基于前体物多情景排放的兰州市2030年夏季臭氧预测

近年来,兰州市夏季臭氧污染问题日渐凸显,已成为影响当地环境空气质量达标的首要污染因子和制约环境空气质量持续改善的突出短板.解决臭氧污染问题需结合城市经济发展的实际情况定量评估前体物减排量并提出切实可行的减排对策,为环境管理的中长期规划提供科学依据.在2015年本地排放清单的基础上,通过情景分析法预测了兰州市2030年3种梯度城市发展与污染控制情景下臭氧的两类主要前体物氮氧化物（NO_x）和挥发性有机物（VOCs）的排放量,利用WRF-Chem模型对不同情景下的2030年夏季臭氧污染程度进行了数值模拟,分析了臭氧浓度与生成敏感性的时空变化情况,并提出了兰州市臭氧前体物的总量控制参考和针对不同行政区的减排对策建议.结果表明,3种不同的城市发展与污染控制情景下兰州市2030年NO_x排放量为4.57×10⁴～12.14×10⁴ t, VOCs排放量为5.30×10⁴～7.69×10⁴ t, NO_x排放可通过调整能源结构,加强末端治理和限制机动车...     

Trends analysis of vegetation exposure indices in rural areas of the U.S.

In this work, statistical models based on a linear time term are tested to determine if they can adequately represent the behavior over time of indices that relate vegetation exposure to air pollutants at a large number of monitoring sites in the rural U.S. Three pollutants are addressed: ozone (O₃), sulfur dioxide (SO₂)and nitrogen dioxide (NO₂. The formulations selected to generate the values of the exposure indices were the sum of all hourly average concentrations (SUM0); in addition, for O₃, the sum of all hourly average concentrations weighted with a sigmoidal function, which assigned larger weights to the higher concentrations. The basic hourly average concentration data were selected from routine air monitoring stations of existing networks that met minimum criteria for quality assurance and data completeness. The statistical methodology used was based on a linear regression model which accounted for seasonality and changes in experimental procedures. An additional lag-one autoregressive term was added to the model for those stations which exhibited significant autocorrelation in the data, based on the Durbin-Watson statistic. Long-term analyses included data for 7 to 10 years; short-term analyses included data for 4 to 5 years. Results show that over rural areas of the U.S., these models do not adequately represent the behavior of vegetation exposure indices, both in the long-term and the short-term analyses; the majority of stations did not have statistically significant (5% level) coefficients for the term representing linear dependence on time. Emissions data for SO₂, NO_x and volatile organic compounds (VOC) over the same time period are also presented. Over the contiguous U.S., emissions between 1979 and 1987 have decreased by a maximum of 3%; emission changes for individual states have generally decreased between 1979 and 1987, but between 1983 and 1987 both increases and decreases have occurred.     

CO and NOx levels at the center of city roads in Jerusalem

CO and NO_x monitors in conjunction with a data acquisition system were installed inside a small van, together with an independent battery operated power supply, to study air pollution levels in the zones where Jerusalem commuters are exposed. The results revealed that along most sections of the test road, CO and NO_x concentrations exceed the short term lower Israeli national air quality standards of 30 and 0.5 ppm, respectively. In addition, there were also a large number of violations of the higher standard for NO_x (1.0 ppm). Traffic volume correlated reasonably well with pollution levels; however, the geometry of the road was found to be equally important. The highest pollution levels were recorded in the narrower segment of the test road near the market place, despite the fact that the traffic counts along these road segments were relatively low. This phenomenon is related to the trapping caused by the canyon effect resulting from the buildings bordering the road. No significant relationship with the general meteorological conditions was found, however, rain washout of NO_x was observed during one sampling trip, while CO concentrations ramained almost unaffected.     

Ozone in Central England: the impact of 20 years of precursor emission controls in Europe

Episodic peak ozone levels over the 1990–2007 period appear to have declined strongly whilst annual mean daily maximum levels have risen over the same period at monitoring sites within the midlands regions of the UK. Sensitivity studies carried out with a photochemical trajectory model have shown that European policies to control Volatile Organic Compound (VOC) and Nitrogen Oxides (NO_x) emissions are the likely cause of the decline in episodic peak levels. There appeared to have been little influence on the episodic peak from changes in intercontinental trans-Atlantic transport but an overwhelming influence on the annual mean daily maximum levels. Non-linear relationships between VOC and NO_x emission controls and ozone, together with the ambition level set by policy-makers, appear to explain why ozone levels in Central England still do not meet internationally accepted air quality guidelines despite two decades of policy actions within Europe.     

