Relationship of non-methane hydrocarbons and NOx to ozone formation in the atmosphere of Bahrain

The hourly air quality monitoring data for hydrocarbons, NO_x, and ozone were analyzed from two sites; one north of the industrial areas in Sitra and the other one located south on the east coast. The background levels of non-methane hydrocarbons at both sites were in excess of the U.S. federal ambient air quality standard of 0.24 ppm most of the time. The U.S. ozone air quality hourly standard of 0.12 ppm. however, was exceeded twice only at Sitra during high ambient NO _x concentrations greater than 0.15 ppm and high non-methane hydrocarbon levels of 10 ppm. The suitability of introducing the U.S. standard for non-methane hydrocarbons to the region is discussed.     

Carbonyl compounds in dining areas, kitchens and exhaust streams in restaurants with varying cooking methods in Kaohsiung, Taiwan

Eighteen carbonyl species in C₁–C₁₀ were measured in the dining areas, kitchens and exhaust streams of six different restaurant types in Kaohsiung, southern Taiwan. Measured results in the dining areas show that Japanese barbecue (45.06 ppb) had the highest total carbonyl concentrations (sum of 18 compounds), followed by Chinese hotpot (38.21 ppb), Chinese stir-frying (8.99 ppb), Western fast-food (8.22 ppb), Chinese–Western mixed style (7.38 ppb), and Chinese buffet (3.08 ppb), due to their different arrangements for dining and cooking spaces and different cooking methods. On average, low carbon-containing species (C₁–C₄), e.g., formaldehyde, acetaldehyde, acetone and butyraldehyde were dominant and contributed 55.01%–94.52% of total carbonyls in the dining areas of all restaurants. Meanwhile, Chinese–Western mixed restaurants (45.48 ppb) had high total carbonyl concentrations in kitchens mainly because of its small kitchen and poor ventilation. However, high carbon-containing species (C₅–C₁₀) such as hexaldehyde, heptaldehyde and nonanaldehyde (16.62%–77.00% of total carbonyls) contributed comparatively with low carbon-containing compounds (23.01%–83.39% of total carbonyls) in kitchens. Furthermore, Chinese stir-frying (132.10 ppb), Japanese barbecue (125.62 ppb), Western fast-food (122.67 ppb), and Chinese buffet (119.96 ppb) were the four restaurant types with the highest total carbonyl concentrations in exhaust streams, indicating that stir-frying and grilling are inclined to produce polluted gases. Health risk assessments indicate that Chinese hotpot and Japanese barbecue exceeded the limits of cancer risk (10^− 6) and hazard index (= 1), mainly due to high concentrations of formaldehyde. The other four restaurants were below both limits.     

Chemical speciation and anthropogenic sources of ambient volatile organic compounds(VOCs)during summer in Beijing,2004

Volatile organic compounds (VOCs) were measured at six sites in Beijing in August, 2004. Up to 148 VOC species, including C₃ to C₁₂ alkanes, C₃ to C₁₁ alkenes, C₆ to C₁₂ aromatics, and halogenated hydrocarbons, were quantified. Although the concentrations differed at the sites, the chemical compositions were similar, except for the Tongzhou site where aromatics were significantly high in the air. Based on the source profiles measured from previous studies, the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance (CMB) model. The results show that urban VOCs are predominant from mobile source emissions, which contribute more than 50% of the VOCs (in mass concentrations) to ambient air at most sites. Other important sources are gasoline evaporation, painting, and solvents. The exception is at the Tongzhou site where vehicle exhaust, painting, and solvents have about equal contribution, around 35% of the ambient VOC concentration. As the receptor model is not valid for deriving the sources of reactive species, such as isoprene and 1,3-butadiene, other methodologies need to be further explored.     

