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1.
The influence of soluble compounds leached from real atmospheric aerosol particles (size range Dae: 0.17–1.6 μm) and dissolved NO 2 on S(IV) oxidation in aqueous solution is presented. Experiments were conducted with aerosol particles of two different origins (i.e., urban and industrial) and at concentrations of trace gases in the gas mixtures (SO 2/air and SO 2/NO 2/air) typical for a polluted atmosphere. During the introduction of SO 2/air into the aqueous aerosol suspensions under dark conditions at pH 4, the formation of SO 42− was very slow with a long induction period. However, in the presence of NO 2 the oxidation rate of dissolved SO 2 in suspensions of aerosols from both origins increased substantially (about 10 times). The results suggest that soluble compounds eluted from atmospheric aerosols have not only a catalytic (e.g. Fe, Mn), but also a pronounced inhibiting effect (e.g., oxalate, formate, acetate, glycolate) on S(IV) autoxidation. When NO 2 was also introduced into the aerosol suspensions, the inhibition was not so highly expressed. An explanation for this is that the radical chain mechanism is mainly initiated by the interaction of dissolved NO 2 and HSO 3−. Therefore, at conditions typical for a polluted atmosphere dissolved NO 2 can have a significant influence on the secondary formation of SO 42−. 相似文献
2.
The effects of the burning of fireworks on air quality in Beijing was firstly assessed from the ambient concentrations of various air pollutants (SO 2, NO 2, PM 2.5, PM 10 and chemical components in the particles) during the lantern festival in 2006. Eighteen ions, 20 elements, and black carbon were measured in PM 2.5 and PM 10, and the levels of organic carbon could be well estimated from the concentrations of dicarboxylic acids. Primary components of Ba, K, Sr, Cl −, Pb, Mg and secondary components of C 5H 6O 42−, C 3H 2O 42−, C 2O 42−, C 4H 4O 42−, SO 42−, NO 3− were over five times higher in the lantern days than in the normal days. The firework particles were acidic and of inorganic matter mostly with less amounts of secondary components. Primary aerosols from the burning of fireworks were mainly in the fine mode, while secondary formation of acidic anions mainly took place on the coarse particles. Nitrate was mainly formed through homogeneous gas-phase reactions of NO 2, while sulfate was largely from heterogeneous catalytic transformations of SO 2. Fe could catalyze the formation of nitrate through the reaction of α-Fe 2O 3 with HNO 3, while in the formation of sulfate, Fe is not only the catalyst, but also the oxidant. A simple method using the concentration of potassium and a modified method using the ratio of Mg/Al have been developed to quantify the source contribution of fireworks. It was found that over 90% of the total mineral aerosol and 98% of Pb, 43% of total carbon, 28% of Zn, 8% of NO 3−, and 3% of SO 42− in PM 2.5 were from the emissions of fireworks on the lantern night. 相似文献
3.
Zero-valent iron (Fe0) has been widely used for Cr(VI) removal; however, the removal mechanisms of Cr(VI) from aqueous solution under complex hydrogeochemical conditions were poorly understood. In this research, the mixed materials containing cast iron and activated carbon were packed in columns for the treatment of aqueous Cr(VI)-Cr(III) in groundwater with high concentration of Ca2+, Mg2+, HCO3
−, NO3
−, and SO4
2−. We investigate the influences of those ions on Cr(VI) removal, especially emphasizing on the reaction mechanisms and associated precipitations which may lead to porosity loss by using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The results show that the precipitations accumulated on the material surface were (Fe/Cr) (oxy)hydroxide, mixed Fe(III)-Cr(III) (oxy)hydroxides, Fe2O3, CaCO3, and MgCO3. During these reactions, the Cr(VI) was reduced to Cr(III) coupled with the oxidated Fe0 to Fe(II) through the galvanic corrosion formed by the Fe0-C and/or the direct electron transfer between Fe0 and Cr(VI). In addition, Cr(VI) could be reduced by aqueous Fe(II), which dominated the whole removal efficiency. The primary aqueous Cr(III) was completely removed together with Cr(III) reduced from Cr(VI) even when Cr(VI) was detected in the effluent, which meant that the aqueous Cr(III) could occupy the adsorption sites. In general, the combined system was useful for the Cr(VI)-Cr(III) treatment based on galvanic corrosion, and the hardness ions had a negative effect on Cr(VI) removal by forming the carbonates which might promote the passivation of materials and decrease the removal capacity of the system. 相似文献
4.
