南通市典型臭氧污染过程VOCs特征及来源分析

利用在线挥发性有机物自动监测仪TH300B对2020年8月12—17日南通市典型臭氧污染过程中VOCs排放进行监测。结果表明,南通市此次臭氧污染过程主要受VOCs排放影响,污染中VOCs体积浓度均值为23.44 ppb,较污染前下降了12.0%,其中芳香烃体积浓度占比下降幅度最大,较污染前下降23.4%,OVOCs体积浓度绝对值下降最大,较污染前下降1.42 ppb。污染中,VOCs总OFP贡献为162.0μg/m3,较污染前下降22.2%,OPF与臭氧的日变化呈明显的相反关系,关键活性物种为甲苯、乙烯和异戊烷等。PMF模型解析结果显示,机动车尾气、工业排放、油气挥发、涂料和溶剂使用、天然气源对VOCs的贡献占比分别为38.6%,35.4%,9.5%,8.8%和7.8%。     

成都市冬季挥发性有机物污染特征及来源研究

利用挥发性有机物在线监测仪(GC-FID/MS)在成都市市区开展为期一个月的挥发性有机物监测,分析了VOCs浓度水平、组分构成、日变化规律,并分别利用PMF模型和排放清单法对VOCs的来源进行解析研究。结果表明,监测期间,VOCs小时平均浓度为7610~(-9),最高浓度为26210~(-9),最低浓度为14.810~(-9);监测物种类别中烷烃类占VOCs总体积浓度为38%,炔烃为17%,芳香烃为15%,烯烃为13%,卤代烃为9%,含氧(氮)类化合物为8%,浓度前十的物种分别为乙烷、乙炔、乙烯、丙烷、甲苯、己醛、二氯甲烷、苯、正丁烷和异戊烷,占总浓度的70%以上。烷烃、炔烃、烯烃、芳香烃在8点～10点间均出现浓度峰值,芳香烃、卤代烃以及含氧(氮)化合物浓度最高值出现在凌晨2点～5点;最低浓度则均出现在下午17点左右。基于PMF的方法,VOCs的来源解析结果为工业源贡献32%,机动车贡献26%,生物质燃烧贡献22%,溶剂源贡献7%,油气挥发贡献6%,本底混合源贡献7%;基于排放清单法,2015年成都市VOCs年排放量为36.9万t,工艺过程源、溶剂使用源、移动源分别贡献32%、32%、30%。     

沥青铺路挥发性有机物排放特征研究

基于现场采样监测法,对沥青铺路现场和沥青搅拌站开展挥发性有机物(VOCs)组分及浓度的监测,利用排放因子法对四川省17个城市的沥青铺路排放源VOCs排放量进行了计算。结果表明,摊铺过程的VOCs浓度水平为1～3mg/m3,摊铺后浓度水平在0. 1～1mg/m3范围,在施工作业位旁瞬时样品浓度高达10mg/m3以上。沥青搅拌站和铺路现场的主要共同物种为萘、甲苯、间对二甲苯、异丁烷;四川省17城市对应的沥青铺路排放源VOCs的排放量为0. 63万t,主要的活性贡献物种为萘、间/对-二甲苯、顺-2-丁烯、1,2,4-三甲基苯、甲苯等。     

成都春季VOCs污染特征及其对SOA和O3生成贡献的研究——以2020年4～5月发生的PM2.5和O3污染过程为例

成都市2020年4月15～16日和4月28～5月6日分别发生了细颗粒物(PM_2.5)污染过程和臭氧(O₃)污染过程,利用2020年4月13～5月10日成都市区57种挥发性有机物(VOCs)小时数据,研究两次污染过程中VOCs对PM_2.5污染和O₃污染的影响。通过计算VOCs的臭氧生成潜势(OFP)、二次有机气溶胶生成潜势(SOAFP),以及使用比值分析法,探讨成都市VOCs优先控制物种及来源。结果表明,污染时段VOCs浓度较清洁时段均有所升高,但烷烃占比有所下降。污染时段的OFP和SOAFP较清洁时段均有所升高,间/对二甲苯和甲苯对SOA生成和O₃生成贡献均排名前列,控制这两种组分的排放是成都市控制O₃和SOA前体物的有效途径。比值分析结果得出,VOCs气团受本地排放影响较大,PM_2.5污染时段和清洁时段的VOCs受机动车尾气排放影响较多,O₃污染时段的VOCs除受到机动车尾气排放影响以外,还受溶剂使用的影响。作...     

