Peroxyacetyl nitrate observed in Beijing in August from 2005 to 2009

Measurements of peroxyacetyl nitrate（PAN） were made at a Beijing urban site each August from2005 to 2009. Over this 5-year period, the average PAN concentration for August in each year increased from 3（2005） to 11.7 μg/m3（2007）; however, it decreased rapidly in 2008（4.1 μg/m3）.Generally, the variation over the 5 years showed a rise in the first part of the study period,followed by a decline. We considered two categories of local and regional air masses in this study, which revealed that the PAN concentration in Beijing was affected mainly by southeastern air masses. The August PAN variation was influenced predominantly by local air masses in 2005,but by 2009 regional air masses had become more important. This study showed the level and variation of PAN in the month of August in 5 consecutive years for the first time, and proved that control measures are useful in decreasing photochemical pollution; hence, these measures are probably feasible for other megacities too. Furthermore, this method of analyzing regional and local impacts might be useful for other studies as well.     

Seasonal and diurnal variations of atmospheric peroxyacetyl nitrate, peroxypropionyl nitrate, and carbon tetrachloride in Beijing

Atmospheric peroxyacetyl nitrate(PAN), peroxypropionyl nitrate(PPN), and carbon tetrachloride(CCl4) were measured from September 2010 to August 2011 in Beijing. PAN exhibited low values from mid-autumn to early spring(October to March) with monthly average concentrations ranging from 0.28 to 0.73 ppbV, and increased from early spring to summer(March to August), ranging from 1.37–3.79 ppbV. The monthly variation of PPN was similar to PAN, with low values(below detection limit to 0.18 ppbV) from mid-autumn to early spring, and a monthly maximum in September(1.14 ppbV). The monthly variation of CCl4was tightly related to the variation of temperature, exhibiting a minimum in winter(69.3 pptV) and a maximum of 180.6 pptV in summer. Due to weak solar intensity and short duration, PAN and O3showed no distinct diurnal patterns from morning to night during winter, whereas for other seasons, they both exhibited maximal values in the late afternoon(ca. 15:00 to 16:00 local time) and minimal values during early morning and midnight. Good linear correlations between PAN and PPN were found in autumn(R = 0.91), spring(R = 0.94), and summer(R = 0.81), with slopes of 0.130, 0.222, and 0.133, respectively, suggesting that anthropogenic hydrocarbons dominated the photochemical formation of PANs in Beijing. Positive correlation between PAN and O3 in summer with the low slopes( O3 / PAN) ranging from 9.92 to 18.0 indicated serious air pollution in Beijing, and strong negative correlation in winter reflected strong O3consumption by NO titration and less thermal decompositin of PAN.     

Two-year measurements of surface ozone at Dangxiong, a remote highland site in the Tibetan Plateau

Measurements of surface O3 and carbon monoxide(CO) were made from September 2009 to August 2011 at Dangxiong(30.48°N, 91.10°E, 4187 m a.s.l.), a remote highland site in a southern valley of the Nyainqêntanglha Mountains in the Tibetan Plateau, China. The monthly mean O3 mixing ratio ranged from 29.1 to 51.4 ppb, with an average of 38.5 ppb, and the maximum value was observed in May. The average diurnal cycle of O3 concentration showed a minimum in early morning and a maximum in the afternoon, with a broader "high platform" from the late morning to the late afternoon, and resembled that of surface wind speed. The concentration of surface O3 was highly significantly correlated with tropospheric column O3 over the regions surrounding Dangxiong and with that of surface O3 observed at a site north of the Nyainqêntanglha Mountains, suggesting a good regional representativeness of surface O3 at Dangxiong. In the afternoon when stronger winds blew, surface air showed distinct features of free-atmospheric air, with higher O3, lower CO, and lower relative humidity(RH). The negative O3–CO and O3–RH correlations in most months indicate a significant influence of air masses from the free troposphere. Trajectory analysis suggests that air masses originating from the south of the site make a negative net contribution to surface O3 and a positive contribution to CO and humidity, and those from the northwest sector contribute conversely to the respective quantities.     

