曹軍驥，李建軍

（1.中國科學(xué)院地球環(huán)境研究所，西安 710061；2.中國科學(xué)院氣溶膠化學(xué)與物理重點實驗室，西安 710061；3. 黃土與第四紀(jì)地質(zhì)國家重點實驗室，西安 710061）

二次有機(jī)氣溶膠的形成及其毒理效應(yīng)

曹軍驥1,2，李建軍1,3

（1.中國科學(xué)院地球環(huán)境研究所，西安 710061；2.中國科學(xué)院氣溶膠化學(xué)與物理重點實驗室，西安 710061；3. 黃土與第四紀(jì)地質(zhì)國家重點實驗室，西安 710061）

有機(jī)物是大氣氣溶膠中非常重要的化學(xué)組分，對我國空氣污染及灰霾事件發(fā)生具有顯著的貢獻(xiàn)，是當(dāng)前大氣化學(xué)研究的最前沿課題之一。有機(jī)氣溶膠中包含大量有毒物質(zhì)（如多環(huán)芳香烴、多氯聯(lián)苯及有機(jī)胺類等），直接危害人體健康。目前氣溶膠中有機(jī)組分的體內(nèi)/體外生物毒性研究多集中于污染源直接排放的一次顆粒物，對于大氣中二次有機(jī)氣溶膠的形成和毒性效應(yīng)的關(guān)注很少。本文以多環(huán)芳烴、有機(jī)胺及自然源萜烯類揮發(fā)性有機(jī)物為例，簡要綜述了大氣中二次有機(jī)氣溶膠的形成及其生物毒性效應(yīng)，重點關(guān)注這些二次有機(jī)氣溶膠的形成對母體有機(jī)組分生物毒性的增強(qiáng)作用，以增進(jìn)對大氣氣溶膠污染的健康危害認(rèn)識。

二次有機(jī)氣溶膠；毒性；多環(huán)芳烴；有機(jī)胺；萜烯

近年來隨著經(jīng)濟(jì)社會的快速發(fā)展，污染物的大量排放使得我國大部分城市遭受了嚴(yán)重的空氣污染，重霾天氣時有發(fā)生（Liu et al，2013；Xu et al，2013；Huang et al，2014；Li and Zhang， 2014）。空氣中懸浮的顆粒物（Particulate matter，PM）亦稱大氣氣溶膠（Aerosol），由不同類型化學(xué)組分組成（戴文婷等，2011；孫濤等，2013），不僅對氣候、環(huán)境具有重要的影響，且能對人體健康產(chǎn)生不同程度的危害（Davidson et al，2005；Ito et al，2006；Schlesinger，2007；曹軍驥，2014）。與可吸入顆粒物（PM10，空氣動力學(xué)當(dāng)量直徑小于等于10 μm的顆粒物）相比，細(xì)顆粒物（PM2.5，空氣動力學(xué)當(dāng)量直徑小于等于2.5 μm的顆粒物）對人體健康的危害更大（曹軍驥，2012；Schwartz and Neas，2000），因為其粒徑更小，細(xì)顆粒物在大氣中的停留時間增加，比表面積大易吸附金屬和毒性有機(jī)物，且通過呼吸進(jìn)入人體肺部的能力更強(qiáng)（PM1甚至可達(dá)肺泡）（Seagrave et al，2006；Happo et al，2008；Boldo et al，2011；曹軍驥，2014）。大量流行病學(xué)研究表明，個體細(xì)顆粒物及其化學(xué)組分暴露與呼吸道疾病、心血管疾病、肺癌等疾病發(fā)病率及死亡率的增加存在不同程度的顯著相關(guān)關(guān)系（Pope et al，2002）。最新研究表明，全球范圍內(nèi)室外空氣污染每年會造成330萬人的過早死亡，其中主要分布在亞洲地區(qū)（Lelieveld et al，2016）。同時，Thurston et al（2016）也證實空氣中的細(xì)顆粒物會提高死亡風(fēng)險系數(shù)。

由于顆粒物的微尺度效應(yīng)、比表面積和化學(xué)構(gòu)成的差異，其所產(chǎn)生的生物效應(yīng)也不同。早在20世紀(jì)后期，國內(nèi)外學(xué)者就已經(jīng)發(fā)現(xiàn)大氣顆粒物中的特定化學(xué)組分對人體健康具有一定的危害性。例如除顆粒物本身對人體呼吸道系統(tǒng)的產(chǎn)生危害之外，多環(huán)芳烴（PAHs）類有機(jī)物的存在對人體具有致畸、致癌和致突變毒性效應(yīng)（Ohura et al，2004；Srogi，2007）。而大氣顆粒物中的鉛、砷、汞等重金屬組分可通過生態(tài)系統(tǒng)的富集作用影響到人體健康（Utsunomiya et al，2004）。后來的流行病學(xué)研究更證明了大氣顆粒物中的不同化學(xué)組分對人體健康的影響存在一定的差異。Cao et al（2012）對西安長達(dá)5年的研究數(shù)據(jù)發(fā)現(xiàn)，PM2.5中OC、EC、、、Cl-、Cl和Ni對全病因死亡率、心血管疾病死亡率和呼吸系統(tǒng)死亡率有顯著影響。其中全病因死亡率和心血管疾病死亡率與的關(guān)系高于其與PM2.5質(zhì)量濃度的關(guān)系。此外，研究認(rèn)為顆粒物的人體健康造成危害的主要作用機(jī)制是大氣顆粒物誘導(dǎo)的氧化應(yīng)激和炎癥反應(yīng)（Pavagadhi et al，2013）。PM2.5刺激肺部中性粒細(xì)胞聚集、腫瘤壞死因子釋放、氧化損傷等毒性效應(yīng)是導(dǎo)致呼吸和心血管系統(tǒng)疾病的主要因素之一。因此大氣顆粒物誘導(dǎo)的活性氧簇的生成和炎癥指標(biāo)的變化是研究關(guān)注的焦點，可以幫助理解顆粒物對人體健康危害的機(jī)理（Spector，2000；Seifried et al，2007）。

