Land-sea breeze(LSB)is an atmospheric mesoscale circulation that occurs in the vicinity of the coast and is caused by uneven heating resulting from the difference in specific heat capacity between the sea and land sur...Land-sea breeze(LSB)is an atmospheric mesoscale circulation that occurs in the vicinity of the coast and is caused by uneven heating resulting from the difference in specific heat capacity between the sea and land surfaces.The circulation structure of LSB was quantitatively investigated with a Doppler wind lidar Windcube100s on the west coast of the Yellow Sea for the first time.The time of observation was 31 August to 28 September 2018.It was found that the height of LSB development was 700 m to 1300 m.The duration of conversion of LSB was between 6 h and 8 h.The biggest average horizontal sea-breeze wind speed at 425 m was 5.6 m s^(-1),and at 375 m it was 4.5 m s^(-1).During the conversion process from sea breeze to land breeze,the maximum wind shear exponent was 2.84 at 1300 m altitude.During the conversion process from land breeze to sea breeze,the maximum wind shear exponent was 1.28 at 700 m altitude.The differences in wind shear exponents between sea-breeze and landbreeze systems were between 0.2 and 3.6 at the same altitude.The maximum value of the wind shear exponent can reflect the height of LSB development.展开更多
Aerosol observational data for 2012 obtained from Dunhuang Station of CARE-China（Campaign on Atmospheric Aerosol Research Network of China） were analyzed to achieve in-depth knowledge of aerosol optical properties o...Aerosol observational data for 2012 obtained from Dunhuang Station of CARE-China（Campaign on Atmospheric Aerosol Research Network of China） were analyzed to achieve in-depth knowledge of aerosol optical properties over Dunhuang region. The results showed that the annual average aerosol optical depth（AOD） at 500 nm was 0.32 ± 0.06, and the ？ngstr？m exponent（α） was 0.73 ± 0.27. Aerosol optical properties revealed significant seasonal characteristics. Frequent sandstorms in MAM（March–April–May） resulted in the seasonal maximum AOD, 0.41 ± 0.04, and a relatively smaller αvalue, 0.44 ± 0.04. The tourism seasons, JJA（June–July–August） and SON（September–October–November） coincide with serious emissions of small anthropogenic aerosols. While in DJF（December–January–February）, the composition of the atmosphere was a mixture of dust particles and polluted aerosols released by domestic heating; the average AOD and αwere 0.29 ± 0.02 and 0.66 ± 0.17, respectively. Different air masses exhibited different degrees of influence on the aerosol concentration over Dunhuang in different seasons. During MAM, ranges of AOD（0.11–1.18） and α（0.06–0.82） were the largest under the dust influence of northwest-short-distance air mass in the four trajectories. Urban aerosols transported by northwest-short-distance air mass accounted for a very large proportion in JJA and the mixed aerosols observed in SON were mainly conveyed by air masses from the west. In DJF, the similar ranges of AOD and α under the three air mass demonstrated the analogous diffusion effects on regional pollutants over Dunhuang.展开更多
The attainment of suitable ambient air quality standards is a matter of great concern for successfully hosting the ⅩⅩⅣ Olympic Winter Games(OWG). Transport patterns and potential sources of pollutants in Zhangjiako...The attainment of suitable ambient air quality standards is a matter of great concern for successfully hosting the ⅩⅩⅣ Olympic Winter Games(OWG). Transport patterns and potential sources of pollutants in Zhangjiakou(ZJK) were investigated using pollutant monitoring datasets and a dispersion model. The PM_(2.5) concentration during February in ZJK has increased slightly(28%) from 2018 to 2021, mostly owing to the shift of main potential source regions of west-central Inner Mongolia and Mongolian areas(2015–18) to the North China Plain and northern Shanxi Province(NCPS) after 2018.Using CO as an indicator, the relative contributions of the different regions to the receptor site(ZJK) were evaluated based on the source-receptor-relationship method(SRR) and an emission inventory. We found that the relative contribution of pollutants from NCPS increased from 33% to 68% during 2019–21. Central Inner Mongolia(CIM) also has an important impact on ZJK under unfavorable weather conditions. This study demonstrated that the effect of pollution control measures in the NCPS and CIM should be strengthened to ensure that the air quality meets the standard during the ⅩⅩⅣ OWG.展开更多