沿海地区不同来向气团中非甲烷挥发性有机物的组成特征研究

在我国东部沿海城市两个采样点上对不同来向气团中非甲烷挥发性有机物(NMVOCs)的组成特征进行了观测研究.采用离线方法(苏玛罐采样、三级冷阱预浓缩、GC-FID分析)进行样品测定;利用拉格朗日混合单粒子轨道模型(HYSPLIT-4)模拟计算气团后向轨迹.结果表明,观测期间总非甲烷挥发性有机物(TNMVOCs)浓度的变化范围为4.31×10~(-9)～68.97×10~(-9)(体积分数,下同),主要受工业活动、溶剂和液化石油气使用影响;不同来向气团的NMVOCs组成特征有明显差异,陆地气团的NMVOCs浓度高于海洋气团,途经工业较发达地区的气团其烯烃、芳香烃和烷烃占比较高,受机动车排放的影响较大.     

Ozone concentrations at a remote mountain site and at two regional locations in southwestern Alberta

Ozone concentrations at a remote site in the Rocky Mountains of southwestern Alberta averaged 43.4 ppb over a 2 year period and the Canadian air quality objective of an 80 ppb hourly average was exceeded 1.5% of the time. The diurnal variation in O₃ concentrations was small, 2.9 ppb, indicative of a remote location, above the nocturnal inversion and not greatly influenced by local emissions. During the period when O₃ concentrations were highest, winds were generally from the southwest, suggestive of the long range transport of anthropogenic pollutants from distant sources rather than the generation of O₃ from local emissions. In contrast, hourly O₃ concentrations at two regional air quality monitoring sites showed an average diurnal variation of 14 ppb. Only two hourly averages exceeded 80 ppb during the 2 years, and the mean O₃ concentration was 26 ppb. When these regional sites were within the urban plume from Calgary, the O₃ concentrations were depressed to a mean of 18 ppb. Ozone concentrations in downtown Calgary averaged 13 ppb. Under Alberta climatological and meteorological conditions, hourly O₃ objectives are most likely to be exceeded in remote areas, rather than in cities or in areas under the direct influence of urban emissions.     

一个沿海城市大气臭氧的本地生成过程及其对前体物的敏感性

在威海市两个采样点用苏码罐采集了全空气样品,利用三级冷阱预浓缩-GC/MS方法离线测定了空气样品中109种大气挥发性有机物(VOCs).使用基于观测的MCM机理大气化学模式(OBM-MCM)分析了大气臭氧生成对VOCs组分的敏感性及本地生成过程.结果表明:观测期间两个采样点的总挥发性有机物(TVOCs)平均浓度分别为27.84×10~(-9)和17.85×10~(-9),对TVOCs贡献最大的均是烷烃.模拟分析表明,大气臭氧生成与前体物的控制关系存在空间差异性,在一个观测点受VOCs控制,而在另一个观测点受NO_x和VOCs共同控制;模拟结果还表明,臭氧生成对活性烃类最为敏感,但是,含氧有机物、卤代烃和高碳烷烃对臭氧生成的影响和贡献也不可忽视;此外,计算了日平均臭氧净生成速率P(O_3)_(net),分别为6.41×10~(-9) h~(-1)和3.22×10~(-9) h~(-1),臭氧的本地生成过程扮演重要角色.     

宿迁市VOCs污染特征和来源解析

利用2019年8-9月宿迁市4个站点的采样资料,分析了宿迁大气中挥发性有机物（VOCs）的化学组成及其时空分布特征;估算了VOCs的臭氧生成潜势（OFP）;并结合PMF受体模型,开展了VOCs来源解析.结果表明,观测期间宿迁市总挥发性有机物（TVOCs）体积分数为8.6×10^-9~79.4×10^-9,平均体积分数为26.9×10^-9,浓度水平较低.VOCs质量浓度表现为乡镇工业区（宿迁技师学院：（29.8±18.4）×10^-9） > 城郊工业区（生态化工园：（28.4±20.6）×10^-9） > 城市住宅区（宿迁中学：（22.6±11.5）×10^-9） > 城市商业区（市供电局：（22.3±15.1）×10^-9）.各采样点4种组分（烷烃、烯烃、乙炔及芳香烃）日均浓度变化较为一致,且均表现出较为明显的周末效应.宿迁市典型污染物为C₂~C₅烷烃、乙炔、乙烯、甲苯,间/对-二甲苯,不同采样点的关键组分基本相同,表明VOCs的来源比较稳定.OFP计算表明芳香烃和烯烃是臭氧最大贡献源.特征量比值分析发现,观测期间宿迁市VOCs有明显老化现象.源解析表明交通排放、溶剂涂料和工业过程是宿迁市VOCs的主要来源.     