顆粒物及污染氣體會在大氣環(huán)境中與O3、OH自由基及NOx等氧化劑發(fā)生光化學(xué)氧化反應(yīng)形成二次粒子，該氧化過程對大氣顆粒物的健康及毒理效應(yīng)具有十分重要的影響。Verma et al（2015）結(jié)合氣溶膠質(zhì)譜儀（Aerosol mass spectrometer，AMS）和二硫蘇糖醇（Dithiothreitol，DTT）試驗法表征活性氧簇（Reactive oxygen species，ROS）的研究表明，PM2.5的水溶性化學(xué)組分中，有機(jī)物對ROS的貢獻(xiàn)更甚于金屬物質(zhì)；其中更氧化的含氧有機(jī)氣溶膠（More-oxidized oxygenated organic aerosol，MO-OOA）與生物質(zhì)燃燒有機(jī)氣溶膠（Biomass burning organic aerosol，BBOA）的貢獻(xiàn)更甚于其他有機(jī)組分。Liu et al（2014）采用正交矩陣因子分解法（Positive matrix factorization，PMF）對北京市PM2.5的來源進(jìn)行了解析，并分析了不同來源與ROS的關(guān)系，結(jié)果表明二次源是北京市PM2.5的氧化潛能及炎癥效應(yīng)的重要貢獻(xiàn)因子。然而，目前國內(nèi)外對二次有機(jī)氣溶膠在大氣中形成及其毒理效應(yīng)的研究很少。本文主要從分子角度出發(fā)，簡述幾種典型化合物在大氣氧化過程中發(fā)生的毒理性質(zhì)改變，闡明大氣中二次有機(jī)氣溶膠的形成對人體健康的影響。

1 多環(huán)芳烴的氧化

多環(huán)芳烴（Polycyclic aromatic hydrocarbons，PAHs）類化合物對人體具有顯著的致癌、致畸及致突變效應(yīng)，是氣溶膠中最受關(guān)注的有機(jī)組分之一。流行病學(xué)研究表明暴露于含有PAHs的焦?fàn)t、廚房和香煙煙氣等的人群患有肺癌的幾率更高。PAHs通過生物轉(zhuǎn)化形成強(qiáng)活性中間體附著在細(xì)胞大分子中，從而激活了其致突變性和致癌活性（特別是DNA）。大量關(guān)于單體PAHs代謝物對動物致瘤性的系統(tǒng)研究表明，鄰位或所謂的靶-區(qū)域的二醇環(huán)氧化物是PAHs衍生物最終誘變和致癌的原因之一（Jernstrom et al，1984；Jernstrom and Graslund，1994）。這些二醇的環(huán)氧化物很容易被環(huán)氧化物開環(huán)轉(zhuǎn)換成帶電碳離子，成為烷基并共價結(jié)合到DNA堿基和蛋白質(zhì)的親核點位。PAHs具有脂溶性，因而能夠吸附在哺乳動物的肺、腸和皮膚中。Weyand 和 Bevan（1986）對喂食有PAHs微晶體與灌注PAHs溶液的雌性大鼠的肺保留時間進(jìn)行研究，結(jié)果表明PAHs不能迅速從呼吸道中清除。根據(jù)PAHs對人體和動物的致癌風(fēng)險研究，美國國家環(huán)保局在國家大氣排放清單（NAEI）中規(guī)定了16種優(yōu)先控制PAHs（USEPA，1997）。由于其健康風(fēng)險，很多國家都設(shè)立了空氣質(zhì)量監(jiān)測網(wǎng)絡(luò)來監(jiān)測環(huán)境空氣中PAHs的含量。例如日本環(huán)保署自1997年開始了PAHs的檢測（Japan Environmental Agency，1997）。

