Changes in air pollutants during the COVID-19 lockdown in Beijing:Insights from a machine-learning technique and implications for future control policy

基于2015-2020年北京35个环境空气站和20个气象站观测资料,应用机器学习方法(随机森林算法)分离了气象条件和源排放对大气污染物浓度的影响.结果发现,为应对疫情采取的隔离措施使北京2020年春节期间大气污染物浓度降低了35.1％-51.8％;其中,背景站氮氧化物和一氧化碳浓度的降幅最大,超过了以往报道较多的交通站...     

几种环境因子对虾蟹类非特异性免疫的影响

综述了近10a国内外有关重金属、氨态氮、亚硝酸盐、有机污染物等几种环境因子对虾蟹类非特异性免疫影响的研究成果,以期为通过改善养殖环境条件提高虾蟹类自身免疫抗病力提供理论依据.同时,为进一步深入开展该领域的研究工作积累资料.     

工业部门污染物治理协同控制温室气体效应评价——基于重庆市的实证分析

以高能耗为主要特征的工业部门是大气污染物和温室气体的重要排放源.为推动协同管控,文中结合生态环境部在重庆市组织开展的试点工作,对工业企业NOx污染治理协同控制温室气体的效应进行了量化分析.结果表明,以末端治理为手段的NOx治理措施协同控制温室气体的效果为负,即工业企业去除1 t NOx会直接或间接增加CO2排放1.81...     

南宁市大气能见度变化特征及影响因子分析

对2000至2006年的南宁市能见度资料进行统计分析。分析表明,南宁市近7a能见度年均值在13~17km之间,总体呈下降趋势。一年之中,能见度最小值主要出现在1至3月,最大值出现在6至7月,汛期能见度明显好于非汛期。一日之中,能见度的日变化为:08时<02时<20时<14时。能见度与气象因子的相关分析表明,能见度与温度、风速成正比,与压强、降水、湿度成反比。与污染物的相关分析表明,能见度与PM10浓度的相关性较强,达到-0.58。     

南极乔治王岛环境质量现状调查

本文以１９９２／１９９３年度中国第九次南极考察期间对南极乔治王岛的表土、地衣、苔藓等样品的分析资料为基础，研究探讨了８种无机重金属元素、５种有机污染物的浓度水平。其结果表明，重金属在三种环境样品中的含量分布存在着明显的差异；地衣、苔藓两种植物呈现对不同重金属元素的不同富集能力；∑６６６、∑ＤＤＴ和ＰＣＢｓ及油的沾污亦很明显。本文还对污染物质的来源、南极环境样品历次调查分析的结果以及世界部分地区的背景水平进行了讨论和比较     

我国西南地区地面和低层大气臭氧的观测分析

本文介绍了1987—1989年在以重庆、成都和贵阳三地区为代表的西南地区进行了地面和低层大气臭氧的观测结果,给出了该地区大气臭氧时空分布的一些特征.分析表明,成都、重庆和贵阳等地区O_3浓度的时空分布及变化规律不尽相同,但都与前体污染物特征以及日照强度、大气层结稳定度.天气过程等密切相关.     

厦门酸雨与气象要素的关系及污染源的分析

根据厦门市１９８３－１９９１年９年春雨，梅雨及台风雨酸度的观测结果，结合各场雨水同步观测的气象要素资料，分析各类型雨水酸度与气象要素的关系。同时依降水的酸化原理估计了外来源及局的地源对厦门酸雨形成的贡献。     

PRESENT STATUS OF EXPERIMENTAL STUDY ON HEAVY METAL POLLUTANT ADSORPTION－DESORPTION BY SEDIMENT IN CHINA

ＰＲＥＳＥＮＴＳＴＡＴＵＳＯＦＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＹＯＮＨＥＡＶＹＭＥＴＡＬＰＯＬＬＵＴＡＮＴＡＤＳＯＲＰＴＩＯＮ－ＤＥＳＯＲＰＴＩＯＮＢＹＳＥＤＩＭＥＮＴＩＮＣＨＩＮＡＨＵＡＮＧＳｕｉｌｉａｎｇａｎｄＷＡＮＺｈａｏｈｕｉ（Ｐｏｓｔｄｏｃ...     

