The impact of sea surface temperature(SST)on winter haze in Guangdong province(WHDGD)was analyzed on the interannual scale.It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading...The impact of sea surface temperature(SST)on winter haze in Guangdong province(WHDGD)was analyzed on the interannual scale.It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading role in the variation of WHDGD.Cold(warm)SST anomalies over the northern Indian Ocean and the Northwest Pacific stimulate the eastward propagation of cold(warm)Kelvin waves through the Gill forced response,causing Ekman convergence(divergence)in the western Pacific,inducing abnormal cyclonic(anticyclonic)circulation.It excites the positive(negative)Western Pacific teleconnection pattern(WP),which results in the temperature and the precipitation decrease(increase)in Guangdong and forms the meteorological variables conditions that are conducive(not conducive)to the formation of haze.ENSO has an asymmetric influence on WHDGD.In El Niño(La Niña)winters,there are strong(weak)coordinated variations between the northern Indian Ocean,the northwest Pacific,and the eastern Pacific,which stimulate the negative(positive)phase of WP teleconnection.In El Niño winters,the enhanced moisture is attributed to the joint effects of the horizontal advection from the surrounding ocean,vertical advection from the moisture convergence,and the increased atmospheric apparent moisture sink(Q2)from soil evaporation.The weakening of the atmospheric apparent heat source(Q1)in the upper layer is not conducive to the formation of inversion stratification.In contrast,in La Niña winters,the reduced moisture is attributed to the reduced upward water vapor transport and Q2 loss.Due to the Q1 increase in the upper layer,the temperature inversion forms and suppresses the diffusion of haze.展开更多
The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issue...The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issues in this region,necessitating development of an effective control strategy.Herein,we use observations,and state-of-the-art model simulations with scenario analysis and process analysis to quantify the effectiveness of the future SO_(2)-NO_(X)-VOC-NH_(3) emission control on nitrate pollution mitigation in“2+26”cities.Focusing on a serious winter haze episode,we find that limited NO_(X)emission reduction alone in the short-term period is a less effective choice than VOC or NH_3emission reduction alone to decrease nitrate concentrations,due to the accelerated NO_(X)-HNO_(3)conversion by atmospheric oxidants and the enhanced HNO_(3)to NO_(3)^(-)partition by ammonia,although deep NO_(X)emission reduction is essential in the long-term period.The synergistic NH_(3) and VOC emission control is strongly recommended,which can counteract the adverse effects of nonlinear photochemistry and aerosol chemical feedback to decrease nitrate more.Such extra benefits will be reduced if the synergistic NH_(3) and VOC reduction is delayed,and thus reducing emission of multiple precursors is urgently required for the effective control of increasingly severe winter nitrate pollution in“2+26”cities.展开更多
