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1.
Carboxylic Acids: Seasonal Variation and Relation to Chemical and Meteorological Parameters 总被引：1，自引：0，他引：1
Formic and acetic acid measured as daily averages in 1993–1994show equal and highly correlated concentrations up to 3 ppb in the summer(May–August). In the winter (October–March) the formicacid/acetic acid ratio was 0.6 and the formic acid concentrations wereusually below 1 ppb. In winter the carboxylic acids correlate withOx, NOy, SO2 and particulatesulphur. The main sources are suggested to be ozonolysis of anthropogenicalkenes and reactions between peroxyacetyl radicals and RO2radicals. In spring–summer the carboxylic acids correlate withO3, Ox, HNO3, PAN,NOy, SO2, particulate sulphur and temperature.In addition to the sources of the winter a contribution from ozonolysis ofbiogenic alkenes is likely. Quite similar formic acid/acetic acid ratios forall wind directions suggest that the source(s) are atmospheric oxidationprocesses distributed over large areas. The highest concentrations occurringfor winds from east to south and the correlation with e.g., particulatesulphur indicate chemical production in polluted air masses during longrange transport. 相似文献
2.
Randal S. Martin Hal Westberg Eugene Allwine Lynne Ashman J. Carl Farmer Brian Lamb 《Journal of Atmospheric Chemistry》1991,13(1):1-32
Ambient concentrations of isoprene and several of its atmospheric oxidation productsmethacrolein, methylvinyl ketone, formaldehyde, formic acid, acetic acid, and pyruvic acid-were measured in a central Pennsylvania deciduous forest during the summer of 1988. Isoprene concentrations ranged from near zero at night to levels in excess of 30 ppbv during daylight hours. During fair weather periods, midday isoprene levels normally fell in the 5–10 ppbv range. Methacrolein and methylvinyl ketone levels ranged from less than 0.5 ppbv to greater than 3 ppbv with average midday concentrations in the 1 to 2 ppbv range. The diurnal behavior of formaldehyde paralleled that of isoprene with ambient concentrations lowest (1 ppbv) in the predawn hours and highest (>9.0 ppbv) during the afternoon. The organic acids peaked during the midday period with average ambient concentration of 2.5, 2.0, and 0.05 ppbv for formic, acetic, and pyruvic acid, respectively. These data indicate that oxygenated organics comprise a large fraction of the total volatile organic carbon containing species present in rural, forested regions of the eastern United States. Consequently, these compounds need to be included in photochemical models that attempt to simulate oxidant behavior and/or atmospheric acidity in these forested regions. 相似文献
3.
The partitioning of formic and acetic acid between the atmospheric liquid and gaseous phase is modelled for a range of liquid water contents. At low liquid water content, formic acid is dissolved preferentially over acetic acid. Applying these results to the analysis of processes taking place in clouds, one can explain the frequently found enrichment of formic over acetic acid in rainwater, which results from selective transport by washout. We assess the ability of dew to act as a temporary sink and source for organic acids, and propose that the diel variation of mixing ratios often found during surface measurements, may in part be due to the dissolution in dew and subsequent evaporation on the following day. 相似文献
4.
M. G. Alishaev 《Russian Meteorology and Hydrology》2013,38(8):522-530
Presented are the computations of condensation and precipitation of atmospheric moisture at night depending on the diurnal variations of air temperature and air humidity. Used are the meteorological data for northern Dagestan. Determined is the contribution of the dew to the moistening of the soil. The examples of the exponential and lognormal distribution of droplets revealed that the use of the velocity of medium-size droplet underestimates the value of the moisture mass precipitated on the soil. A concept of the mean mass precipitation velocity is introduced, and the formulae are provided for determining the average mass of deposited condensate depending on humidity, the temperature drop, and size distribution of droplets. Posed is a new problem of diurnal condensate precipitation in the soil in summer and of technology of its increase. 相似文献
5.
