Thirty-six daily time interval PM2.5 samples were collected in different seasonal dates in urban Shanghai, and the concentrations of four anions （Cl- , NO3-, SO4^2-, C2O4^2-） and five cations （NH＋, Na＋, K＋, Ca2...Thirty-six daily time interval PM2.5 samples were collected in different seasonal dates in urban Shanghai, and the concentrations of four anions （Cl- , NO3-, SO4^2-, C2O4^2-） and five cations （NH＋, Na＋, K＋, Ca2＋, Mg2＋） were analyzed with ion chromatography. Sulfate, nitrate and ammonium were found to be the dominant species, accounting for about 80% of the total ions. The daily nitrate to sulfate mass ratio ranged from 0.31 to 0.82, indicating that coal combustion was still the main pollution source in Shanghai. The equivalent ratio of ammonium to stun of nitrate and sulfate showed fixed diurnal variation pattern in all the sampling days with higher values in the nighttime, suggesting that fine particles in the night were more neutralized. The oxalate to sulfate ratio was lower in the winter sampling days than that in hotter summer and autumn sampling days. Oxalate was significantly correlated with sulfate in winter sampling days, but not in the summer and autumn, suggesting that the formation mechanism of oxalate and sulfate was similar in winter, however different in hot days.展开更多
To further understand the variations of water-soluble ions in PM2.5 in Beijing,the authors observed their concentrations continuously and in high temporal resolution by the system for rapid collection of fine particle...To further understand the variations of water-soluble ions in PM2.5 in Beijing,the authors observed their concentrations continuously and in high temporal resolution by the system for rapid collection of fine particles and ion chromatography(RCFP-IC) during 12–18 July 2010.These results combined with those of earlier backward trajectory research are used analyzed to determine the causes of concentration changes in water-soluble ions under the influences of two kinds of air masses in summer.The results indicate that concentrations of NO3-,SO42-,and NH4+ were influenced strongly by the continental air mass than by the marine air mass.Cl- and Na+ were not changed significantly.Because the sources of K+,Mg2+,and Ca2+ are mainly concentrated on land,their concentration levels were slightly higher under the control of continental air mass than that of the marine air mass.Variations of NO2- during the observation differed from those of other ions;its concentration was significantly higher under the influence of marine air mass.Moreover,the authors obtain the diurnal variations of eight water-soluble inorganic ions including NH4+,K+,Mg2+,Ca2+,Cl-,NO2-,NO3-,and SO42-.Diurnal variations of NH4+,NO3-,and Cl- showed single peak,which appeared before noon,while SO42- showed two peaks that appeared during rush hours.Those of Mg2+,Ca2+,and K+ showed single peak that appeared in the afternoon.That of NO2- showed with a peak appearing at sunrise and a valley appearing at sunset.展开更多
PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National ...PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National Forest Park in Chongming Island （CM）, Dinghu Mountain Nature Reserve （DH）, Jianfengling Nature Reserve in Hainan Island （HN）. The mass concentrations of PM2.5, organic carbon （OC）, elemental carbon （EC）, water soluble organic carbon （WSOC） as well as concentrations of ten inorganic ions （F？, Cl？, NO3？, SO42？, C2O42？, NH4＋, Na＋, K＋, Ca2＋, Mg2＋） were determined. Aerosol chemical mass closures were achieved. The 24-hr average concentrations of PM2.5 were 38.8, 89.2, 30.4, 18 μg/m3 at CB, CM, DH and HN, respectively. Organic matter and EC accounted for 21%–33% and 1.3%–2.3% of PM2.5 mass, respectively. The sum of three dominant secondary ions （SO42-, NO3-, NH4＋） accounted for 44%, 50%, 45% and 16% of local PM2.5 mass at CB, CM, DH and HN, respectively. WSOC comprised 35%–65% of OC. The sources of PM2.5 include especially important regional anthropogenic pollutions at Chinese forest areas.展开更多
The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between...The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between normal and haze days.The highest contributors to PM2.5 were organic carbon（OC）,nitrate,and sulfate in haze days and were OC,sulfate,and elemental carbon（EC） in normal days.The concentrations of secondary species such as,NO3^-,SO4^2-,and NH4^＋ in haze days were 6.5,3.9,and 5.3 times higher than those in normal days,respectively,while primary species（EC,Ca^2＋,K^＋） show similar increase from normal to haze days by a factor about 2.2-2.4.OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC（secondary organic carbon） accounted more than 36.6% for the total organic carbon in haze days.The significantly increase in the secondary species（SOC,NO3^-,SO4^2-,and NH4^＋）,especially in NO3^-,caused the worst air quality in this region.Simultaneously,the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions.During the sampling periods,air pollution and visibility had a good relationship with the air mass transport distance;the shorter air masses transport distance,the worse air quality and visibility in Guangzhou,indicating the strong domination of local sources contributing to haze formation.High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species.展开更多
Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing country.In this study, aerosols and their precursor gas were collected by NILU fil...Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing country.In this study, aerosols and their precursor gas were collected by NILU filter pack at two distinct urban sites during the winter and summer in Osaka, Japan and dry and rainy seasons in Ho Chi Minh City(HCMC),Vietnam.The aims are to investigate the contribution of water-soluble inorganic ions(WSIIs) to PM2.5, thermodynamic characterization and possible formation pathway of secondary inorganic aerosol(SIA).The PM2.5 concentration in Osaka(15.8 μg/m^3) is lower than that in HCMC(23.0 μg/m^3), but the concentration of WSIIs in Osaka(9.0 μg/m^3) is two times higher than that in HCMC(4.1 μg/m^3).Moreover, SIA including NH4^+, NO3^-and SO4^2-are major components in WSIIs accounting for 90% and 76%(in molar) in Osaka and HCMC,respectively.Thermodynamic models were used to understand the thermodynamic characterization of urban aerosols.Overall, statistical analysis results indicate that very good agreement(R2> 0.8) was found for all species, except for nitrate aerosol in HCMC.We found that when the crustal species present at high amount, those compositions should be included in model calculation(i.e.in the HCMC situation).Finally, we analyzed the characteristics of NH4^+– NO3^-– SO4^2-system.A possible pathway to produce fine nitrate aerosol in Osaka is via the homogeneous reaction between NH3 and HNO3, while nonvolatile nitrate aerosols can be formed by the heterogeneous reactions in HCMC.展开更多
To better understand the characteristics and transformation mechanisms of secondary inorganic aerosols,hourly mass concentrations of water-soluble inorganic ions(WSIIs)in PM_(2.5)and their gaseous precursors were meas...To better understand the characteristics and transformation mechanisms of secondary inorganic aerosols,hourly mass concentrations of water-soluble inorganic ions(WSIIs)in PM_(2.5)and their gaseous precursors were measured online from 2016 to 2018 at an urban site in Beijing.Seasonal and diurnal variations in water-soluble ions and gaseous precursors were discussed and their gas-particle conversion and partitioning were also examined,some related parameters were characterized.The(TNH_(3))Rich was also defined to describe the variations of the excess NH_(3)in different seasons.In addition,a sensitivity test was carried out by using ISORROPIA II to outline the driving factors of gas-particle partitioning.In Beijing,the relative contribution of nitrate to PM_(2.5)has increased markedly in recent years,especially under polluted conditions.In the four seasons,only a small portion of NO_(2)in the atmosphere was converted into total nitrate(TNO_(3)),and more than 80%of TNO_(3)occurred in the form of nitrate due to the abundant ammonia.The concentration of total ammonia(TNH_(3))was much higher than that required to neutralize acid gases,and most of the TNH_(3)occurred as gaseous NH_(3).The nitrous acid(HONO)concentration was highly correlated with NH_(3)concentration and had increased significantly in Beijing compared with previous studies.The total chloride(TCl)was the highest in winter,andε(Cl^(-))was more sensitive to variations in the ambient temperature(T)and relative humidity(RH)thanε(NO_(3)^(-)).展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.20877052)the Shanghai Leading Academic Discipline Project(Grant No.S30109)
文摘Thirty-six daily time interval PM2.5 samples were collected in different seasonal dates in urban Shanghai, and the concentrations of four anions （Cl- , NO3-, SO4^2-, C2O4^2-） and five cations （NH＋, Na＋, K＋, Ca2＋, Mg2＋） were analyzed with ion chromatography. Sulfate, nitrate and ammonium were found to be the dominant species, accounting for about 80% of the total ions. The daily nitrate to sulfate mass ratio ranged from 0.31 to 0.82, indicating that coal combustion was still the main pollution source in Shanghai. The equivalent ratio of ammonium to stun of nitrate and sulfate showed fixed diurnal variation pattern in all the sampling days with higher values in the nighttime, suggesting that fine particles in the night were more neutralized. The oxalate to sulfate ratio was lower in the winter sampling days than that in hotter summer and autumn sampling days. Oxalate was significantly correlated with sulfate in winter sampling days, but not in the summer and autumn, suggesting that the formation mechanism of oxalate and sulfate was similar in winter, however different in hot days.