We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest...We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity （RH） were simulated well （mean biases are 0.2K and 2.7%, respectively）, but wind speeds were overestimated （mean bias is 0.5 m.s -1）. At the Beijing station, sulfur dioxide （SO2） concentrations were overpredicted and sulfhte concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide （NO2） on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulthte concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO, substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS （heterogeneous oxidation by NO2） case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain （NCP） are mostly due to errors in SO2 emission inventory.展开更多
This study compares the impacts of interarmual Arctic sea ice loss and ENSO events on winter haze days m mare- land China through observational analyses and AGCM sensitivity experiments. The results suggest that （1）...This study compares the impacts of interarmual Arctic sea ice loss and ENSO events on winter haze days m mare- land China through observational analyses and AGCM sensitivity experiments. The results suggest that （1） Arctic sea ice loss favors an increase in haze days in central-eastern China; （2） the impact of ENSO is overall contained within southern China, with increased （reduced） haze days during La Nifia （El Nifio） winters; and （3） the impacts from sea ice loss and ENSO are linearly additive. Mechanistically, Arctic sea ice loss causes quasi-barotropic positive height anomalies over the region from northem Europe to the Ural Mountains （Urals in brief） and weak and negative height anomalies over the region from central Asia to northeastem Asia. The former favors intensified frequency of the blocking over the regions from northern Europe to the Urals, whereas the latter favors an even air pressure distribu- tion over Siberia, Mongolia, and East Asia. This large-scale circulation pattern favors more frequent occurrence of calm and steady weather in northern China and, as a consequence, increased occurrence of haze days. In comparison, La Nifia （El Nifio） exerts its influence along a tropical pathway by inducing a cyclonic （anticyclonic） lower-tropo- spheric atmospheric circulation response over the subtropical northwestern Pacific. The northeasterly （southwesterly） anomaly at the northwestern rear of the cyclone （anticyclone） causes reduced （intensified） rainfall over southeastern China, which favors increased （reduced） occurrence of haze days through the rain-washing effect.展开更多
目的 观察冬病夏治对雾霾暴露下支气管哮喘患者的临床疗效和炎性因子影响,为防治雾霾暴露下致哮喘急性发作提供思路。方法 选取2020年5月1日—2020年7月10日期间就诊于河北省中医院呼吸一科门诊的68例支气管哮喘患者,采用随机数字法分...目的 观察冬病夏治对雾霾暴露下支气管哮喘患者的临床疗效和炎性因子影响,为防治雾霾暴露下致哮喘急性发作提供思路。方法 选取2020年5月1日—2020年7月10日期间就诊于河北省中医院呼吸一科门诊的68例支气管哮喘患者,采用随机数字法分为对照组和贴敷组,每组各34例。对照组予基础治疗,贴敷组在对照组基础上予冬病夏治贴敷治疗。以低浓度雾霾月份7月为暴露前,高浓度雾霾月份12月为暴露后,观察比较两组患者临床疗效,暴露前后急性发作次数、哮喘控制测试问卷评分(Asthma Control Test questionnaire, ACT)、肺功能[第1秒用力呼气容积(Forced expiratory volume in 1 sec, FEV1)、第1秒用力呼气容积/用力肺活量(Forced expiratoryvolume in one second to forced vital capacity ratio, FEV1/FVC)、最大呼气流量(Peak Expiratory Flow, PEF)]、外周血嗜酸性粒细胞计数(Eosinophil count, EOS)及炎性因子[白细胞介素-4(Interleukin-4,IL-4)、白细胞介素-8(Interleukin-8,IL-8)]水平。结果 治疗后贴敷组总有效率91.18%(31/34)明显高于对照组70.59%(24/34),差异有统计学意义(P<0.05)。暴露后两组患者急性发作次数较暴露前降低,ACT评分较暴露前升高,差异有统计学意义(P<0.05);且贴敷组急性发作次数明显低于对照组,ACT评分明显高于对照组,差异有统计学意义(P<0.05)。暴露后两组患FEV1、FEV1/FVC、PEF均较暴露前升高,差异有统计学意义(P<0.05);且贴敷组FEV1、FEV1/FVC、PEF明显高于对照组,差异有统计学意义(P<0.05)。暴露后两组患者IL-4、IL-8、EOS水平均较暴露前降低,差异有统计学意义(P<0.05);且贴敷组IL-4、IL-8、EOS水平明显低于对照组,差异有统计学意义(P<0.05)。结论 冬病夏治穴位贴敷治疗雾霾暴露下哮喘临床疗效显著,可改善哮喘患者急性发作次数、肺功能、ACT评分,降低血清EOS、IL-4、IL-8水平,减轻炎性反应,值得进一步推广。展开更多