Influence of forest fire episodes on the distribution of gaseous air pollutants over Uttarakhand,India

ABSTRACT

Widespread forest fire events occurred in the foothills of North Western Himalaya during 24 April to 2 May 2016 (Event-1) and 20–30 May 2018 (Event-2). Their impacts were investigated on the distribution of pollutant gases ozone (O₃), carbon monoxide (CO), and oxides of nitrogen (NOx) over Uttarakhand using simulations of Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and in-situ observations of these gases over Dehradun, the capital of Uttarakhand. During Event-1, the observed CO mixing ratio over Dehradun increased from 25 April 2016 onwards, attained maximum (705.8 ± 258 ppbv) on 2 May 2016 and subsequently decreased. The rate of increase of daily baseline CO was 29 ppbv/day during HFAP (High Fire Activity Period). During Event-2, daily average concentrations of CO, O₃, and NOx showed systematic increase over Dehradun during HFAP period. The rate of increase of CO was 9 ppbv/day, while it was very small for NOx and O₃. To quantitatively estimate the influence of forest fire emissions, two WRF-Chem simulations were made: one with biomass burning (BB) emissions and other without BB emissions. These simulations showed 52% (34%) enhancement in CO, 52% (32%) enhancement in NOx, and 11% (9%) enhancement in O₃ during HFAP for Event-1 (Event-2). A clear positive correlation (r = 0.89 for Event-1, r = 0.69 for Event-2) was found between ?O₃ (O_{3with BB} minus O_{3without BB}) and ?CO (CO_{with BB} minus CO_{without BB}), indicating rapid production of ozone in the fire plumes. For both the events, the vertical distribution of ?O₃, ?CO, and ?NOx showed that forest fire emissions influenced the air quality upto 6.5 km altitude. Peaks in ?O₃, ?CO, and ?NOx during different days suggested the role of varying dispersion and horizontal mixing of fire plumes.     

Atmospheric pollution assessment near potential source of natural aerosols in the South Gobi Desert region,China

ABSTRACT

Rapid economic growth, a high degree of urbanization and the proximity of a large number of desert and semidesert landscapes can have a significant impact on the atmosphere of adjacent territories, leading to high levels of atmospheric pollution. Therefore, identifying possible sources of atmospheric pollution is one of the main tasks. In this study, we carried out an analysis of spatial and temporal characteristics of five main atmospheric pollutants (PM_2.5, PM₁₀, SO₂, NO₂, and CO) near potential source of natural aerosols, affecting seven cities (Wuhai, Alashan, Wuzhong, Zhongwei, Wuwei, Jinchang, Zhangye), located in immediate proximity to the South Gobi deserts. The results, obtained for the period from 1 January 2016 to 31 December 2018, demonstrate total concentrations of PM_2.5 and PM₁₀ are 38.2 ± 19.5 and 101 ± 80.7 μg/m³ exceeding the same established by the Chinese National Ambient Air Quality Standard (CNAAQS), being 35 and 70 μg/m³, respectively. Based on the data from Moderate Resolution Imaging Spectroradiometer (MODIS) for the whole period, Clean Сontinental (71.49%) and Mixed (22.29%) types of aerosols prevail in the region. In the spring and winter seasons maximum concentrations of pollutants and high values of Aerosol Optical Depth (AOD) in the region atmosphere are observed. PM_2.5 and PM₁₀ ratio shows the presence of coarse aerosols in the total content with value 0.43. The highest concentrations of pollutants were in the period of dust storms activity, when PM_2.5 and PM₁₀ content exceeded 200 and 1000 µg/m³, and AOD value exceeded 1. UV Aerosol Index (UVAI), Aerosol Absorbing Optical Depth (AAOD), and Single Scattering Albedo (SSA), obtained from Ozone Monitoring Instrument (OMI), demonstrate the high content of dust aerosols in the period of sandstorms. Analysis of backward trajectories shows that dust air masses moved from North to Northwest China, affecting large deserts such as Taklamakan, Gurbantunggut, Badain Jaran, Tengger, and Ulan Buh deserts.