Industrial pollution has a significant effect on aerosol properties in Changsha City,a typical city of central China.Therefore,year-round measurements of aerosol optical,radiative and chemical properties from 2012 to ...Industrial pollution has a significant effect on aerosol properties in Changsha City,a typical city of central China.Therefore,year-round measurements of aerosol optical,radiative and chemical properties from 2012 to 2014 at an urban site in Changsha were analyzed.During the observation period,the energy structure was continuously optimized,which was characterized by the reduction of coal combustion.The aerosol properties have obvious seasonal variations.The seasonal average aerosol optical depth(AOD)at 500 nm ranged from 0.49 to 1.00,single scattering albedo(SSA)ranged from 0.93 to 0.97,and aerosol radiative forcing at the top of the atmosphere(TOA)ranged from−24.0 to 3.8 W m^−2.The chemical components also showed seasonal variations.Meanwhile,the scattering aerosol,such as organic carbon,SO42−,NO3−,and NH4+showed a decrease,and elemental carbon increased.Compared with observation in winter 2012,AOD and TOA decreased by 0.14 and−1.49 W m^−2 in winter 2014.The scattering components,SO42−,NO3−and NH4+,decreased by 12.8μg m^−3(56.8%),9.2μg m^−3(48.8%)and 6.4μg m^−3(45.2%),respectively.The atmospheric visibility and pollution diffusion conditions improved.The extinction and radiative forcing of aerosol were significantly controlled by the scattering aerosol.The results indicate that Changsha is an industrial city with strong scattering aerosol.The energy structure optimization had a marked effect on controlling pollution,especially in winter(strong scattering aerosol).展开更多
The quality of the MODIS C6 3-km and 10-km aerosol optical depth（AOD） products retrieved by the Dark Target（DT）method is discussed using ground-based observations in the Beijing–Tianjin–Hebei region from 1 Augus...The quality of the MODIS C6 3-km and 10-km aerosol optical depth（AOD） products retrieved by the Dark Target（DT）method is discussed using ground-based observations in the Beijing–Tianjin–Hebei region from 1 August 2007 to 31 July2008. Good consistency exists between the 3-km and 10-km products and ground-based observations. The retrieval accuracy of the two products both show distinctive seasonality. The percentage falling within the expected error（EE） is largest in the winter, moderate in the spring and autumn, and smallest in the summer. A worse overestimation appears in the spring and summer（27%–66%）. However, the 3-km and 10-km products over different surfaces still exhibit obvious deviations. The 10-km product performs better in the large cities, while the 3-km product has advantages in the suburbs. In urban areas, the percentage falling within EE of the 3-km AOD product（18%–59%） is lower than that for the 10-km AOD product（31%–69%）. However, in suburban areas, the percentage falling within EE of the 3-km AOD product（61%–84%） is higher than for the 10 km AOD product（54%–83%）.The percentages falling within EE differ considerably when the AOD is greater than1.5（73% and 63% for the 3-km and 10-km products, respectively）. On the whole, the 3-km（10-km） AOD product performs better in suburban（urban） areas.展开更多
Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 201...Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 2014 to 2017 to study the pollution characteristics in Baoding,a case city of the NCP.The annual average concentration of total PM_(2.5)components showed a declining trend,decreasing by 11μg m^(−3)(water-soluble inorganic ions),23μg m^(−3)(carbonaceous aerosols),and 1796 ng m^(−3)(inorganic elements).Contributing 82.9%to the concentration of total ions,the dominant components,NH 4+,NO 3−,and SO_(4)^(2−)became the main pollutants in PM_(2.5)pollution.Based on the IMPROVE algorithm,the average reconstructed PM_(2.5)mass concentration was 93±69μg m^(−3)during the observation period.Meanwhile,the light extinction coefficients were 373.8±233.6 M^(m−1),405.3±300.1M^(m−1),554.3±378.2M^(m−1)and 1005.2±750.3M^(m−1),in spring,summer,autumn,and winter,respectively.Ammonium sulfate,ammonium nitrate,and organic matter were the largest contributors to light extinction,accounting for a total of 55%–77%in the four seasons.The b sca(light scattering by particles and gases)reconstructed from PM_(2.5)components(Rb_(sca))and the b sca converted from visibility(Vb_(sca))were compared to evaluate the performance of the IMPROVE algorithm,revealing a high correlation coefficient of 0.84.The high values of Vb_(sca)were underestimated while the low values were overestimated,as determined through comparison with the one-to-ne line.Especially,when Rb_(sca)>1123M^(m−1)(corresponding to<2.0 km,approximately),Vb_(sca)was underestimated by 17.6%.PM_(2.5)mass concentration and relative humidity also had an impact on the estimation.展开更多
Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on...Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a nebulizer.The results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/L.The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events.The geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process.Additionally,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,respectively.The scavenging ratio of rBC particles was estimated to be 0.06 on average.This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.展开更多
