Catalytic activity of cerium-doped Ru/Al2O3 during ozonation of dimethyl phthalate

In this paper, factors influencing the mineralization of dimethyl phthalate (DMP) during catalytic ozonation with a cerium-doped Ru/Al₂O₃ catalyst were studied. The catalytic contribution was calculated through the results of a comparison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 min reached 75.1%, 61.3% using Ru/Al₂O₃ catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium were simultaneously loaded onto Al₂O₃ support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion’s and heterogeneous catalytic ozonation confirmed that the contribution of heterogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru-Ce/Al₂O₃ on catalytic activity. __________ Translated from China Environmental Science, 2006, 26(4): 445–448 [译自: 中国环境科学]     

深圳市2022年春季新冠疫情管控期间空气质量分析

短期减排是我国城市应对大气污染事件的重要应急管控手段,但短期减排的效益尚未得到完善分析.2022年3月14～20日,广东省深圳市为抑制新冠疫情传播实施了全市管控,为评估短期减排对华南城市春季空气质量的影响提供独特机会.结合深圳市高精度环境空气质量监测与气象观测等多源数据,分析了深圳市管控期间前后的空气质量变化.此次管控前和管控期中均有部分日期天气形势静稳,局地污染水平主要反映本地排放,有利于分析本地减排的影响.观测与WRF-GC区域化学模拟都表明,与珠三角周边城市相比,深圳市管控期间由于市内交通源排放显著减少,深圳市二氧化氮(NO₂)浓度降低(-26±9.5)%,可吸入颗粒物(PM₁₀)浓度降低(-28±6.4)%,细颗粒物(PM_2.5)浓度降低(-20±8.2)%,但臭氧(O₃)浓度无显著变化[(-1.0±6.5)%].TROPOMI卫星观测的甲醛和二氧化氮柱浓度数据对比表明,2022年春季珠三角臭氧光化学主要受挥发性有机物(VOCs)浓度控制,对氮氧化物浓度降低不敏感,反而可能因氮氧化物对臭氧滴...     

An intercomparison of ozone taken from the Copernicus atmosphere monitoring service and the second Modern-Era retrospective analysis for research and applications over China during 2018 and 2019

Spatiotemporal variations of ozone (O₃) taken from the Copernicus Atmosphere Monitoring Service (CAMS) and the second Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) were intercompared and evaluated with ground and ozone-sonde observations over China in 2018 and 2019. Intercomparison of the surface ozone from CAMS and MERRA-2 reanalysis showed significant negative bias (CAMS minus MERRA-2, same below) at Tibetan Plateau of up to 80 µg/m³, and the average R² was about 0.6 across China. Evaluated with the ground observations from China National Environmental Monitoring Center (CNEMC), we found that CAMS and MERRA-2 reanalysis were capable of capturing the key patterns of monthly and diurnal variations of surface ozone over China except for the western region, and MERRA-2 overestimated the observations compared to CAMS. Vertically, the CAMS profiles overestimated the ozone-sonde from the World Ozone and Ultraviolet Radiation Data Center (WOUDC) above 200 hPa with the magnitude reaching up to 150 µg/m³, while little bias was found between the reanalysis and observations below 200 hPa. Intercomparison drawn from the vertical distribution between CAMS and MERRA-2 reanalysis showed that the negative bias appeared throughout the troposphere over China, while the positive bias emerged in the upper troposphere and lower stratosphere (UTLS) with high order of magnitude exceeding 100 µg/m³, indicating large uncertainties at higher altitudes. In summary, we concluded that CAMS reanalysis showed better agreement with the observations in contrast to MERRA-2, and the large discrepancy especially at higher altitudes between these two reanalysis datasets could not be ignored.     

