The application of non-suppressed ion chromatography for monitoring of trace elements in air particulate matter was studied in the present investigation. The results indicate that the use of microwave acid digestion m...The application of non-suppressed ion chromatography for monitoring of trace elements in air particulate matter was studied in the present investigation. The results indicate that the use of microwave acid digestion method is superior in comparison with the conventional thermal acid digestion method as it leads to higher recovery, better reproducibility, lower volatility loss, better protection against environmental contamination and much less digestion time (5 minutes vs. 24 hours). The use of eluent as extractant is shown to reduce the water dip problem in the chro-matogram. The addition of chelating agent in the eluent coupled with UV detection is shown to provide satisfactory chromatographic separation and good sensitivity for the analysis of transition metals present in the air particulate matter. Using the U.S. National Bureau of Standards Reference Material 1648 Urban Particulate Matter as standard for checking, the analytical procedure is shown to give good recovery and reproducibility for the detection of the following cations and anions in air particulate matter: Fe2 Cu, Mn, Pb, Zn, Mg, Na, HN4+, Cl-, NO3- and SO42-. Field test was also performed to check the applicability of the method and the results obtained were discussed in the present paper.展开更多
A method was developed for the determination of trace arsenic by spectrophotometry. The proposed method is rapid, simple, and inexpensive. This method can be used for sensitive determination of trace arsenic in enviro...A method was developed for the determination of trace arsenic by spectrophotometry. The proposed method is rapid, simple, and inexpensive. This method can be used for sensitive determination of trace arsenic in environmental samples and especially in air particulates. The results obtained by this method as a proposed method were compared with those obtained by hydride generation atomic absorption spectrometry as a popular reported method for the determination of arsenic and an excellent agreement was found between them. The method was also used for determination of arsenic associated with airborne particulate matter and diesel exhaust particulates. The results showed that considerable amount of arsenic are associated with diesel engine particulates. The variation in concentration of arsenic was also investigated. The atmospheric concentration of arsenic was different in different sampling stations was dependent to the traffic density.展开更多
Objective: to explore the correlation between particulate air pollution and dynamic heart rate variability and arrhythmia in elderly patients with coronary heart disease. Methods: a total of 120 elderly patients with ...Objective: to explore the correlation between particulate air pollution and dynamic heart rate variability and arrhythmia in elderly patients with coronary heart disease. Methods: a total of 120 elderly patients with coronary heart disease were included in the study. The clinical data were statistically analyzed, and the dynamic heart rate variability and arrhythmia were recorded. Particulate air pollutant levels (SO2, NO2, O3, CO, PM10, and PM2.5) are monitored at monitoring points. The generalized linear model was used to analyze the relationship between the concentration of atmospheric pollutants and dynamic heart rate variability and arrhythmia, and the Logistic regression model was used to analyze the correlation between particulate air pollution and dynamic heart rate variability and arrhythmia in elderly patients with coronary heart disease. Results: except for the negative correlation between O3 and NO2 and CO, there was a positive correlation between the other particulate air pollutants. There was a significant correlation between CO, SO2, O3, PM10 and PM2.5 and heart rate variability and arrhythmia (P < 0.05). There was no correlation between NO2 and heart rate variability and arrhythmia (P > 0.05). Conclusion: the particulate air pollutants CO, SO2, O3, PM10 and PM2.5 are the independent risk factors for heart rate variability and arrhythmia in elderly patients with coronary heart disease.展开更多
O3 and PM2.5 were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China＇s urban air quality will be evaluated usin...O3 and PM2.5 were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China＇s urban air quality will be evaluated using six factors （SO2, NO2, O3, CO, PM2.5 and PM10） from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2 and PMlo were observed in 26 cities, and the pollutants O3, CO and PM2.5 were measured in 15 of the 26 cities. The concentrations of SO2 and CO were much higher in the cities in north China than those in the south. As for O3 and NO2, however, there was no significant difference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5 to PMI0 ranging from 55% to 77%. The concentrations of PM2.5 （57.5 μg/m3） and PMlo （91.2 μg/m3） were much higher than the values （PM2.5：11.2μg/m3; PMI0：35.6 μg/m3） recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more efforts will to be taken to control air pollution in China.展开更多