某沿海城市典型行业NMHCs排放特征及对二次污染物生成潜势研究

采用SUMMA罐采样、GC-FID技术分析了威海市渔具、造船和橡胶等6种典型行业代表企业废气中59种非甲烷碳氢化合物(NMHCs)组分及占比,并计算了各行业NMHCs的臭氧(O3)和二次有机气溶胶(SOA)生成潜势,提出了NMHCs治理建议.结果表明,涉及溶剂使用的渔具、造船、汽车制造业喷涂工序的NMHCs组分以芳香烃...     

Automatic unattended sampling and analysis of background levels of C2;C5 hydrocarbons

As part of the European program for monitoring anthropogenic air pollutants (EUROTRAC), C₂C₅ hydrocarbons (gas phase) are being routinely measured at a background station at Rörvik, Sweden. A 2 ℓ air sample is taken every 4 h, and a compressed air standard and helium blank are analysed daily. The method is based on adsorption of the hydrocarbons onto an active charcoal based adsorbent, desorption/crofocusing onto a capillary trap, and analysis using capillary gas chromatography with a flame ionization detector. A Perma Pure dryer is used to remove water from the sample, and hydrocarbons > C₆ are removed using a Tenax adsorbent. The analytical instrument can be left unattended for up to 2 weeks at a time, depending on the consumption of liquid nitrogen and the compressed gases. Baseline or near baseline resolution is obtained for the 23 hydrocarbons monitored in this study. Reproducibility for the C₂C₄ isomers is 1–2%, and 2–15% for the C₅ isomers. The detection limit is 1–7 pptv. Preliminary mean hydrocarbon concentrations are presented for the period 21 February–9 April 1989.     

厦门冬春季大气VOCs的污染特征及臭氧生成潜势

2014年1~4月在厦门市城区和郊区开展冬春季节大气样品的采集,采用大气预浓缩系统与GC/MS联用技术定量了48种大气挥发性有机物(VOCs),对比分析了冬春季城区和郊区大气VOCs的污染特征,并利用最大增量反应活性(MIR)估算了大气VOCs的臭氧生成潜势(OFP).结果表明,冬季厦门城区和郊区大气中VOCs的平均体积分数分别为11.13×10-9和7.17×10-9,春季厦门城区和郊区大气中VOCs的平均体积分数分别为24.88×10-9和11.27×10-9,且均表现为烷烃芳香烃烯烃.通过B/T值探讨城区和郊区VOCs的来源发现,机动车和溶剂挥发是城区VOCs的主要来源,郊区VOCs除了局地源的贡献外,还受到外来污染物扩散传输的影响.城、郊区的主要VOCs包括丙烯、正丁烷、异丁烷、正戊烷、异戊烷、正己烷、苯、甲苯、乙苯和间对二甲苯,这10种组分对两地VOCs的贡献表现为春季(城区和郊区分别为62.83%和53.74%)高于冬季(城区和郊区分别为61.57%和45.83%).城、郊区VOCs的臭氧生成潜势分析显示,芳香烃的相对贡献率最大,其次是烯烃,烷烃最小.C3、C4类烯烃和苯系物是厦门城区和郊区活性较高的物种,对臭氧的贡献较大.比较观测期间城区和郊区VOCs的平均MIR值可知,郊区VOCs的活性高于城区.     