A box model is used to explore the detailed chemistry of C2 and C3 organic compounds in the marine troposphere by tracing the individual reaction paths resulting from the oxidation of ethane,
ethene, acetylene, propane, propene and acetic acid. The mechanisms include chemical reactions in the gas phase and in the
aqueous phase of clouds and aerosol particles at cloud level under conditions resembling those in the northern hemisphere.
Organic hydroperoxides are found to be important intermediate products, with subsequent reactions leading partly to the formation
of mixed hydroxy or carbonyl hydroperoxides that are readily absorbed into cloud water, where they contribute significantly
to the formation of multifunctional organic compounds and organic acids. Organic hydroperoxides add little to the oxidation
of sulfur dioxide dissolved in the aqueous phase, which is dominated by H2O2. Next to acetaldehyde and acetone, glycol aldehyde, glyoxal, methyl glyoxal and hydroxy propanone are prominent oxidation
products in the gas and the aqueous phase. Acetaldehyde is not efficiently converted to acetic acid in clouds; the major local
sources of acetic acid are gas-phase reactions. Other acids produced include hydroperoxy acetic, glycolic, glyoxylic, oxalic,
pyruvic, and lactic acid. The mechanism of Schuchmann et al. (1985), which derives glycolic and glyoxylic acid from the oxidation of acetate, is found unimportant in the marine atmosphere.
The principal precursors of glyoxylic acid are glyoxal and glycolic acid. The former derives mainly from acetylene and ethene,
the latter from glycolaldehyde, also an oxidation product of ethene. The oxidation of glyoxylic acid leads to oxalic acid,
which accumulates and is predicted to reach steady state concentrations in the range 30–90 ng m−3. This is greater, yet of the same magnitude, than the concentrations observed over the remote Pacific Ocean. 相似文献
6.
利用HYSPLIT后向轨迹模式和2004年8月—2007年12月NCEP再分析气象资料,计算每天15:00抵达北京地区10、100和500m高度上的后向气流轨迹.对整个研究时段、采暖季和非采暖季期间的后向气流轨迹分别进行聚类分析,得到这3个时段到达北京地区的主要后向气流轨迹聚类.其中整个研究时段的后向气流轨迹分成3个聚类,采暖季和非采暖季的后向气流轨迹都分成5个聚类.结合各段时间中国科学院大气物理研究所观测的大气污染物体积分数资料,分析不同时段气流输送作用对北京主要大气污染物体积分数的影响.发现采暖季和非采暖季北京气体污染物体积分数高值主要集中在来自风速较小的西北方气流聚类.采暖季污染物体积分数低值主要出现在偏北方向风速较大的后向气流轨迹聚类.非采暖季污染物体积分数低值主要出现在偏北低速气流聚类和西北向高速气流轨迹聚类中.从各时段污染物最值分布情况可以看出:在风速较大的后向气流轨迹聚类影响下,北京的污染物体积分数较低;途经了较严重工业排放地带的后向气流轨迹聚类会使北京气体污染物体积分数显著增高.此外,虽然非采暖季的大气污染物分布与气流输送的影响基本符合,但各聚类污染物分布结果与气流输送作用的影响存在偏差. 相似文献
7.