The chemical composition of pollutant species in precipitation sampled daily or weekly at 10 sites in Ireland for the five-year period, 1994–1998, is presented. Sea salts accounted for 81% of the total ionic concentration. Approximately 50% of the SO 42− in precipitation was from sea-salt sources. The proportion of sea salts in precipitation decreased sharply eastwards. In contrast, the concentration of NO 3− and the proportion of non-sea-salt SO 42− increased eastwards reflecting the closer proximity to major emission sources. The mean (mol c) ratio of SO 42−:NO 3− was 1.6 for all sites, indicating that SO 42− was the major acid anion.The spatial correlation between SO 42−, NO 3− and NH 4+ concentrations in precipitation was statistically significant. The regional trend in NO 3− concentration was best described by linear regression against easting. SO 42− concentration followed a similar pattern. However, the regression was improved by inclusion of elevation. Inclusion of northing in the regression did not significantly improve any of the relationships except for NH 4+, indicating a significant increase in concentrations from northwest to southeast.The spatial distribution of deposition fluxes showed similar gradients increasing from west and southwest to east and northeast. However, the pattern of deposition shows the influence of precipitation volume in determining the overall input. Mean depositions of sulphur and nitrogen in precipitation were ≈30 ktonnes S yr −1 and 48 ktonnes N yr −1 over the five-year period, 1994–1998, for Ireland.Least-squares linear regression analysis indicated a slight decreasing trend in precipitation concentrations for SO 42− (20%), NO 3− (13%) and H + (24%) and a slight increasing trend for NH 4+ (15%), over the period 1991–1998. 相似文献
5.
A year-long field study to characterize the ionic species in PM2.5 was carried out in Shanghai and Beijing, China, in 1999–2000. Weekly samples of PM2.5 were collected using a special low flow rate (0.4 l min −1) sampler. In Shanghai, SO 42− NO 3− and NH 4+ were the dominant ionic species, which accounted for 46%, 18% and 17% of the total mass of ions, respectively. Local SO 2 emissions were an important source of SO 42− in PM2.5 because the SO 42− concentration was correlated with the SO 2 concentration ( r=0.66). The relatively stable SO 42−/SO 2 mass ratio over a large range of temperatures suggests that gas-phase oxidation of SO 2 played a minor role in the formation of SO 42−. The sum of SO 42− and NO 3− was highly correlated with NH 4+ ( r=0.96), but insufficient ammonium was present to totally neutralize the aerosol. In Beijing, SO 42−, NO 3− and NH 4+ were also the dominant ionic species, constituting 44%, 25% and 16% of the total mass of water-soluble ions, respectively. Local SO 2 emissions were an important source of SO 42− in the winter since SO 42− was correlated with SO 2 ( r=0.83). The low-mass SO 42−/SO 2 ratio (0.27) during winter, which had low humidity, suggests that gas-phase oxidation of SO 2 was a major route of sulfate formation. In the summer, however, much higher mass ratios of SO 42−/SO 2 (5.6) were observed and were ascribed to in-cloud sulfate formation. The annual average ratio of NO 3−/SO 42− was 0.4 and 0.6 in Shanghai and in Beijing, respectively, suggesting that stationary emissions were still a dominant source in these two cities. 相似文献
6.
The concentrations of PM 2.5−10, PM 2.5 and associated water-soluble inorganic species (WSIS) were determined in a coastal site of the metropolitan region of Rio de Janeiro, Southeastern Brazil, from October 1998 to September 1999 ( n=50). Samples were dissolved in water and analyzed for major inorganic ions. The mean (± standard deviation; median) concentrations of PM 2.5−10 and PM 2.5 were, respectively, 26 (± 16; 21) μg m −3 and 17 (± 13; 14) μg m −3. Their mean concentrations were 1.7–1.8 times higher in dry season (May–October) than in rainy season (November–April). The WSIS comprised, respectively, 34% and 28% of the PM 2.5−10 and PM 2.5 masses. Chloride, Na + and Mg 2+ were the predominant ions in PM 2.5−10, indicating a significant influence of sea-salt aerosols. In PM 2.5, SO 42− (∼97% nss-SO 42−) and NH 4+ were the most abundant ions and their equivalent concentration ratio (SO 42−/NH 4+ ∼1.0) suggests that they were present as (NH 4) 2SO 4 particles. The mean concentration of (NH 4) 2SO 4 was 3.4 μg m −3. The mean equivalent PM 2.5 NO 3− concentration was eight times smaller than those of SO 42− and NH 4+. The PM 2.5 NO 3− concentration in dry season was three times higher than in rainy season, probably due to reaction of NaCl (sea salt) with HNO 3 as a result of higher levels of NO y during the dry season and/or reduced volatilization of NH 4NO 3 due to lower wintertime temperature. Chloride depletion was observed in both size ranges, although more pronouncely in PM 2.5. 相似文献
7.