北京市典型汽修企业VOCs排放特征与臭氧影响分析

对北京地区27家汽修企业进行调研,选取2家典型汽修企业进行气袋采样-GC-MS-FID采集及分析,定量分析其VOCs的排放特征,并计算其臭氧生成潜势（OFP）。结果表明:使用不同漆料的汽修企业排放特征不同,水性漆企业非甲烷总烃的排放浓度为0.62~36.49 mg/m3,油性漆企业的排放浓度为0~100.39 mg/m3;水性漆排放的VOCs以烷烃为主,占比高达57.16%,丙烷（39.65%）和甲苯（11.41%）是首要污染物;卤代烃（55.51%）是油性漆企业的主要VOCs排放物种,主要组分为1,2-二氯丙烷和1,2-二氯乙烷;水性漆企业的OFP值为144.78 mg/m3,油性漆企业的OFP值为664.43 mg/m3,大气反应活性最大的物种多为芳香烃,芳香烃对OFP的贡献率分别为52.18%和88.44%。     

郑州市典型工业企业VOCs排放特征及风险评估

为了解郑州市不同行业企业挥发性有机物(VOCs)污染特征及潜在危害,通过Summa罐和气袋采集样品,之后采用GC-MS/FID对样品进行测定分析.结果表明:郑州市包装印刷企业排放VOCs组分主要为含氧VOCs(OVOCs),包括乙酸乙酯和异丙醇,占比93.1%以上;汽车制造、家具制造和涂料生产企业VOCs组分主要为芳香烃,占比为33.5%～90.0%,以间/对-二甲苯、邻-二甲苯和乙苯为主;食品加工企业VOCs中卤代烃占比较高,为52.3%;橡胶企业VOCs主要为卤代烃和烷烃,占比分别为25.5%和28.8%;石墨碳素企业VOCs主要为芳香烃和OVOCs,占比分别为28.5%和24.1%.对比以往研究发现,郑州市与其他城市溶剂使用企业VOCs排放特征较为类似,但由于生产工艺及原辅料使用不同,相同行业企业中不同环节VOCs组分存在差异.风险评估结果显示,各企业排放的VOCs组分对臭氧生成潜势(OFP)和危害指数(HI)贡献具有一定正关联性,尤其苯、甲苯、乙苯及二甲苯等C_6～C_8芳香烃对OFP和HI贡献较大.汽车制造企业3号和家具企业5号HI值分别为1.18和2.74,均高于EPA规定限值,主要与该企业生产过程中使用溶剂型原辅料有关,且排放的主要以芳香烃为主,尤其苯、甲苯、乙苯、二甲苯和三甲基苯等C_6～C_9苯系物对HI和OFP的贡献较高,今后需重点管控溶剂型企业VOCs的排放.     

A passive sampler for airborne formaldehyde

A simple, inexpensive passive sampler is described that is capable of reliable measurements of formaldehyde at the parts per billion (ppb) levels relevant to indoor and outdoor air quality. The passive sampler consists of a modified dual filter holder in which the upper stage serves as the diffusion barrier, the lower stage includes a 2,4-dinitrophenylhydrazine (DNPH)-coated filter which collects formaldehyde, and the space between the two stages serve as the diffusion gap. The measured sampling rate, 18.8 ± 1.8 ml min⁻¹, was determined in experiments involving sampling of ppb levels of formaldehyde with the passive sampler and with DNPH-coated C₁₈ cartridges and agrees well with the value of 19.4 ± 2.0 ml min⁻¹ calculated from theory. The measured sampling rate was independent of formaldehyde concentration (16–156 ppb) and sampling duration (1.5–72 h). The precision of the measurements for colocated passive samplers averaged 8.6% in purified and indoor air (office and museums) and 10.2% in photochemically polluted outdoor air. With a 1.2-μm pore size Teflon filter as the diffusion barrier, the detection limit is 32 ppb h, e.g. 4 ppb in an 8-h sample, 1.3 ppb in a 24-h sample, and so on. Perceived advantages and limitations of the sampler are discussed including flexibility, cost effectiveness and possible negative bias at high ambient levels of ozone.     