南京典型站点春节期间大气污染特征

2017年1月27日～2月2日,在南京市江东北路176号站点对各类污染物进行在线观测,研究春节期间污染特征。结果表明:采样期间,ρ(PM_(2.5))、ρ(PM_(10))最大值分别为142μg/m~3、172μg/m~3。ρ(PM_(2.5))/ρ(PM_(10))平均值为74.5%; OC与EC的平均浓度分别为11.0μg/m~3和1.91μg/m~3,两者的相关系数为0.92,表明两者的污染来源相对稳定、集中。OC/EC比值在3.4～14.0之内,均值为6.8,表明本站点二次有机物污染主要来自于燃煤排放与机动车尾气排放。春节期间,该站点的VOCs关键活性物种主要为丙烯、乙烯、间/对二甲苯、甲苯、正丁烷、异戊烷、异丁烷、反-2-丁烯、丙烷和1-丁烯;春节期间出现明显"假日效应",污染排放强度显著降低,空气质量良。     

粘胶纤维工艺过程中VOCs的排放特征

为了研究再生纤维素纤维生产过程VOCs的排放影响,选择四川宜宾某纤维生产企业为重点监测对象,对企业厂界上下风向以及侧边界设监测点采样。对工艺车间无组织排放VOCs进行采样,利用在线仪器TT24-7-TOF-MS对采集的样品进行VOCs定量分析。结果表明:无组织排放源的主要特征VOCs包括二硫化碳、1,2,4-三甲基苯、苯乙烯、对二甲苯、间二甲苯、甲苯、邻二甲苯、乙苯、氯甲苯、丙酮等。黄化车间、纺丝车间、厂界上下风向空气中CS2的最高浓度分别为71.53μg/m~3、127.21μg/m~3、152.60μg/m~3、368.89μg/m~3,分别占VOCs总量的41.29%、41.18%、74.36%、76.85%。为了更好的模拟和计算,应该建立一套测试成分谱的标准方法,将VOCs成分谱数据本地化。     

滕州市木石镇秋季大气VOCs污染特征及来源解析

使用大气挥发性有机物(VOCs)在线连续自动监测系统,对滕州市木石镇2019年11月环境空气中VOCs进行观测,并分析了VOCs的浓度状况、组成特征、光化学影响和来源。结果表明：观测期间,木石镇大气中TVOC平均体积分数为(32.75±28.96)×10^-9,各物种体积分数从大到小顺序依次为烷烃>烯烃>OVOC>芳香烃>卤代烃>乙炔>含硫化合物;日变化规律呈双峰型,峰值在6:00～7:00时与0:00～1:00时出现。大气VOCs的平均臭氧生成潜势(OFP)为102.02×10^-9,烯烃对臭氧生成潜势贡献率最大,为69.5%;乙烯、丙烯、正丁烯、萘和1,3-丁二烯等是臭氧生成潜势较高的物种。对OH自由基消耗速率(L_OH)贡献最大的为烯烃,其次为芳香烃,两者贡献率占到76.8%。VOCs对二次气溶胶(SOA)浓度的贡献值为0.85μg/m³,其中芳香烃对SOA生成贡献占比为92.8%,对SOA生成贡献最大的前5个物种为萘、甲苯、苯、乙苯、间/对二甲苯。利用PMF模型...     

典型人造板制造企业VOCs排放特征及成分谱研究

为研究人造板制造企业VOCs排放特征及源成分谱,通过现场采样的方法,对A和B两家典型人造板制造企业VOCs各排放环节进行了采样和分析。结果表明:调胶、施胶排放口VOCs和甲醛排放浓度均最高,分别为13. 06 mg/m~3和33. 23mg/m~3。对于无组织排放,调胶工段的VOCs和甲醛排放浓度相对较高。A企业和B企业的VOCs排放系数分别为13. 4 g/m~3和208. 3 g/m~3,排放系数差异较大与企业原辅料的种类及使用量有关。人造板制造业有组织排放VOCs以含氧VOC和烷烃为主,浓度占比排名前三的物种为乙醇、丙酮和癸烷,占比分别为57. 38%、13. 04%和7. 64%。无组织排放VOCs则以含氧VOC和芳香烃为主,浓度占比排名前三的物种为乙醇、苯乙烯和丙酮,占比分别为22. 33%,8. 51%和8. 47%。     

便携式GC-MS在石油污染土壤应急监测中的应用

针对石油污染土壤中VOCs含量的应急监测,便携式气相色谱-质谱联用仪适用于土壤中甲苯、乙苯、二甲苯、三氯苯等13种苯系物的快速定量检测,通过对某废弃炼油厂土壤样品测定,该方法在快速定性的同时,定量测定5~20411μg/kg土壤样品具有很高的可靠性。     