Response of ozone to changes in hydrocarbon and nitrogen oxide concentrations in outdoor smog chambers filled with Los Angeles air

During the summer portion of the 1987 Southern California Air Quality Study (SCAQS), outdoor smog chamber experiments were performed on Los Angeles air to determine the response of maximum ozone levels, O₃(max), to changes in the initial concentrations of hydrocarbons, HC, and nitrogen oxides, NO_x. These captive-air experiments were conducted in downtown Los Angeles and in the downwind suburb of Claremont. Typically, eight chambers were filled with LA air in the morning. In some chambers the initial HC and/or NO_x concentrations were changed by 25% to 50% by adding various combinations of a mixture of HC, clean air, or NO_x. The O₃ concentration in each chamber was monitored throughout the day to determine O₃(max).An empirical mathematical model for O₃(max) was developed from regression fits to the initial HC and NO_x concentrations and to the average daily temperature at both sites. This is the first time that a mathematical expression for the O₃-precursor relationship and the positive effect of temperature on O₃(max) have been quantified using captive-air experiments. An ozone isopleth diagram prepared from the empirical model was qualitatively similar to those prepared from photochemical mechanisms. This constitutes the first solely empirical corroboration of the O₃ contour shape for Los Angeles.To comply with the Federal Ozone Standard in LA, O₃(max) must be reduced by approximately 50%. Several strategies for reducing O₃(max) by 50% were evaluated using the empirical model. For the average initial conditions that we measured in LA, the most efficient strategy is one that reduces HC by 55–75%, depending on the ambient HC/NO_x ratio. Any accompanying reduction in NO_x would be counter-productive to the benefits of HC reductions. In fact, reducing HC and NO_x simultaneously requires larger percentage reductions for both than the reduction required when HC alone is reduced. The HC-reduction strategy is the most efficient on average, but no single strategy is the optimum every day.     

夏季长三角地区臭氧非线性响应曲面模型的建立及应用

2013年8月上旬,长三角地区发生了一次大范围高浓度臭氧污染事件.本研究基于WRF-CMAQ空气质量模型系统,结合长三角地区大气污染物排放清单,构建了臭氧与其前体物之间的非线性响应曲面模型(Response surface modeling,RSM).基于RSM探讨了长三角地区O_3化学的敏感性特征,分析了上海市O_3的来源并预测不同情景下O_3的变化,提出O_3污染的最优控制方案.研究结果表明,长三角地区夏季O3主控因素区域差别较大,上海环科院、杭州卧龙桥、南京玄武湖等城区点位属于VOC控制型;徐州铜山、合肥肥西、丽水青田等郊区属于NOx控制型.O_3的敏感性特征在不同浓度水平下也呈现较大差异,随着O_3浓度水平的升高,各地区NOx敏感性均有所增加.从区域来源来看,远距离传输对平日上海O_3贡献较大,占50%以上;而在O_3污染日,本地及区域贡献为72.1%,而远距离传输贡献下降至27.9%.快速预测了110组减排情景,表明在本地及区域前体物均减排70%的情况下,2013年8月上海O_3浓度能完全达标.     

Non-methane hydrocarbon and aldehyde measurements in Budapest,Hungary

During three summer measuring campaigns the atmospheric concentration of non-methane hydrocarbons and aldehydes were measured at two sites in Budapest. Two hundred and forty-five flask samples were analyzed for non-methane hydrocarbon concentration and hydrocarbon composition. For formaldehyde and acetaldehyde concentration 185 and 122 samples were analyzed, respectively. The total non-methane hydrocarbon concentration shows a characteristic diurnal variation with a peak between 6 a.m. and 9 a.m. At the two sites the average concentrations between 6 a.m. and 9 a.m. are 802 and 606 ppbC, respectively. Comparing the speciation of hydrocarbons in the air of Budapest with that measured in other cities we have realized a relative surplus in C₆ alkanes which is balanced by the low contribution of C₃–C₄ alkanes.Both the formaldehyde and acetyldehyde concentration were found rather high. In the downtown the average concentrations are 10.4 and 4.4 ppb, while 3 km away from the center of the city the corresponding values are 28.0 and 5.8 ppb.     

Air quality management in China: Issues, challenges, and options

This article analyzed the control progress and current status of air quality,identified the major air pollution issues and challenges in future,proposed the long-term air pollution control targets,and ...     