Ground-high altitude joint detection of ozone and nitrogen oxides in urban areas of Beijing

Based on observational data of ozone(O3) and nitrogen oxide(NOx) mixing ratios on the ground and at high altitude in urban areas of Beijing during a period of six days in November 2011,the temporal and spatial characteristics of mixing ratios were analyzed.The major findings include:urban O3 mixing ratios are low and NOx mixing ratios are always high near the road in November.Vertical variations of the gases are significantly different in and above the planetary boundary layer.The mixing ratio of O3 is negatively correlated with that of NOx and they are positively correlated with air temperature,which is the main factor directly causing vertical variation of O3 and NOx mixing ratios at 600-2100m altitude.The NOx mixing ratios elevated during the heating period,while the O3 mixing ratios decreased:these phenomena are more significant at high altitudes compared to lower altitudes.During November,air masses in the urban areas of Beijing are brought by northwesterly winds,which transport O3 and NOx at low mixing ratios.Due to Beijing’s natural geographical location,northwest air currents are beneficial to the dilution and dispersion of pollutants,which can result in lower O3 and NOx background values in the Beijing urban area.     

Tropospheric NO2 vertical column densities retrieved from ground-based MAX-DOAS measurements at Shangdianzi regional atmospheric background station in China

Ground-basedMulti-AXis Differential Optical Absorption Spectroscopy(MAX-DOAS)measurements were performed at Shangdianzi(SDZ)regional atmospheric background station in northern China from March 2009 to February 2011.The tropospheric NO_2vertical column densities(VCDs)were retrieved to investigate the background condition of the Beijing–Tianjin–Hebei developed economic circle in China.The seasonal variation of mean NO_2tropospheric VCDs(VCD_(Trop))at SDZ is apparent,with the maximum(1.3×10~(16)molec/cm~2)in February and the minimum(3.5×10~(15)molec/cm~2)in August,much lower than those observed at the Beijing city center.The average daytime diurnal variations of NO_2VCD_(Trop )are rather consistent for all four seasons,presenting the minimum at noon and the higher values in the morning and evening.The largest and lowest amplitudes of NO_2VCD_(Trop)diurnal variation appear in winter and in summer,respectively.The diurnal pattern at SDZ station is similar to those at other less polluted stations,but distinct from the ones at the urban or polluted stations.Tropospheric NO_2VCDs at SDZ are strongly dependent on the wind,with the higher values being associated with the pollution plumes from Beijing city.Tropospheric NO_2VCDs derived from ground-based MAX-DOAS at SDZ show to be well correlated with corresponding OMI(Ozone Monitoring Instrument)satellite products with a correlation coefficient R=0.88.However,the OMI observations are on average higher than MAX-DOAS NO_2VCDs by a factor of 28%,probably due to the OMI grid cell partly covering the south of SDZ which is influenced more by the pollution plumes from the urban areas.     

Investigation of air pollution concentration in Kathmandu valley during winter season

The monthly concentrations of NO2, NOx, SO2 and O3 measured by a passive sampler from February 2003 to January 2004 showed that the air pollution during the winter season in Kathmandu valley was higher than the summer season. The O3 level was found the highest during April, May and June due to strong radiation. The hourly concentrations of NO2, NOx, O3 and suspended particulate matter（SPM） were also measured by automatic instruments on December 2003. Temperature at the height of 60 m and 400 m at Raniban Mountain in the northwest of Kathmandu valley was measured on February 2001 in the winter season and the average potential temperature gradient was estimated from observed temperature. Wind speed was also measured at the department of hydrology, airport section, from 18 February to 6 March 2001. It was found that the stable layer and the calm condition in the atmosphere strongly affected the appearance of the maximum concentrations of NO2 and SPM in the morning, and that the unstable layer and the windy condition in the atmosphere was considerably relevant to the decrease of air pollution concentrations at daytime. The emission amounts of NOx, HCs and total suspended particle（TSP） from transport sector in 2003 were estimated from the increasing rate of vehicles on the basis of the emission amounts in 1993 to be 3751 t/a, 30570 t/a and 1317 t/a, respectively. The diurnal concentrations in 2003 calculated by the two-layers box model reproduced the characteristics of air pollution in Kathmandu valley such as the maximum value of O3 and its time, the maximum value of NO in the morning, and the decrease of NO and NO2 at daytime. The comparison with the concentrations in 1993 calculated suggested that the main cause of air pollution was the emission from transport sector.     