利用常规气象观测资料、加密自动站观测资料、污染物PM2.5质量浓度数据等,对近3年天津秋冬季出现的重度霾天气过程进行分析。主要从重度霾天气发生的天气形势、气象要素特征、减弱消散条件等方面进行分析。结果表明:秋冬季重度霾天气发...利用常规气象观测资料、加密自动站观测资料、污染物PM2.5质量浓度数据等,对近3年天津秋冬季出现的重度霾天气过程进行分析。主要从重度霾天气发生的天气形势、气象要素特征、减弱消散条件等方面进行分析。结果表明:秋冬季重度霾天气发生时500 h Pa环流形势基本为弱西北气流或偏西气流,低层850 h Pa为高压脊前偏北气流或暖高压脊或高压后部西南气流等控制;地面气压场较弱,多为鞍形场、低压或高压后部控制,风力较小。重度霾天气发生时,海平面气压值基本在1 023~1 028.5 h Pa之间,地面多为南到东南风,风速<1.0 m/s,水平能见度较差(基本在2.0 km以下),当空气湿度较大、雾和霾同时存在时能见度会降至1.0 km以下,另外霾天气发生时在850 h Pa以下均存在较强逆温层或双层逆温现象。对于重度霾天气减弱消散条件,除冷空气东移南下能对污染物起到很好消除作用外,当地面西南风明显加大、出现浓雾天气近地层空气达到饱和以及受偏东路径冷空气影响时,也会对重度霾过程减弱消散起到较好的作用。另外受海风环流影响时,天津大气污染扩散条件会好转、污染物浓度降低、重度霾过程会减弱消散;但因存在海风锋锋前累积增长特征,受海风影响地区会出现霾污染加重的现象(一般为3 h左右,与海风强度及移动速度有关)。展开更多
利用2013—2020年1月内蒙古呼和浩特市环境监测数据、气象观测数据、美国国家海洋和大气局(National Oceanic and Atmospheric Administration,NOAA)月平均北极涛动(Arctic Oscillation,AO)指数、欧洲中期天气预报中心(European Centre ...利用2013—2020年1月内蒙古呼和浩特市环境监测数据、气象观测数据、美国国家海洋和大气局(National Oceanic and Atmospheric Administration,NOAA)月平均北极涛动(Arctic Oscillation,AO)指数、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)ERA5再分析资料等,对2020年1月呼和浩特市雾霾天气偏多的气象成因进行分析。结果表明:(1)2020年1月较弱的冬季风环流背景、高湿度条件、维持较低的边界层高度、逆温结构等是造成呼和浩特市雾霾偏多的主要原因;(2)2013—2020年1月同期呼和浩特市逐日平均相对湿度、前期累计降水量、逐小时2 min平均风速小于等于1.5 m·s^(-1)的日数与雾霾日数均呈显著正相关,其中逐小时2 min平均风速小于等于1.0 m·s^(-1)更利于雾霾的发生;(3)地面积雪对呼和浩特市持续雾霾天气影响较大,积雪越深、持续时间越长,则雾霾日数也越多;(4)2020年1月呼和浩特市雾霾天气持续时,边界层平均高度约430~550 m,最低约210 m,较低的边界层利于污染物在近地层集聚,导致水平能见度较低,雾霾加重,边界层高度越低,污染越重。展开更多
基金Guangdong Basic and Applied Basic Research Foundation(2019A1515011808)Science and Technology Planning Program of Guangdong Province(2021B1212020016)。
文摘The impact of sea surface temperature(SST)on winter haze in Guangdong province(WHDGD)was analyzed on the interannual scale.It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading role in the variation of WHDGD.Cold(warm)SST anomalies over the northern Indian Ocean and the Northwest Pacific stimulate the eastward propagation of cold(warm)Kelvin waves through the Gill forced response,causing Ekman convergence(divergence)in the western Pacific,inducing abnormal cyclonic(anticyclonic)circulation.It excites the positive(negative)Western Pacific teleconnection pattern(WP),which results in the temperature and the precipitation decrease(increase)in Guangdong and forms the meteorological variables conditions that are conducive(not conducive)to the formation of haze.ENSO has an asymmetric influence on WHDGD.In El Niño(La Niña)winters,there are strong(weak)coordinated variations between the northern Indian Ocean,the northwest Pacific,and the eastern Pacific,which stimulate the negative(positive)phase of WP teleconnection.In El Niño winters,the enhanced moisture is attributed to the joint effects of the horizontal advection from the surrounding ocean,vertical advection from the moisture convergence,and the increased atmospheric apparent moisture sink(Q2)from soil evaporation.The weakening of the atmospheric apparent heat source(Q1)in the upper layer is not conducive to the formation of inversion stratification.In contrast,in La Niña winters,the reduced moisture is attributed to the reduced upward water vapor transport and Q2 loss.Due to the Q1 increase in the upper layer,the temperature inversion forms and suppresses the diffusion of haze.