1997~2011年北京市空气中酸性物质与降水组分变化趋势的相关性分析

依据北京市环境保护监测中心1997～2011年降水监测资料、大气环境质量监测资料,结合北京经济发展和能源结构变化,分析了酸雨前体物的排放与环境空气中酸性物质及降水中组分的相关性,为政府部门评定大气污染治理效果,制定未来防控政策和规划提供科学决策依据.研究表明,环境空气中NO2、NOx、SO2年均浓度显著相关,说明北京地区环境空气中氮与硫的来源基本相同,均来自化石燃料燃烧排放,这也是酸雨形成的根本原因.北京市大气中的污染物主要来自局地排放源,而降水中硫、氮的湿沉降量与环境空气中SO2、NO2、NOx浓度变化趋势的相关性较差,表明降水中各离子浓度受局地源和外来大气输送共同作用的影响.同时发现降水中硝酸根浓度与机动车数量呈现相同变化趋势,反映出机动车尾气排放的NOx与降水中硝酸根浓度增长密切相关.     

Urban NO2 concentrations in the U.K. in 1987

A mational air quality monitoring network has been established in the U.K. by Warren Spring Laboratory, on behalf of the U.K. Department of the Environment, to determine compliance with the European Community Directive for nitrogen dioxide. Data from the six network sites for 1987 are presented and analysed.No site in the U.K. breached the NO₂ Directive Limit Value during this year, though the closest approaches were at the two London stations. Annual average NO₂ concentrations, which varied from 23 to 39 ppb, were consistent with the top five percentile of long-term measurements from a national survey of over 360 U.K. urban areas carried out in 1986.The temporal variability of NO₂ concentrations was substantially lower over all time scales than that for NO: winter/summer ratios for all sites averaged 2.9 for NO and 1.3 for NO₂. Most sites showed strong diurnal variations for NO which were primarily influenced by traffic emissions during rush hours, although these variations were less marked for NO₂.A markedly non-proportional relationship between annual and daily average NO₂ and NO_x levels was observed, and this has important implications for its efficacy of possible NO_x emission control strategies. An analysis of measured NO₂/NO_x ratios over weekends and weekday periods demonstrates, for instance, that a 20% emission cutback may result, typically, in a corresponding NO₂ reduction of 12% at urban locations in the U.K. NO_x reductions, however, exert a more proportional effect on NO₂ concentrations at kerbside and rural locations.     

A captive-air irradiation study of the response of nitric acid and peroxyacetyl nitrate to ozone control strategies in Los Angeles

Outdoor smog chamber experiments were used to study the sensitivity of the yields of two important nitrogen-containing pollutants, nitric acid (HNO₃) and peroxyacetyl nitrate (PAN) to changes in nonmethane hydrocarbon (HC) and nitrogen oxide (NO_x) concentrations in Los Angeles. The experiments were conducted at two sites in the Los Angeles Basin using eight chambers filled with morning Los Angeles air on 33 days. At least one chamber was unchanged and served as a control, while the initial HC and/or NO_x concentrations were changed by 25–50% in up to seven chambers to simulate O₃ control strategies and to broaden the range of HC - NO_x conditions studied. Empirical models that predict the maximum yields of HNO₃ and PAN were used to determine the response of these pollutants to three possible ozone control strategies. All three strategies (reductions in HC, NO_x or both HC and NO_x) reduced PAN while only NO_x reductions decreased HNO₃. However, reducing NO_x increased the HC reductions required to attain lower O₃ levels. Thus, there is a conflict between the O₃ and HNO₃ control strategies.     

Sulfur dioxide,hydrogen sulfide,total reduced sulfur,chlorinated hydrocarbons and photochemical oxidants in southern California museums

Indoor and outdoor concentrations of the air pollutants ozone, NO₂, SO₂, H₂S, total reduced sulfur (TRS), peroxyacetyl nitrate (PAN), methyl chloroform and tetrachloroethylene, have been measured at three southern California museums. Indoor maxima were 175 ppb for NO₂, 77 ppb for O₃, 0.7 ppb for PAN, 1.2 ppb for C₂Cl₄, >6.3 ppb for CH₃CCl₃, 2.5 ppb for SO₂, 1.4 ppb for TRS, and 46 ppt for H₂S. Indoor levels and indoor/outdoor (I/O) ratios for the chlorinated hydrocarbons pointed out to indoor sources. Outdoor and indoor levels of SO₂ and TRS were low at all three museums, but I/O ratios for SO₂ were high and averaged 0.89. H₂S concentrations were low, 16–46 ppt at one museum and less than 6 ppt at the other two museums. I/O ratios for the air pollutants with outdoor sources (ozone, PAN and NO₂) showed substantial variations, from low values of 0.02–0.33 at locations without influx of outdoor air to high values of 0.85–0.88 at locations experiencing high influx of outdoor air. Of the 10 institutions we have surveyed in southern California to date, eight exhibit high I/O ratios, e.g. 0.60–1.00 for PAN. Of the four museums surveyed that were equipped with HVAC and chemical filtration, only two yielded the expected low I/O ratios.     