Seasonal variation of particulate organic compounds in atmospheric PM10 in the biggest municipal waste landfill of Algeria 总被引：1，自引：0，他引：1
Riad Ladji Noureddine Yassaa Angelo Cecinato Brahim Youcef Meklati 《Atmospheric Research》2007,86(3-4):249-260
The average composition and seasonal variations of atmospheric organic particulates with respect to n-alkanes, n-alkanoic acid, polycyclic aromatic hydrocarbon (PAHs), and nitrated polycyclic aromatic hydrocarbons (N-PAHs) were determined at the biggest municipal waste landfill in Algeria located in Oued Smar, 13 km east of downtown Algiers. Samplings were carried out from August 2002 to February 2003, and organic compounds adsorbed in air particles having an aerodynamic diameter lower than 10 μm (PM10) were characterized using gas chromatography coupled with mass spectrometric detection (GC/MSD). Total concentrations ranged from 828 to 11,068 ng per cubic meter of air for n-alkanes, from 1714 to 21,710 ng per cubic meter of air for n-alkanoic acids, from 13 to 212 ng per cubic meter of air for PAHs and from 93 to 205 pg per cubic meter of air for N-PAHs. n-Alkanoic acids accounted for 85 and 56% of the total organic composition of the aerosol measured in summer and winter, respectively, were the biggest fraction. The distribution profiles and the diagnostic ratios of some marker compounds allowed to identify the combustion and microbial activity as the major sources of particulate organic pollutants associated with direct emission. The year-time dependence of organic fraction content of aerosol in Oued Smar appeared to be related to average meteorological conditions as well as variability of rate and nature of materials wasted into the landfill. 相似文献
8.
《Atmospheric Research》2008,87(3-4):249-260
The average composition and seasonal variations of atmospheric organic particulates with respect to n-alkanes, n-alkanoic acid, polycyclic aromatic hydrocarbon (PAHs), and nitrated polycyclic aromatic hydrocarbons (N-PAHs) were determined at the biggest municipal waste landfill in Algeria located in Oued Smar, 13 km east of downtown Algiers. Samplings were carried out from August 2002 to February 2003, and organic compounds adsorbed in air particles having an aerodynamic diameter lower than 10 μm (PM10) were characterized using gas chromatography coupled with mass spectrometric detection (GC/MSD). Total concentrations ranged from 828 to 11,068 ng per cubic meter of air for n-alkanes, from 1714 to 21,710 ng per cubic meter of air for n-alkanoic acids, from 13 to 212 ng per cubic meter of air for PAHs and from 93 to 205 pg per cubic meter of air for N-PAHs. n-Alkanoic acids accounted for 85 and 56% of the total organic composition of the aerosol measured in summer and winter, respectively, were the biggest fraction. The distribution profiles and the diagnostic ratios of some marker compounds allowed to identify the combustion and microbial activity as the major sources of particulate organic pollutants associated with direct emission. The year-time dependence of organic fraction content of aerosol in Oued Smar appeared to be related to average meteorological conditions as well as variability of rate and nature of materials wasted into the landfill. 相似文献
9.
利用2015年1月至2017年6月桂林国家基本气象站能见度、相对湿度、气温、气压、降水等气象要素和PM10、PM2.5、PM1.0颗粒物质量浓度资料,分析桂林城区大气能见度与颗粒物浓度和气象因子之间关系。结果表明：桂林城区大气能见度和PM10、PM2.5、PM1.0呈对数关系,相关系数分别为-0.341、-0.461、-0.509,颗粒物对大气能见度影响在相对湿度为60%—70%时最为显著。在各气象因子中,大气能见度与风速的相关性最好,其次为相对湿度,与风速呈二次函数关系,与相对湿度呈幂指数关系,与温度相关性较小,与气压在秋冬季节呈正相关,相关系数冬季可达0.301,但在春、夏季节相关性不显著;利用颗粒物浓度和气象要素建立8种大气能见度非线性统计回归模型,比较后发现利用PM1.0、风速、相对湿度、气温等因子建立的不同季节大气能见度拟合公式在实际检验中效果最优,能较好地模拟桂林地区大气能见度的变化。 相似文献
10.