中国典型城市O3与前体物变化特征及相关性研究

为了解我国不同气候背景城市O₃污染及其与前体物的关系,选取北京市、沈阳市、银川市、成都市、南京市和广州市作为典型代表城市,基于这6个城市2014-2016年ρ（O₃）、ρ（NO₂）和ρ（CO）资料对O₃与其前体物质量浓度变化特征及二者相关性进行研究.结果表明:①2014-2016年6个城市ρ（O₃）年均值大小顺序依次为南京市>沈阳市>北京市>银川市>成都市>广州市,ρ（NO₂）年均值大小顺序依次为北京市>成都市>南京市>沈阳市>广州市>银川市,ρ（CO）年均值大小顺序依次为北京市>银川市>成都市>沈阳市>南京市>广州市.2014-2016年除广州市ρ（O₃）下降、沈阳市变化不明显外,其他城市ρ（O₃）总体呈上升趋势;各城市ρ（NO₂）和ρ（CO）普遍呈下降趋势.②广州市ρ（O₃）夏季最高、春季最低,其他城市四季ρ（O₃）大小顺序依次为夏季>春季>秋季>冬季;北京市、沈阳市和银川市四季ρ（NO₂）和ρ（CO）大小顺序依次为冬季>秋季>春季>夏季,成都市、广州市和南京市为冬季>春季>秋季>夏季.各城市ρ（O₃）和ρ（O_x）日变化呈单峰型,ρ（NO₂）和ρ（CO）日变化呈双峰型.③6个城市城区ρ（O₃）均低于清洁对照点,城区ρ（NO₂）和ρ（CO）均高于清洁对照点,并且城区与清洁对照点O₃及其前体物质量浓度差值随城市和月份变化存在一定的差异.④各城市ρ（O₃）与ρ（NO₂）和ρ（CO）均呈负相关,与ρ（O_x）呈显著正相关;城区ρ（O₃）与ρ（NO₂）和ρ（CO）的相关性均好于清洁对照点,清洁对照点ρ（O₃）与ρ（O_x）的相关性则好于城区.⑤各城市ρ（O₃）超标率随ρ（NO₂）和ρ（CO）的增加均呈先迅速上升再快速减小,之后缓慢变化的特征,但ρ（O₃）超标率峰值对应的ρ（NO₂）和ρ（CO）有所差异.研究显示,日照条件较好的银川市、北京市和沈阳市O₃与其前体物相关性较成都市、南京市和广州市强.      

泰山顶臭氧及其前体物一氧化碳浓度变化规律

监测泰山顶O₃及其前体物CO的浓度,分析O₃和CO浓度的变化规律及其相关性.结果表明,泰山顶O₃小时平均浓度超过国家一级标准的频率为15.81%,CO小时平均浓度均达标;O₃浓度的日变化幅度较小,说明该地区受周围工业污染影响较小;O₃和CO浓度的日变化均呈一高一低的双峰型变化规律,二者具有很好的相关性,O₃浓度峰值一般滞后于CO,该区域O₃及其前体物CO浓度的变化主要受局地光化学过程控制;O₃浓度与CO浓度的日际变化的相关性也较好.     

基于总过氧自由基观测研究合肥市西郊夏季O3生成特征

2020年8月利用化学放大法对合肥市西郊大气总过氧自由基RO^*₂·(RO₂·+HO₂·)体积分数进行监测,并结合O₃和其前体物,分析了过氧自由基体积分数、O₃生成速率和O₃生成对前体物的敏感性.结果表明,观测期间总过氧自由基体积分数的日均值呈典型的单峰型变化,12:00左右出现最高值,日间峰值体积分数为43.8×10^-12,日间RO^*₂·与太阳辐射强度、温度和O₃呈明显的相关性.利用实测RO^*₂·和NO,获得合肥市西郊夏季O₃生成速率,日间峰值为10.6×10^-9h^-1,O₃生成速率对NO变化更为敏感.基于大气自由基和NO_x(NO+NO₂)反应去除速率占比(Ln/Q),对合肥...     