A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_...A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_x）, carbon monoxide（CO） and particulate matter（PM_2.5and PM_（10）） before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_（10） and PM_2.5mass concentration is as high as2070 μg/m^3 and 1620 μg/m3, respectively（24 hr mean）, which was about 20 and 27 times to National Ambient Air Quality Standards（NAAQS）. For Diwali-2011, the increase in PM_（10） and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m^3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.展开更多
Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed b...Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3-2.s and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources： natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B tung cells were exposed to PM0.3-2.5, or to the Extractable Organic Matter （EOM） of PM0.3-2.5 and PM2.s. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction （PM2.5） containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.展开更多
Lanzhou is one of the most aerosol-polluted cities in China. In this study, an online analyzer for Monitoring for AeRosols and GAses was deployed to measure major water-soluble inorganic ions in PM10 at 1-hour time re...Lanzhou is one of the most aerosol-polluted cities in China. In this study, an online analyzer for Monitoring for AeRosols and GAses was deployed to measure major water-soluble inorganic ions in PM10 at 1-hour time resolution, and 923 samples were obtained from Apr 1 to May 24, 2011. During the field campaign, air pollution days were encountered with Air Quality Index more than 100 and daily average concentration of PM10 exceeding 150 itg/m3. Based on the variation of water-soluble ions and results of Positive Matrix Factorization 3.0 model execution, the air pollution days were classified as crustal species- or secondary aerosol-induced, and the different formation mechanisms of these two air pollution types were studied. During the crustal species pollution days, the content of Ca2＋ increased and was about 2.3 times higher than the average on clear days, and the air parcel back trajectory was used to analyze the sources of crustal species. Data on sulfate, trace gases and meteorological factors were used to reveal the formation mechanism of secondary aerosol pollution. The sulfur oxidation ratio （SOR） was derived from the 923 samples, and the SOR had high positive correlation with relative humidity in early summer in Lanzhou.展开更多
Eddy-covariance observations from the Beijing 325-m meteorological tower are used to evaluate the effects of coordinate rotation on the turbulent exchange of momentum and scalars during wintertime haze pollution(Janua...Eddy-covariance observations from the Beijing 325-m meteorological tower are used to evaluate the effects of coordinate rotation on the turbulent exchange of momentum and scalars during wintertime haze pollution(January-February 2013). Two techniques are used in the present evaluation; namely, the natural wind coordinate(NWC) and the planar fit coordinate(PFC), with the latter being applied by means of two methods for linear regression(i.e., overall and sector-wise). The different techniques show a general agreement in both turbulent fluxes and transport efficiencies, especially evident at the lower, 140-m level above the ground(compared to the higher, 280-m level), perhaps implying that the selection of a technique for coordinate rotation(NWC or PFC) is less of a concern for a sufficiently low level, despite the complexities of urban terrain. Additionally, sector-wise regression is a recommended approach for practical application of the PFC in a complex urban environment subjected to particulate pollution, because this method is found to produce a better correlation between the mean vertical velocity at the 140- and 280-m heights.展开更多
A severe particulate matter pollution event occurred in Shanghai from 1 to 9 December 2013. The mean hourly mass concentrations of PM2.5 and PM10 were 211.9 and 249.0 μg/m3, respectively. Reanalysis data, in situ, an...A severe particulate matter pollution event occurred in Shanghai from 1 to 9 December 2013. The mean hourly mass concentrations of PM2.5 and PM10 were 211.9 and 249.0 μg/m3, respectively. Reanalysis data, in situ, and remote-sensing measurements were used to examine the impacts of meteorological conditions on this event. It was found that the synoptic pattern of weak pressure, the reduced planetary boundary layer height, and the passage of two cold fronts were key factors causing the event. Four stages were identified during this event based on the evolution of its PM2.5 levels and weather conditions. The highest concentration of PM2.5 （602 μg/m3） was observed in stage 3. High PM2.5 concentrations were closely associated with a low local ventilation index, with an average of 505 m2/s, as well as with the influx of pollutants from upstream, transported by the cold fronts.展开更多
