11月3日，最新出版的國(guó)際環(huán)境學(xué)科重要期刊——《環(huán)境監(jiān)測(cè)》（Journal of Environmental Monitoring）雜志在線發(fā)表了復(fù)旦大學(xué)環(huán)境科學(xué)與工程系陳建民教授領(lǐng)銜的課題組以李想博士為第一作者所作的有關(guān)霧污染及污染物痕量檢測(cè)方面的最新成果,。該文同時(shí)被選為了雜志當(dāng)期的封面重點(diǎn)推薦論文之一（J. Environ. Monit., 2011, 13, 2988）,。
這篇題為《霧-雨事件中多環(huán)芳烴的污染特征（Characterization of polycyclic aromatic hydrocarbons in fog–rain events）》的文章是陳建民教授課題組,，經(jīng)過近年來的深入研究，在霧化學(xué)及有機(jī)污染物分布機(jī)理方面取得的實(shí)質(zhì)性研究成果,。
霧,，又稱為接近地面的云，是近地面空氣達(dá)到飽和時(shí)水汽在氣溶膠粒子上凝結(jié)(或凝華) 為水滴(或冰晶)而使能見距離降低到1000 m以內(nèi)的天氣現(xiàn)象,。濃霧造成的低能見度對(duì)交通運(yùn)輸事業(yè)危害極大,，尤其是對(duì)航空、海運(yùn),、河運(yùn)和高速公路交通具有極大的危害性,。據(jù)統(tǒng)計(jì)，國(guó)內(nèi)外航班不能正常飛行的79%是因霧的緣故,；因大霧等惡劣天氣造成的交通事故約占事故總數(shù)的1/4,。霧常發(fā)生在逆溫較強(qiáng)的時(shí)段，受逆溫層的阻擋,，近地面的污染物不易擴(kuò)散,。在城市高污染條件下發(fā)生的霧，污染物溶于霧水中,，更加劇了污染程度,，其污染成分會(huì)灼傷植物葉莖、污損橋梁,、建筑和雕塑,，更會(huì)導(dǎo)致人畜各種呼吸道疾病，對(duì)人體健康構(gòu)成威脅,。由于傳輸作用,，污染物上升到大氣邊界層，污染高山區(qū)域,，影響云霧化學(xué)組成,，對(duì)當(dāng)?shù)卮嗳醯纳鷳B(tài)系統(tǒng)和區(qū)域氣候變化產(chǎn)生重大影響。濃霧已成為影響經(jīng)濟(jì)和社會(huì)發(fā)展及人民健康的重要災(zāi)害性天氣之一,。至今,，有關(guān)霧化學(xué)及其有機(jī)污染貢獻(xiàn)方面，一直缺少定量化的研究方法,。
陳建民教授課題組通過自行設(shè)計(jì)的霧水收集器對(duì)上海地區(qū)的霧水進(jìn)行了收集,，運(yùn)用霧監(jiān)測(cè)儀對(duì)霧過程進(jìn)行了全程觀測(cè)。通過固相微萃取技術(shù)對(duì)霧水中多環(huán)芳烴等有機(jī)物污染物進(jìn)行富集提取,，氣相色譜-質(zhì)譜聯(lián)用儀定性定量分析,，得出了多環(huán)芳烴等有機(jī)物污染物在霧過程中的分布規(guī)律。上海市區(qū)采集到的霧水,，大多顏色較深,，存在污染,。霧水中可檢測(cè)到多種致癌致畸物-多環(huán)芳烴，其總量大概在0.03 ~ 6.67 μg L-1（微克/升）范圍內(nèi),，該濃度值與國(guó)內(nèi)外其他地區(qū)相比偏高,。同時(shí)，萘,、蒽,、菲等化合物占霧水中多環(huán)芳烴總量的80%左右。源解析表明上海大霧中的多環(huán)芳烴多來自本地化石燃料的燃燒,。上海霧水pH值介于弱酸性（pH,，4.68）和弱堿性（pH，6.58）之間,，電導(dǎo)率平均值約為1270 μS/cm,，與其它地方相比偏高。霧水中還含有大量的銨離子NH4+（5308 μN） ,、鈣離子Ca2+ ( 1828 μN) ,、 硫酸根SO42- (4378 μN)、硝酸根NO3- (2341 μN)等無機(jī)離子,。
同時(shí),，陳建民課題組還針對(duì)霧-雨過程進(jìn)行了深入分析，發(fā)現(xiàn)霧雨沉降作用確實(shí)能降低空氣中的污染物濃度,，但是由于上海汽車尾氣和工業(yè)廢氣的排放量大,，加之起霧或下雨的時(shí)候空氣濕度大，加之大氣層較為穩(wěn)定,，水平對(duì)流和垂直對(duì)流都比較弱,，這種情況會(huì)導(dǎo)致污染物在空氣中短時(shí)間內(nèi)大量聚集，污染加重,，而且極易演變成災(zāi)害性霧霾天氣,。結(jié)果表明，大霧中致癌物多環(huán)芳烴雨前雨后的濃度相差近500倍,。另外,，研究還對(duì)霧過程中的氣溶膠顆粒物的粒徑分布特征，粒徑成長(zhǎng)特性進(jìn)行了分析,。
多年來，陳建民教授領(lǐng)銜的課題組,，一直對(duì)大氣污染物進(jìn)行了的長(zhǎng)期的跟蹤研究,，他們相關(guān)的霧水中污染物含量研究成果還發(fā)表在大氣環(huán)境領(lǐng)域國(guó)際頂尖雜志《Atmospheric Environment》（2011） (《大氣環(huán)境》雜志)等學(xué)術(shù)期刊上。