PAHs在大氣中的一系列化學(xué)反應(yīng)，如氧化和硝化反應(yīng)，可以改變一次排放的母體PAHs的性質(zhì)及毒性（Atkinson and Arey，1994；沈國鋒和王格慧，2012）。含氧多環(huán)芳烴（Oxygenated-PAHs，OPAHs）含有一個或多個羰基，其毒性比相應(yīng)的母體PAHs毒性更大。Wang et al（2011）發(fā)現(xiàn)PM2.5中的OPAHs對艾姆斯沙門氏菌直接作用的誘變性與致突變性比PAHs高出200%。OPAHs在不同類型的顆粒物中，如空氣、柴油和汽油尾氣顆粒中都有檢出（Jakober et al，2006；Jakober et al，2007）。OPAHs也通常在PAHs大氣光化學(xué)反應(yīng)過程中形成（Wang et al，2011）。OPAHs的強(qiáng)毒性已引起越來越多的關(guān)注。Wei et al（2010）研究了PM2.5中蒽醌（Anthraquinone，AQ）和24種PAHs的氧化應(yīng)激反應(yīng)，發(fā)現(xiàn)交通站的兩名保安人員體內(nèi)蒽醌含量和氧化應(yīng)激的增加之間有很強(qiáng)的相關(guān)性。蒽醌已被國際癌癥研究機(jī)構(gòu)列為對人類可能的致癌物質(zhì)（IARC，2013）。Ringuet et al（2012）發(fā)現(xiàn)OPAHs對人體健康的不利影響可能與其在PM2.5中的占比有關(guān)。含氮多環(huán)芳烴（Nitrated-PAHs，NPAHs）由于其顯著毒性已備受關(guān)注。在人體細(xì)胞和細(xì)菌菌株為基礎(chǔ)的分析試驗中，大多數(shù)NPAHs比其母體PAHs表現(xiàn)出更高的致突變性和致癌性（Durant et al，1996；Yang et al，2010）。大氣中NPAHs的主要來源分為兩種：直接排放（如從柴油發(fā)動機(jī)）及通過大氣反應(yīng)二次生成（Phousongphouang and Arey，2003；Reisen and Arey，2005）。大氣中PAHs的轉(zhuǎn)換可以通過與OH或NO3自由基和NO2的氣態(tài)反應(yīng)，或通過與NO2的多相反應(yīng)轉(zhuǎn)化為NPAHs（Atkinson and Arey，1994；Zhou and Wenger，2013；Roueintan et al，2014）。以皮膚損害（包括皮膚癌）為例，多環(huán)芳烴及其光氧化生成的OPAHs、NPAHs及其他產(chǎn)物的健康毒性機(jī)制如圖1所示。多環(huán)芳烴在光照條件下氧化生成OPAHs、NPAHs及鹵代多環(huán)芳烴等產(chǎn)物，母體PAHs及其產(chǎn)物繼續(xù)在光照條件下生成單線態(tài)氧（1O2）及過氧自由基離子等ROS產(chǎn)物，或與其他溶劑反應(yīng)或脫去氫原子生成烷氧自由基。生成的ROS及烷氧自由基均具有顯著的脂質(zhì)過氧化作用及DNA損傷，對人體健康具有一定的毒性作用（Fu et al，2012）。

圖1 多環(huán)芳烴及其光氧化產(chǎn)物對皮膚損傷的生物毒性機(jī)制（Fu et al，2012）Fig.1 Bio-toxicity mechanism of PAHs and their photochemical products on skin damage (Fu et al, 2012)

2 有機(jī)胺的形成及氧化

有機(jī)胺（Amines）是氨分子中氫原子被烷基或芳基取代而生成的衍生物。研究表明，即使在氨存在的情況下，只有氨濃度水平14%—23%的胺也具有較強(qiáng)的堿性（Sorooshian et al，2008）。Chang and Novakov（1975）認(rèn)為有機(jī)胺的存在是由于縮合反應(yīng)，但Dod et al（1984）指出它們可能是高溫下煙灰粒子表面上的碳-氧復(fù)合物與NH3或NO反應(yīng)生成的。Qiu and Zhang（2013）總結(jié)了目前大氣中氣態(tài)前體物通過非均相氧化生成有機(jī)胺的主要反應(yīng)機(jī)制，包括酸催化反應(yīng)、自由基氧化等途徑（反應(yīng)式1—11）。

烷基胺（Alkyl-amine），如甲胺、二甲胺、乙胺、二乙胺、丙胺、丁胺和二丁胺等，其氣味惡臭、毒性較強(qiáng)，是重要的大氣污染物，被廣泛應(yīng)用于化學(xué)和制藥工業(yè)中作為中間物（Pan et al，1997；Namiesnik et al，2003）。烷基胺能夠刺激皮膚、粘膜和呼吸道并引起過敏反應(yīng)。芳香胺（Aromaticamine），如嗎啉、苯胺、氯代苯胺、哌嗪、萘胺、氨基苯酚、甲苯二胺和4-氨基聯(lián)苯具有生物活性，是具有毒性和致癌性的環(huán)境污染物，被廣泛地應(yīng)用于工業(yè)制染料、化妝品、藥品、橡膠、紡織、農(nóng)用化學(xué)品等工業(yè)中，并在許多化學(xué)合成中作為試劑的中間體（Palmiotto et al，2001；Zhu and Aikawa，2004）。汽車尾氣、木材和橡膠的燃燒、煙草煙霧和烤肉、魚的過程中也會釋放出芳香胺（Ge et al，2011）。流行病學(xué)研究表明，芳香胺和患癌癥風(fēng)險之間有一定相關(guān)性。芳香胺可以被N-乙酰轉(zhuǎn)移酶催化形成代謝產(chǎn)物，并最終產(chǎn)生其他的致癌化學(xué)物質(zhì)。越來越多的證據(jù)表明，吸煙者中多發(fā)的膀胱癌主要是由香煙煙霧中的芳香胺所引起的。