Cohort evidence linking long-term survival of older adults with exposure to fine particulate matter(PM_(2.5))constituents remains scarce in China.By constructing a dynamic cohort based on the Chinese Longitudinal Heal...Cohort evidence linking long-term survival of older adults with exposure to fine particulate matter(PM_(2.5))constituents remains scarce in China.By constructing a dynamic cohort based on the Chinese Longitudinal Healthy Longevity Study,we aimed to assess the individual and joint associations of major PM_(2.5)constituents with all-cause death in Chinese oldest-old(≥80 years)adults.Time-dependent Cox proportional hazards models were adopted to estimate death risks of long-term exposure to PM_(2.5)constituents.Among 14,884 participants,totaling 56,342 person-years of follow-up,12,346 deaths were identified.The highest mortality risk associated with an interquartile range(IQR)increase in exposure was 1.081(95%confidence interval[CI]:1.055–1.108)for sulfate(IQR=4.1μg m^(-3)),followed by 1.078(95%CI:1.056–1.101)for black carbon(IQR=1.6μg m^(-3)),1.056(95%CI:1.028–1.084)for ammonium(IQR=3.2μg m^(-3)),1.050(95%CI:1.021–1.080)for nitrate(IQR=5.8μg m^(-3)),and 1.049(95%CI:1.024–1.074)for organic matter(IQR=10.3μg m^(-3)).In joint exposure,each IQRequivalent rise of all five PM_(2.5)constituents was associated with an 8.2%(95%CI:4.0%–12.6%)increase in mortality risk.The weight analysis indicated the predominant role of sulfate and black carbon in driving PM_(2.5)-related mortality.Octogenarians(aged 80–89 years)and rural dwellers were at significantly greater risk of mortality from individual and joint exposures to PM_(2.5)constituents.This study suggests that later-life exposure to PM_(2.5)constituents,particularly sulfate and black carbon,may curtail long-term survival of the oldest-old in China.展开更多
文摘The application of non-suppressed ion chromatography for monitoring of trace elements in air particulate matter was studied in the present investigation. The results indicate that the use of microwave acid digestion method is superior in comparison with the conventional thermal acid digestion method as it leads to higher recovery, better reproducibility, lower volatility loss, better protection against environmental contamination and much less digestion time (5 minutes vs. 24 hours). The use of eluent as extractant is shown to reduce the water dip problem in the chro-matogram. The addition of chelating agent in the eluent coupled with UV detection is shown to provide satisfactory chromatographic separation and good sensitivity for the analysis of transition metals present in the air particulate matter. Using the U.S. National Bureau of Standards Reference Material 1648 Urban Particulate Matter as standard for checking, the analytical procedure is shown to give good recovery and reproducibility for the detection of the following cations and anions in air particulate matter: Fe2 Cu, Mn, Pb, Zn, Mg, Na, HN4+, Cl-, NO3- and SO42-. Field test was also performed to check the applicability of the method and the results obtained were discussed in the present paper.
文摘A method was developed for the determination of trace arsenic by spectrophotometry. The proposed method is rapid, simple, and inexpensive. This method can be used for sensitive determination of trace arsenic in environmental samples and especially in air particulates. The results obtained by this method as a proposed method were compared with those obtained by hydride generation atomic absorption spectrometry as a popular reported method for the determination of arsenic and an excellent agreement was found between them. The method was also used for determination of arsenic associated with airborne particulate matter and diesel exhaust particulates. The results showed that considerable amount of arsenic are associated with diesel engine particulates. The variation in concentration of arsenic was also investigated. The atmospheric concentration of arsenic was different in different sampling stations was dependent to the traffic density.
文摘Objective: to explore the correlation between particulate air pollution and dynamic heart rate variability and arrhythmia in elderly patients with coronary heart disease. Methods: a total of 120 elderly patients with coronary heart disease were included in the study. The clinical data were statistically analyzed, and the dynamic heart rate variability and arrhythmia were recorded. Particulate air pollutant levels (SO2, NO2, O3, CO, PM10, and PM2.5) are monitored at monitoring points. The generalized linear model was used to analyze the relationship between the concentration of atmospheric pollutants and dynamic heart rate variability and arrhythmia, and the Logistic regression model was used to analyze the correlation between particulate air pollution and dynamic heart rate variability and arrhythmia in elderly patients with coronary heart disease. Results: except for the negative correlation between O3 and NO2 and CO, there was a positive correlation between the other particulate air pollutants. There was a significant correlation between CO, SO2, O3, PM10 and PM2.5 and heart rate variability and arrhythmia (P < 0.05). There was no correlation between NO2 and heart rate variability and arrhythmia (P > 0.05). Conclusion: the particulate air pollutants CO, SO2, O3, PM10 and PM2.5 are the independent risk factors for heart rate variability and arrhythmia in elderly patients with coronary heart disease.