宜宾市冬季挥发性有机物污染特征及来源

为了解宜宾市冬季VOCs（volatile organic compounds,挥发性有机物）污染特征,于2016年12月选取宜宾市2个国控环境监测点位,采集冬季环境空气VOCs样品,利用三级冷阱预浓缩仪-气相色谱质谱联用仪（GC-MS）测定大气中89种VOCs物种,分析VOCs体积分数及其物种组成情况,并对其主要来源进行识别.结果表明:宜宾市区冬季环境空气中φ（VOCs）平均值为35.10×10-9,φ（VOCs）最高值和最低值分别为67.34×10-9、20.58×10-9;监测VOCs物种类别中芳香烃占比最高,其次为烷烃、卤代烃;体积分数较大的VOCs物种主要为苯、甲苯、氯甲烷、二氯甲烷、异丁烷、异丙醇、正丁烷等.CMB（化学质量平衡）模型源解析宜宾市冬季环境空气VOCs的六大主要贡献源分别为移动源、油气挥发源、溶剂使用源、工艺过程源、生物质燃烧源和其他源.以2015年为基准年,利用排放因子法对宜宾市VOCs进行排放量计算发现,宜宾市VOCs年排放量为39.54×103 t,其中,工艺过程源、溶剂使用源、移动源、化石燃料燃烧源的贡献率分别为35.5%、24.5%、28.9%、8.0%.研究显示,对宜宾市冬季环境空气中VOCs贡献率较大的污染源分别为移动源、溶剂使用源、工艺过程源等。      

重庆市北碚城区大气中VOCs组成特征研究

2012年3月~2013年2月,使用特制的不锈钢钢瓶采集重庆市北碚城区大气样品,并采用三步预浓缩-气相色谱/质谱法对所采集的气体样品进行检测.本研究共检出78种挥发性有机物(volatile organic compounds,VOCs),其中烷烃25种,烯烃15种,芳香烃28种,卤代烃10种.结果表明,重庆市北碚大气中年均浓度最高的前7种VOCs分别为:二氯甲烷(3.08×10-9,体积分数,下同)、苯(2.09×10-9)、异戊烷(1.85×10-9)、甲苯(1.51×10-9)、丙烷(1.51×10-9)、间/对-二甲苯(1.43×10-9)、苯乙烯(1.39×10-9).北碚大气中总挥发性有机物(total volatile organic compounds,TVOCs)浓度为33.89×10-9,季节变化表现为:春季(42.57×10-9)>秋季(33.89×10-9)>冬季(31.91×10-9)>夏季(27.04×10-9).从组成来看,烷烃和芳香烃对TVOCs贡献最大,分别达到31.5%和30.7%;其次是卤代烃类,占27.4%;含量最少的组分是烯烃,所占比例仅为10.4%.采用臭氧生成潜势对VOCs组分活性分析结果表明,烯烃类和芳香烃类化合物是对北碚大气O3生成贡献最大的物质.利用主成分分析法对大气样品中VOCs来源进行分析,发现北碚大气VOCs主要源于机动车尾气排放,贡献比为50.41%.北碚大气中T/B年均值为0.73,表明大气中的苯类物质主要来源于机动车的尾气排放,受溶剂挥发的影响较小.     

Evaluation of auto exhaust contribution to atmospheric C2C5 hydrocarbons at Deonar,Bombay

One of the major sources for the C₂C₅ hydrocarbons in the urban air is the auto exhaust. Measurements of C₂C₅ hydrocarbon (HC) concentrations in Deonar, Bombay are reported in this paper. The auto exhaust emissions of C₂C₅ HCs for some of the petrol-driven vehicles in Bombay are also measured. The auto exhaust contribution to atmospheric C₂C₅ HCs evaluated by a comparison of the ratios of individual HC to acetylene concentrations in air and auto exhaust samples. About 10% of the C₂C₅ HCs in the Deonar region are calculated to be due to auto exhaust emissions. Only a small portion (1.2%) of the isobutane is from auto exhausts while a large fraction is attributed to possible emissions from refinery operations in the region.     

