.5 %, 36.8 %) and 13.8 % (1.4 %, 27.8 %) per 10 μg/m3 increases in PM2.5 and PM10 in the entire pregnancy, respectively. PM2.5 and PM10 exposures in the first trimester were significantly associated with an increased risk of GDM. Exposure to O3, SO2, NO2, and CO in early pregnancy could be associated with GDM risk. Geographic region and season of conception may influence the associations of GH and PE with air pollution. ConclusionsAmbient particulate matter pollution adversely affects GH, GDM, and PE among Chinese pregnant women. Since most regions of China still suffer from hazardous levels of air pollution, our findings indicate importance of better protecting pregnant women from the risk of air pollution.

Years of Life Lost (YLL) Due to Short-Term Exposure to Ambient Air Pollution in China: A Systematic Review and Meta-Analysis.

(1) Background: Years of life lost (YLL) as a surrogate of health is important for supporting ambient air pollution related policy decisions. However, there has been little comprehensive evaluation of the short-term impact of air pollution on cause-specific YLL, especially in China. Hence in this study, we selected China as sentinel region in order to conduct a meta-analysis to evaluate disease-specific YLL due to all the main ambient air pollutants. (2) Methods: A meta-analysis was conducted to evaluate disease-specific YLL due to the main ambient air pollutants in China, and 19 studies were included. We conducted methodological quality and risk of bias assessment for each included study as well as for heterogeneity and publication bias. Subgroup analysis and sensitivity analysis were also performed. (3) Results: Meta-analysis indicated that increases in PM2.5, PM10, SO2 and NO2 were associated with 1.99–5.84 years increase in YLL from non-accidental diseases. The increase in YLL to cardiovascular disease (CVD) was associated with PM10 and NO2, and the increase in YLL to respiratory diseases (RD) was associated with PM10. (4) Conclusions: Ambient air pollution was observed to be associated with several cause-specific YLL, increasing especially for elderly people and females.

First Technical Specifications for Health Risk Assessment of Ambient Air Pollution in China.

First Technical Specifications for Health Risk Assessment of Ambient Air Pollution in China.

Deaths attributed to ambient air pollution in China between 2006 and 2016

Objective: To analyze the deaths attributed to ambient air pollution in China between 2006 and 2016. Methods: The data were collected from the project of Global Burden of Disease in 2016 (GBD2016). The Data Integration Model for Air Quality were used to estimate exposure to particulate matter smaller than 2.5 μm in aerodynamic diameter (PM(2.5)). The attributable death number was calculated based on the calculation of population attributable fraction (PAF), and the results were compared by gender, diseases and provinces. An average world population age structure was adopted to calculate age-standardized rates. Results: In 2016, a total of 1 075 000 deaths attributed to ambient air pollution occurred in China, accounting for 11.1% of the total deaths, and 57.6% of the deaths attributed to ambient air pollution were due to ischemic heart disease and stroke. The death number among men was 1.7 times higher than that in women, Compared with 2006, the proportion of ambient air pollution related deaths in total deaths decreased by 6.8%; the age- standardized death rate attributed to ambient air pollution decreased by 26.5% and the decrease rate of lower respiratory infections (37.6%) and chronic obstructive pulmonary disease (42.1%) were greater than ischemic heart disease (5.3%). The age-standardized rate of death attributed to ambient air pollution decreased both in men and in women, but the decrease rate was higher in women (34.8%) than that in men (20.4%). The PAFs varied among provinces, it was highest in Tianjin (13.9%), lowest in Tibet (6.1%), and it was relatively higher in Beijing, Hebei, Shandong, Henan and the three provinces in the northeast and relatively lower in Hong Kong, Macao, Fujian and Hainan etc.. The age-standardized rate of death attributed to ambient air pollution was highest in Xinjiang (120.1/100 000) and lowest in Hong Kong (30.9/100 000), and it was relatively higher in Qinghai, Guizhou, Henan and relatively lower in Macao, Shanghai and Fujian, etc.. Compared with 2006, the PAFs of 17 provinces decreased, the decrease rate ranged from 4.1% to 16.8%, whereas the PAF of Jilin (5.0%) and Heilongjiang (8.1%) increased, and the PAFs of other 14 provinces showed no significant change. The attributable age-standardized death rate decreased in all provinces with the decrease rate ranging from 11.9% (Heilongjiang) to 43.2% (Fujian), and the decrease rate was relatively higher in Guangdong, Zhejiang and Guizhou, and lower in the three provinces in the northeast, Hubei and Hebei etc. Conclusions: In 2016, the disease burden attributable to PM(2.5) in China was heavy, but mitigated compared with 2006. The gender and area specific distributions of deaths attributed to ambient air pollution were observed.