十堰市汽车涂装VOCs污染状况及变化趋势分析

通过调查,初步摸清了十堰市汽车涂装行业的规模、产生VOCs的原辅材料消耗情况及污染治理情况,在此基础上,冬季、春季采样监测十堰市VOCs的环境背景值及污染现状。结果表明,VOCs在十堰各点位均有检出,但不同季节VOCs的浓度不同,总VOCs平均浓度1月份为2 113.29μg/m3,5月份为1 816.70μg/m3。各采样点VOCs质量浓度排序是:工业区商业区办公居住区。十堰市VOCs的日变化情况与工业区内工厂生产作业情况密切相关,通过对苯系物相关性的研究,得知涂料喷涂行业是十堰大气中苯及VOCs的重要来源。     

Experimental study of benzene,toluene, ethylbenzene,and xylene (BTEX) contributions in the air pollution of Tehran,Iran

Urbanization and development are associated with air pollution, including emissions of volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylene (BTEX). For this study, we measured and investigated the outdoor concentrations of BTEX in Tehran, Iran. National Institute for Occupational Safety and Health (NIOSH, 1996) methods were applied to measure the concentrations of BTEX in winter and spring of 2015 at 46 air monitoring stations. BETX concentrations were also measured at 19 monitoring stations in June and July of 2003. In 2003, BTEX compound pollutants were observed at greater concentration in the eastern, central, and southern zones of Tehran than in other zones. The average concentrations of the BTEX compounds were 238 parts per billion (ppb), 130 ppb, 69 ppb, and 118 ppb, respectively, for benzene, toluene, ethylbenzene, and xylene. The benzene to toluene (B/T) ratios ranged from 0.8 to 3.2, which indicated that the gasoline used in the city was of poor quality at that time. In 2015, the BTEX concentrations in District 19 (south of Tehran) were higher than in the eastern and central regions, which included restricted “traffic zones” and the extensive development of public transportation systems. In the restricted traffic zones, only public vehicles, such as buses, taxis, ambulances, etc., and other authorized vehicles are allowed to operate. By ameliorating the quality of gasoline, encouraging the use of late model private cars, and development of subway and public transportation during the years between 2003 and 2015, the BTEX concentrations have fallen to levels that comply with Iran's air quality standards. The 2015 measurements revealed that the average concentrations of the BTEX compounds were 5.3, 9.2, 1.5, and 2.6 ppb, respectively. The B/T ratio fluctuated from 0.39 to 0.76, demonstrating the remarkable role that vehicle traffic plays in BTEX pollution.     

Blowing Smoke in Yellowstone: Air Quality Impacts of Oversnow Motorized Recreation in the Park

Snowmobile use in Yellowstone National Park has been shown to impact air quality, with implications for the safety and welfare of Park staff and other Park resource values. Localized impacts have been documented at several high-use sites in the Park, but the broader spatial variability of snowmobile emissions and air quality was not understood. Measurements of 87 volatile organic compounds (VOCs) were made for ambient air sampled across the Park and West Yellowstone, Montana, during 2 days of the 2002–2003 winter use season, 1 year before the implementation of a new snowmobile policy. The data were compared with similar data from pristine West Coast sites at similar latitudes. Backward trajectories of local air masses, alkyl nitrate-parent alkane ratios, and atmospheric soundings were used to identify the VOC sources and assess their impact. Different oversnow vehicle types used in the Park were sampled to determine their relative influence on air mass pollutant composition. VOCs were of local origin and demonstrated strong spatiotemporal variability that is primarily influenced by levels of snowmobile traffic on given road segments at different times of day. High levels of snowmobile traffic in and around West Yellowstone produced consistently high levels of benzene, toluene, and carbon monoxide.     

The Atmosphere can be a Source of Certain Water Soluble Volatile Organic Compounds in Urban Streams

Surface water and air volatile organic compound (VOC) data from 10 U.S. Geological Survey monitoring sites were used to evaluate the potential for direct transport of VOCs from the atmosphere to urban streams. Analytical results of 87 VOC compounds were screened by evaluating the occurrence and detection levels in both water and air, and equilibrium concentrations in water (C_w^s) based on the measured air concentrations. Four compounds (acetone, methyl tertiary butyl ether, toluene, and m‐ & p‐xylene) were detected in more than 20% of water samples, in more than 10% of air samples, and more than 10% of detections in air were greater than long‐term method detection levels (LTMDL) in water. Benzene was detected in more than 20% of water samples and in more than 10% of air samples. Two percent of benzene detections in air were greater than one‐half the LTMDL in water. Six compounds (chloroform, p‐isopropyltoluene, methylene chloride, perchloroethene, 1,1,1‐trichloroethane, and trichloroethene) were detected in more than 20% of water samples and in more than 10% of air samples. Five VOCs, toluene, m‐ & p‐xylene, methyl tert‐butyl ether (MTBE), acetone, and benzene were identified as having sufficiently high concentrations in the atmosphere to be a source to urban streams. MTBE, acetone, and benzene exhibited behavior that was consistent with equilibrium concentrations in the atmosphere.     

