【摘要】：伴隨著經(jīng)濟(jì)高速發(fā)展,近年來西安城區(qū)近地面O3濃度明顯升高,作為臭氧和光化學(xué)煙霧的重要前體物,VOCs的污染問題已經(jīng)引起了廣泛關(guān)注。本文基于2012年9月至2013年8月在西安市大氣環(huán)境綜合實(shí)驗(yàn)室觀測空氣中56個(gè)VOCs物種的濃度數(shù)據(jù),開展了西安城區(qū)VOCs污染特征、化學(xué)反應(yīng)活性和健康風(fēng)險(xiǎn)評價(jià)研究。研究結(jié)果表明,空氣中VOCs的小時(shí)平均體積分?jǐn)?shù)為73.78×10-9,其中烷烴、烯烴、芳香烴、炔烴的小時(shí)平均濃度分別為40.38×10-9、23.86×10-9、8.31×10-9、1.23×10-9。對西安空氣中VOCs貢獻(xiàn)率最大的是烷烴,占54.73%,其次是烯烴、芳香烴和炔烴,分別占總VOCs的32.34%、11.26%和1.67%,其中C2~C5的烷烴和乙烯、丙烯等是體積濃度較大的主要物種;空氣中VOCs的月均濃度呈單峰分布,其中1、2月份VOCs的平均濃度在全年中較高,7、8月份平均濃度較低;空氣中VOCs的關(guān)鍵組分在不同月份和季節(jié)中基本相同,這說明西安市城區(qū)空氣中各VOCs物種的來源比較固定�？俈OCs、烷烴、烯烴和芳香烴的日變化規(guī)律基本一致,在早中晚交通高峰時(shí)期為較高值,說明機(jī)動(dòng)車尾氣排放和燃料燃燒對西安城區(qū)空氣中VOCs的影響較大�；瘜W(xué)反應(yīng)活性計(jì)算結(jié)果表明,西安VOCs與OFP的相關(guān)性較好,最大增量反應(yīng)活性為3.6615mol·mol-1,化學(xué)反應(yīng)活性較強(qiáng)。對OFP貢獻(xiàn)最大的是烯烴,其次是烷烴和芳香烴,其貢獻(xiàn)率分別為77.47%、12.75%和9.53%;西安城區(qū)空氣VOCs中的關(guān)鍵活性組分是C2~C5的烯烴和甲苯、間/對二甲苯等芳香烴類物質(zhì)。利用USEPA健康風(fēng)險(xiǎn)評價(jià)模型對西安空氣中6種苯系物進(jìn)行健康風(fēng)險(xiǎn)評價(jià)研究,結(jié)果顯示西安空氣中的VOCs對人體存在一定的健康風(fēng)險(xiǎn)。非致癌風(fēng)險(xiǎn)危害指數(shù)為2.44E-01,苯的致癌風(fēng)險(xiǎn)值為4.25E-05,表明苯系物對研究區(qū)人群的非致癌風(fēng)險(xiǎn)處在安全范圍之內(nèi);苯對研究區(qū)居民身體健康存在潛在的致癌風(fēng)險(xiǎn)。
[Abstract]:With the rapid development of economy, the concentration of O _ 3 near the surface of Xi'an City has increased obviously in recent years. As an important precursor of ozone and photochemical smog, the pollution of VOCs has been paid more and more attention. Based on the concentration data of 56 VOCs species observed in Xi'an Atmospheric Environment Laboratory from September 2012 to August 2013, the characteristics of VOCs pollution, chemical reaction activity and health risk assessment in Xi'an urban area were studied. The results showed that the hourly average volume fraction of VOCs in air was 73.78 脳 10 脳 10 9, and the hourly average concentrations of alkanes, alkenes, aromatic hydrocarbons and alkynes were 40.38 脳 10 ~ (9), 23.86 脳 10 ~ (9), 8.31 脳 10 ~ (9) and 1.23 脳 10 ~ (- 9), respectively. The largest contribution to VOCs in Xi'an was alkanes, accounting for 54.73%, followed by olefins, aromatic hydrocarbons and alkynes, accounting for 32.34%, 11.26% and 1.67% of total VOCs, respectively. Among them, alkanes and ethylene of C2~C5, Propylene is the main species with high volume concentration. The monthly mean concentration of VOCs in the air showed a single peak distribution, in which the average concentration of VOCs in January and February was higher in the whole year, and lower in July and August. The key components of VOCs in the air were basically the same in different months and seasons, which indicated that the sources of VOCs species in the air of Xi'an city were relatively fixed. The diurnal variation of total VOCs, alkanes, olefins and aromatic hydrocarbons is basically the same, with a high value in the peak period of early, middle and late traffic, indicating that the exhaust emissions of motor vehicles and fuel combustion have a great effect on the VOCs in the air of Xi'an urban area. The results of chemical reaction activity calculation show that Xi'an VOCs has a good correlation with OFP, the maximum incremental reaction activity is 3.6615mol 路mol-1, and the chemical reaction activity is strong. The largest contribution to OFP was olefins, followed by alkanes and aromatics, which contributed 77.47%, 12.75% and 9.53%, respectively. The key active components of VOCs in urban air of Xi'an are olefins and toluene, m / p xylene and other aromatic hydrocarbons of C2~C5. The USEPA health risk assessment model was used to evaluate the health risks of six benzene derivatives in Xi'an air. The results showed that VOCs in Xi'an air had certain health risks to human body. The non-carcinogenic risk hazard index is 2.44E 路01and the carcinogenic risk value of benzene is 4.25E 路055.This indicates that the non-carcinogenic risk of benzene to the population in the study area is within the safe range, and benzene has potential carcinogenic risk to the health of residents in the study area.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X511

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