The burden of overall and cause-specific respiratory morbidity due to ambient air pollution in Sichuan Basin, China: A multi-city time-series analysis

Few studies have investigated the respiratory morbidity burden due to ambient air pollution in China, especially in a multi-city setting. This study aimed to estimate the short-term effects of ambient air pollutants (PM10, PM2.5, NO2 and SO2) on hospital admissions (HAs) for overall and cause-specific respiratory diseases, as well as the associated burden in 17 cities of Sichuan Basin, China during 2015–2016. Firstly, city-specific effect estimates for each pollutant on respiratory HAs were obtained using generalized additive model with quasi-Poisson link, and then random- or fixed-effects meta-analysis was applied to pool the effect estimates at the regional level. Subgroup analyses by sex, age, season and region were also performed. A total of 757,712 respiratory HAs were collected from all the tertiary and secondary hospitals located in the 17 cities. Risks of HAs for overall and cause-specific respiratory diseases were elevated following increased PM10, PM2.5, NO2 and SO2 exposure. An increase of 10 μg/m3 in PM10 at lag01, PM2.5 at lag01, NO2 at lag0 and SO2 at lag02 was associated with a 0.43% (95% CI: 0.33%, 0.53%), 0.53% (95% CI: 0.39%, 0.68%), 2.36% (95% CI: 1.75%, 2.98%) and 2.54% (95% CI: 1.51%, 3.59%) increases in total respiratory HAs, respectively. Children (≤ 14 years) and elderly (≥ 65 years) appeared to be more vulnerable to the effects of ambient air pollutants. Comparing to the WHO's air quality guidelines, we estimated that 1.84% (95%CI: 1.42%, 2.25%), 1.73% (95%CI: 1.27%, 2.19%) and 0.34% (95%CI: 0.21%, 0.48%) of respiratory HAs were due to PM10, PM2.5 and SO2 exposure, respectively. This study suggests that air pollution might be an important trigger of respiratory admissions, and result in substantial burden of HAs for respiratory diseases in Sichuan Basin.

Ambient air pollution and daily hospital admissions: A nationwide study in 218 Chinese cities

There have been few large multicity studies to evaluate the acute health effects of ambient air pollution on morbidity risk in developing counties. In this study, we examined the short-term associations of air pollution with daily hospital admissions in China. We conducted a nationwide time-series study in 218 Chinese cities between 2014 and 2016. Data on daily hospital admissions counts were obtained from the National Health Insurance Database for Urban Employees covering 0.28 billion enrollees. We used generalized additive model with Poisson regression to estimate the associations in each city, and we performed random-effects meta-analysis to pool the city-specific estimates. More than 60 million hospital admissions were analyzed in this study. At the national-average level, each 10 μg/m3 increase in PM10, SO2, and NO2, and 1 mg/m3 increase in CO at lag 0 day was associated with a 0.29% (95% CI, 0.23%–0.36%), 1.16% (95% CI, 0.92%–1.40%), 1.68% (95% CI, 1.40%–1.95%), and 2.59% (95% CI, 1.69%–3.50%) higher daily hospital admissions, respectively. The associations of air pollution with hospital admissions remained statistically significant at levels below the current Chinese Ambient Air Quality Standards. The effect estimates were larger in cities with lower air pollutants levels or higher air temperatures and relative humidity, as well as in the elderly. In conclusion, our findings provide robust evidence of increased hospital admissions in association with short-term exposure to ambient air pollution in China.

Quantifying regional consumption-based health impacts attributable to ambient air pollution in China

Serious air pollution has caused about one million premature deaths per year in China recently. Besides cross-border atmospheric transport of air pollution, trade also relocates pollution and related health impacts across China as a result of the spatial separation between consumption and production. This study proposes an approach for calculating the health impacts of emissions due to a region's consumption based on a multidisciplinary methodology coupling economic, atmospheric, and epidemiological models. These analyses were performed for China's Beijing and Hebei provinces. It was found that these provinces' consumption-based premature deaths attributable to ambient PM2.5 were respectively 22,500 and 49,700, which were 23% higher and 37% lower than the numbers solely within their boundaries in 2007. The difference between the effects of trade and trade-related emissions on premature deaths attributable to air pollution in a region has also been clarified. The results illustrate the large and broad impact of domestic trade on regional air quality and the need for comprehensive consideration of supply chains in designing policy to mitigate the negative health impacts of air pollution across China.