基金funded by the National Natural Science Foundation of China (41175107 and 41275139)
文摘To further understand the variations of water-soluble ions in PM2.5 in Beijing,the authors observed their concentrations continuously and in high temporal resolution by the system for rapid collection of fine particles and ion chromatography(RCFP-IC) during 12–18 July 2010.These results combined with those of earlier backward trajectory research are used analyzed to determine the causes of concentration changes in water-soluble ions under the influences of two kinds of air masses in summer.The results indicate that concentrations of NO3-,SO42-,and NH4+ were influenced strongly by the continental air mass than by the marine air mass.Cl- and Na+ were not changed significantly.Because the sources of K+,Mg2+,and Ca2+ are mainly concentrated on land,their concentration levels were slightly higher under the control of continental air mass than that of the marine air mass.Variations of NO2- during the observation differed from those of other ions;its concentration was significantly higher under the influence of marine air mass.Moreover,the authors obtain the diurnal variations of eight water-soluble inorganic ions including NH4+,K+,Mg2+,Ca2+,Cl-,NO2-,NO3-,and SO42-.Diurnal variations of NH4+,NO3-,and Cl- showed single peak,which appeared before noon,while SO42- showed two peaks that appeared during rush hours.Those of Mg2+,Ca2+,and K+ showed single peak that appeared in the afternoon.That of NO2- showed with a peak appearing at sunrise and a valley appearing at sunset.
基金supported by the National Natrual Science Foundation of China (No. 20677036, 20877051)the Shanghai Leading Academic Disciplines (No. S30109)+1 种基金the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministrysupported by the Graduate Innovative Fund from Shanghai University
文摘PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve （CB）, Dongping National Forest Park in Chongming Island （CM）, Dinghu Mountain Nature Reserve （DH）, Jianfengling Nature Reserve in Hainan Island （HN）. The mass concentrations of PM2.5, organic carbon （OC）, elemental carbon （EC）, water soluble organic carbon （WSOC） as well as concentrations of ten inorganic ions （F？, Cl？, NO3？, SO42？, C2O42？, NH4＋, Na＋, K＋, Ca2＋, Mg2＋） were determined. Aerosol chemical mass closures were achieved. The 24-hr average concentrations of PM2.5 were 38.8, 89.2, 30.4, 18 μg/m3 at CB, CM, DH and HN, respectively. Organic matter and EC accounted for 21%–33% and 1.3%–2.3% of PM2.5 mass, respectively. The sum of three dominant secondary ions （SO42-, NO3-, NH4＋） accounted for 44%, 50%, 45% and 16% of local PM2.5 mass at CB, CM, DH and HN, respectively. WSOC comprised 35%–65% of OC. The sources of PM2.5 include especially important regional anthropogenic pollutions at Chinese forest areas.