红外掩日遥感监测炼油厂非甲烷烷烃排放通量

采用红外掩日通量遥感监测(SOF)技术分别在2014年5月~2015年12月和2021年10月监测了我国7座大型炼油厂(其中6座原油年加工量均超过1000万t)非甲烷烷烃排放通量(kg/h)及分布.每座炼油厂监测3~8d,测量18~73次,总计获得328个排放通量测量数据,根据国内炼油厂VOCs排放烟羽中非甲烷烷烃质量分数估算了VOCs排放量,结合监测期间实际原油加工量计算了非甲烷烷烃和VOCs排放系数.结果显示:7座炼油厂2014~2015年的非甲烷烷烃排放系数测定值为0.016%~0.11%,平均为0.081%;VOCs排放系数估算为0.020%~0.14%,平均为0.10%.无组织排放约占炼油厂非甲烷烷烃排放总量的70%以上,其中轻油贮罐排放占比过半.国内7座炼油厂2014~2015年非甲烷烷烃排放系数的最好水平与美国南加州6座炼油厂同期SOF监测的最好水平相当,但非甲烷烷烃排放系数的平均水平约为其平均水平的3.9倍,国内炼油厂的VOCs排放控制水平更加参差不齐.国内1座千万吨级炼油厂2021年监测的非甲烷烷烃排放通量和排放系数分别较2015年削减72.4%和74.2%.SOF可为石化VOCs无组织排放监测、量化和排放清单修订提供最佳实用技术,本研究结果提供了国内石化行业VOCs综合整治初期典型炼油厂非甲烷烷烃和VOCs的基线排放实测数据,以及1座千万t级炼油厂6a后治理攻坚效果.     

沧州市春季NMHCs空间分布特征

2015年春季在沧州市城区、郊区和潜在污染源附近选择了15个采样点进行同期采样.研究表明沧州市NMHCs总体上市区高于近郊及远郊区县;市区以高新区NMHCs浓度最高;郊县采样点除河间市略高外,其它采样点的浓度均明显低于市区浓度;机动车的道路排放是沧州市NMHCs的重要来源之一;沧州大化和沧州炼油在停产期间未对市区NMHCs产生明显影响;大港油田采油三厂采取了较完善的油气回收措施,未对市区NMHCs产生明显影响;平均来看,沧州市NMHCs中烷烃占65%,烯烃占16%,芳烃占19%;臭氧生成潜势(ozone formation potential,OFPs)主要来源于二甲苯(19%)、乙烯(14%)、甲苯(11%)、丙烯(5%)、异戊烷(5%)和异戊烯(5%)等;气溶胶生成潜势(formation potential of secondary organic aerosol,SOAFPs)主要来源于甲苯(28%)、蒎烯(28%)、二甲苯(16%)、乙苯(9%)和苯(9%)等.     

室内空气中的甲醛检测分析及其预测模型

对 2003年哈尔滨市居室室内空气中的甲醛污染检测与统计分析表明,随机检测的 246 个样本中甲醛浓度范围0.017～1.302mg/m³,年均值为0.219mg/m³,样品超标率 77.24%.夏季 6～8 月的甲醛浓度月平均值是冬季采暖期的2.0倍.各月室内甲醛平均浓度与各月平均温度具有良好的线性相关性,相关系数 R²=0.8652.依据影响甲醛浓度的因素及其实测数据,建立了预测室内空气中甲醛浓度的数学模型.     

Sources of ambient non-methane hydrocarbon compounds and their impacts on O3 formation during autumn, Beijing

The field observation of 54 non-methane hydrocarbon compounds (NMHCs) was conducted from September 1 to October 20 in 2020 during autumn in Haidian District, Beijing. The mean concentration of total NMHCs was 29.81 ± 11.39 ppbv during this period, and alkanes were the major components. There were typical festival effects of NMHCs with lower concentration during the National Day. Alkenes and aromatics were the dominant groups in ozone formation potential (OFP) and OH radical loss rate (L_OH). The positive matrix factorization (PMF) running results revealed that vehicular exhaust became the biggest source in urban areas, followed by liquefied petroleum gas (LPG) usage, solvent usage, and fuel evaporation. The box model coupled with master chemical mechanism (MCM) was applied to study the impacts of different NMHCs sources on ozone (O₃) formation in an O₃ episode. The simulation results indicated that reducing NMHCs concentration could effectively suppress O₃ formation. Moreover, reducing traffic-related emissions of NMHCs was an effective way to control O₃ pollution at an urban site in Beijing.