Urban air pollution and health risks of parent and nitrated polycyclic aromatic hydrocarbons in two megacities, southwest China

Ambient air pollution in China has a significant spatial variation due to the uneven development and different energy structures. This study characterized ambient pollution of parent and nitrated polycyclic aromatic hydrocarbons (PAHs) through a 1-year measurement in two megacities in southwest China where regional PM2.5 levels were considerably lower than other regions. Though the annual average BaP levels in both two cities were below the national standard of 1.0 ng/m3, however, by taking other PAHs into account, PAHs pollution were serious as indicated by high BaP equivalent concentrations (BaPEQ) of 3.8 ± 2.6 and 4.4 ± 1.9 ng/m3, respectively. Risk assessment would be underestimated by nearly an order of magnitude if only using BaP in risk assessment compared to the estimation based on 26 PAHs including 16 priority and 10 non-priority isomers targeted in this study. Estimated incremental lifetime cancer risks (ILCR) were comparable at two cities, at about 330–380 persons per one million, even though the mass concentrations were significantly different. Nitrated PAHs showed distinct temporal and site differences compared to the parent PAHs. High cancer risks due to inhalation exposure of PAHs and their polar derivatives in the low PM2.5-pollution southwest China suggest essential and effective controls on ambient PAHs pollution in the region, and controls should take potential health risks into account instead of solely mass concentration.

Urgency to Assess the Health Impact of Ambient Air Pollution in China.

As the world's second-largest economy, China is going on suffering from environmental pollution, especially for ambient air pollution, which has become a major threat to public health; public awareness of the detrimental effects of air pollution on health is increasing-particularly in relation to haze days. Considering the nonlinear relationship of ambient air pollution exposure and health impacts, and the differences in specific sources of air pollution with those in North America and Europe, conducting health impact assessments of ambient air pollution in China has thus become an urgent task for public health practitioners. Systematic review of the health effects of exposure to ambient air pollution from quantitative studies conducted in Chinese could provide vital information for epidemiology-based health impact assessments and the implementation of a national environmental protection policy.

Air Pollution, Disease Burden, and Health Economic Loss in China.

As the largest developing country in the world, China is now facing one of the severest air pollution problems. The objective of this section is to evaluate the disease burden and corresponding economic loss attributable to ambient air pollution in China. We reviewed a series of studies by Chinese or foreign investigators focusing on the disease burden and economic loss in China. These studies showed both the general air pollution and haze episodes have resulted in substantial disease burden in terms of excess number of premature deaths, disability-adjusted life-year loss, and years of life lost. The corresponding economic loss has accounted for an appreciable proportion of China's national economy. Overall, the disease burden and health economic loss due to ambient air pollution in China is greater than in the remaining parts of the world, for one of the highest levels of air pollution and the largest size of exposed population. Consideration of both health and economic impacts of air pollution can facilitate the Chinese government to develop environmental policies to reduce the emissions of various air pollutants and protect the public health.

Perspective for Future Research Direction About Health Impact of Ambient Air Pollution in China.

Air pollution has become one of the major risks to human health because of the progressive increase in the use of vehicles powered by fossil fuels. Although lots of works on the health impact of ambient air pollution have been done in China, the following recommendations for future research were identified in this chapter: (1) the synergistic effect of indoor air pollution with climate change; (2) develop new technologies to improve accurate assessment of air pollution exposure; (3) well-designed cohort study of sensitive populations including children, older people, and people with chronic health problems; (4) multi-omics technologies in the underlying mechanisms study; and (5) benefits evaluation of improvement of air quality. In conclusion, China is becoming a suitable study site, providing an ideal opportunity to evaluate the effects of environmental pollution, including air pollution, on human health, which might serve as an example for developing countries where health impacts of air pollution are as serious as in China.

The Regional Impacts of Cooking and Heating Emissions on Ambient Air Quality and Disease Burden in China.

