Evolution of chemical composition of fogwater in winter in Chengdu, China

Two sampling sites representing the urban and suburban area of Chengdu, China were sampled and analyzed for selected chemicals to characterize the evolution of the chemical composition of fogwater. A trend of total organic carbon (TOC) > total nitrogen (TN) > total inorganic carbon (TIC) was observed for both sites. Variation of inorganic ions indicated that inorganic pollutants were not accumulated in the fog. Concentrations of n-alkanes (C11-C37) at the urban site ranged from 7.58 to 27.75 ng/mL while at the suburban site concentrations were 2.57-21.55 ng/mL. The highest concentration of n-alkanes was observed in the mature period of fog (393.12 ng/mL) which was more than ten times that in the fog formation period (27.83 ng/mL) and the fog dissipation period (14.87 ng/mL). Concentrations of Σ15PAHs were in the range of 7.27-38.52 ng/mL at the urban site and 2.59-22.69 ng/mL at the suburban site. Contents of PAHs in the mature period of fog (27.15 ng/mL) > fog dissipation period (11.59 ng/mL) > fog formation period (6.42 ng/mL). Concentrations of dicarboxylic acids (C5-C9) ranged from 10.92 to 40.78 ng/mL, with glutaric acid (C5) as the dominant dicarboxylic acid. These data provide strong indications of the accumulation of certain organic chemicals of environmental concern in fog and fog water, and provide additional insights about processes in urban and suburban air acting on organic chemicals with similar physical chemical properties.     

Seasonal variation and source apportionment of organic and inorganic compounds in PM2.5 and PM10 particulates in Beijing, China

The distribution and source of the solvent-extractable organic and inorganic components in PM 2.5(aerodynamics equivalent diameter below 2.5 microns),and PM 10(aerodynamics equivalent diameter below 10 microns) fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing.The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes,PAHs(polycyclic aromatic hydrocarbons),fatty acids and water soluble ions.The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index(CPI),%waxC n,selected diagnostic ratios of PAHs and principal component analysis in both size ranges.The mean cumulative concentrations of n-alkanes reached 1128.65ng/m3 in Beijing,74% of which(i.e.,831.7ng/m3) was in the PM 2.5 fraction,PAHs reached 136.45ng/m3(113.44ng/m3 or 83% in PM 2.5),and fatty acids reached 436.99ng/m3(324.41ng/m3 or 74% in PM 2.5),which resulted in overall enrichment in the fine particles.The average concentrations of SO42-,NO3-,and NH4+ were 21.3±15.2,6.1±1.8,12.5±6.1μg/m3 in PM 2.5,and 25.8±15.5,8.9±2.6,16.9±9.5μg/m3 in PM 10,respectively.These three secondary ions primarily existed as ammonium sulfate((NH4)2SO4),ammonium bisulfate(NH4HSO4) and ammonium nitrate(NH4NO3).The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion,followed by gasoline combustion.The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles.The major alkane sources were biogenic sources and fossil fuel combustion.The major sources of PAHs were vehicular emission and coal combustion.     

Biogenic and anthropogenic organic compounds in eolian particulates in the East Mediterranean region—I. Occurrence and origin

Lipids of biogenic and anthropogenic origin were determined in aerosol samples, collected seasonally, in a coastal area on the north of the island of Crete. Lipid classes such as n-alkanes, hopanes, polycyclic aromatic hydrocarbons, fatty alcohols, fatty acids, fatty acid salts and α,ω-dicarboxylic acids were characterized by GC/MS and GC/FID analysis, in terms of their contents of homologous compound series. The concentrations ranged between 56 and 215 ng m⁻³ for n-alkanes, 10 and 52 ng m⁻³ for polycyclic aromatic hydrocarbons, 2 and 31 ng m⁻³ for fatty alcohols, 13 and 279 ng m⁻³ for fatty acids, 24 and 220 ng m⁻³ for fatty acid salts and 0.4 and 7.5 ng m⁻³ for α, ω-dicarboxylic acid salts. The prevailing winds were influencing the composition of the eolian particles. Generally, aerosols sampled during south wind events predominantly contained lipids originating from higher plants, while when north and northwest winds prevailed the major components were of marine origin. The absence of unsaturated fatty acids in all aerosol samples is related to the presence of α,ω-dicarboxylic acids, which are believed to be their photo-oxidation products.     