VOC emission caps constrained by air quality targets based on response surface model: A case study in the Pearl River Delta Region, China

Because of the recent growth in ground-level ozone and increased emission of volatile organic compounds (VOCs), VOC emission control has become a major concern in China. In response, emission caps to control VOC have been stipulated in recent policies, but few of them were constrained by the co-control target of PM_2.5 and ozone, and discussed the factor that influence the emission cap formulation. Herein, we proposed a framework for quantification of VOC emission caps constrained by targets for PM_2.5 and ozone via a new response surface modeling (RSM) technique, achieving 50% computational cost savings of the quantification. In the Pearl River Delta (PRD) region, the VOC emission caps constrained by air quality targets varied greatly with the NO_x emission reduction level. If control measures in the surrounding areas of the PRD region were not considered, there could be two feasible strategies for VOC emission caps to meet air quality targets (160 µg/m³ for the maximum 8-hr-average 90th-percentile (MDA8-90%) ozone and 25 µg/m³ for the annual average of PM_2.5): a moderate VOC emission cap with <20% NOx emission reductions or a notable VOC emission cap with >60% NO_x emission reductions. If the ozone concentration target were reduced to 155 µg/m³, deep NO_x emission reductions is the only feasible ozone control measure in PRD. Optimization of seasonal VOC emission caps based on the Monte Carlo simulation could allow us to gain higher ozone benefits or greater VOC emission reductions. If VOC emissions were further reduced in autumn, MDA8-90% ozone could be lowered by 0.3-1.5 µg/m³, equaling the ozone benefits of 10% VOC emission reduction measures. The method for VOC emission cap quantification and optimization proposed in this study could provide scientific guidance for coordinated control of regional PM_2.5 and O₃ pollution in China.     

臭氧污染动态源贡献分析方法及应用初探

论文创新提出了基于RSM/CMAQ臭氧污染动态源贡献分析方法,并以佛山市顺德区2014年10月为例,分析了不同区域的人为可控源NO_x和VOCs减排情景下(10%、70%和100%)对本地O_3浓度变化的量化贡献.研究结果表明顺德区O_3的人为可控比例约43%,且受区域排放影响非常明显,主导上风向广州排放源总贡献(14%)超过顺德本地贡献(7%).VOCs的减排可有效削减顺德区O_3浓度,当减排力度较小时(12%),若仅控制区域NO_x排放将导致顺德区O_3浓度上升,随着减排力度的加大,区域NO_x的削减贡献会反超VOCs.RSM/CMAQ动态源贡献分析方法可为空气质量管理提供科学决策依据.     

Calculation of long-term averaged and episodic oxidant concentrations for the Netherlands

Ground-level ozone and oxidant (sum of O₃ and NO₂) concentrations in The Netherlands are calculated during the growing season (May–September) by means of a Lagrangian long-range transport model. Two air parcels—one representative of the mixed layer, the other representative of the polluted layer above the mixed layer (aged smog layer)—are followed along 96 h back trajectories. Long-term averaged and 98 percentile values of hourly averaged concentrations are estimated on the basis of concentrations calculated for four arrival times per day for all days in the period considered.In a number of sensitivity runs the influence of European anthropogenic NO_x and VOC emissions on the oxidant concentrations in The Netherlands has been investigated. In general, the influence of European emissions on the 98-percentile values is 2–3 times as large as on the averaged concentrations. This indicates that long-term averaged concentrations more strongly depend on the concentrations in the free troposphere whereas the episodic concentrations are determined by photochemical production over Europe. VOC emission reduction is more effective in lowering episodic concentrations than NO_x emission reduction. For long-term averaged concentrations, however, NO_x and VOC emission reduction of 50% or more are nearly equally effective.     