有機(jī)胺也可與大氣中的氧化劑，如O3和NOx反應(yīng)進(jìn)一步生成新的二次有機(jī)氣溶膠（Murphy et al，2007）。有機(jī)酸如蘋果酸（Barsanti and Pankow，2006）或順式十八碳烯酸（Zahardis et al，2008）與有機(jī)胺反應(yīng)，得到氮原子連接于?；≧—C ═ O）的酰胺。烷基胺可與亞硝酸鹽反應(yīng)，形成致癌的亞硝胺 （Nitrosamine）（Skarping et al，1986；Santagati et al，2002）。很多種致癌的亞硝胺如二甲基亞硝胺是由OH自由基與二甲胺（Lindley et al，1979；Grosjean，1991）、二甲肼（Ge et al，2011）和三甲胺等反應(yīng)生成的（Pitts et al，1978）。這些非均相反應(yīng)產(chǎn)生的二次有機(jī)胺類污染物可以改變氣溶膠的毒性效應(yīng)。

3 萜烯類VOCs氧化

大氣中萜烯類揮發(fā)性有機(jī)物（Volatile organic compounds，VOCs）包括異戊二烯、蒎烯、檸檬烯及沉香醇等物質(zhì)，是一類非常重要的是自然源（如樹木、草類）VOCs產(chǎn)物，其在大氣的含量僅次于非甲烷烴（Non-methane hydrocarbon，NMHC）。研究表明，全球自然源排放的VOCs含量約比人為源VOCs高一個數(shù)量級（Guenther et al，2006）。高濃度的自然源VOCs排放能促進(jìn)大氣中二次有機(jī)氣溶膠的生成，從而通過吸收或散射太陽光的直接效應(yīng)或作為云凝結(jié)核（Cloud condensation nuclei，CCN）的間接效應(yīng)影響大氣輻射強(qiáng)迫（Turpin and Huntzicker，1995；Kanakidou et al，2005；Kawamura and Yasui，2005）。室內(nèi)自然源萜烯類VOCs氧化引起的健康效應(yīng)備受關(guān)注，因為室內(nèi)家具及服飾等消費(fèi)品均可排放出大量的萜烯類揮發(fā)性有機(jī)物，并能與空氣中的O3及氮氧化物等氧化劑發(fā)生氧化反應(yīng)，生成二次有機(jī)氣溶膠，影響室內(nèi)人體的健康。

Chen et al（2011）通過煙霧箱實驗證明了α-蒎烯（α-pinene）、沉香醇（Linalool）及檸檬烯（Limonene）等自然源揮發(fā)性有機(jī)物（Biogenic volatile organic compounds，BVOCs）與臭氧發(fā)生反應(yīng)形成的二次有機(jī)氣溶膠促進(jìn)了大氣顆粒誘發(fā)細(xì)胞活性氧簇的能力，因此可能對人體產(chǎn)生危害。如表1所示，多數(shù)體內(nèi)及體外實驗均證實暴露于萜烯類VOCs及一定氧化劑（O3或NOx）條件下，其SOA的生成會增加細(xì)胞的炎癥反應(yīng)或者降低細(xì)胞活性。如Doyle et al（2004）使用煙霧箱中將A549及人體支氣管上皮細(xì)胞暴露于1,4-丁二烯及異戊二烯等自然源VOCs，并往煙霧箱中引入太陽光和NO促使VOCs等發(fā)生光化學(xué)氧化反應(yīng)。其中異戊二烯的主要產(chǎn)物包括異丁烯醛、甲基乙烯醛等物質(zhì)。盡管異戊二烯本身也對具有一定的毒性，但其大氣氧化產(chǎn)物的細(xì)胞毒性明顯增強(qiáng)。Jang et al（2006）通過體外實驗，使用磁性納米粒子暴露系統(tǒng)將BEAS-2B 細(xì)胞引入蒎烯及萜品油烯所產(chǎn)生的二次有機(jī)氣溶膠中，并使用乳酸脫氫酶作為細(xì)胞毒性指標(biāo)，IL-6（白細(xì)胞介素-6），IL-8（白細(xì)胞介素-8）和 TNF-α（腫瘤壞死因子-α）等作為炎癥指標(biāo)，證實蒎烯類SOA能明顯提高IL-8含量。Gaschen et al（2010）的研究證明當(dāng)α-蒎烯產(chǎn)生的SOA濃度達(dá)到實際環(huán)境相當(dāng)濃度（約104個/cm3）時，2小時左右即可引起中等程度的細(xì)胞反應(yīng)。

表1 萜烯類物質(zhì)氧化產(chǎn)物的毒理學(xué)及人體暴露研究總結(jié)Tab.1 Summary of terpene oxidation product toxicology and controlled human exposure studies

（續(xù)表1 Continued Tab.1）

盡管以上煙霧箱的體外實驗還存在如條件控制不充分等缺陷，但均能證實大氣中萜烯類VOCs氧化生成的二次有機(jī)氣溶膠比起母體化合物具有更強(qiáng)的生物毒性效應(yīng)?？紤]到室內(nèi)環(huán)境中萜烯類化合物的排放量，這對居民的人體健康具有十分重要的意義（Rohr，2013）。