基金supported by the National Excellent Youth Foundation of China (No. 20625722)the China Postdoctoral Science Foundation (No. 20080430396)
文摘The chemical characteristics（water-soluble ions and carbonaceous species） of PM2.5 in Guangzhou were measured during a typical haze episode.Most of the chemical species in PM2.5 showed significant difference between normal and haze days.The highest contributors to PM2.5 were organic carbon（OC）,nitrate,and sulfate in haze days and were OC,sulfate,and elemental carbon（EC） in normal days.The concentrations of secondary species such as,NO3^-,SO4^2-,and NH4^＋ in haze days were 6.5,3.9,and 5.3 times higher than those in normal days,respectively,while primary species（EC,Ca^2＋,K^＋） show similar increase from normal to haze days by a factor about 2.2-2.4.OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC（secondary organic carbon） accounted more than 36.6% for the total organic carbon in haze days.The significantly increase in the secondary species（SOC,NO3^-,SO4^2-,and NH4^＋）,especially in NO3^-,caused the worst air quality in this region.Simultaneously,the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions.During the sampling periods,air pollution and visibility had a good relationship with the air mass transport distance;the shorter air masses transport distance,the worse air quality and visibility in Guangzhou,indicating the strong domination of local sources contributing to haze formation.High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species.
基金partially supported by the Japan Science and Technology Agency, the Japan International Cooperation Agency, and the Science and Technology Research Partnership for Sustainable Development (SATREPS project entitled “Multi-Beneficial Measure for Mitigation of Climate Change in Vietnam and Indochina Countries by Development of Biomass Energy”).
文摘Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing country.In this study, aerosols and their precursor gas were collected by NILU filter pack at two distinct urban sites during the winter and summer in Osaka, Japan and dry and rainy seasons in Ho Chi Minh City(HCMC),Vietnam.The aims are to investigate the contribution of water-soluble inorganic ions(WSIIs) to PM2.5, thermodynamic characterization and possible formation pathway of secondary inorganic aerosol(SIA).The PM2.5 concentration in Osaka(15.8 μg/m^3) is lower than that in HCMC(23.0 μg/m^3), but the concentration of WSIIs in Osaka(9.0 μg/m^3) is two times higher than that in HCMC(4.1 μg/m^3).Moreover, SIA including NH4^+, NO3^-and SO4^2-are major components in WSIIs accounting for 90% and 76%(in molar) in Osaka and HCMC,respectively.Thermodynamic models were used to understand the thermodynamic characterization of urban aerosols.Overall, statistical analysis results indicate that very good agreement(R2> 0.8) was found for all species, except for nitrate aerosol in HCMC.We found that when the crustal species present at high amount, those compositions should be included in model calculation(i.e.in the HCMC situation).Finally, we analyzed the characteristics of NH4^+– NO3^-– SO4^2-system.A possible pathway to produce fine nitrate aerosol in Osaka is via the homogeneous reaction between NH3 and HNO3, while nonvolatile nitrate aerosols can be formed by the heterogeneous reactions in HCMC.
基金supported by the National Natural Science Foundation of China(No.42005079,41675131)the Beijing Natural Science Foundation(No.8131003)the Beijing Talents Fund(No.2014000021223ZK49)。
文摘To better understand the characteristics and transformation mechanisms of secondary inorganic aerosols,hourly mass concentrations of water-soluble inorganic ions(WSIIs)in PM_(2.5)and their gaseous precursors were measured online from 2016 to 2018 at an urban site in Beijing.Seasonal and diurnal variations in water-soluble ions and gaseous precursors were discussed and their gas-particle conversion and partitioning were also examined,some related parameters were characterized.The(TNH_(3))Rich was also defined to describe the variations of the excess NH_(3)in different seasons.In addition,a sensitivity test was carried out by using ISORROPIA II to outline the driving factors of gas-particle partitioning.In Beijing,the relative contribution of nitrate to PM_(2.5)has increased markedly in recent years,especially under polluted conditions.In the four seasons,only a small portion of NO_(2)in the atmosphere was converted into total nitrate(TNO_(3)),and more than 80%of TNO_(3)occurred in the form of nitrate due to the abundant ammonia.The concentration of total ammonia(TNH_(3))was much higher than that required to neutralize acid gases,and most of the TNH_(3)occurred as gaseous NH_(3).The nitrous acid(HONO)concentration was highly correlated with NH_(3)concentration and had increased significantly in Beijing compared with previous studies.The total chloride(TCl)was the highest in winter,andε(Cl^(-))was more sensitive to variations in the ambient temperature(T)and relative humidity(RH)thanε(NO_(3)^(-)).