Climate and air quality-driven scenarios of ozone and aerosol precursor abatement

In addition to causing domestic and regional environmental effects, many air pollutants contribute to radiative forcing (RF) of the climate system. However, climate effects are not considered when cost-effective abatement targets for these pollutants are established, nor are they included in current international climate agreements. We construct air pollution abatement scenarios in 2030 which target cost-effective reductions in RF in the EU, USA, and China and compare these to abatement scenarios which instead target regional ozone effects and particulate matter concentrations. Our analysis covers emissions of PM (fine, black carbon and organic carbon), SO₂, NO_x, CH₄, VOCs, and CO. We find that the effect synergies are strong for PM/BC, VOC, CO and CH₄. While an air quality strategy targeted at reducing ozone will also reduce RF, this will not be the case for a strategy targeting particulate matter. Abatement in China dominates RF reduction, but there are cheap abatement options also available in the EU and USA. The justification for international cooperation on air quality issues is underlined when the co-benefits of reduced RF are considered. Some species, most importantly SO₂, contribute a negative forcing on climate. We suggest that given current knowledge, NO_x and SO₂ should be ignored in RF-targeted abatement policies.     

我国北方两地环境臭氧浓度对矮菜豆生长的影响

地表臭氧对植物具有显著毒害作用,矮菜豆(Phaseolus vulgaris L.)已被证实对臭氧非常敏感.选用对臭氧敏感性不同的矮菜豆(R123,臭氧耐受性及S156,臭氧敏感性)分别在3个地点(北京昌平、北京生态中心、哈尔滨市)进行室外直接暴露实验,旨在探讨当前环境臭氧浓度对矮菜豆生长的影响.结果表明,生态中心和昌平两地菜豆在当前臭氧浓度下叶片都出现严重臭氧损伤症状,整个生长季S156型菜豆平均臭氧损伤比例比R123型菜豆高23.5%;臭氧损伤自开花期开始,开花期至结荚期损伤加剧,在豆荚成熟期臭氧损伤比例达到最大值.豆荚产量对比发现,昌平和生态中心两地S156型与R123型豆荚产量比值分别为0.48和0.24,哈尔滨地区为0.73,二者比值为1视为生长不受臭氧影响.可见,北京地区较高的环境臭氧浓度已使敏感性作物矮菜豆显著减产.     

Application of AERMOD on near future air quality simulation under the latest national emission control policy of China：A case study on an industrial city

Air quality model can be an adequate tool for future air quality prediction, also atmospheric observations supporting and emission control strategies responders. The influence of emission control policy (emission reduction targets in the national "China’s 12th Five-Year Plan (2011-2015)") on the air quality in the near future over an important industrial city of China, Xuanwei in Yunnan Province, was studied by applying the AERMOD modeling system. First, our analysis demonstrated that the AERMOD modeling system could be used in the air quality simulation in the near future for SO2 and NOx under average meteorology but not for PM10. Second, after evaluating the simulation results in 2008 and 2015, ambient concentration of SO2, NOx and PM10 (only 2008) were all centered in the middle of simulation area where the emission sources concentrated, and it is probably because the air pollutions were source oriented. Last but not least, a better air quality condition will happen under the hypothesis that the average meteorological data can be used in near future simulation. However, there are still heavy polluted areas where ambient concentrations will exceed the air quality standard in near future. In spatial allocation, reduction effect of SO2 is more significant than NOx in 2015 as the contribution of SO2 from industry is more than NOx. These results inspired the regulatory applications of AERMOD modeling system in evaluating environmental pollutant control policy     

Field tests of a passive sampler for atmospheric ozone at California mountain forest locations

Field tests of a colorant-based ozone passive sampler have been carried out during the 1990 smog season at five mountain forest locations in California. Co-located measurements of ambient ozone were made at all field sites using the passive sampler and a reference method, ultraviolet (u.v.) photometry. The sampling duration ranged from 3 to 30 days. Nitrogen dioxide, aldehydes and the phytotoxic oxidants peroxyacetyl nitrate (PAN) and peroxypropionyl nitrate (PPN) were measured at one location to assess possible interferences. The average precision of the measurements, calculated from data for 42 sets of colocated passive samplers, was 12%. Data for all field locations could be reduced to a single equation relating color change (ΔE units) to ozone dose (units: ppb-days). This polynomial equation could be reduced to a linear equation for color changes not exceeding 8 ΔE units (equivalent to sampling durations of up to 15 days), with good agreement between field data and earlier calibration results obtained in the laboratory. Both polynomial and linear equations can be used to obtain quantitative, time-integrated measurements of ambient ozone. The performance of the passive sampler showed no dependence on changes in ambient temperature and humidity. Interferences from air pollutants other than ozone contributed a total positive bias of less than 5% to the measured ozone concentrations: 3% for NO₂, 1.3% for PAN, 0.2% for PPN, and 0.% or less for formaldehyde and acetaldehyde.