《Journal of Environmental Monitoring》是英國(guó)皇家化學(xué)學(xué)會(huì)主辦的重要環(huán)境類雜志,。該成果正式發(fā)表,，定量揭示了霧水中多環(huán)芳烴等有機(jī)污染物分布規(guī)律及源解析,，進(jìn)一步提升了我國(guó)在霧化學(xué)領(lǐng)域的學(xué)術(shù)地位。同時(shí),，為我國(guó)控制化石燃料及汽車尾氣排放的發(fā)展戰(zhàn)略,，以及降低大霧帶來的危害提供了科學(xué)依據(jù)。(生物谷 Bioon.com)
doi:10.1039/C1EM10543D
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Characterization of polycyclic aromatic hydrocarbons in fog–rain events
Xiang Li, Pengfei Li, Lili Yan, Jianmin Chen, Tiantao Cheng and Shifen Xu
Atmospheric polycyclic aromatic hydrocarbons (PAHs) mainly originate from incomplete combustion or pyrolysis of materials containing carbon and hydrogen. They exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). Current studies in atmospheric PAHs are predominantly focused on fog and rainwater samples. Some sampling difficulties are associated with fog samples. This study presented the first observation of the characteristics of PAHs in fog samples using a solid phase microextraction (SPME) technique. Eighteen fog samples were collected during ten fog events from March to December 2009 in the Shanghai area. PAHs were extracted by SPME and analyzed by gas chromatography-mass spectrometry (GC-MS). As the compounds were partially soluble in water, with solubility decreasing with increasing molecular weight, low molecular weight (LMW) PAH compounds were universally found in the fog water samples. Naphthalene (NaP), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flo) were dominant compounds in fog water. The total PAH concentration in fog water ranged from 0.03 to 6.67 μg L−1 (mean of 1.06 μg L−1), and was much higher in winter than in summer. The concentration of PAHs in fog or rain water decreased after undergoing a pre-rain or pre-fog wash. The average concentration of PAHs was higher in fog than in rain. Diagnostic ratio analysis suggested that petroleum and combustion were the dominant contributors to PAHs in urban Shanghai. Backward trajectories were calculated to determine the origin of the air masses, showing that air masses were mostly from the northeast territory.