利用缺氧反硝化处理难降解有机物的探讨

本文研究了厌氧、缺氧实验夺件下难降解苯、甲苯、乙苯、二甲苯的同分异构体（BTEX）的生物降解性能。得出了不同底物的厌氧降解变化情况和缺氧降解条件下不同底物适宜的C／N比。通过对实验结果的分析，初步确定了不同底物具有各不相同的C／N比的原因，同时得出了缺氧反硝化与厌氧生物降解过程有可能同时发生的结论。     

钢铁企业无组织排放特征污染物的监测分析

东部老工业区是济南市大气污染重点防控区域。工业区大型企业的无组织排放废气对区域及周边大气环境质量产生的影响,一直没有引起人们的足够重视,因对其排放量大小和污染物种类不清楚,难以进行监管。本文以济南东部老工业区一家大型钢铁企业为例,选取五项有代表性的特征污染物(苯、甲苯、二甲苯、非甲烷总烃和氨)进行布点监测,在不同气象条件下,分析特征污染物的浓度变化,了解钢铁企业无组织排放特征。经对监测数据的分析得出:与上风向相比,下风向各污染物监测的小时浓度和日均浓度均有不同程度的增加,表明该厂区污染源对周边环境空气质量有一定影响。最后,提出防范或改进措施,如应加严相应的无组织排放标准,增加大气在线监测点位及监测项目,建议企业加强对生产工艺环节无组织排放废气的收集和处理。     

Identification and quantitation of volatile organic compounds emitted from dairy silages and other feedstuffs

High ground-level ozone continues to be an important human, animal, and plant health impediment in the United States and especially in California's San Joaquin Valley (SJV). According to California state and regional air quality agencies, dairies are one of the major sources of volatile organic compounds (VOCs) in the SJV. A number of recently conducted studies reported emissions data from different dairy sources. However, limited data are currently available for silage and otherfeed storages on dairies, which could potentially contribute to ozone formation. Because the impact of different VOCs on ozone formation varies significantly from one molecular species to another, detailed characterization of VOC emissions is essential to include all the important contributors to atmospheric chemistry and especially atmospheric reactivity. The present research study identifies and quantifies the VOCs emitted from various silages and other feedstuffs. Experiments were conducted in an environmental chamber under controlled conditions. Almost 80 VOCs were identified and quantified from corn (Zea mays L.), alfalfa (Medicago sativa L.),and cereal (wheat [Triticum aestivum L.] and oat [Avena sativava L.] grains) silages, total mixed ration (TMR), almond (Amygdalus communis L.) shells and hulls using gas chromatography-mass spectrometry and high performance liquid chromatography. The results revealed high concentrations of emitted alcohols and other oxygenated species. Lower concentrations of highly reactive alkenes and aldehydes were also detected. Additional quantitation and monitoring of these emissions are essential for assessment of and response to the specific needs of the regional air quality in the SJV.     

Ground-level ozone in the Pearl River Delta and the roles of VOC and NO(x) in its production

In many regions of China, very rapid economic growth has been accompanied by air pollution caused by vehicle emissions. In one of these regions, the Pearl River Delta, the variations of ground-level ozone and its precursors were investigated. Overall, the ambient concentrations of NO(2) increased quickly between 1995 and 1996, but then slightly decreased due to stringent nitrogen oxide (NO(x)) emission controls. Nonetheless, ambient NO(2) levels in the Pearl River Delta remained high. The regional average concentrations of volatile organic compounds (VOCs) were 290 ppbC in summer and 190 ppbC in autumn. Local emissions and long-distance transportation of pollutants play important roles in the regional distribution of VOCs. Ambient O(3) production is significant in urban areas and also downwind of cities. The relative incremental reactivities (RIRs), determined by an observation-based model, showed that ground-level ozone formation in the Guangzhou urban area is generally limited by the concentrations of VOCs, but there are also measurable impacts of NO(x).     

罐采样-GC/MS法测定环境空气中挥发性有机物

采用SUMMA罐采样,空气预浓缩与气相色谱/质谱联用技术,建立了39种常见挥发性有机物的分析方法。选取攀枝花市不同功能区的5个测点,采集了4个季度的环境空气样品220个,定性检出挥发性有机物54种,其中烃类占24%,卤代烃类占52%,含氧化合物占22%,其它化合物占2%。苯系物的检出率最高。定量的挥发性有机物最大浓度和平均浓度最高的项目均为苯,平均浓度4.59μg/m3,最大浓度29.8μg/m3。苯系物时间分布呈现出旱季高,雨季低的特点;日变化特征为早晨最高,整体呈下降趋势。