Exposure to air pollution is a major risk factor globally and particularly in Asia. A large portion of air pollutants result from residential combustion of solid biomass and coal fuel for cooking and heating. This study presents a regional modeling sensitivity analysis to estimate the impact of residential emissions from cooking and heating activities on the burden of disease at a provincial level in China. Model surface PM2.5 fields are shown to compare well when evaluated against surface air quality measurements. Scenarios run without residential sector and residential heating emissions are used in conjunction with the Global Burden of Disease 2013 framework to calculate the proportion of deaths and disability adjusted life years attributable to PM2.5 exposure from residential emissions. Overall, we estimate that 341 000 (306 000-370 000; 95% confidence interval) premature deaths in China are attributable to residential combustion emissions, approximately a third of the deaths attributable to all ambient PM2.5 pollution, with 159 000 (142 000-172 000) and 182 000 (163 000-197 000) premature deaths from heating and cooking emissions, respectively. Our findings emphasize the need to mitigate emissions from both residential heating and cooking sources to reduce the health impacts of ambient air pollution in China.

Energy saving potential of natural ventilation in China: The impact of ambient air pollution

Natural ventilation (NV) is a key sustainable solution for reducing the energy use in buildings, improving thermal comfort, and maintaining a healthy indoor environment. However, the energy savings and environmental benefits are affected greatly by ambient air pollution in China. Here we estimate the NV potential of all major Chinese cities based on weather, ambient air quality, building configuration, and newly constructed square footage of office buildings in the year of 2015. In general, little NV potential is observed in northern China during the winter and southern China during the summer. Kunming located in the Southwest China is the most weather-favorable city for natural ventilation, and reveals almost no loss due to air pollution. Building Energy Simulation (BES) is conducted to estimate the energy savings of natural ventilation in which ambient air pollution and total square footage at each city must be taken into account. Beijing, the capital city, displays limited per-square-meter saving potential due to the unfavorable weather and air quality for natural ventilation, but its largest total square footage of office buildings makes it become the city with the greatest energy saving opportunity in China. Our analysis shows that the aggregated energy savings potential of office buildings at 35 major Chinese cities is 112GWh in 2015, even after allowing for a 43GWh loss due to China’s serious air pollution issue especially in North China. 8–78% of the cooling energy consumption can be potentially reduced by natural ventilation depending on local weather and air quality. The findings here provide guidelines for improving current energy and environmental policies in China, and a direction for reforming building codes.

Ambient Air Pollution in China: Predicting a Turning Point

One of the most debatable questions among developmental economists and sinologists today is the question that deals with the time it would take China to reduce its current ambient air pollution levels to the levels acceptable by the World Health Organization. Some studies suggest that an increase in the standard of living would improve the environmental situation, a phenomenon that is termed the environmental Kuznets curve (EKC). The objective of this study is to estimate the EKC and identify major factors leading to ambient air pollution in China during 2004–2013. We use time-series panel data in 27 provinces to estimate the variability in the levels of ambient air pollution as measured by particulate matter, sulfur dioxide and nitrogen dioxide. Some policy implications are drawn.

The association between lung cancer incidence and ambient air pollution in China: A spatiotemporal analysis

BackgroundChina is experiencing more and more days of serious air pollution recently, and has the highest lung cancer burden in the world. ObjectivesTo examine the associations between lung cancer incidence and fine particles (PM2.5) and ozone in China. MethodsWe used 75 communities’ data of lung cancer incidence from the National Cancer Registration of China from 1990 to 2009. The annual concentrations of fine particles (PM2.5) and ozone at 0.1°×0.1° spatial resolution were generated by combing remote sensing, global chemical transport models, and improvements in coverage of surface measurements. A spatial age-period-cohort model was used to examine the relative risks of lung cancer incidence associated with the air pollutants, after adjusting for impacts of age, period, and birth cohort, sex, and community type (rural and urban) as well as the spatial variation on lung cancer incidence. ResultsThe relative risks of lung cancer incidence related to a 10µg/m3 increase in 2-year average PM2.5 were 1.055 (95% confidence interval (CI): 1.038, 1.072) for men, 1.149 (1.120, 1.178) for women, 1.060 (1.044, 1.075) for an urban communities, 1.037 (0.998, 1.078) for a rural population, 1.074 (1.052, 1.096) for people aged 30–65 years, and 1.111 (1.077, 1.146) for those aged over 75 years. Ozone also had a significant association with lung cancer incidence. ConclusionsThe increased risks of lung cancer incidence were associated with PM2.5 and ozone air pollution. Control measures to reduce air pollution would likely lower the future incidence of lung cancer.