A coupled aerosol–cloud model is essential for investigating the formation of haze and fog and the interaction of aerosols with clouds and precipitation. One of the key tasks of such a model is to produce correct mas...A coupled aerosol–cloud model is essential for investigating the formation of haze and fog and the interaction of aerosols with clouds and precipitation. One of the key tasks of such a model is to produce correct mass and number size distributions of aerosols. In this paper, a parameterization scheme for aerosol size distribution in initial emission,which took into account the measured mass and number size distributions of aerosols, was developed in the GRAPES–CUACE [Global/Regional Assimilation and Pr Ediction System–China Meteorological Administration（CMA） Unified Atmospheric Chemistry Environment model]—an online chemical weather forecast system that contains microphysical processes and emission, transport, and chemical conversion of sectional multi-component aerosols. In addition, the competitive mechanism between nucleation and condensation for secondary aerosol formation was improved, and the dry deposition was also modified to be in consistent with the real depositing length. Based on the above improvements, the GRAPES–CUACE simulations were verified against observational data during 1–31 January 2013, when a series of heavy regional haze–fog events occurred in eastern China. The results show that the aerosol number size distribution from the improved experiment was much closer to the observation, whereas in the old experiment the number concentration was higher in the nucleation mode and lower in the accumulation mode. Meanwhile, the errors in aerosol number size distribution as diagnosed by its sectional mass size distribution were also reduced. Moreover, simulations of organic carbon, sulfate, and other aerosol components were improved and the overestimation as well as underestimation of PM2.5 concentration in eastern China was significantly reduced,leading to increased correlation coefficient between simulated and observed PM2.5 by more than 70%. In the remote areas where bad simulation results were produced previously, the correlation coefficient grew from 0.35 to 0.61, and the mean mass concentration went up from 43% to 87.5% of the observed value. Thus, the simulation of particulate matters in these areas has been improved considerably.展开更多
基金supported by the National Key Research and Development Program of China[Grant number 2016YFC0202001]the Chinese Academy of Sciences Strategic Priority Research Program[Grant number XDA23020301]the National Natural Science Foundation of China[Grant number 41375036]。
文摘Land-sea breeze(LSB)is an atmospheric mesoscale circulation that occurs in the vicinity of the coast and is caused by uneven heating resulting from the difference in specific heat capacity between the sea and land surfaces.The circulation structure of LSB was quantitatively investigated with a Doppler wind lidar Windcube100s on the west coast of the Yellow Sea for the first time.The time of observation was 31 August to 28 September 2018.It was found that the height of LSB development was 700 m to 1300 m.The duration of conversion of LSB was between 6 h and 8 h.The biggest average horizontal sea-breeze wind speed at 425 m was 5.6 m s^(-1),and at 375 m it was 4.5 m s^(-1).During the conversion process from sea breeze to land breeze,the maximum wind shear exponent was 2.84 at 1300 m altitude.During the conversion process from land breeze to sea breeze,the maximum wind shear exponent was 1.28 at 700 m altitude.The differences in wind shear exponents between sea-breeze and landbreeze systems were between 0.2 and 3.6 at the same altitude.The maximum value of the wind shear exponent can reflect the height of LSB development.
基金supported by the National Natural Science Foundation of China(Grant Nos.41375036 and 41222033)the National Basic Research Program of China(Grant No.2016YFC0202001,973 Program 2014CB441200)the CAS Strategic Priority Research Program(Grant No.XDB05020103).
文摘Aerosol observational data for 2012 obtained from Dunhuang Station of CARE-China（Campaign on Atmospheric Aerosol Research Network of China） were analyzed to achieve in-depth knowledge of aerosol optical properties over Dunhuang region. The results showed that the annual average aerosol optical depth（AOD） at 500 nm was 0.32 ± 0.06, and the ？ngstr？m exponent（α） was 0.73 ± 0.27. Aerosol optical properties revealed significant seasonal characteristics. Frequent sandstorms in MAM（March–April–May） resulted in the seasonal maximum AOD, 0.41 ± 0.04, and a relatively smaller αvalue, 0.44 ± 0.04. The tourism seasons, JJA（June–July–August） and SON（September–October–November） coincide with serious emissions of small anthropogenic aerosols. While in DJF（December–January–February）, the composition of the atmosphere was a mixture of dust particles and polluted aerosols released by domestic heating; the average AOD and αwere 0.29 ± 0.02 and 0.66 ± 0.17, respectively. Different air masses exhibited different degrees of influence on the aerosol concentration over Dunhuang in different seasons. During MAM, ranges of AOD（0.11–1.18） and α（0.06–0.82） were the largest under the dust influence of northwest-short-distance air mass in the four trajectories. Urban aerosols transported by northwest-short-distance air mass accounted for a very large proportion in JJA and the mixed aerosols observed in SON were mainly conveyed by air masses from the west. In DJF, the similar ranges of AOD and α under the three air mass demonstrated the analogous diffusion effects on regional pollutants over Dunhuang.