Analysis of air quality characteristics of Beijing–Tianjin–Hebei and its surrounding air pollution transport channel cities in China

Beijing–Tianjin–Hebei(BTH) and its surrounding areas are very important to air pollution control in China.To analyze the characteristics of BTH and its surrounding areas of China,we collected 5,641,440 air quality data from 161 air monitoring stations and 37,123,000 continuous monitoring data from air polluting enterprises in BTH and surrounding cities to establish an indicator system for urban air quality portraits.The results showed that particulate matter with aerodynamic diameters of 2.5 μm(PM_(2.5)),particulate matter with aerodynamic diameters of 10 μm(PM_(10)) and SO_2 improved significantly in 31 cities from2015 to 2018,but ozone deteriorated.Air quality in BTH and the surrounding areas showed obvious seasonal characteristics,among which PM_(2.5),PM_(10),SO_2,and NO_2 showed a "U" type distribution from January to December,while O_3 had an "inverted U" distribution.The hourly changes in air quality revealed that peaks of PM_(2.5),PM_(10) and NO_2 appeared from 8:00 to 10:00,while those for O_3 appeared at 15:00–16:00.The exposure characteristics of the 31 cities showed that six districts in Beijing had the highest air quality population exposure,and that exposure levels in Zhengzhou,Puyang,Anyang,Jincheng were higher than the average of the 31 investigated cities.Additionally,multiple linear regression revealed a negative correlation between meteorological factors(especially wind and precipitation) and air quality,while a positive correlation existed between industrial pollution emissions and air quality in most of BTH and its surrounding cities.     

A preliminary analysis of the surface chemistry of atmospheric aerosol particles in a typical urban area of Beijing

Atmospheric aerosol particle samples were collected using an Ambient Eight Stage(Non-Viable) Cascade Impactor Sampler in a typical urban area of Beijing from 27 th Sep.to 5th Oct.,2009.The surface chemistry of these aerosol particles was analyzed using Static Time of Flight-Secondary Ion Mass Spectrometry(Static TOF-SIMS).The factors influencing surface compositions were evaluated in conjunction with the air pollution levels,meteorological factors,and air mass transport for the sampling period.The results show that a variety of organic ion groups and inorganic ions/ion groups were accumulated on the surfaces of aerosol particles in urban areas of Beijing;and hydrophobic organic compounds with short-or middle-chain alkyl as well as hydrophilic secondary inorganic compounds were observed.All these compounds have the potential to affect the atmospheric behavior of urban aerosol particles.PM1.1–2.1and PM3.3–4.7had similar elements on their surfaces,but some molecules and ionic groups demonstrated differences in Time of Flight-Secondary Ion Mass Spectrometry spectra.This suggests that the quantities of elements varied between PM1.1–2.1and PM3.3–4.7.In particular,more intense research efforts into fluoride pollution are required,because the fluorides on aerosol surfaces have the potential to harm human health.The levels of air pollution had the most significant influence on the surface compositions of aerosol particles in our study.Hence,heavier air pollution was associated with more complex surface compositions on aerosol particles.In addition,wind,rainfall,and air masses from the south also greatly influenced the surface compositions of these urban aerosol particles.     