Air Pollution Exposure and Physical Activity in China: Current Knowledge, Public Health Implications, and Future Research Needs.

Deteriorating air quality in China has created global public health concerns in regard to health and health-related behaviors. Although emerging environmental regulations address ambient air pollution in China, the level of enforcement and long-term impact of these measures remain unknown. Exposure to air pollution has been shown to lead to multiple adverse health outcomes, including increased rates of heart disease and mortality. However, a lesser-known but increasingly significant concern is the relationship between air pollution and its effects on outdoor exercise. This is especially important in China, which has a culturally rooted lifestyle that encourages participation in outdoor physical activity. This article evaluates the intersection of air pollution and outdoor exercise and provides a discussion of issues related to its public health impact in China, where efforts to promote a healthy lifestyle may be adversely affected by the ambient air pollution that has accompanied rapid economic development and urbanization.

Lung cancer incidence and ambient air pollution in China: a spatial age–period cohort study 1990–2009

BackgroundThe International Agency for Research on Cancer has concluded that exposure to outdoor fine particles (PM2·5) is a risk factor for lung cancer. China is experiencing unprecedentedly high levels of PM2·5 air pollution and has the highest lung cancer burden in the world. However, until now, no study has assessed the association between ambient PM2·5 and lung cancer incidence in China. MethodsData of lung cancer incidence between 1990 and 2009 were obtained from the National Cancer Registration of China. The annual concentrations of PM2·5 at 0·1°×0·1° spatial resolution between 1990 and 2005 were estimated by combining remote sensing, global chemical transport models, and ground monitoring air pollution data. A spatial age–period cohort model was used to examine the relative risks (RR) and 95% CI for incident lung cancer associated with increments in 2-year mean PM2·5 concentrations after adjusting for age, period, birth cohort, sex, community type (rural and urban), smoking rate at the community level, as well as the spatial variation in lung cancer incidence. This study was approved by the University of Queensland's behaviour and social sciences ethical review committee (2013000739). FindingsDuring study period, there were 368 762 cases of lung cancer, including 247 533 men and 312 678 cases living in urban areas. The mean concentration of PM2·5 was 69·4 ug/m3. Incident lung cancer was positively associated with increments in 2-year mean PM2·5, and the risk was more pronounced in women (RR 1·149, 95% CI 1·120–1·178) than in men (RR 1·055, 95% CI 1·038–1·072; psex interaction <0·0001). The association was smaller in rural areas (RR 1·037, 95% CI 0·998–1·078) than in urban areas (RR 1·060, 95%CI 1·044–1·075; pinteraction=0·03) and stronger in elderly people (>75 years of age; 1·111 95% CI 1·077–1·146) than young people (30–65 years of age; RR 1·074 95% CI 1·052–1·096; pinteraction=0.007). InterpretationIn China, lung cancer incidence is associated with PM2·5 air pollution. Effective control measures to reduce levels of air pollution are likely to reduce the incidence of lung cancer in the Chinese population. Further studies are still needed to examine causality of the association between PM2·5 and lung cancer incidence, as this study is an observational epidemiology investigation. This study used community-level incidence and air pollution exposure, but not individual-level information on exposure and outcome. We only had air pollution data for the years 1990 and 2005, and interpolated the data to 1990–2009. These might underestimate the association between air pollution and lung cancer incidence, because random measurement error in exposure will bias the effect estimates towards the null. FundingHope Run Malathon Fund (Cancer Institute & Hospital, Chinese Academy of Medical Sciences, LC2011Y41), and University of Queensland Research Fellowship (YG).

Ambient air pollution and lung disease in China: health effects, study design approaches and future research.

Ambient air pollution in China has worsened following dramatic increases in industrialization, automobile use and energy consumption. Particularly bothersome is the increase in the PM2.5 fraction of pollutants. This fraction has been associated with increasing rates of cardio-respiratory disease in China and elsewhere. Ambient pollutant levels have been described in many of China's cities and are comparable to previous levels in southern California. Lung cancer mortality in China has increased since the 1970s and has been higher in men and in urban areas, the exact explanation for which has not been determined. The estimation of individual risk for Chinese citizens living in areas of air pollution will require further research. Occupational cohort and case-control designs each have unique attributes that could make them helpful to use in this setting. Other important future research considerations include detailed exposure assessment and the possible use of biomarkers as a means to better understand and manage the threat posed by air pollution in China.