4 結(jié)語

大氣中有機(jī)氣溶膠包括眾多對人體有害的化合物，如多環(huán)芳烴、有機(jī)胺、多氯聯(lián)苯及鄰苯二甲酸酯等物質(zhì)，其健康效應(yīng)已經(jīng)受到國內(nèi)外學(xué)者的高度關(guān)注。目前很多研究證實大氣中氣相或顆粒相中有機(jī)物可進(jìn)一步與空氣中氧化劑反應(yīng)，生成產(chǎn)物甚至比其母體化合物的毒性更強(qiáng)。但目前國際上對二次有機(jī)氣溶膠形成及生物毒性效應(yīng)的研究非常缺乏，亟需加強(qiáng)如下兩方面的研究。

（1）二次有機(jī)氣溶膠的化學(xué)與其毒理學(xué)特征相結(jié)合的系統(tǒng)研究。當(dāng)前二次有機(jī)氣溶膠研究中有關(guān)化學(xué)形成及生物效應(yīng)機(jī)制的聯(lián)合研究不夠深入，為對其健康效應(yīng)有深入的了解，需要全面模擬實際環(huán)境下二次有機(jī)氣溶膠的形成過程，并對其毒理效應(yīng)進(jìn)行更加深入的分析，如不同氧化劑、反應(yīng)途徑等對氣溶膠活性氧簇、炎癥指標(biāo)以及蛋白質(zhì)的影響。

（2）特定污染源二次有機(jī)氣溶膠的毒理特征研究。了解不同污染源（如燃煤排放、機(jī)動車尾氣及生物質(zhì)燃燒等）產(chǎn)生二次有機(jī)氣溶膠的生物效應(yīng)的差異，有助于制定有針對性且有效的控制對策及法規(guī)，益于公眾健康。

致謝：本文寫作過程中得到了何建輝、何世恒研究員的幫助，在此表示感謝。

曹軍驥. 2012. 我國PM2.5污染現(xiàn)狀與控制對策[J].地球環(huán)境學(xué)報, 3(5): 1030–1036. [Cao J J. 2012. Pollution status and control strategies of PM2.5in China [J].Journal of Earth Environmen, 3(5): 1030–1036.]

曹軍驥. 2014. PM2.5與環(huán)境[M]. 北京:科學(xué)出版社. [Cao J J. 2014. PM2.5& environment [M]. Beijing: Science Press.]

戴文婷, 李建軍, 成春雷, 等. 2011. 中國中東部高山和城市夏季大氣氣溶膠濃度及粒徑分布[J].地球環(huán)境學(xué)報, 2(1): 263–271. [Dai W T, Li J J, Cheng C L, et al. 2011.Concentrations and size distributions of summertime atmospheric aerosols at urban and alpine sites in east and central China [J].Journal of Earth Environmen, 2(1): 263–271.]

沈國鋒, 王格慧. 2012. 南京大氣PM2.5中羥基多環(huán)芳烴分子組成和季節(jié)變化特征[J].地球環(huán)境學(xué)報, 3(5): 1066–1069. [Shen G F, Wang G H. 2012. Molecular composition and seasonal variation of hydroxylated polycyclic aromatic hydrocarbons in atmospheric PM2.5of Nanjing, China [J].Journal of Earth Environmen, 3(5): 1066–1069.]

孫 濤, 王格慧, 李建軍. 2013. 西安市夏季大氣中生物二次有機(jī)氣溶膠的分子組成與粒徑分布[J].地球環(huán)境學(xué)報, 4(1): 1230–1235. [Sun T, Wang G H, Li J J. 2013. The molecular composition and mass-size distribution of biogenic secondary organic aerosol from Xi’an [J].Journal of Earth Environmen, 4(1): 1230–1235.]

Anderson S E, Jackson L G, Franko J, et al. 2010. Evaluation of dicarbonyls generated in a simulated indoor air environment using an in vitro exposure system [J].Toxicological Sciences, 115: 453–461.

Anderson S E, Khurshid S S, Meade B J, et al. 2013. Toxicological analysis of limonene reaction products using an in vitro exposure system [J].Toxicology in Vitro, 27: 721–730.

Atkinson R, Arey J. 1994. Atmospheric chemistry of gasphase polycyclic aromatic hydrocarbons: Formation of atmospheric mutagens [J].Environmental Health Perspectives, 102: 117–126.

Barsanti K C, Pankow J F. 2006. Thermodynamics of the formation of atmospheric organic particulate matter by accretion reactions-part 3: Carboxylic and dicarboxylic acids [J].Atmospheric Environment, 40: 6676–6686.

Boldo E, Linares C, Lumbreras J, et al. 2011. Health impact assessment of a reduction in ambient PM2.5levels in Spain [J].Environment International, 37: 342–348.

Cao J J, Xu H, Xu Q, et al. 2012. Fine particulate matter constituents and cardiopulmonary mortality in a heavily polluted Chinese city [J].Environmental Health Perspectives, 120: 373–378.

Chang S G, Novakov T. 1975. Formation of pollution particulate nitrogen compounds by NO-soot and NH3-soot gas-particle surface reactions [J].Atmospheric Environment, 9: 495–504.