Semivolatile organic compounds in the ambient air of Denver,Colorado

A filter-polyurethane foam plug high volume air sampler was used to collect the particle (P) and vapor (V) phases of four classes of semivolatile organic compounds (SOC) in Denver, CO: n-alkanes. polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH), and organochlorine pesticides. The carbon preference index (CPI) of n-alkanes in the V or P phases alone was skewed by temperature-dependent V/P partitioning; a combined gaseous + particulate CPI was preferred. The CPI suggested that the alkanes in Denver air were predominently petrogenic. Total PCB were calculated as the sum of individual congeners and also as Aroclor equivalents, with good agreement between the two methods. Apparent V/P distributions of these compound classes were expressed as A(TSP)/F, were A and F are the adsorbent- and filter-retained SOC concentrations (ng m⁻³) and TSP is the total suspended particle concentration (μg m⁻³). Values of A(TSP)/F were related to the average sampling temperature (T, K) through: log [A(TSP)/F] = m/T + b. Fitted log A(TSP)/F at 5°C correlated well with p_L⁰ at 5°C, the SOC liquid vapor pressure. No differences were observed in partitioning behavior among the four SOC types.     

黄河河南段水体中正构烷烃的分布特征与来源解析

本研究于2010年8月采集黄河河南段26个表层水及悬浮颗粒物样品,采用气相色谱-质谱联用仪(GC-MS)测定22种正构烷烃(C_(14)~C_(36))的含量,分析其组成特征,并利用特征参数解析其来源.结果表明,黄河河南段水相中正构烷烃浓度为521~5 843 ng·L~(-1),平均浓度为1 409 ng·L~(-1),组成特征以C_(25)为主峰碳的高碳单峰型.悬浮颗粒相中正构烷烃浓度范围为463~11 142 ng·L~(-1),平均浓度为1 951 ng·L~(-1),组成特征表现为双峰型,C_(25)为主峰碳的高碳烃占优势,同时存在低碳峰.多特征参数OEP、CPI、%Wax C_n以及TAR表明,黄河河南段水相及悬浮颗粒物中正构烷烃主要来源于化石燃料的燃烧,同时存在陆生植物来源.     

Chlorinated organic compounds in the troposphere over the western North Atlantic Ocean measured by aircraft

Results of 32 individual flights during 1985, 1986 and 1988 using a King Air research aircraft over the western North Atlantic Ocean and the Adirondack Mountains are presented. Measurements were made for selected trace organic compounds including α- and γ-isomers of hexachlorocyclohexane (HCH), the summed isomers of α- and γ-chlordane, dieldrin and polychlorinated biphenyls (PCBs). The concentrations of compounds at altitudes of 300–10,000 ft indicate that these compounds were well mixed in the atmosphere and that for the most part, ground-level and higher-altitude concentrations were similar in magnitude. There was a high degree of variability due to time, meteorological events and location. Concentrations over the Adirondack Mountains in 1985 were the highest measured with means of 0.198 ng m⁻³ for HCB, 0.388 ng m⁻³ for α-HCH, 0.509 ng m⁻³ for γ-HCH, 0.340 ng m⁻³ for dieldrin, 0.480 ng m⁻³ for chlordane and 0.951 ng m⁻³ for total PCBs. Concentrations over the western North Atlantic south-east of Bermuda in summer 1988 wer lower, with means of 0.093 ng m⁻³ for HCB, 0.142 ng m⁻³ for α-HCH, 0.012 ng m⁻³ for γ-HCH, 0.016 ng m⁻³ for dieldrin 0.020 ng m⁻³ for chlordane and 0.600 ng m⁻³ for PCBs. During 1988 concentrations of most of the compounds were similar in the atmosphere of the coastal zone, 50–100 km off the U.S., to those measured near Bermuda. Chlordane, and to a lesser extent dieldrin, showed a decrease in concentration away from North America.     