Environmental impact and health risk assessment of volatile organic compound emissions during different seasons in Beijing

Volatile organic compounds (VOCs) are major contributors to air pollution. Based on the emission characteristics of 99 VOCs that daily measured at 10 am in winter from 15 December 2015 to 17 January 2016 and in summer from 21 July to 25 August 2016 in Beijing, the environmental impact and health risk of VOC were assessed. In the winter polluted days, the secondary organic aerosol formation potential (SOAP) of VOC (199.70 ± 15.05 μg/m³) was significantly higher than that on other days. And aromatics were the primary contributor (98.03%) to the SOAP during the observation period. Additionally, the result of the ozone formation potential (OFP) showed that ethylene contributed the most to OFP in winter (26.00% and 27.64% on the normal and polluted days). In summer, however, acetaldehyde was the primary contributor to OFP (22.00% and 21.61% on the normal and polluted days). Simultaneously, study showed that hazard ratios and lifetime cancer risk values of acrolein, chloroform, benzene, 1,2-dichloroethane, acetaldehyde and 1,3-butadiene exceeded the thresholds established by USEPA, thereby presenting a health risk to the residents. Besides, the ratio of toluene-to-benzene indicated that vehicle exhausts were the main source of VOC pollution in Beijing. The ratio of m-/p-xylene-to-ethylbenzene demonstrated that there were more prominent atmospheric photochemical reactions in summer than that in winter. Finally, according to the potential source contribution function (PSCF) results, compared with local pollution sources, the spread of pollution from long-distance VOCs had a greater impact on Beijing.     

Spatial and temporal variation of particulate matter and gaseous pollutants in 26 cities in China

O3and PM2.5were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China's urban air quality will be evaluated using six factors(SO2, NO2, O3, CO, PM2.5and PM10) from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2and PM10were observed in 26 cities, and the pollutants O3, CO and PM2.5were measured in 15 of the 26 cities. The concentrations of SO2and CO were much higher in the cities in north China than those in the south. As for O3and NO2, however, there was no significant diference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5to PM10ranging from 55% to 77%. The concentrations of PM2.5(57.5 μg/m3) and PM10(91.2 μg/m3) were much higher than the values(PM2.5: 11.2 μg/m3; PM10 : 35.6 μg/m3) recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more eforts will to be taken to control air pollution in China.     

天津夏季边界层低层大气中PAN和O3的输送特征分析

采用在线仪器监测分析2017年夏季天津气象铁塔220 m观测平台大气中过氧乙酰硝酸酯(PAN)和O_3的体积分数,并结合气象观测资料和后向轨迹分析PAN和O_3的输送特征.观测期间PAN和O_3体积分数平均值分别为(0.73±0.56)×10~(-9)和(53±25)×10~(-9),最大小时体积分数分别为3.49×10~(-9)和137×10~(-9),PAN和O_3体积分数具有相似的日变化特征,白昼PAN和O_3浓度高于夜间,且PAN和O_3浓度相关系数(R2=0.52)显著高于夜间(R2=0.21).观测期间偏南风下PAN和O_3浓度最高,偏东风下最低,风玫瑰图和后向轨迹聚类分析都表明,来源于西南方向的气流轨迹对应的污染物浓度最高,途经渤海和河北、辽宁沿海地区的偏东气流对应的PAN和O_3体积分数最低,边界层内输送对PAN和O_3的体积分数分布起到了重要作用.     