Chen X, Hopke P K, Carter W P L. 2011. Secondary organic aerosol from ozonolysis of biogenic volatile organic compounds: Chamber studies of particle and reactive oxygen species formation [J].Environmental Science & Technology, 45: 276–282.

Davidson C I, Phalen R F, Solomon P A. 2005. Airborne particulate matter and human health: A review [J].Aerosol Science and Technology, 39: 737–749.

Dod R L, Gundel L A, Benner W H, et al. 1984. Nonammonium reduced nitrogen species in atmospheric aerosol-particles [J].Science of the Total Environment, 36: 277–282.

Doyle M, Sexton K G, Jeffries H, et al. 2004. Effects of 1,3-butadiene, isoprene, and their photochemical degradation products on human lung cells [J].Environmental Health Perspectives, 112: 1488–1495.

Durant J L, Busby W F, La fl eur A L, et al. 1996. Human cell mutagenicity of oxygenated, nitrated and unsubstituted polycyclic aromatic hydrocarbons associated with urban aerosols [J].Mutation Research-Genetic Toxicology, 371: 123–157.

Fu P P, Xia Q, Sun X, et al. 2012. Phototoxicity and environmental transformation of polycyclic aromatic hydrocarbons (PAHs)-light-induced reactive oxygen species, lipid peroxidation, and DNA damage [J].Journal of Environmental Science and Health. Part C, Environmental Carcinogenesis & Ecotoxicology Reviews, 30: 1–41.

Gaschen A, Lang D, Kalberer M, et al. 2010. Cellular responses after exposure of lung cell cultures to secondary organic aerosol particles [J].Environmental Science & Technology, 44: 1424–1430.

Ge X, Wexler A S, Clegg S L. 2011. Atmospheric amines–partⅠ: A review [J].Atmospheric Environment, 45: 524–546.

Grosjean D. 1991. Atmospheric chemistry of toxic contaminants. 6. Nitrosamines-dialkyl nitrosamines and nitrosomorpholine [J].Journal of the Air & Waste Management Association, 41: 306–311.

Guenther A, Karl T, Harley P, et al. 2006. Estimates of global terrestrial isoprene emissions using megan (model of emissions of gases and aerosols from nature) [J].Atmospheric Chemistry and Physics, 6: 3181–3210.

Happo M S, Hirvonen M R, Halinen A I, et al. 2008. Chemical compositions responsible for inflammation and tissuedamage in the mouse lung by coarse and fi ne particulate samples from contrasting air pollution in Europe [J].Inhalation Toxicology, 20: 1215–1231.

Huang R J, Zhang Y, Bozzetti C, et al. 2014. High secondary aerosol contribution to particulate pollution during haze events in China [J].Nature, 514: 218–222.

International Agency for Research on Cancer (IARC). 2013. Monographs on the evaluation of carcinogenic risks to humans: Some chemicals present in industrial and consumer products, food and drinking-water [M]. Lyon: International Agency for Research on Cancer.

Ito K, Christensen W F, Eatough D J, et al. 2006. PM source apportionment and health effects: 2. An investigation of intermethod variability in associations between sourceapportioned fine particle mass and daily mortality in Washington, DC [J].Journal of Exposure Science and Environmental Epidemiology, 16: 300–310.

Jakober C A, Charles M J, Kleeman M J, et al. 2006. LC-MS analysis of carbonyl compounds and their occurrence in diesel emissions [J].Analytical Chemistry, 78: 5086–5093.

Jakober C A, Riddle S G, Robert M A, et al. 2007. Quinone emissions from gasoline and diesel motor vehicles [J].Environmental Science & Technology, 41: 4548–4554.

Jang M, Ghio A J, Cao G. 2006. Exposure of BEAS-2B cells to secondary organic aerosol coated on magnetic nanoparticles [J].Chemical Research in Toxicology, 19: 1044–1050.

Japan Environmental Agency. 1997. Quality of the environment in Japan [M]. Tokyo: Environmental Agency, Government of Japan.

Jernstrom B, Lycksell P O, Graslund A, et al. 1984. Spectroscopic studies of DNA complexes formed after reaction with anti-benzo[a]pyrene-7,8-dihydrodiol-9,10-oxide enantiomers of different carcinogenic potency [J].Carcinogenesis, 5:1129–1135.

Jernstrom B, Graslund A. 1994. Covalent binding of benzo[a] pyrene-7,8-dihydrodiol-9,10-epoxides to DNA: Molecular structures, induced mutations and biological consequences [J].Biophysical Chemistry, 49: 185–199.

Kanakidou M, Seinfeld J H, Pandis S N, et al. 2005. Organic aerosol and global climate modelling: A review [J].Atmospheric Chemistry and Physics, 5: 1053–1123.

Kawamura K, Yasui O. 2005. Diurnal changes in the distribution of dicarboxylic acids, ketocarboxylic acids and dicarbonyls in the urban Tokyo atmosphere [J].Atmospheric Environment, 39: 1945–1960.

Lelieveld J, Evans J S, Fnais M, et al. 2015. The contribution of outdoor air pollution sources to premature mortality on a global scale [J].Nature, 525: 367–371.

Li M, Zhang L. 2014. Haze in China: Current and future challenges [J].Environmental Pollution, 189: 85–86.