The influences of different kinds of anthropogenic activities on rainwater chemistry in a tropical area were studied during one uninterrupted year at Piracicaba River Basin (Southeast Brazil). A total of 272 rainwater samples collected continuously from August 1997 to July 1998 at four different sites were analyzed for F −, CH 3COO −, HCOO −, MSA, Cl −, NO 2−, Br −, NO 3−, SO 42−, C 2O 42−, PO 43−, Na +, NH 4+, K +, Mg 2+, Ca 2+, DOC (dissolved organic carbon), DIC (dissolved inorganic carbon), pH and conductivity. The most abundant ion was H + and rain acidity was significant at all sampling sites (average pH of 4.4–4.5). The sources of this free acidity differ among sites and appear to be correlated to the different land-uses. The composition of rainwater appeared to be controlled mostly by three sources: soil dust, sugar cane burning and industrial emissions. 相似文献
8.
Ambient suspended particulate (PM 2.5, PM 2.5–10, TSP) was collected from June 1998 to February 2001 in Taichung, central Taiwan. In addition, the related water-soluble ionic species (Cl −, NO 3−, SO 42−, Na +, NH 4+, K +, Mg 2+, Ca 2+) and metallic species (Fe, Zn, Pb, Ni) were also analyzed in this study. The results showed that the concentrations of particulate mass are higher in the traffic site (CCRT) than the other sampling sites in this study. Also, the fine particle (PM 2.5) concentration is the dominant species of the total suspended particles in Taichung, central Taiwan. The dominant species for PM 2.5 are sulfate and ammonium at all sampling sites during the period of 1998–2001. The results of diurnal variation at THUC sampling site are also discussed in this study. Overall, acidic and secondary aerosol (Cl −, NO 3−, SO 42− and NH 4+) is a more serious air pollutant issue in southern and central Taiwan than at several sites around the world. Therefore, ambient suspended particulate monitoring in Taichung, central Taiwan will be continuing in our following study to provide more information for the government to formulate environmental strategy. 相似文献
9.
Precipitation samples over the Arabian Sea collected during Arabian Sea Monsoon Experiment (ARMEX) in 2002–2003 were examined for major water soluble components and acidity of aerosols during the period of winter and summer monsoon seasons. The pH of rain water was alkaline during summer monsoon and acidic during winter monsoon. Summer monsoon precipitation showed dominance of sea-salt components (∼90%) and significant amounts of non-sea salt (nss) Ca 2+ and SO 42−. Winter monsoon precipitation samples showed higher concentration of NO 3− and NH 4+ compared to that of summer monsoon, indicating more influence of anthropogenic sources. The rain water data is interpreted in terms of long-range transport and background pollution. In summer monsoon, air masses passing over the north African and Gulf continents which may be carrying nss components are advected towards the observational location. Also, prevailing strong southwesterly winds at surface level produced sea-salt aerosols which led to high sea-salt contribution in precipitation. While in winter monsoon, it was observed that, air masses coming from Asian region towards observational location carry more pollutants like NO 3−and nss SO 42− that acidify the precipitation. 相似文献
10.
The concentrations and characteristics of the major components in ambient fine particles in the urban city of Kaohsiung, Taiwan were measured and evaluated. PM 2.5 samples were collected using a dichotomous sampler from November 1998 to April 1999 and analyzed for water-soluble ion species using ion chromatography and for carbonaceous species using an elemental analyzer. It was found that SO 42−, NO 3−, and NH 4+ dominated the identifiable components, and occupied 42.2% and 90.0% of PM 2.5 mass and total dissolved ionic concentrations. Carbonaceous species (organic and elemental carbon) accounted for 20.8% of PM 2.5. The secondary aerosol formed through the NO 2/SO 2 gas-to-particle conversion was estimated based on the sulfur/nitrogen oxidation ratio (SOR/NOR), i.e., sulfate sulfur/nitrate nitrogen to total sulfur/total nitrogen. The average SOR and NOR values were 0.25 and 0.07 for PM 2.5. The high SOR and NOR values obtained in this study suggested that there existed a secondary formation of SO 42− from SO 2 along with NO 3− from NO 2 in the atmosphere. The secondary organic carbon formed through the volatile organic compound gas-to-particle conversion was estimated from the minimum ratio between organic and elemental carbon obtained in this study, and was found to constitute 40.0% of the total organic carbon for PM 2.5 (6.6% of the particle mass). The results obtained in this study suggest that the formation of secondary aerosols due to conversion from gaseous precursors is significant and important in urban locations. 相似文献
11.