应用自动识别与定量分析数据库筛查黄河和长江水中有机污染物

采用气质联用分析,并应用自动识别与定量分析数据库(AIQS-DB)对黄河下游和长江下游水样中近1000种有机污染物进行了筛查.结果表明,黄河下游山东段和长江下游江苏段水样分别检出95种和121种化合物,主要包括正构烷烃、多环芳烃、酚类、硝基化合物、酞酸酯类、农药和药物等.其中,黄河和长江水样中正构烷烃平均浓度分别为1806ng/L和720ng/L;16种优控PAHs平均浓度分别为27ng/L和30ng/L;6种优控PAEs的平均浓度分别为77ng/L和2166ng/L;黄河和长江水样分别检出9种和17种农药.黄河各采样点间污染物浓度差别较大,而长江采样点间浓度相差较小.研究表明,气质联用结合AIQS-DB可有效用于区域性污染物的筛查.     

太原市空气颗粒物中正构烷烃分布特征及来源解析

为明确城市空气颗粒物中正构烷烃分布特征及污染来源,采集采暖和非采暖季环境空气PM10样品和典型排放源(高等植物、燃煤和机动车)样品,利用GC-MS测定正构烷烃,选取诊断参数并结合污染源排放特征讨论PM10中正构烷烃分布和来源,采用主成分分析法定量解析源贡献率.结果表明,环境空气PM10中正构烷烃含量呈较强时空变化,采暖和非采暖季浓度分别为213.74~573.32 ng·m-3和22.69~150.82 ng·m-3,前者总浓度最高是后者的18倍;采暖季郊区点位(JY、JCP、XD和SL)浓度均高于市区,以JY最高(577.32 ng·m-3),非采暖季工业区(JS)总烷烃量(150.82 ng·m-3)明显高于其它点位,是SL总量的7倍.采暖季化石燃料来源烷烃(C n≤C24)与总烷烃量相关性优于植物来源烷烃(C n≥C25),非采暖季相反,表明前者化石燃料输入较后者高.CPI和%WNA指示非采暖季植物贡献率较采暖季高,且植物蜡烷烃随环境压力的增大总产率增加;C max和OEP表明非采暖季PM10中有机质成熟度低于采暖季;两季样品TIC图均存在UCM鼓包,机动车尾气是该城市的重要污染源.PCA解析结果表明太原市环境空气PM10中正构烷烃首要排放源为机动车尾气和高等植物,约占51.28%;其次为煤烟尘,贡献率为43.14%.煤烟尘污染控制协同机动车尾气净化措施的完善将成为降低城市空气颗粒物中正构烷烃浓度的有效途径.     

滇池沉积物有机质沉积特征与来源解析

以滇池湖泊东南部和东部沉积柱为研究对象,对沉积柱中不同层的沉积物样品使用210Pb定年,分析不同年代沉积物中总有机碳(TOC)和正构烷烃的含量及沉积通量,利用正构烷烃相关指标示踪有机质来源.结果表明:1两采样点沉积物中TOC含量和沉积通量随时间增长均表现为总体上升的变化趋势;正构烷烃沉积通量随沉积年代的变化,分为上升期、下降期与再次上升期这3个阶段.2正构烷烃与TOC沉积通量均增大时,两者来源具有一致性,均来自于湖泊内部和入湖河流携带的泥沙物质之中;20世纪80年代至20世纪末,正构烷烃沉积通量在减小,TOC沉积通量在增大,说明该时期两者来源存在较大差异,湖泊内的细菌、藻类对正构烷烃的贡献较大,而TOC受湖泊内部与入湖泥沙的影响较大.3两采样点检测到的正构烷烃碳数范围为C12~C35,由正构烷烃基本特征与源解析指标分析得出:挺水植物对滇池湖泊沉积物中有机质来源贡献较大,浅层深度,细菌和藻类的贡献突出.     