冬小麦田O3气孔与非气孔沉降及风险评估

为了深入了解农田生态系统的O_3干沉降过程,并基于O_3通量(尤其是气孔O_3累积通量)指标进行风险评估,利用涡度相关系统对冬小麦田的O_3干沉降过程进行了连续动态观测,初步分析O_3浓度和总O_3通量的变化过程,着重探析气孔O_3沉降和非气孔O_3沉降的变化特征及其与主要气象因子的关系,并基于剂量指标(AOT40)和通量指标(DF_s06)分别推算出冬小麦的产量损失率.结果表明,观测期间(自2016年3月16日至5月30日)日平均O_3浓度(cO_3)为32.9 n L·L-1;白天(08:00~18:00)和夜间平均总O_3通量(F_(O3))分别为-7.6 nmol·(m~2·s)~(-1)和-3.1 nmol·(m~2·s)~(-1),日均F_(O3)为-5.1nmol·(m~2·s)~(-1).逐日平均气孔O_3通量(F_s)的变化范围为0~-5.1 nmol·(m~2·s)~(-1),日均F_s为-1.43 nmol·(m~2·s)~(-1).逐日平均非气孔O_3通量(F_(ns))的变化范围为-1.43~-10.31 nmol·(m~2·s)~(-1),日均F_(ns)为-3.66 nmol·(m~2·s)~(-1).较强的太阳辐射(SR)、较高的温度(T)和适度湿润的条件有利于冬小麦气孔沉降;较强的SR、适度的T和湿润条件是有利于冬小麦非气孔沉降.在整个观测期间,总O_3累积吸收通量(DF_(O3))、气孔O_3累积吸收通量(DF_s)和非气孔O_3累积吸收通量(DF_(ns))分别为31.58、9.99和21.59 mmol·m~(-2),总DF_s和总DF_(ns)分别占总DF_(O3)的32%和68%.通过剂量指标AOT40和通量指标DF_s06响应方程计算出的冬小麦产量损失率分别为11.58%~20.37%和20%~23.56%.     

Large variability in ambient ozone sensitivity across 19 ethylenediurea-treated Chinese cultivars of soybean is driven by total ascorbate

The sensitivity of Chinese soybean cultivars to ambient ozone(O3) in the field is unknown,although soybean is a major staple food in China. Using ethylenediurea(EDU) as an O3 protectant, we tested the gas exchange, pigments, antioxidants and biomass of 19 cultivars exposed to 28 ppm·hr AOT40(accumulated O3 over an hourly concentration threshold of40 ppb) over the growing season at a field site in China. By comparing the average biomass with and without EDU, we estimated the cultivar-specific sensitivity to O3 and ranked the cultivars from very tolerant( 10% change) to highly sensitive( 45% change), which helps in choosing the best-suited cultivars for local cultivation. Higher lipid peroxidation and activity of the ascorbate peroxidase enzyme were major responses to O3 damage, which eventually translated into lower biomass production. The constitutional level of total ascorbate in the leaves was the most important parameter explaining O3 sensitivity among these cultivars. Surprisingly, the role of stomatal conductance was insignificant. These results will guide future breeding efforts towards more O3-tolerant cultivars in China, while strategies for implementing control measures of regional O3 pollution are being implemented. Overall, these results suggest that present ambient O3 pollution is a serious concern for soybean in China, which highlights the urgent need for policy-making actions to protect this critical staple food.     

夏季城市大气O3浓度影响因素及其相关关系

利用2003年夏季济南市区近地面大气O₃、相关前体物和气象因素等观测数据,研究了O₃浓度的分布特征及时间变化规律,分析了7月份O₃与NO、NO₂和CO等前体物及太阳辐射和气温气象条件的相关性.结果表明,济南市区夏季O₃污染比较严重,观测期间各污染物O₃、NO、NO₂、NO_x和CO浓度都相对较高,昼间O₃与各前体物的浓度呈较好的负相关关系,与太阳辐射具有非常明显的相关性,而与气温的相关性不明显.根据以上分析结果,利用回归分析方法,建立了昼间O₃浓度与前体物、气象因子之间的相关模式,结果表明O₃浓度的计算值与观测值符合性较好.     

长三角地区大气污染物对新冠肺炎封城的时空响应特征

利用2020年1月1日—2月29日上海、南京、合肥和杭州4个城市常规污染物的逐时监测资料,结合卫星反演的NO₂垂直柱浓度信息,探讨了新冠肺炎封城的前、中、后期长三角地区城市大气污染物的污染水平及响应特征.结果显示：除O₃外,其余大气污染物的平均浓度在时间上的整体变化趋势均表现为封城前>封城中（1月24日—2月10日）>封城后,表明空气质量并非完全受封城导致的污染减排控制.封城期间的PM_2.5/PM₁₀比值高于封城前和封城后,表明气溶胶二次生成对封城期间仍出现的颗粒物污染可能有重要贡献.O_x浓度在封城期间也有显著上升（p<0.01）,表明大气氧化性可能在NO₂减少的背景下得到强化,从而促进二次气溶胶的生成.从空间看,O₃分布呈以城市为中心的包围式往内聚集分布,表明以局地生成为主.PM_2.5、PM₁₀、CO、SO₂和NO₂分布特征为北高南低,表明冬季自北向南的区域传输对封城期间的空气污染有重要贡献.卫星反演结果进一步证实华北平原是污染的主要源区,这也得到轨迹来源分析的佐证.     