Two-stage aerosol samples (PM 10–2.5 and PM 2.5) were collected at a coastal rural site located in the northeastern Mediterranean, between April 2001 and 2002. A total of 562 aerosol samples were analyzed for trace elements (Fe, Ti, Mn, Ca, V, Ni, Zn, Cr) and water-soluble ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl −, Br −, NO 3−, SO 42−, C 2O 42− and MS −:methane sulfonate). PM 10, crustal elements, sea salt aerosols and NO 3− were mainly associated with the coarse mode whereas non-sea salt (nss)SO 42−, C 2O 42−; MS −, NH 4+, Cr and Ni were found predominantly in the fine fraction. Concentrations of aerosol species exhibited orders of magnitude change from day to day and the aerosol chemical composition is heavily affected by dust events under the influence of airflow from North Africa. During the sampling period, 11 specific mineral dust events of duration varying from 1 day to a week have been identified and their influence on the chemical composition of aerosols has been studied in detail. Ionic balance analysis performed in the coarse and fine aerosol fractions indicated anion and cation deficiency due to CO 32− and H +, respectively. A relationship between nssSO 42− and NH 4+ denoted that sulfate particles were partially neutralized (70%) by ammonium. Excess-K/BC presented two distinct ratios for winter and summer, indicating two different sources: fossil fuel burning in winter and biomass burning in summer. 相似文献
12.
研究Fe/Cr6+比值和不同浓度的NO3-、Cl-和SO42-对金属铁去除Cr6+效果的影响.结果表明,金属铁对水中Cr6+有很好的还原去除效果;当金属铁的使用量为Cr6+量的1/2000时,铁对Cr6+的去除效果较差且易失去活性,而当金属铁的使用量为Cr6+量的8 000倍时,铁对Cr6+的去除效果较好且其活性的持续... 相似文献
13.
Cloud water investigations have been performed at the highest elevation of Central Germany in 1997. Results of extensive trace element measurements are presented. Besides conductivity, pH, liquid water content and major ions the data set includes 49 minor and trace elements. Estimation of crustal enrichment factors (EFs) provides an indication of the anthropogenic contributions to the cloud water concentrations. The variation of cloud composition with time has been illustrated for two selected events with different air mass origins. The chemical composition of the cloud condensation nuclei on which the droplets grow mainly determines the cloud water chemistry. For a cloud event in June 1997 the concentrations of the crustally derived elements Si, Al, Fe, Ti, Ce, La and Nd follow each other closely. The fact that SO 42−, NO 3− and NH 4+ are only moderately correlated with the particular pollutants with high enrichment factors such as Cd, Sb, Pb, Zn, Cu, As, Bi, Sn, Mo, Ni, Tl and V indicates that their source regions are more widespread. During an event in October 1997 the time trends for most minor and trace elements follow rather closely those for the major ions NH 4+, SO 42− and NO 3−. Back trajectories show that the transport from continental and marine European sources was the likely cause of the sample concentrations. EFs of trace elements in cloud water samples during the June and October event show a strong correlation with those obtained for urban particulate matter. Although both events are influenced by air masses of different origin, there is a good agreement between the EF signatures. 相似文献
14.
A goal of the acidic deposition control program in the United States has been to link emissions control policies, such as those mandated under Title IV of the US Clean Air Act Amendments (CAAA) of 1990, to improvements in air and water quality. Recently, several researchers have reported trends in the time series of pollutant data in an effort to evaluate the effectiveness of the CAAA in reducing the acidic deposition problem. It is well known that pollutant concentrations are highly influenced by meteorological and climatic variations. Also, spatial and temporal inhomogeneities in time series of pollutant concentrations, induced by differences in the data collection, reduction, and reporting practices, can significantly affect the trend estimates. We present a method to discern breaks or discontinuities in the time series of pollutants stemming from emission reductions in the presence of meteorological and climatological variability. Using data from a few sites, this paper illustrates that linear trend estimates of concentrations of SO 2, aerosol SO 42−, and precipitation-weighted SO 42− and NO 3− can be biased because of such complex features embedded in pollutant time series. 相似文献
15.