广西十万大山背景点PM2.5中非极性有机气溶胶组成及来源解析

大气细颗粒物(PM_2.5)中的非极性化合物包括多环芳烃（PAHs）和正构烷烃（n-alkanes）等,通常用于识别污染来源,且对人体健康和环境有很重要的影响.为探究广西背景点PM_2.5中非极性有机气溶胶的污染特征及来源,于2017年11月至2018年10月,对野外采集的PM_2.5样品分析了其中17种多环芳烃和20种正构烷烃.结果表明,多环芳烃和正构烷烃全年的平均值分别为（4.28±4.25）ng·m^-3和（13.7±14.72）ng·m^-3;季节变化规律均是：冬季[（7.86±5.19）ng·m^-3和（27.51±16.9）ng·m^-3]>春季[（2.73±1.76）ng·m^-3和（7.64±4.71）ng·m^-3]>秋季[（2.34±1.45）ng·m^-3和（7.01±4.55）ng·m^-3]>夏季[（1.91±1.67）ng·...     

Nitrated phenols in fog

Five nitrated phenols and some of their possible photochemical precursors as phenol, cresol and nitrate were identified in fog water from northeastern Bavaria. The concentrations in a rural and an urban area are presented, and the relationships observed between several of the compounds are discussed in terms of gas phase formation mechanisms. The levels of the nitrated phenols (5–300 nmoleℓ⁻¹) and phenol (<10–1000 nmoleℓ⁻¹) in fog were higher than the concentrations reported for rain.     

麦草及其烟尘中正构烷烃的组成

在明火和闷烧条件下对6种麦草进行焚烧试验,用GC/MS测定了秸秆和烟尘中正构烷烃的组成.结果表明,从麦秆和烟尘中检出的正构烷烃主要是C16~C33.麦秸中正构烷烃的总含量变化范围是19.6~62.3 mg·kg-1,平均值为36.0mg·kg-1.低碳数(碳数相似文献   

多环芳烃在岩溶地下河表层沉积物-水相的分配

利用实测老龙洞地下河水中和沉积物中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的实际浓度,获取了溶解相-沉积物中PAHs的分配系数Kp值.研究了老龙洞地下河PAHs在水相和沉积物中的质量浓度变化及其在水相和沉积物间的分配.研究结果表明水相和沉积物中PAHs质量浓度分别为81.5~8 089 ng·L-1,平均值(1 439±2 248)ng·L-1和58.2~1 051 ng·g-1,平均值(367.9±342.6)ng·g-1;PAHs组成均以2~3环为主,但沉积物中明显富集高环PAHs.沉积物-水相Kp值分布在55.74~46 067 L·kg-1范围内,随PAHs环数的增加而增大.沉积物-水相中实测的有机碳分配系数(lg Koc)大部分高于预测值上限,PAHs强烈吸附在沉积物上.lg Koc与正辛醇-水分配系数(lg Kow)呈较好的线性自由能关系(R2=0.75),但其斜率小于1,推测地下河沉积物对PAHs化合物的吸收能力较差.     

Photochemical formation of particulate dicarboxylic acids under long-range transport in central Japan

Long-range transport (LRT) of photochemical air pollution from the coastal area with large emission sources to the inland mountainous region occurs very frequently in the central Japan region on clear summer days. It is caused by local winds and the transport route is almost-fixed geographically. Along this route, behavior of dicarboxylic acids in the airborne aerosols was investigated in the cooperative field observation of meteorology and chemistry. Measurements were made every 3-h at inland sites.The concentrations of dicarboxylic acids as well as NO₃⁻ and total organic C increased in the daytime and decreased at night. The maximum are attained when the transported air mass was arrived at the sampling sites. These diurnal variations were similar to that of O₃.In the daytime, although the phthalates (di-n-butyl and dioctyl), n-alkanes (C₂₁C₃₂) and pinon aldehyde were abundant in the airborne aerosols, the dicarboxylic acids (C₂C₁₀) were the most abundant species and the total concentrations attained from 30 to 50% of the total organic particulate matter. In addition, of the dicarboxylic acids, more than 70% were estimated to be produced by photochemical reactions in the daytime. Thus, it was concluded that most of the dicarboxylic acids were produced by the photochemical oxidation of anthropogenic compounds during LRT.     