我国地级及以上城市臭氧污染来源及控制区划分

为划分我国臭氧污染控制区,制定更加科学合理的臭氧污染控制措施,根据2018年地面臭氧浓度监测数据,分析了全国338个地级及以上城市的臭氧超标情况,利用TCEQ方法计算出各城市的本地生成O₃量与区域传输O₃量,对本地生成O₃量与O₃日最大8 h平均值进行相关性分析,根据决定系数（R²）确定了各城市臭氧污染的主要来源.结果表明,2018年全国共有121个城市O₃浓度超标,超标率达35.8%;104个城市本地生成O₃对当地O₃污染影响较大,是O₃污染的主要来源;另外234个城市O₃污染的主要来源则以区域传输O₃为主.利用城市O₃超标情况与O₃污染来源将城市分为4类：超标-以本地生成O₃为主的城市（N-L）、超标-以区域传输O₃为主的城市（N-T）、达标-以本地生成O₃为主的城市（S-L）和达标-以区域传输O₃为主的城市（S-T）.最终根据各个省份中4类城市的占比,将全国划分为3类控制区：重度控制区、中度控制区及一般控制区.重度控制区中的N-L城市在3类控制区中占比最多（20.3%）,污染最为严重;中度控制区中4类城市的占比均属于中等水平;一般控制区中S-T城市占比最多（65.4%）,污染程度较轻.     

Identification of close relationship between atmospheric oxidation and ozone formation regimes in a photochemically active region

Understanding ozone (O₃) formation regime is a prerequisite in formulating an effective O₃ pollution control strategy. Photochemical indicator is a simple and direct method in identifying O₃ formation regimes. Most used indicators are derived from observations, whereas the role of atmospheric oxidation is not in consideration, which is the core driver of O₃ formation. Thus, it may impact accuracy in signaling O₃ formation regimes. In this study, an advanced three-dimensional numerical modeling system was used to investigate the relationship between atmospheric oxidation and O₃ formation regimes during a long-lasting O₃ exceedance event in September 2017 over the Pearl River Delta (PRD) of China. We discovered a clear relationship between atmospheric oxidative capacity and O₃ formation regime. Over eastern PRD, O₃ formation was mainly in a NO_x-limited regime when HO₂/OH ratio was higher than 11, while in a VOC-limited regime when the ratio was lower than 9.5. Over central and western PRD, an HO₂/OH ratio higher than 5 and lower than 2 was indicative of NO_x-limited and VOC-limited regime, respectively. Physical contribution, including horizontal transport and vertical transport, may pose uncertainties on the indication of O₃ formation regime by HO₂/OH ratio. In comparison with other commonly used photochemical indicators, HO₂/OH ratio had the best performance in differentiating O₃ formation regimes. This study highlighted the necessities in using an atmospheric oxidative capacity-based indicator to infer O₃ formation regime, and underscored the importance of characterizing behaviors of radicals to gain insight in atmospheric processes leading to O₃ pollution over a photochemically active region.     