Y. S. Chung Hak-Sung Kim Youngsin Chun 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(3):345-354
Dust air pollution has been routinely monitored in central Korea for the last two decades. In 2009, there were eight typical episodes of significant dust loadings in the air: four were caused by dust storms from deserts in Mongolia and Northern China, while the remaining were typical cases of anthropogenic air pollution masses arriving from the Yellow Sea and East China. These natural dust loadings occurred with cool northwesterly airflows in the forward side of an intense anticyclone coming from Mongolia and Siberia. The mean concentrations of the four natural dustfall cases for TSP, PM10 and PM2.5 were 632, 480 and 100 μg m?3, respectively. In contrast, the anthropogenic dust-pollution episodes occurred with the warm westerly and southwesterly airflows in the rear side of an anticyclone. This produced a favorable atmospheric and chemical condition for the build-up of anthropogenic dust air pollution in the Yellow Sea. The mean concentrations of the four anthropogenic dust loadings for TSP, PM10 and PM2.5 were 224, 187 and 137 μg m?3, respectively. The contents of fine dust loadings of PM2.5 were comparatively high in the cases of anthropogenic air pollution. High atmospheric concentrations of fine particles in the atmosphere cause poor visibility and constitute a health hazard. Satellite observations clearly showed the movement of dust-pollution masses from Mongolia and Northern China and from the Yellow Sea and East China that caused these dust pollution episodes in Korea. 相似文献
11.
回顾了湿空气热动力学的研究进展,对未饱和湿大气、饱和湿大气及非均匀饱和湿大气的动热力方程、能量方程、连续方程等进行了梳理,指出饱和湿空气动量方程与非均匀饱和湿空气动量方程的最大区别在于对凝结过程的处理不同。饱和湿大气中,由于大气均是饱和的,由饱和造成的水凝物可处处出现,不能区分真正发生水汽凝结的区域。而非均匀饱和湿空气中,凝结发生与相对湿度的幂次方有关(即与凝结概率函数的分布有关),在相对湿度较小的区域不会出现水汽凝结,凝结区与非凝结区可自动区别,其描述的凝结过程与实际大气更接近。同时,总结了湿大气水汽凝结饱和非均匀分布的动热力物理量在高影响天气分析中的应用,最后讨论了未来推进湿空气动力学研究需重点考虑的一个内容。 相似文献
12.
利用改进的Bigg型混合云室于2011年5-11月在辽宁省气象局抚顺大气成分站对近地层大气冰核浓度进行了测量。根据测量结果,分析冰核浓度日际变化和季节变化特征,讨论了风、气压、气温和湿度以及天气状况等气象要素对大气冰核浓度的影响。结果表明：观测期间,抚顺市大气冰核浓度平均为30个·L-1（-20 ℃时）;冰核浓度随活化温度的降低呈指数式增加;气象因子对冰核浓度有一定的影响,不同季节影响的程度不同。 相似文献
13.
降水中甲酸和乙酸研究综述 总被引：1，自引：0，他引：1
对大气降水中甲酸和乙酸的相关研究进行了综述。介绍了过去曾采用的研究降水样品中两种有机酸的处理和分析方法,以及目前最常用的实验室分析方法。对降水中两种有机酸的浓度范围、全球时空分布以及受影响因素等相关研究工作进行了系统归纳,并且结合理论计算说明了有机酸对降水酸度的影响是不可忽视的。介绍了历史研究工作中得出的降水中两种有机酸的来源,包括天然源、人为源和有机物的二次化学转化等,以及有机酸源研究对于开展其它降水有机酸工作的研究意义。 相似文献
14.