油田区土壤石油烃组分残留特性研究

为了揭示石油开采区土壤石油烃组成及残留特性,探讨石油污染物的来源与风化程度,采集了胜利油田孤岛和河口采油区共5口油井周边土壤样品及原油样品,利用气相色谱-质谱联用仪(GC-MS)分析原油及土壤样品中的链烷烃(正烷烃+姥鲛烷+植烷)及多环芳烃(polycyclic aromatic hydrocarbons,PAHs)共51种石油烃单体的含量.结果表明,与原油相比,油田区土壤总提取物中链烷烃与PAHs所占的比例明显偏低;土壤石油烃的组分构成与原油相比,链烷烃中碳数小于12的正烷烃比例明显降低,而高碳数正烷烃比例增加.选择正十八烷/植烷作为指示土壤风化程度的标志,利用主成分分析(principal component analysis,PCA)法分析其与土壤中各石油烃组分的关系,结果显示碳数大于33的正烷烃与中环芳香烃具有高残留性.利用主成分分析综合分析用于土壤石油烃来源识别的4个指标,结果表明,土壤中的石油烃具有明显的原油"指纹".研究结果为油田土壤污染特性的认识提供了依据与基础.     

油田污染土壤残油组成与特征参数分析

为揭示石油在土壤中的降解规律、残油组分特征,筛选土壤残油的生物降解性评价参数,选取大庆、胜利、百色3个油田区共18个深度降解的石油污染土样,利用气相色谱-质谱联用仪(GC-MS)分析了土壤残油中链烷烃(正烷烃+姥鲛烷+植烷)、多环芳烃(PAHs)、萜烷、甾烷及三芳甾烃等5类超过100种石油烃单体.结果表明,经长期降解后残留在土壤残油中总烷烃残留率低于10%,总PAHs残留率低于30%,而萜烷、甾烷及三芳甾烃等生物标志物较难降解.正烷烃降解性随碳数增加有下降的趋势,但碳数<37的正烷烃降解率平均值>80%;PAHs中2～4环PAHs降解率平均值>70%,5～6环PAHs较难生物降解;萘系列、菲系列、系列及苯并[e]芘系列中随烷基取代数增多而残留率增高.残油中可被GC-MS识别的组分<3%,主要为碳数高于20的正烷烃、烷基取代萘和菲、萜烷、甾烷及三芳甾烃等生物标志物.基于烷烃及多环芳烃组成特征,筛选出6个由易降解组分含量与总油或难降解组分含量的比值构成的标准残油的特征参数,可用于判断污染土壤中石油污染物的生物降解性.     

上海夏季PM2.5中有机物的组分特征、空间分布和来源

有机物是大气细颗粒物(PM_(2.5))的重要组成部分,其来源和组分非常复杂,是大气科学研究的难点和热点.本研究定量表征了上海地区夏季3个不同功能站点PM_(2.5)中78种有机组分,分析了其组成特征及空间差异,并采用后向轨迹、指示物、特征比值等方法对其来源进行了探讨.结果表明,上海西部郊区青浦和徐汇的有机组分检出浓度相近,约为(317±129)ng·m~(-3),高于东部沿海.78种有机组分中,脂肪酸类物质的占比最高,之后依次为左旋葡聚糖、正构烷烃和多环芳烃,藿烷的占比最低.基于示踪物比值法初步分析结果表明,上海地区的颗粒有机物主要来源于汽油车尾气排放,此外中心城区和西部郊区在观测期间受到了一定程度的生物质燃烧污染,可能与西北方向的污染输送有关.就具体组分而言,在西部郊区青浦,脂肪酸主要来自于陆生植物排放,而在东部沿海地区临港,其还会受到海洋浮游植物和微生物的影响;PAH特征比值的分析表明煤燃烧和机动车尾气对多环芳烃具有重要贡献.相关研究结果有助于对上海有机气溶胶的污染特征及来源的深入认识,为开展颗粒有机物的防治提供一定的基础支撑.     