Air pollutants are associated with adverse respiratory effects mainly in susceptible groups. This study was designed to assess the impact of the ionic composition of particulate matter on asthmatic respiratory functions in São Paulo city. From May to July 2002, fine and coarse particulate matter fractions were collected and their respective chemical composition with respect to major ions (Na +, Mg 2+, K +, Ca 2+, NH 4+, Cl −, NO 3− and SO 42−) were determined in each aqueous-extract fraction. The results showed predominant concentrations of SO 42− (48.4%), NO 3− (19.6%) and NH 4+ (12.5%) in the fine fraction, whereas NO 3− (35.3%), SO 42− (29.1%), Ca 2+ (13.1%) and Cl − (12.5%) were the predominant species in the coarse fraction. The association between the chemical components of both fractions and the daily peak expiratory flow (PEF) measurements (morning and evening) of the 33 asthmatic individuals were assessed through a linear mixed-effects model. The results showed a significant negative correlation (decrease of PEF) between morning PEF and coarse chloride (3-day moving average) and between evening PEF and coarse Na + (3-day moving average), coarse Mg 2+ (3-day moving average) and coarse NH 4+ (2- and 3-day moving average). A significant negative correlation has also been observed between morning and evening PEF and Mg 2+ in the fine fraction. These results suggest that some particle chemical constituents may increase the responsiveness of airways and that coarse particles that deposit in the upper airways may be more relevant for asthmatic response and irritation. However, the results do not prove a clear causal relationship. 相似文献
16.
In this study, we present ∼1 yr (October 1998–September 1999) of 12-hour mean ammonia (NH 3), ammonium (NH 4+), hydrochloric acid (HCl), chloride (Cl −), nitrate (NO 3−), nitric acid (HNO 3), nitrous acid (HONO), sulfate (SO 42−), and sulfur dioxide (SO 2) concentrations measured at an agricultural site in North Carolina's Coastal Plain region. Mean gas concentrations were 0.46, 1.21, 0.54, 5.55, and 4.15 μg m −3 for HCl, HNO 3, HONO, NH 3, and SO 2, respectively. Mean aerosol concentrations were 1.44, 1.23, 0.08, and 3.37 μg m −3 for NH 4+, NO 3−, Cl −, and SO 42−, respectively. Ammonia, NH 4+, HNO 3, and SO 42− exhibit higher concentrations during the summer, while higher SO 2 concentrations occur during winter. A meteorology-based multivariate regression model using temperature, wind speed, and wind direction explains 76% of the variation in 12-hour mean NH 3 concentrations ( n=601). Ammonia concentration increases exponentially with temperature, which explains the majority of variation (54%) in 12-hour mean NH 3 concentrations. Dependence of NH 3 concentration on wind direction suggests a local source influence. Ammonia accounts for >70% of NH x (NH x=NH 3+NH 4+) during all seasons. Ammonium nitrate and sulfate aerosol formation does not appear to be NH 3 limited. Sulfate is primarily associated ammonium sulfate, rather than bisulfate, except during the winter when the ratio of NO 3−–NH 4+ is ∼0.66. The annual average NO 3−–NH 4+ ratio is ∼0.25. 相似文献
17.
Twelve hours integrated fine particles (PM 2.5) and 24-h average size-segregated particles were collected to investigate the chemical characteristics and to determine the size distribution of ionic species during October–December 1999 in three cities of different urban scale; Chongju, Kwangju, and Seoul, Korea. Concentrations of 5-min PM 2.5 black carbon (BC) and hourly criteria air pollutants (PM 10, CO, NO x, SO 2, and O 3) were also measured using the Aethalometer and ambient air monitoring system, respectively.Highest PM 2.5 mass concentrations at Chongju, Kwangju, and Seoul sites were 63.0, 77.9, and 143.7 μg m −3, respectively. For the time period when highest PM 2.5 mass occurred, BC level out of PM 2.5 chemical species was highest at both Chongju and Kwangju, and highest NO 3− (23.6 μg m −3) followed by BC (23.1 μg m −3) were observed at Seoul site, indicating that highest PM 2.5 pollution is closely associated with the traffic emissions. Strong relationships of Fe with BC and Zn at both Kwangju and Seoul sites support that the Fe and Zn measured there are originated partly from same source as BC, i.e. diesel traffics. However, it is suggested that the Fe measured at Chongju is most likely derived from dispersion of soil dust.The size distributions of SO 42−, NO 3−, and NH 4+ ionic species indicated similar unimodal distributions at all sampling sites. However, different unimodal patterns in the accumulation mode size range with a peak in the smaller size (0.28–0.53 μm, condensation mode) in both Kwangju and Seoul, and in the relatively larger size (0.53–1.0 μm, droplet mode) in Chongju, were found. The potassium ion under the study sites dominates in the fine mode, and its size distribution showed unimodal character with a maximum in the size range 0.56–1.0 μm. 相似文献
18.