Influences of characteristic meteorological conditions on atmospheric carbonyls in Beijing, China 总被引：2，自引：0，他引：2
Atmospheric pollutants are controlled not only by their production rates but also by meteorological conditions. The influences of dust storm, sauna weather (haze with high temperature and high humidity), wet precipitation and wind speed on atmospheric carbonyls in Beijing were investigated. During a severe dust episode (April 17, 2006), the mixing ratios of carbonyls were significantly elevated to 13–27 ppbV from 7 to 13 ppbV in the previous non-dust days (April 15 and 16) with the increasing extents of 38–154%. The accumulating effect and the lower photolysis rate in the dust day may be responsible for the increases of carbonyls' levels. Additionally, the contribution from heterogeneous reactions occurring on dust particles to formaldehyde and acetaldehyde cannot be ruled out. During the period of typical sauna weather, the concentrations of atmospheric carbonyls increased to 18–60 ppbV from 10 to 17 ppbV before the sauna days. The air mass over Beijing during the sauna days was controlled by a subtropical anticyclone and the boundary layer became quite stable, which was beneficial to the rapid accumulation of air pollutants including carbonyls. Wet precipitation was found to be an effective removal process to the atmospheric carbonyls. After one-hour of rain in summer, the total concentrations of atmospheric carbonyls decreased to less than half of that before the rainfall. The similar temporal varying patterns of carbonyls and inorganic ions in rainwater indicated that carbonyls were mainly washed out from the atmosphere into rainwater as inorganic ions were. Strong wind could evidently dilute atmospheric carbonyls and a negative correlation was found between wind speeds and the concentrations of carbonyls in spring in Beijing. 相似文献
15.
Equilibria of the marine multiphase ammonia system 总被引：3，自引：0，他引：3
A lack of empirical data has made it difficult to ascertain whether ammonia is in equilibrium between the oceanic, atmospheric gas and atmospheric particle phases in the remote marine environment. Reported here are simultaneous measurements of the saturation concentration of ammonia relative to ammonia concentrations in ocean surface waters; total seawater ammonia; atmospheric gas phase ammonia; and atmospheric particulate-phase ammonium, non-seasalt sulfate, methanesulfonate, and nitrate. Sampling was performed in May of 1987 in the northeast Pacific Ocean environment and in April and May of 1988 in the central Pacific Ocean environment.These measurements were used to determine the degree to which ammonia approached equilibrium between the oceanic and atmospheric gas and aerosol particle phases. The experimental atmospheric gas phase ammonia concentrations were compared with calculated equilibrium concentrations assuming a Henry's law type of partitioning between the gas and condensed phases. Characteristic times of the processes controlling the fate of ammonia in the marine environment also were compared.The measured atmospheric gas phase and oceanic concentrations of ammonia indicate that ammonia is not in a Henry's law equilibrium across the air/sea interface. This disequilibrium is a result of the long air/sea exchange equilibration time relative to the lifetime of ammonia in the atmosphere. Comparison of the calculated equilibrium gas phase ammonia concentrations with the measured gas phase ammonia concentrations shows that attainment of equilibrium between the atmospheric gas and particle phases is a strong function of the chemical composition of the aerosol particles. The data suggest that fully neutralized aerosol particles are not in Henry's law equilibrium with the gas phase while equilibrium is observed for particles with an average ammonium to non-seasalt sulfate molar ratio less than 1.8. 相似文献
16.
J. J. Schultz Tokos S. Tanaka T. Morikami H. Shigetani Y. Hashimoto 《Journal of Atmospheric Chemistry》1992,14(1-4):85-94
Gaseous formic acid (HCOOHg) and acetic acid (CH3COOHg) were measured every 30 minutes during a 10 hour daylight period in August, and a 24 hour period in October, 1990 in the urban atmosphere of Yokohama, Japan. An aqueous nebulizer sampler and ion-chromatography exclusion (ICE) were used for the measurements. In the August experiment (0800–1800 local time) the mean HCOOHg concentration was found to be 7.3±2.5 ppbv. The mean CH3COOHg concentration was 3.8±1.2 ppbv. In the 24 hour experiment in October, concentrations of both acids were lower between 0800–1800 than during the same time-period in August (mean HCOOHg=4.4±2.7 ppbv, mean CH3COOHg=1.4±0.5 ppbv). In October, concentrations of both acids were higher in daylight hours than at night; sporadic high HCOOHg concentrations were observed. In both experiments the ratio HCOOHg/CH3COOHg of individual samples was usually 2.0 (mean ratio of 2.0 in August, 3.1 in October). 相似文献
17.