基金supported by the National Natural Scientific Foundation of China(No.41005065,41375132)the National Department Public Benefit Research Foundation(Ministry of Environmental Protection of the People’s Republic of China(No.201009001,201409003,201309011)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB05030400)
文摘O3 and PM2.5 were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China＇s urban air quality will be evaluated using six factors （SO2, NO2, O3, CO, PM2.5 and PM10） from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2 and PMlo were observed in 26 cities, and the pollutants O3, CO and PM2.5 were measured in 15 of the 26 cities. The concentrations of SO2 and CO were much higher in the cities in north China than those in the south. As for O3 and NO2, however, there was no significant difference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5 to PMI0 ranging from 55% to 77%. The concentrations of PM2.5 （57.5 μg/m3） and PMlo （91.2 μg/m3） were much higher than the values （PM2.5：11.2μg/m3; PMI0：35.6 μg/m3） recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more efforts will to be taken to control air pollution in China.
基金supported by the Ministry of Earth Sciences (Mo ES), Government of India, New Delhi
文摘A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_x）, carbon monoxide（CO） and particulate matter（PM_2.5and PM_（10）） before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_（10） and PM_2.5mass concentration is as high as2070 μg/m^3 and 1620 μg/m3, respectively（24 hr mean）, which was about 20 and 27 times to National Ambient Air Quality Standards（NAAQS）. For Diwali-2011, the increase in PM_（10） and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m^3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.
基金supported by the Institut National du Cancer (INCa Convention no. 2010-368)+2 种基金the Hauts-de-France Region (Convention No. 14003399)the French Agency of the Environment and Energy (ADEME Convention no. 1494c008283-84)
文摘Particulate matter in ambient air constitutes a complex mixture of fine and ultrafine particles composed of various chemical compounds including metals, ions, and organics. A multidisciplinary approach was developed by studying physico-chemical characteristics and mechanisms involved in the toxicity of particulate atmospheric pollution. PM0.3-2.s and PM2.5 including ultrafine particles were sampled in Dunkerque, a French industrialized seaside city. PM samples were characterized from a chemical and toxicological point of view. Physico-chemical characterization evidenced that PM2.5 comes from several sources： natural ones, such as soil resuspension and marine sea-salt emissions, as well as anthropogenic ones, such as shipping traffic, road traffic, and industrial activities. Human BEAS-2B tung cells were exposed to PM0.3-2.5, or to the Extractable Organic Matter （EOM） of PM0.3-2.5 and PM2.s. These exposures induced several mechanisms of action implied in the genotoxicity, such as oxidative DNA adducts and DNA Damage Response. The toxicity of PM-EOM was higher for the sample including the ultrafine fraction （PM2.5） containing also higher concentrations of polycyclic aromatic hydrocarbons. These results evidenced the major role of organic compounds in the toxicity of PM.
基金supported by the National Natural Science Foundation of China (No. 20307005)the Technological Project of Gansu (No. 0804GKCA029)Gansu Province science and technology research funded projects (No. 2GS057-A52-001-02)
文摘Lanzhou is one of the most aerosol-polluted cities in China. In this study, an online analyzer for Monitoring for AeRosols and GAses was deployed to measure major water-soluble inorganic ions in PM10 at 1-hour time resolution, and 923 samples were obtained from Apr 1 to May 24, 2011. During the field campaign, air pollution days were encountered with Air Quality Index more than 100 and daily average concentration of PM10 exceeding 150 itg/m3. Based on the variation of water-soluble ions and results of Positive Matrix Factorization 3.0 model execution, the air pollution days were classified as crustal species- or secondary aerosol-induced, and the different formation mechanisms of these two air pollution types were studied. During the crustal species pollution days, the content of Ca2＋ increased and was about 2.3 times higher than the average on clear days, and the air parcel back trajectory was used to analyze the sources of crustal species. Data on sulfate, trace gases and meteorological factors were used to reveal the formation mechanism of secondary aerosol pollution. The sulfur oxidation ratio （SOR） was derived from the 923 samples, and the SOR had high positive correlation with relative humidity in early summer in Lanzhou.