Concentrations of major ions, SO 42−, NO 3−, Cl −, H +, Ca 2+, K +, Mg 2+, Ca 2+ and conductivity were measured in approximately 300 daily, wet-only rain samples collected at a permanent rural station between 1993 and 1998. Concentrations of anthropogenic ions NH 4+, SO 42− and NO 3− were among the highest values reported in whole EMEP network, suggesting that the Anatolian plateau is under strong influence of distant emission sources. Although transport of pollutants have significant influence on the chemical composition of precipitation, average pH of the rainwater is 6.2 due to extensive neutralization of acidity. Approximately 95% of the acidity in collected samples is neutralized, particularly in summer season. The neutralizing agents are primarily CaCO 3 and NH 3. Concentrations of crustal ions are higher in summer season due to enhanced resuspension of soil particles from dry surface soil. Concentrations of anthropogenic ions SO 42− and NO 3− do not change significantly between summer and winter due to higher intensity of rains in summer season. Although concentrations of ions measured in this study is among the highest reported in EMEP network, wet deposition fluxes are low compared to flux values reported for similar sites in Europe, due to low annual precipitation in the Anatolia. Wet deposition fluxes of all measured parameters are highly episodic. Source regions affecting chemical composition precipitation in the Central Anatolia is investigated using trajectory statistics. 相似文献
19.
Agricultural waste burning is a widespread practice throughout the world but there is little information about its pollutant impact. This paper deals with a preliminary study of the pollution observed in Vitoria (Northern Spain) caused by cereal waste burning. The mean hourly flux of pollutants produced by cereal waste burning fires can reach values of 1.4 kt of CO 2, 13 t of TPM and 3 t of NO x in the area around Vitoria. Measurements obtained in the area of emission and inside fire plumes show high ratios (NO 2/NO x) indicating that nitrogen oxides emitted by the source undergo a rapid transformation in the same area of emission. Results relating to aerosol composition collected in Vitoria during burning periods show an increase in the concentration of K +, NO 3− and Cl − ions, that are inter-correlated. The modification of the ionic composition of aerosols also affects the chemistry of the rain collected in Vitoria. During the burning period, it is particularly noticeable that anthropogenic pollution (usually identifiable by the correlation between SO 42− and NO 3− concentrations) disappears, indicating the existence of an independent source of NO 3− not linked to the SO 42− source. Similar results were deduced studying BAPMON data collected in Spain during cereal waste burning. Finally, we note that ozone concentration measured at Vitoria is not affected by the pollution generated by the burning fires. 相似文献
20.
Long-range transport of mineral dust such as Yellow sand (YS) is not restricted to the springtime periods in Northeast Asia. A YS phenomenon was observed during 25–27 January 1999, which was a remarkably distinctive episode in the occurrence time and intensity that had ever observed in the wintertime in Korea. This YS event was traced to be originated from the arid region of central and eastern Asia; the Gobi desert and Loess plateau. The traveling speed of the dust storm was found to be about 70 km h −1 with it's horizontal size of larger than the whole Korean peninsula during this episode. Aerosol mass loadings changed by an order of magnitude within a few hours. The dominant ion components were SO 42−, NO 3−, Ca 2+ and Na + during the passage of YS. The mode diameter of these compounds of YS was around 4 μm, compared to 0.4–0.9 μm after the passage of YS. SO 42− and NO 3− concentrations were found to be well correlated with Ca 2+ concentration in the coarse mode during the YS event, whereas they were well correlated with NH 4+ concentration during the non-YS period, indicating a significant amount of SO 42− and NO 3− formations on the Ca 2+-rich coarse aerosol during the long-range transport of YS. 相似文献
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