Synoptic and mesoscale weather conditions during air pollution episodes in Athens,Greece 总被引：2，自引：0，他引：2
Based on regular climatological and air quality data from the Greater Athens Area (GAA), the air pollution episodes observed in Athens during the period 1983–1990 were analysed and classified. The main characteristics of atmospheric conditions during days with high air pollution concentrations are summarized too. Model simulations show that the worst air pollution episodes in Athens occur during days with a critical balance between synoptic and mesoscale circulations and/or during days with warm advection in the lower troposphere. 相似文献
18.
Seven carboxylic acids in rainwater were simultaneously determined using ion chromatography for 13 months in two different
sites, Guiyang and Shangzhong, southwest of China. Results showed formic, acetic and oxalic acids were the three predominant
carboxylic acids. Their volume-weighted average concentrations were 14.24, 9.35, 2.79 μmol/L in Guiyang and 4.95, 1.35, 2.31 μmol/L
in Shangzhong, respectively. A distinctive diurnal pattern in carboxylic acid concentrations (daytime>nighttime, t test, p < 0.05) was observed during the growing season in Guiyang. Shangzhong witnessed higher concentration of these acids during
the growing season than that during the non-growing season. Direct emissions from growing vegetation or soils probably account
for the main provenance of the acids in the rural area. However, the opposite trend were found in Guiyang and the anthropogenic
sources during the non-growing season were the main reason. By comparison of our result with the previous data about 20 years
ago, we calculated that at least 42% of acetic acids and 69% of formic acid originated from the anthropogenic sources in Guiyang.
Furthermore, the ratio of formate/acetate in gas phase larger than 1 suggest the oxidation of unsaturated hydrocarbons from
the human activity and/or natural sources were the main origin of carboxylic acids in Guiyang. While The F/A ratio in gas
phase was less than 1 in Shangzhong which indicate the direct emissions from biogenic sources. Oxalic acid was in similar
amounts in both sites, indicating the common source of the acid. 相似文献
19.
The results of heavy metal measurements in monthly precipitation samples are analyzed at biological station Dal’nie Zelentsy to define the role of the atmospheric precipitation in the marine environment pollution in the Barents Sea coastal region. Peculiarities of the atmospheric processes and the genesis of air masses bringing the precipitation and the extent of their effect on the precipitation pollution with heavy metals are considered based on the data obtained in 2001–2002. Of the air masses brining the precipitation to the Kola Peninsula coast the air masses of a marine origin have significant advantage. It is shown that weight average heavy metal (except copper) concentrations in the precipitation from the marine air masses on the Kola coast are higher than in the precipitation from the continental air masses. The emissions from local metallurgic enterprises influence the extent of the precipitation pollution with copper. 相似文献
20.
Aerosol samples (205) were collected from January 2005 to November 2006 at a coastal site at Keelung City (Taiwan), on the
southern East China Sea. The atmospheric concentrations of major ions indicated that the area was dominated by different air
masses at different times of the year: continental Asia from January to May and November to December; air masses from Indonesia
and surrounding islands (south-eastern region) dominated during early-summer (July 2005 and June 2006), and air masses directly
from the adjacent ocean dominated during late-summer (July to August 2006) and early-autumn (September to October 2005). The
atmospheric concentrations of water soluble organic nitrogen (WSON) corresponded to the different sources and weather conditions.
The results of a factor analysis of combined major ions, water soluble inorganic nitrogen (WSIN) and WSON indicated that a
fossil fuel combustion source and biomass burning were the two major controlling factors during the sampling period. We discuss
the correlations between WSON, WSIN and major anthropogenic ions in relation to the different formation mechanisms for the
various sources. We propose a mechanism whereby biomass burning is the major input of aerosols derived from mainland China.
Fossil fuel combustion was found to be important during periods when aerosols were derived from the south-eastern area. Our
data indicate that WSON was predominantly associated with aerosols derived from biomass burning when the origin of the air
mass was mainland China. 相似文献