基金National Natural Science Foundation of China (No.22206106)the Scientific Research Start-up Funds from Tsinghua Shenzhen International Graduate School (No.QD2021015C)the Natural Science Foundation of Guangdong Province (No.2022A1515010705)。
文摘The“2+26”cities,suffering the most severe winter haze pollution,have been the key region for air quality improvement in China.Increasing prominent nitrate pollution is one of the most challenging environmental issues in this region,necessitating development of an effective control strategy.Herein,we use observations,and state-of-the-art model simulations with scenario analysis and process analysis to quantify the effectiveness of the future SO_(2)-NO_(X)-VOC-NH_(3) emission control on nitrate pollution mitigation in“2+26”cities.Focusing on a serious winter haze episode,we find that limited NO_(X)emission reduction alone in the short-term period is a less effective choice than VOC or NH_3emission reduction alone to decrease nitrate concentrations,due to the accelerated NO_(X)-HNO_(3)conversion by atmospheric oxidants and the enhanced HNO_(3)to NO_(3)^(-)partition by ammonia,although deep NO_(X)emission reduction is essential in the long-term period.The synergistic NH_(3) and VOC emission control is strongly recommended,which can counteract the adverse effects of nonlinear photochemistry and aerosol chemical feedback to decrease nitrate more.Such extra benefits will be reduced if the synergistic NH_(3) and VOC reduction is delayed,and thus reducing emission of multiple precursors is urgently required for the effective control of increasingly severe winter nitrate pollution in“2+26”cities.
文摘We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity （RH） were simulated well （mean biases are 0.2K and 2.7%, respectively）, but wind speeds were overestimated （mean bias is 0.5 m.s -1）. At the Beijing station, sulfur dioxide （SO2） concentrations were overpredicted and sulfhte concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide （NO2） on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulthte concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO, substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS （heterogeneous oxidation by NO2） case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain （NCP） are mostly due to errors in SO2 emission inventory.
基金Supported by the Strategic Project of the Chinese Academy of Sciences(XDA11010401)China Meteorological Administration Special Public Welfare Research Fund(GYHY201306026)National(Key) Basic Research and Development(973)Program of China(2015CB453202 and 2016YFA0601802)
文摘This study compares the impacts of interarmual Arctic sea ice loss and ENSO events on winter haze days m mare- land China through observational analyses and AGCM sensitivity experiments. The results suggest that （1） Arctic sea ice loss favors an increase in haze days in central-eastern China; （2） the impact of ENSO is overall contained within southern China, with increased （reduced） haze days during La Nifia （El Nifio） winters; and （3） the impacts from sea ice loss and ENSO are linearly additive. Mechanistically, Arctic sea ice loss causes quasi-barotropic positive height anomalies over the region from northem Europe to the Ural Mountains （Urals in brief） and weak and negative height anomalies over the region from central Asia to northeastem Asia. The former favors intensified frequency of the blocking over the regions from northern Europe to the Urals, whereas the latter favors an even air pressure distribu- tion over Siberia, Mongolia, and East Asia. This large-scale circulation pattern favors more frequent occurrence of calm and steady weather in northern China and, as a consequence, increased occurrence of haze days. In comparison, La Nifia （El Nifio） exerts its influence along a tropical pathway by inducing a cyclonic （anticyclonic） lower-tropo- spheric atmospheric circulation response over the subtropical northwestern Pacific. The northeasterly （southwesterly） anomaly at the northwestern rear of the cyclone （anticyclone） causes reduced （intensified） rainfall over southeastern China, which favors increased （reduced） occurrence of haze days through the rain-washing effect.