VOCs源强不确定性对臭氧生成及污染防治影响的模拟分析

本文基于三维区域空气质量模式WRF-Chem,通过修改模式化学模块,量化输出过程量和诊断量,提供了一种定量分析挥发性有机化合物(VOCs)源强不确定性对O3生成影响的方法.为无法定量计算VOCs源强导致的臭氧生成率[P(O3)]偏差,以及由此对O3体积分数分布和污染控制相关联的VOCs敏感区和NOx 敏感区分布的误判提供了方法参考.采用标准统计参数对WRF-Chem模式的气象场与污染场模拟性能进行了评估,相关指标均优于前人结果.以INTEX-B(intercontinental chemical transport experiment-phase B)人为源、FINNv1(fire inventory from NCAR version 1)生物质燃烧源和 MEGAN(model of emissions of gases and aerosols from nature)生物源作为基准源,并以卫星观测数据作为约束,对排放源进行改进,评估了源改进前后臭氧生成率[P(O3)]、O3体积分数和O3控制敏感区指标(Ln/Q)的变化情况.仅人为VOCs(AVOCs)源增加68％后,P(O3)模拟峰值增升比例达13％～82％,以北京观测站点为例,P(O3)模拟月均峰值增加42％(22.5×10-9 h-1).对P(03)形成贡献比例最大的主要化学反应是HO2+NO(占比约68％),AVOCs源增加68％后,该反应贡献比例下降至65％.在改进源下,P(O3)普遍增加达到2×10-9～4×10-9h-O3各季节增幅较大的区域均主要集中在京津冀、长三角和珠三角中心城市及周边区域,与我国大型城市区基本都是VOCs敏感区的结论一致.整体而言,VOCs源强改进后,Nox敏感区O3体积分数增加幅度不大,不超过4×10-9,而部分VOCs敏感区增幅超过20 x10-9.VOCs源强的不确定性会影响O3形成过程中Nox和VOCs敏感区的判断,特别是VOCs源强明显低估会夸大VOCs敏感区的范围,从而降低O3调控对策的有效性.     

Emission inventory evaluation using observations of regional atmospheric background stations of China

Any accurate simulation of regional air quality by numerical models entails accurate and up-to-date emissions data for that region.The INTEX-B2006 (I06),one of the newest emission inventories recently popularly used in China and East Asia,has been assessed using the Community Multiscale Air Quality model and observations from regional atmospheric background stations of China.Comparisons of the model results with the observations for the species SO2,NO 2,O 3 and CO from the three regional atmospheric background stations of Shangdianzi,Longfengshan and Linan show that the model can basically capture the temporal characteristics of observations such as the monthly,seasonal and diurnal variance trends.Compared to the other three species,the simulated CO values were grossly underestimated by about two-third or one-half of the observed values,related to the uncertainty in CO emissions.Compared to the other two stations,Shangdianzi had poorer simulations,especially for SO2 and CO,which partly resulted from the site location close to local emission sources from the Beijing area;and the regional inventory used was not capable of capturing the influencing factors of strong regional sources on stations.Generally,the fact that summer gave poor simulation,especially for SO2 and O 3,might partly relate to poor simulations of meteorological fields such as temperature and wind.     

Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway

This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300 km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO₂) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO₂ revealed that the concentrations were higher within major cities along the highway. The highest NO₂ vertical column densities (NO₂ VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO₂ VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO₂ columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO₂ VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.     

长江三角洲夏季一次典型臭氧污染过程的模拟

利用WRF/Chem空气质量模式对长江三角洲夏季一次典型臭氧(O3)污染过程的时空分布特征和物理化学机制进行了数值模拟研究.结果表明,模式能够合理地再现这次长江三角洲夏季典型O3污染过程的时空分布特征和演变规律.2013年8月10~18日,长江三角洲主要受副热带高压影响,晴天、高温和小风的气象条件有利于光化学污染的形成.模拟结果表明,长江三角洲地区气象场、地理位置、区域输送和化学生成都对O3的时空分布有影响.敏感性实验表明,上海O3浓度在海洋性气流影响下较低,但上海排放源对长江三角洲O3浓度时空分布的影响较为显著;南京近地面高浓度O3主要贡献为化学生成(烯烃和芳香烃)和高层O3的垂直输送,杭州和苏州近地面高浓度O3主要来源于物理过程.在O3生成速率最大时(11~13h)对O3前体物减排,对长江三角洲15:00的O3峰值浓度影响较为明显.     

Impact of chronic ozone on soybean growth and biomass partitioning

This study evaluated yield production and changes in the patterns of functional growth analysis parameters of greenhouse-grown soybeans exposed to low concentrations of ozone (O₃). Plants were exposed over a 113-day interval for 341 h to four concentrations of O₃ (2.0, 4.6, 7.0 and 9.7 pphm O₃) on an intermittent basis. Destructive harvests were periodically taken from all treatments to monitor plant response and to provide the basis for growth analysis techniques. Relative to the ambient greenhouse air control treatment (2.0 pphm O₃), 7.0 and 9.7 pphm O₃ typically reduced plant biomass accumulation, leaf area and expansion, relative growth rate, unit leaf rate, seeds per plant (35% reduction), and other yield components; however, the growth and yield parameters of the 4.6 pphm O₃ treatment were often stimulated. With this one exception, O₃ reduced soybean vegetative growth and altered the pattern of biomass partitioning. As a consequence, the soybean yields were also reduced.     