基金the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (Earth Lab)
文摘The attainment of suitable ambient air quality standards is a matter of great concern for successfully hosting the ⅩⅩⅣ Olympic Winter Games(OWG). Transport patterns and potential sources of pollutants in Zhangjiakou(ZJK) were investigated using pollutant monitoring datasets and a dispersion model. The PM_(2.5) concentration during February in ZJK has increased slightly(28%) from 2018 to 2021, mostly owing to the shift of main potential source regions of west-central Inner Mongolia and Mongolian areas(2015–18) to the North China Plain and northern Shanxi Province(NCPS) after 2018.Using CO as an indicator, the relative contributions of the different regions to the receptor site(ZJK) were evaluated based on the source-receptor-relationship method(SRR) and an emission inventory. We found that the relative contribution of pollutants from NCPS increased from 33% to 68% during 2019–21. Central Inner Mongolia(CIM) also has an important impact on ZJK under unfavorable weather conditions. This study demonstrated that the effect of pollution control measures in the NCPS and CIM should be strengthened to ensure that the air quality meets the standard during the ⅩⅩⅣ OWG.
基金This study was supported by the National Key Research and Development Program of China(Grant No.2016YFC0202001)the Chinese Academy of Sciences Strategic Priority Research Program(Grant No.XDA23020301)the National Natural Science Foundation of China(Grant Nos.42061130215 and 41605119).
文摘Industrial pollution has a significant effect on aerosol properties in Changsha City,a typical city of central China.Therefore,year-round measurements of aerosol optical,radiative and chemical properties from 2012 to 2014 at an urban site in Changsha were analyzed.During the observation period,the energy structure was continuously optimized,which was characterized by the reduction of coal combustion.The aerosol properties have obvious seasonal variations.The seasonal average aerosol optical depth(AOD)at 500 nm ranged from 0.49 to 1.00,single scattering albedo(SSA)ranged from 0.93 to 0.97,and aerosol radiative forcing at the top of the atmosphere(TOA)ranged from−24.0 to 3.8 W m^−2.The chemical components also showed seasonal variations.Meanwhile,the scattering aerosol,such as organic carbon,SO42−,NO3−,and NH4+showed a decrease,and elemental carbon increased.Compared with observation in winter 2012,AOD and TOA decreased by 0.14 and−1.49 W m^−2 in winter 2014.The scattering components,SO42−,NO3−and NH4+,decreased by 12.8μg m^−3(56.8%),9.2μg m^−3(48.8%)and 6.4μg m^−3(45.2%),respectively.The atmospheric visibility and pollution diffusion conditions improved.The extinction and radiative forcing of aerosol were significantly controlled by the scattering aerosol.The results indicate that Changsha is an industrial city with strong scattering aerosol.The energy structure optimization had a marked effect on controlling pollution,especially in winter(strong scattering aerosol).
基金supported by the National Natural Science Foundation of China(Grant Nos.41375036,41222033,41305076)the Key Project of National Natural Science Foundation of China(Grant Nos.91644226)+1 种基金the CAS(Chinese Academy of Sciences)Strategic Priority Research Program(Grant No.XDA05100102,XDB05020103)the National Basic Research Program of China(Grant Nos.2016YFC0202001 and 2014CB441200)
文摘The quality of the MODIS C6 3-km and 10-km aerosol optical depth（AOD） products retrieved by the Dark Target（DT）method is discussed using ground-based observations in the Beijing–Tianjin–Hebei region from 1 August 2007 to 31 July2008. Good consistency exists between the 3-km and 10-km products and ground-based observations. The retrieval accuracy of the two products both show distinctive seasonality. The percentage falling within the expected error（EE） is largest in the winter, moderate in the spring and autumn, and smallest in the summer. A worse overestimation appears in the spring and summer（27%–66%）. However, the 3-km and 10-km products over different surfaces still exhibit obvious deviations. The 10-km product performs better in the large cities, while the 3-km product has advantages in the suburbs. In urban areas, the percentage falling within EE of the 3-km AOD product（18%–59%） is lower than that for the 10-km AOD product（31%–69%）. However, in suburban areas, the percentage falling within EE of the 3-km AOD product（61%–84%） is higher than for the 10 km AOD product（54%–83%）.The percentages falling within EE differ considerably when the AOD is greater than1.5（73% and 63% for the 3-km and 10-km products, respectively）. On the whole, the 3-km（10-km） AOD product performs better in suburban（urban） areas.