文摘目的 观察冬病夏治对雾霾暴露下支气管哮喘患者的临床疗效和炎性因子影响,为防治雾霾暴露下致哮喘急性发作提供思路。方法 选取2020年5月1日—2020年7月10日期间就诊于河北省中医院呼吸一科门诊的68例支气管哮喘患者,采用随机数字法分为对照组和贴敷组,每组各34例。对照组予基础治疗,贴敷组在对照组基础上予冬病夏治贴敷治疗。以低浓度雾霾月份7月为暴露前,高浓度雾霾月份12月为暴露后,观察比较两组患者临床疗效,暴露前后急性发作次数、哮喘控制测试问卷评分(Asthma Control Test questionnaire, ACT)、肺功能[第1秒用力呼气容积(Forced expiratory volume in 1 sec, FEV1)、第1秒用力呼气容积/用力肺活量(Forced expiratoryvolume in one second to forced vital capacity ratio, FEV1/FVC)、最大呼气流量(Peak Expiratory Flow, PEF)]、外周血嗜酸性粒细胞计数(Eosinophil count, EOS)及炎性因子[白细胞介素-4(Interleukin-4,IL-4)、白细胞介素-8(Interleukin-8,IL-8)]水平。结果 治疗后贴敷组总有效率91.18%(31/34)明显高于对照组70.59%(24/34),差异有统计学意义(P<0.05)。暴露后两组患者急性发作次数较暴露前降低,ACT评分较暴露前升高,差异有统计学意义(P<0.05);且贴敷组急性发作次数明显低于对照组,ACT评分明显高于对照组,差异有统计学意义(P<0.05)。暴露后两组患FEV1、FEV1/FVC、PEF均较暴露前升高,差异有统计学意义(P<0.05);且贴敷组FEV1、FEV1/FVC、PEF明显高于对照组,差异有统计学意义(P<0.05)。暴露后两组患者IL-4、IL-8、EOS水平均较暴露前降低,差异有统计学意义(P<0.05);且贴敷组IL-4、IL-8、EOS水平明显低于对照组,差异有统计学意义(P<0.05)。结论 冬病夏治穴位贴敷治疗雾霾暴露下哮喘临床疗效显著,可改善哮喘患者急性发作次数、肺功能、ACT评分,降低血清EOS、IL-4、IL-8水平,减轻炎性反应,值得进一步推广。
文摘利用常规气象观测资料、加密自动站观测资料、污染物PM2.5质量浓度数据等,对近3年天津秋冬季出现的重度霾天气过程进行分析。主要从重度霾天气发生的天气形势、气象要素特征、减弱消散条件等方面进行分析。结果表明:秋冬季重度霾天气发生时500 h Pa环流形势基本为弱西北气流或偏西气流,低层850 h Pa为高压脊前偏北气流或暖高压脊或高压后部西南气流等控制;地面气压场较弱,多为鞍形场、低压或高压后部控制,风力较小。重度霾天气发生时,海平面气压值基本在1 023~1 028.5 h Pa之间,地面多为南到东南风,风速<1.0 m/s,水平能见度较差(基本在2.0 km以下),当空气湿度较大、雾和霾同时存在时能见度会降至1.0 km以下,另外霾天气发生时在850 h Pa以下均存在较强逆温层或双层逆温现象。对于重度霾天气减弱消散条件,除冷空气东移南下能对污染物起到很好消除作用外,当地面西南风明显加大、出现浓雾天气近地层空气达到饱和以及受偏东路径冷空气影响时,也会对重度霾过程减弱消散起到较好的作用。另外受海风环流影响时,天津大气污染扩散条件会好转、污染物浓度降低、重度霾过程会减弱消散;但因存在海风锋锋前累积增长特征,受海风影响地区会出现霾污染加重的现象(一般为3 h左右,与海风强度及移动速度有关)。