Lindley C R C, Calvert J G, Shaw J H. 1979. Rate studies of the reactions of the (CH3)2N radical with O2, NO, and NO2[J].Chemical Physics Letters, 67: 57–62.

Liu Q Y, Baumgartner J, Zhang Y X, et al. 2014. Oxidative potential and in fl ammatory impacts of source apportioned ambient air pollution in Beijing [J].Environmental Science & Technology, 48: 12920–12929.

Liu X G, Li J, Qu Y, et al. 2013. Formation and evolution mechanism of regional haze: A case study in the megacity Beijing, China [J].Atmospheric Chemistry and Physics, 13: 4501–4514.

Murphy S M, Sorooshian A, Kroll J H, et al. 2007. Secondary aerosol formation from atmospheric reactions of aliphatic amines [J].Atmospheric Chemistry and Physics, 7: 2313–2337.

Namiesnik J, Jastrzebska A, Zygmunt B. 2003. Determination of volatile aliphatic amines in air by solid-phase microextraction coupled with gas chromatography with fl ame ionization detection [J].Journal of Chromatography A, 1016: 1–9.

Ohura T, Amagai T, Fusaya M, et al. 2004. Polycyclic aromatic hydrocarbons in indoor and outdoor environments and factors affecting their concentrations [J].Environmental Science & Technology, 38: 77–83.

Palmiotto G, Pieraccini G, Moneti G, et al. 2001. Determination of the levels of aromatic amines in indoor and outdoor air in Italy [J].Chemosphere, 43: 355–361.

Pan L, Chong J M, Pawliszyn J. 1997. Determination of amines in air and water using derivatization combined with solidphase microextraction [J].Journal of Chromatography A, 773: 249–260.

Pavagadhi S, Betha R, Venkatesan S, et al. 2013. Physicochemical and toxicological characteristics of urban aerosols during a recent indonesian biomass burning episode [J].Environmental Science and Pollution Research International, 20: 2569–2578.

Phousongphouang P T, Arey J. 2003. Sources of the atmospheric contaminants, 2-nitrobenzanthrone and 3-nitrobenzanthrone [J].Atmospheric Environment, 37: 3189–3199.

Pitts J N, Grosjean D, Vancauwenberghe K, et al. 1978. Photooxidation of aliphatic-amines under simulated atmospheric conditions-formation of nitrosamines, nitramines, amides, and photo-chemical oxidant [J].Environmental Science & Technology, 12: 946–953.

Pope C A, Burnett R T, Thun M J, et al. 2002. Lung cancer, cardiopulmonary mortality, and long-term exposure to fi ne particulate air pollution [J].Journal of the American Medical Association, 287(9): 1132–1141.

Qiu C, Zhang R. 2013. Multiphase chemistry of atmospheric amines [J].Physical Chemistry Chemical Physics, 15: 5738–5752.

Reisen F, Arey J. 2005. Atmospheric reactions influence seasonal PAH and nitro-PAH concentrations in the Los Angeles Basin [J].Environmental Science & Technology, 39(1): 64–73.

Ringuet J, Leoz-Garziandia E, Budzinski H, et al. 2012. Particle size distribution of nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) on traf fi c and suburban sites of a European megacity: Paris (France) [J].Atmospheric Chemistry and Physics, 12(6): 8877–8887.

Rohr A C. 2013. The health signi fi cance of gas- and particlephase terpene oxidation products: A review [J].Environment International, 60: 145-162.

Roueintan M M, Cho J, Li Z. 2014. Kinetics investigation of reaction of naphthalene with OH radicals at 1—3 torr and 240—340 k [J].International Journal of Chemical Kinetics, 46: 578–586.

Santagati N A, Bousquet E, Spadaro A, et al. 2002. Analysis of aliphatic amines in air samples by HPLC with electrochemical detection [J].Journal of Pharmaceutical and Biomedical Analysis, 29: 1105–1111.

Schlesinger R B. 2007. The health impact of common inorganic components of fi ne particulate matter (PM2.5) in ambient air: A critical review [J].Inhalation Toxicology, 19: 811–832.

Schwartz J, Neas L M. 2000. Fine particles are more strongly associated than coarse particles with acute respiratory health effects in schoolchildren [J].Epidemiology, 11: 6–10.

Seagrave J, McDonald J D, Bedrick E, et al. 2006. Lung toxicity of ambient particulate matter from southeastern US sites with different contributing sources: Relationships between composition and effects [J].Environmental Health Perspectives, 114: 1387–1393.

Seifried H E, Anderson D E, Fisher E I, et al. 2007. A review of the interaction among dietary antioxidants and reactive oxygen species [J].Journal of Nutritional Biochemistry, 18: 567–579.

Sexton K, Adgate J L, Ramachandran G, et al. 2004a. Comparison of personal, indoor, and outdoor exposures to hazardous air pollutants in three urban communities [J].Environmental Science & Technology, 38: 423–430.

Sexton K, Jeffries H E, Jang M, et al. 2004b. Photochemical products in urban mixtures enhance inflammatory responses in lung cells [J].Inhalation Toxicology, 16: 107–114.

Skarping G, Bellander T, Mathiasson L. 1986. Determination of piperazine in working atmosphere and in human-urine using derivatization and capillary gas-chromatography with nitrogen-selective and mass-selective detection [J].Journal of Chromatography, 370: 245–258.