Formic acid and acetic acid: Emissions,atmospheric formation and dry deposition at two southern California locations

Emission rates, in situ formation rates and removal rates by dry deposition are estimated for formic acid (HCOOH, C1) and acetic acid (CH₃COOH, C2), which are the most abundant acids in southern California air and together account for much of the airborne acidity and are the leading contributors to acid dry deposition. Using data for eight unreactive tracers, direct emission rates during the fall 1987 are estimated to be 5.6 and 12.8 metric tons d⁻¹ for C1 and C2, respectively, at a coastal source-dominated site. These emissions rates increase to 9.6(C1) and 20.4(C2) metric tons d⁻¹ during the summer. In situ formation in the atmosphere via the ozone-olefin reaction is an important source for both acids. This reaction produces an estimated 25.0 and 10.1 metric tons d⁻¹ of C1 and C2, respectively, during the day and 34.5 (C1) and 4.3 (C2) metric tons d⁻¹ at night. More acetic acid than formic acid is emitted by direct sources, with C2/C1 emission rate ratios of 2.1–2.3. The reverse is true of in situ formation, with C1/C2 production rate ratios of 2.5 (day) and 8.0 (night). Dry deposition removal rates depend on season (fall > summer) and location (inland > coastal) and are 22–52 metric tons d⁻¹ for C1, and 32–83 metric tons d⁻¹ for C2. Source (emissions + in situ formation) and sink (dry deposition) terms are of the same magnitude in all six cases studied and balance each other well in three of these cases. Uncertainties in emission, in situ production and removal rates are discussed and reflect uncertaintes in olefin and unreactive tracer emission rates, yields of organic acids from the Criegee biradical (ozone-olefin reaction), and dry deposition velocity, respectively.     

The stem-II regional scale acid deposition and photochemical oxidant model—IV. The impact of emission reductions on mesoscale acid deposition in the lower ohio river valley

Assessment of the effect of reduction in emissions of primary sources on eventual levels of pollutants, pH of precipitation and total wet deposition is crucial in designing acid-rain control strategies. The STEM-II/ASM model is used to investigate the effect of reduction in emissions on the ultimate deposition patterns and amounts of major acidic pollutants in a mesoscale region. This work also investigates the effect of background levels of primary pollutant species on the eventual levels and deposition amounts of SO₄⁼ and NO₃⁻. A series of mesoscale simulations were conducted in which emissions of primary sources of NO_x and SO₂ were reduced and/or background concentrations of certain key species were changed. The results indicate that the dominant effect on the eventual deposition amounts of SO₄⁼ and NO₃⁻ is due to background concentrations of key precursor species such as SO_x and NO_x. With relatively high background concentrations, reducing SO₂ emissions by 50% and NO_x emissions by 40% resulted in reductions of 2–3% for SO₄⁼ wet deposition aand about 15% for NO₃⁻ wet deposition. However, reducing the background concentrations of SO₂ and SO₄⁼ by 50% and NO, NO₂ and HNO₃ by 40% resulted in substantial reductions in wet deposition; SO₄⁼ deposition was reduced by 40–50% and NO₃⁻ deposition was reduced by approximately 35%.     

餐饮源有机颗粒物排放特征

餐饮油烟是大气有机颗粒物的重要来源之一.本研究在深圳市内选择了西餐、茶餐厅、职工食堂和韩式料理这4种类型的餐馆,通过对这4类餐厅的外场采样,分析各类型餐厅油烟中有机颗粒物的化学组成,筛选了餐饮油烟污染源的有机特征组分.结果表明,各餐馆排放的PM_(2.5)中,有机物占60%以上.在所有定量的有机组分之中,脂肪酸含量最高,其次是二元羧酸和正构烷烃,而多环芳烃、甾醇和单糖等有机组分的含量较低.颗粒物的有机组成特征受到菜系的影响,西餐厅和韩式料理排放脂肪酸、正构烷烃和多环芳烃等有机物含量较高,但却排放了低含量的甾醇和单糖,茶餐厅和职工食堂则相反.餐饮源颗粒物中Fla/(Fla+Pyr)和LG/(Gal+Man)的比值受菜系影响较小,也区别于其他污染源的特征比值,可以作为餐饮源潜在的示踪物.餐饮源为深圳市大气颗粒物贡献了大量的脂肪酸和二元羧酸.