广州番禺大气成分站一次典型光化学污染过程PAN和O3分析

通过对广州番禺大气成分站（GPACS）的光化学相关污染物（O₃、PAN、VOCs、NO₂、NO）以及气象要素进行观测,分析2010~2016年期间发生在广州地区一次典型光化学污染过程.结果表明,该光化学污染过程期间,O₃和PAN总体体积分数比较高,最大O₃小时体积分数为140.6×10^-9,而最大PAN小时体积分数为4.7×10^-9.NO整体体积分数较低,对O₃的化学滴定和PAN的去除影响较小.NO₂整体体积分数较高、辐射较强和风速较低则有利于O₃和PAN的形成和积累.PAN和O₃具有一定的线性关系（R²=0.55）,而形成PAN和O₃前体物VOCs物种不完全相同影响着它们的线性关系,在生成PAN的VOCs物种中,乙烯、丙烷、异戊二烯和甲苯所占的比例较大,而对臭氧生成潜势较大的物种有异戊二烯、1,3,5-三甲苯、丙烯、间,对-二甲苯以及甲苯.对PA自由基体积分数进行估算,发现它的日均值体积分数在0.11×10^-12~0.16×10^-12范围变化,远高于其它地区,表明此次发生的光化学反应较为强烈.     

成都郊区(新津)夏季甲醛污染特征分析

甲醛（HCHO）是大气光化学重要污染物之一,为研究西南地区郊区大气夏季甲醛污染特征选取了四川省成都市新津区进行大气甲醛观测,结合NO_x、O₃、PAN、J-value、温湿度、风速风向、天气数据进行分析.观测期间成都市新津区夏季甲醛浓度为0.76×10^-9~12.50×10^-9（V/V）,均值为3.47×10^-9±2.05×10^-9（V/V）,呈现明显的日变化规律.结合数据分析可知,一次人为排放源在成都郊区夏季日间甲醛贡献中占比较低.观测期间甲醛受光照的影响较大,与O₃、PAN、J-value普遍呈现一致的变化规律,因此成都市夏季日间甲醛主要来源为甲醛前体物的二次光化学反应.     

北京市生物源一次气溶胶数浓度变化特征及影响因素

生物源一次气溶胶（PBAP）,是大气颗粒物的重要组成部分,不论微生物死活,对空气质量和人类健康均会产生影响,同时对大气化学以及气候变化都有重要影响.基于流式细胞仪分析技术,结合碘化丙啶（PI）和SYBR （SYBR Green I）双荧光探针,对北京城区大气环境中死的和活的PBAP进行了识别和定量分析,并探究气象因子和空气污染因子对其影响.结果发现,北京城区死的和活的PBAP数浓度中值夏季（1.03×10⁶个·m^-3和7.43×10⁵个·m^-3）高于冬季（7.34×10⁵个·m^-3和6.18×10⁵个·m^-3）,且两者呈现明显的同步变化趋势.统计学结果分析发现,PBAP数浓度与气象条件和空气质量等环境影响因子相关性并不显著,与温度和湿度呈现弱正相关关系,与O₃、最大风速和日照时数呈现弱负相关关系.PBAP数浓度与细颗粒物PM_2.5浓度相关性较弱,与粗颗粒物（PM_2.5-10）浓度呈现明显的正相关关系.静稳天气和沙尘长距离传输都可以提升北京城区PBAP的数浓度水平.     

基于WRF-Chem模拟的玉溪市大气环境容量精细估算

云南高原的清洁大气环境及其潜在变化是一个值得深入研究的大气环境问题.本文选择云南高原重要工业城市—玉溪作为研究区域,基于中尺度空气质量模式WRF-Chem,开展玉溪市的大气环境容量模拟估算.同时,以2015年冬、春、夏、秋季主要大气污染物模拟为基础,采用以我国环境空气质量标准(GB3095—2012)为约束目标的WRF-Chem模拟迭代大气环境容量算法,设置3 km的精细分辨率,计算得到2015年玉溪市一次PM_(10)、一次PM_(2.5)、SO_2、NO_x和CO的大气环境容量分别为1.284×10~4、0.854×10~4、1.917×10~4、1.796×10~4和51.556×10~4t·a~(-1).最后,研究了整个玉溪市区域和城区大气环境容量的季节变化特征,结果发现,各污染物冬季大气环境容量最小,除PM_(2.5)外的污染物均在春季大气环境容量最大.玉溪市城区剩余容量占全市的比例均在40%左右,反映了工业发展和城市化带来的大气环境的城乡差异及可能的环境变化效应.     