基金funded by the National Basic Research Program of China(Grant No.2014CB447900)National High Technology Research and Development Program(Grant No.2014AA06A512)Ministry of Environmental Protection of China through its Special Funds for Scientific Research on Public Welfare(Grant No.201409001)
文摘Eddy-covariance observations from the Beijing 325-m meteorological tower are used to evaluate the effects of coordinate rotation on the turbulent exchange of momentum and scalars during wintertime haze pollution(January-February 2013). Two techniques are used in the present evaluation; namely, the natural wind coordinate(NWC) and the planar fit coordinate(PFC), with the latter being applied by means of two methods for linear regression(i.e., overall and sector-wise). The different techniques show a general agreement in both turbulent fluxes and transport efficiencies, especially evident at the lower, 140-m level above the ground(compared to the higher, 280-m level), perhaps implying that the selection of a technique for coordinate rotation(NWC or PFC) is less of a concern for a sufficiently low level, despite the complexities of urban terrain. Additionally, sector-wise regression is a recommended approach for practical application of the PFC in a complex urban environment subjected to particulate pollution, because this method is found to produce a better correlation between the mean vertical velocity at the 140- and 280-m heights.
基金supported by the National Natural Science Foundation of China under Grant No.41375014the Project of Science and Technology Commission of Shanghai Municipality under Grant Nos.12dz1202702 and 14DZ1202904and the Project of Scientific and Technological New Star of Shanghai Meteorological Bureau under Grant Nos.QM201204 and MS201212
文摘A severe particulate matter pollution event occurred in Shanghai from 1 to 9 December 2013. The mean hourly mass concentrations of PM2.5 and PM10 were 211.9 and 249.0 μg/m3, respectively. Reanalysis data, in situ, and remote-sensing measurements were used to examine the impacts of meteorological conditions on this event. It was found that the synoptic pattern of weak pressure, the reduced planetary boundary layer height, and the passage of two cold fronts were key factors causing the event. Four stages were identified during this event based on the evolution of its PM2.5 levels and weather conditions. The highest concentration of PM2.5 （602 μg/m3） was observed in stage 3. High PM2.5 concentrations were closely associated with a low local ventilation index, with an average of 505 m2/s, as well as with the influx of pollutants from upstream, transported by the cold fronts.
基金supported by Youth Fund Project of Humanities and Social Sciences Research of the Ministry of Education (21YJCZH229)the Chunhui Program Collaborative Research Project of the Ministry of Education (HZKY20220336)“The 14th Five Year Plan”Hubei Provincial Advantaged Characteristic Disciplines (Groups)Project of Wuhan University of Science and Technology (2023C0102)。
文摘Cohort evidence linking long-term survival of older adults with exposure to fine particulate matter(PM_(2.5))constituents remains scarce in China.By constructing a dynamic cohort based on the Chinese Longitudinal Healthy Longevity Study,we aimed to assess the individual and joint associations of major PM_(2.5)constituents with all-cause death in Chinese oldest-old(≥80 years)adults.Time-dependent Cox proportional hazards models were adopted to estimate death risks of long-term exposure to PM_(2.5)constituents.Among 14,884 participants,totaling 56,342 person-years of follow-up,12,346 deaths were identified.The highest mortality risk associated with an interquartile range(IQR)increase in exposure was 1.081(95%confidence interval[CI]:1.055–1.108)for sulfate(IQR=4.1μg m^(-3)),followed by 1.078(95%CI:1.056–1.101)for black carbon(IQR=1.6μg m^(-3)),1.056(95%CI:1.028–1.084)for ammonium(IQR=3.2μg m^(-3)),1.050(95%CI:1.021–1.080)for nitrate(IQR=5.8μg m^(-3)),and 1.049(95%CI:1.024–1.074)for organic matter(IQR=10.3μg m^(-3)).In joint exposure,each IQRequivalent rise of all five PM_(2.5)constituents was associated with an 8.2%(95%CI:4.0%–12.6%)increase in mortality risk.The weight analysis indicated the predominant role of sulfate and black carbon in driving PM_(2.5)-related mortality.Octogenarians(aged 80–89 years)and rural dwellers were at significantly greater risk of mortality from individual and joint exposures to PM_(2.5)constituents.This study suggests that later-life exposure to PM_(2.5)constituents,particularly sulfate and black carbon,may curtail long-term survival of the oldest-old in China.