南京夏季大气臭氧光化学特征与敏感性分析

对流层臭氧（O₃）主要由氮氧化物（NO_x）和挥发性有机物（VOCs）经过一系列光化学反应生成,反应过程呈现复杂的非线性关系.为深入了解O₃的光化学特征及生成机制,利用2018年夏季大气O₃与VOCs的观测数据,结合大气零维框架模拟模型F0AM-MCM,研究O₃超标日和非O₃超标日的O₃光化学特征之间的差异性.观测结果表明,O₃超标日期间φ（O₃）和φ（TVOCs）的平均值分别为47.8×10^-9和49.0×10^-9,为非O₃超标日期间O₃（26×10^-9）和TVOCs（30×10^-9）体积分数的1.8倍和1.6倍.使用F0AM模型,借助EKMA曲线和RIR分析等识别O₃敏感性,发现南京市O₃超标日和非O₃超标日O₃的形成均主要受VOCs和NO_x的协同控制.F0AM-MCM模拟结果表明,在O₃超标日,·OH和HO₂的日平均混合比分别是非O₃超标日的1.3倍和1.8倍,表明O₃超标日期间具有更强的大气氧化能力,且·OH和HO₂的形成和损失速率也有明显的增加,表明自由基循环的增强.此外,O₃超标日的O₃生成速率明显高于非O₃超标日,从而导致了O₃超标日的O₃净生成速率明显高于非O₃超标日.以上发现提高了对南京夏季O₃超标日大气O₃光化学特征的认识.     

大气O3浓度升高对2种基因型矮菜豆根际微生物的影响

在模拟的大气臭氧浓度升高环境中,用磷脂脂肪酸方法（PLFA）分析大气臭氧浓度升高和接种丛枝菌根（AM）真菌对臭氧敏感性不同的2种基因型矮菜豆（臭氧敏感性：S156;臭氧耐受性：R123）根际和菌丝际微生物量及群落结构的影响,旨在明确大气臭氧浓度变化对植物根际微生物的影响,为全面评价臭氧浓度升高对土壤-植物生态系统的影响...     

京津冀污染物跨界输送通量模拟

发展了关键影响因子加权人为源分配方法(WKIF),增添了依赖于气象条件和下垫面类型的生物源,动态更新了气象场和浓度场的边界条件.然后利用WRF-CAMx模式定量给出了四季北京、天津和河北大气边界层中PM2.5、O3、CO、SO2、NO2和NO跨界输送通量和北京净输入或输出通量.结果表明WKIF方法合理反映了中小城市人为源的空间分布特征,模式重要输入参量、初值与边界条件的改进显著改善了WRF-CAMx模式对京津冀地区6个观测站点近地面NOx、O3和PM2.5浓度的模拟.北京向天津冬、春季主要通过西北方向,夏、秋季主要经过偏西方向输入NO、NO2、SO2、CO、O3、PM2.5,输送通量夏季均最小,冬季均最大,且四季北京向天津输入的CO、O3、PM2.5通量显著高于NO、NO2、SO2通量.河北的污染物冬、春季主要通过西北方向,夏季主要经由偏南方向,秋季主要途径偏西方向进入北京;四季北京向河北输入NO和NO2,但跨界输送通量小于20t·d-1;四季河北向北京输入的CO、O3、PM2.5通量远高于北京向河北输送的NO、NO2通量,明显大于北京向河北输送的SO2通量,且河北向北京输入CO、O3、PM2.5通量夏季均最小,冬季均最大;四季北京大气边界层中NO、NO2、SO2最大净输出通量小于50t.d-1,CO、O3、PM2.5净输入或输出通量分别为111～2309、567～6244、715～1778t·d-1.这些定量结果为京津冀区域污染源调控对策的制定提供了科学依据.