福建茫荡山地区春季大气O3、HONO、HCHO、H2O2对 ·OH的贡献率研究

2009年春季在福建南平市茫荡山地区进行观测,测量了.OH源O3、HONO、HCHO和H2O2的浓度.结果表明O3、HCHO、HONO、H2O2浓度分别为4.96×10-8、3.97×10-10、2.53×10-10、1.18×10-10,低于华北农村的浓度.利用CMAQ计算O3、HCHO、HONO、H2O2对.OH的贡献率,分别为57.0%、7.7%、34.9%、0.4%.O3光解是该地区最重要的.OH来源.O3、HCHO、H2O2对.OH的贡献呈现单峰变化,在12:00～13:00达到峰值.HONO对.OH的贡献曲线呈波动状,和人类居住环境清晨出现峰值的情况不同.     

华北区域大气中羰基化合物体积分数水平及化学反应活性

为了解华北区域光化学污染特征,于2018年5月至2019年4月在石家庄和兴隆地区利用2,4-二硝基苯肼（DNPH）对空气中的羰基化合物进行采样,并利用高效液相色谱对采集样品进行分析,以了解该区域羰基化合物的组成、体积分数、来源、·OH损耗速率和臭氧生成潜势.本研究共测定了13种含羰基的挥发性有机物,其中体积分数最高的3种物质为丙酮、甲醛和乙醛[石家庄地区：（6.46±5.25）×10^-9、（3.76±2.29）×10^-9和（2.65±1.74）×10^-9;兴隆地区：（1.85±1.27）×10^-9、（1.29±1.02）×10^-9和（0.72±0.48）×10^-9];C1/C2和C2/C3值表明石家庄地区工业化水平较高,受机动车尾气和化石燃料燃烧等人为排放影响较明显;兴隆地区采样点处于背景区域,受自然源影响较大;石家庄地区对L_·OH贡献最大的3种物质分别为乙醛（1.77 s^-1）、甲醛（1.57 s^-1）和丁醛（0.42 s^-1）;兴隆地区对L_·OH贡献最大的3种物质为分别为甲醛（0.53 s^-1）、乙醛（0.47 s^-1）和丁醛（0.12 s^-1）;对O₃生成贡献最大的羰基化合物物种为甲醛和乙醛[石家庄地区：34.61×10^-9（以O₃计,下同）和16.73×10^-9;兴隆地区：11.77×10^-9和4.47×10^-9],且甲醛的最大臭氧生成潜势估算（OFP）远高于乙醛.     

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.     

北京市燃煤源排放控制措施的污染物减排效益评估

为分析北京市燃煤源排放控制措施的污染物减排效益,基于MEIC（中国多尺度排放清单模型）,采用情景分析法,评估了北京市电厂能源清洁化与末端治理、燃煤锅炉改造和城区平房区居民采暖改造等措施的污染物减排效益.结果表明,相对于无控情景,2013年北京市电厂能源清洁化与末端治理减少PM_2.5、PM₁₀、SO₂和NO_x排放量为1.28×104、2.10×104、5.13×104和4.98×104 t,分别占无控情景的85%、86%、87%、74%;北京市燃煤锅炉改造减少PM_2.5、PM₁₀、SO₂、NO_x排放量为1.09×104、2.68×104、11.64×104和5.81×104 t,分别占无煤改气情景的83%、89%、83%、83%;北京市老旧平房区的居民采暖改造减少PM_2.5、PM₁₀、SO₂和NO_x排放量分别为630、870、2 070和790 t,均占无煤改电情景的8%.研究显示,北京市从1998年开始采取的各种减排措施有效地减少了污染物的排放,对北京市空气质量改善具有重要意义.