Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscop...Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscopic behaviors of six Na-and K-containing salts commonly found in those primary organic aerosols.Their hygroscopic growths as a function of relative humidity(RH) agree well with thermodynamic model prediction.Temperature dependence of deliquescence RH(DRH) values for five of those salts was also investigated,which are comparable to those in literature within 1%-2% RH,most showing negative dependence on temperature.Hygroscopic growth curves of real-world soil and sea salt samples were also measured.The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition.The substantial amounts of water-soluble ions,including Na+and K+,in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH(>80%) conditions.For three less-hygroscopic dust samples,however,measurements showed higher water uptake ability than that predicted by the thermodynamic model.The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH.The results of this study provide a comprehensive characterization of the hygroscopicity of Na-and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.展开更多
Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reac...Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reaction has not been well understood,and its impact on aerosol hygroscopicity is not yet clear.This work investigated heterogeneous reactions of NO_(2)(∼10 ppmv)with K-feldspar,illite,kaolinite,montmorillonite and Arizona Test Dust(ATD)at room temperature as a function of relative humidity(<1%to 80%)and reaction time(up to 24 hr).Heterogeneous reactivity towards NO_(2) was low for illite,kaolinite,montmorillonite and ATD,and uptake coefficients of NO_(2),γ(NO_(2)),were determined to be around or smaller than 1×10^(−8);K-feldspar exhibited higher reactivity towards NO_(2),and CaCO_(3) is most reactive among the nine mineral dust samples considered in this and previous work.After heterogeneous reaction with NO_(2) for 24 hr,increase in hygroscopicity was nearly insignificant for illite,kaolinite and montmorillonite,and small but significant for K-feldspar;in addition,large increase in hygroscopicity was observed for ATD,although the increase in hygroscopicity was still smaller than CaCO_(3).展开更多
Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezin...Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezing apparatus(Guangzhou Institute of Geochemistry Ice Nucleation Apparatus,GIGINA)was developed in thiswork to measure IN activities of atmospheric particles in the immersion freezingmode,and its performancewas validated by a series of experimental characterizations.This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust(ATD)particles before and after heterogeneous reaction with NO_(2)(10±0.5 ppmv)at 40%relative humidity.The surface coverage of nitrate,θ(NO_(3)^(−)),increased to 3.1±0.2 for feldspar after reaction with NO_(2) for 6 hr,and meanwhile the active site density per unit surface area(ns)at-20℃ was reduced from 92±5 to<1.0 cm^(−2) by about two orders of magnitude;however,no changes in nitrate content or IN activities were observed for further increase in reaction time(up to 24 hr).Both nitrate content and IN activities changed continuously with reaction time(up to 24 hr)for ATD particles;after reaction with NO_(2) for 24 hr,θ(NO_(3)^(−))increased to 1.4±0.1 and ns at-20℃ was reduced from 20±4 to 9.7±1.9 cm^(−2) by a factor of∼2.Our work suggests that heterogeneous reaction with NO_(2),an abundant reactive nitrogen species in the troposphere,may significantly reduce IN activities of mineral dust in the immersion freezing mode.展开更多
基金funded by Ministry of Science and Technology of China(No.2018YFC0213901)National Natural Science Foundation of China(Nos.91744204 and 41675120)+4 种基金Guangdong Foundation for Program of Science and Technology Research(Nos.2017B030314057 and 2019B121205006)the Science and Technology Development Fund,Macao SAR(No.016/2017/A1)the Multi-Year Research grant(No.MYRG2018-00006-FST)from the University of MacaoOpen Grant from State Key Lab of Organic Geochemistry Chinese Academy of Sciencesthe CAS Pioneer Hundred Talents program for providing a starting grant
文摘Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscopic behaviors of six Na-and K-containing salts commonly found in those primary organic aerosols.Their hygroscopic growths as a function of relative humidity(RH) agree well with thermodynamic model prediction.Temperature dependence of deliquescence RH(DRH) values for five of those salts was also investigated,which are comparable to those in literature within 1%-2% RH,most showing negative dependence on temperature.Hygroscopic growth curves of real-world soil and sea salt samples were also measured.The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition.The substantial amounts of water-soluble ions,including Na+and K+,in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH(>80%) conditions.For three less-hygroscopic dust samples,however,measurements showed higher water uptake ability than that predicted by the thermodynamic model.The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH.The results of this study provide a comprehensive characterization of the hygroscopicity of Na-and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.
基金supported by the National Natural Science Foundation of China(No.42022050)Guangdong Foundation for Program of Science and Technology Research(Nos.2019B121205006 and 2020B1212060053)+1 种基金the Guangdong Science and Technology Department(No.2017GC010501)CAS Pioneer Hundred Talents program.
文摘Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reaction has not been well understood,and its impact on aerosol hygroscopicity is not yet clear.This work investigated heterogeneous reactions of NO_(2)(∼10 ppmv)with K-feldspar,illite,kaolinite,montmorillonite and Arizona Test Dust(ATD)at room temperature as a function of relative humidity(<1%to 80%)and reaction time(up to 24 hr).Heterogeneous reactivity towards NO_(2) was low for illite,kaolinite,montmorillonite and ATD,and uptake coefficients of NO_(2),γ(NO_(2)),were determined to be around or smaller than 1×10^(−8);K-feldspar exhibited higher reactivity towards NO_(2),and CaCO_(3) is most reactive among the nine mineral dust samples considered in this and previous work.After heterogeneous reaction with NO_(2) for 24 hr,increase in hygroscopicity was nearly insignificant for illite,kaolinite and montmorillonite,and small but significant for K-feldspar;in addition,large increase in hygroscopicity was observed for ATD,although the increase in hygroscopicity was still smaller than CaCO_(3).
基金supported by the National Natural Science Foundation of China(No.42022050)the Guangdong Basic and Applied Basic Research Fund Committee(No.2020B1515130003)+3 种基金the Guangdong Foundation for Program of Science and Technology Research(Nos.2019B121205006 and 2020B1212060053)the Guangdong Science and Technology Department(No.2017GC010501)the CAS Pioneer Hundred Talents program.We would like to thank Ryan Sullivan(Carnegie Mellon University,USA)the Nadine Borduas-Dedekind(University of British Columbia,Canada)for sharing their original data.
文摘Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezing apparatus(Guangzhou Institute of Geochemistry Ice Nucleation Apparatus,GIGINA)was developed in thiswork to measure IN activities of atmospheric particles in the immersion freezingmode,and its performancewas validated by a series of experimental characterizations.This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust(ATD)particles before and after heterogeneous reaction with NO_(2)(10±0.5 ppmv)at 40%relative humidity.The surface coverage of nitrate,θ(NO_(3)^(−)),increased to 3.1±0.2 for feldspar after reaction with NO_(2) for 6 hr,and meanwhile the active site density per unit surface area(ns)at-20℃ was reduced from 92±5 to<1.0 cm^(−2) by about two orders of magnitude;however,no changes in nitrate content or IN activities were observed for further increase in reaction time(up to 24 hr).Both nitrate content and IN activities changed continuously with reaction time(up to 24 hr)for ATD particles;after reaction with NO_(2) for 24 hr,θ(NO_(3)^(−))increased to 1.4±0.1 and ns at-20℃ was reduced from 20±4 to 9.7±1.9 cm^(−2) by a factor of∼2.Our work suggests that heterogeneous reaction with NO_(2),an abundant reactive nitrogen species in the troposphere,may significantly reduce IN activities of mineral dust in the immersion freezing mode.