基金supported by the National Key Research and Development Program of China grant number 2016YFC0202001the Chinese Academy of Sciences Strategic Priority Research Program grant number XDA23020301+1 种基金the National Natural Science Foundation of China grant numbers 41375036 and 91644226the National Key Research and Development Program of China grant number2018YFC0214002。
文摘Severe air pollution with visibility deterioration has long been a focus in the North China Plain(NCP).In this study,concentration and light extinction analysis of PM_(2.5)chemical components were carried out from 2014 to 2017 to study the pollution characteristics in Baoding,a case city of the NCP.The annual average concentration of total PM_(2.5)components showed a declining trend,decreasing by 11μg m^(−3)(water-soluble inorganic ions),23μg m^(−3)(carbonaceous aerosols),and 1796 ng m^(−3)(inorganic elements).Contributing 82.9%to the concentration of total ions,the dominant components,NH 4+,NO 3−,and SO_(4)^(2−)became the main pollutants in PM_(2.5)pollution.Based on the IMPROVE algorithm,the average reconstructed PM_(2.5)mass concentration was 93±69μg m^(−3)during the observation period.Meanwhile,the light extinction coefficients were 373.8±233.6 M^(m−1),405.3±300.1M^(m−1),554.3±378.2M^(m−1)and 1005.2±750.3M^(m−1),in spring,summer,autumn,and winter,respectively.Ammonium sulfate,ammonium nitrate,and organic matter were the largest contributors to light extinction,accounting for a total of 55%–77%in the four seasons.The b sca(light scattering by particles and gases)reconstructed from PM_(2.5)components(Rb_(sca))and the b sca converted from visibility(Vb_(sca))were compared to evaluate the performance of the IMPROVE algorithm,revealing a high correlation coefficient of 0.84.The high values of Vb_(sca)were underestimated while the low values were overestimated,as determined through comparison with the one-to-ne line.Especially,when Rb_(sca)>1123M^(m−1)(corresponding to<2.0 km,approximately),Vb_(sca)was underestimated by 17.6%.PM_(2.5)mass concentration and relative humidity also had an impact on the estimation.
基金supported by the National Natural Science Foundation of China(No.41877314).
文摘Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation.The lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a nebulizer.The results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/L.The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events.The geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process.Additionally,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,respectively.The scavenging ratio of rBC particles was estimated to be 0.06 on average.This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.
基金Supported by the National Key Project of the Ministry of Science and Technology of China(2016YFC0203306)National Natural Science Foundation of China(91544232)+1 种基金National Science and Technology Support Program of China(2014BAC16B03)China Meteorological Administration Innovation Team Fund for Haze–Fog Monitoring and Forecasts
文摘A coupled aerosol–cloud model is essential for investigating the formation of haze and fog and the interaction of aerosols with clouds and precipitation. One of the key tasks of such a model is to produce correct mass and number size distributions of aerosols. In this paper, a parameterization scheme for aerosol size distribution in initial emission,which took into account the measured mass and number size distributions of aerosols, was developed in the GRAPES–CUACE [Global/Regional Assimilation and Pr Ediction System–China Meteorological Administration（CMA） Unified Atmospheric Chemistry Environment model]—an online chemical weather forecast system that contains microphysical processes and emission, transport, and chemical conversion of sectional multi-component aerosols. In addition, the competitive mechanism between nucleation and condensation for secondary aerosol formation was improved, and the dry deposition was also modified to be in consistent with the real depositing length. Based on the above improvements, the GRAPES–CUACE simulations were verified against observational data during 1–31 January 2013, when a series of heavy regional haze–fog events occurred in eastern China. The results show that the aerosol number size distribution from the improved experiment was much closer to the observation, whereas in the old experiment the number concentration was higher in the nucleation mode and lower in the accumulation mode. Meanwhile, the errors in aerosol number size distribution as diagnosed by its sectional mass size distribution were also reduced. Moreover, simulations of organic carbon, sulfate, and other aerosol components were improved and the overestimation as well as underestimation of PM2.5 concentration in eastern China was significantly reduced,leading to increased correlation coefficient between simulated and observed PM2.5 by more than 70%. In the remote areas where bad simulation results were produced previously, the correlation coefficient grew from 0.35 to 0.61, and the mean mass concentration went up from 43% to 87.5% of the observed value. Thus, the simulation of particulate matters in these areas has been improved considerably.