Sorooshian A, Murphy S N, Hersey S, et al. 2008. Comprehensive airborne characterization of aerosol from a major bovine source [J].Atmospheric Chemistry and Physics, 8: 5489–5520.

Spector A. 2000. Review: Oxidative stress and disease[J].Journal of Ocular Pharmacology and Therapeutics, 16: 193–201.

Srogi K. 2007. Monitoring of environmental exposure to polycyclic aromatic hydrocarbons: A review [J].Environmental Chemistry Letters, 5: 169–195.

Sunil V R, Laumbach R J, Patel K J, et al. 2007. Pulmonary effects of inhaled limonene ozone reaction products in elderly rats [J].Toxicology and Applied Pharmacology, 222: 211–220.

Thurston G D, Ahn J, Cromar K R, et al. 2016. Ambient particulate matter air pollution exposure and mortality in the NIH-AARP diet and health cohort [J].Environmental Health Perspectives,124(4): 484–490.

Turpin B J, Huntzicker J J. 1995. Identification of secondary organic aerosol episodes and quantitation of primary and secondary organic aerosol concentrations during SCAQS [J].Atmospheric Environment, 29(23): 3527–3544.

US Environmental Protection Agency (USEPA). 1997. Compendium of methods for the determination of toxic organic compounds in ambient air, method to-13a: Determination of polycyclic aromatic hydrocarbons (PAHs) in ambient air using gas chromatography/ mass spectrometry (GC / MS) [M]. Washington DC: US Environmental Protection Agency.

Utsunomiya S, Jensen K A, Keeler G J, et al. 2004. Direct identi fi cation of trace metals in fi ne and ultra fi ne particles in the Detroit urban atmosphere [J].Environmental Science & Technology, 38(8): 2289–2297.

Verma V, Fang T, Xu L, et al. 2015. Organic aerosols associated with the generation of reactive oxygen species (ROS) by water-soluble PM2.5[J].Environmental Science & Technology, 49(7): 4646–4656.

Wang W, Jariyasopit N, Schrlau J, et al. 2011. Concentration and photochemistry of PAHs, NPAHs, and OPAHs and toxicity of PM2.5during the Beijing Olympic Games [J].Environmental Science & Technology, 45(16): 6887–6895.

Wei Y, Han I K, Hu M, et al. 2010. Personal exposure to particulate PAHs and anthraquinone and oxidative DNA damages in humans [J].Chemosphere, 81(10): 1280–1285.

Weyand E H, Bevan D R. 1986. Benzo[a]pyrene disposition and metabolism in rats following intratracheal instillation [J].Cancer Research, 46: 5655–5661.

Wolkoff P, Clausen P A, Larsen S T, et al. 2012. Airway effects of repeated exposures to ozone-initiated limonene oxidation products as model of indoor air mixtures [J].Toxicology Letters, 209: 166–172.

Xu P, Chen Y, Ye X. 2013. Haze, air pollution, and health in China [J].Lancet, 382: 2067–2067.

Yang X Y, Igarashi K, Tang N, et al. 2010. Indirect and direct acting mutagenicity of diesel, coal and wood burning derived particulates and contribution of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons [J].Mutation Research / Genetic Toxicology and Environmental Mutagenesis, 695: 29–34.

Zahardis J, Geddes S, Petrucci G A. 2008. The ozonolysis of primary aliphatic amines in fi ne particles [J].Atmospheric Chemistry and Physics, 8: 1181–1194.

Zhou S, Wenger J C. 2013. Kinetics and products of the gasphase reactions of acenaphthene with hydroxyl radicals, nitrate radicals and ozone [J].Atmospheric Environment, 72: 97–104.

Zhu J P, Aikawa B. 2004. Determination of aniline and related mono-aromatic amines in indoor air in selected canadian residences by a modified thermal desorption GC /MS method [J].Environment International, 30(2): 135–143.

Formation and toxicological effect of secondary organic aerosols

CAO Junji1,2, LI Jianjun1,3
(1. Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China; 2. Key Laboratory of Aerosol Chemistry and Physics, Chinese Academy of Sciences, Xi’an 710061, China; 3. State Key Laboratory of Loess and Quaternary Geology, Xi’an 710061, China)

Background, aim, and scopeAlong with the rapid development of Chinese economy, pollutants derived from increasing usage of fossil fuels and biofuels, as well as emissions from waste incineration and dust have been causing serious air pollution problems in many areas of China. Particular matter (PM), especially anthropogenic aerosols, emitted from various sources may alter regional atmospheric stability, and are of significant impact on climate change and human health. Comparing with PM10(aerodynamic diameter ≤10 μm), fi ne particle (PM2.5, aerodynamic diameter ≤2.5 μm) do more damage to human health. Organic matter (OM), an important chemical composition of fi ne particle, takes 20%—90% of the fi ne particles, has a signi fi cant impact on air pollution and haze event which is happening in China, and has become a frontier of atmospheric chemistry research area. Consisting with many toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organic amines and so on, organic aerosol is harmful for human health. Many in-vitro and invito studies of biological toxicity were focused on the primary particulate matters emitted directly from the pollution sources, however, attention for the formation and toxicity of secondary organic aerosols (SOA) are really scarce and therefore urgent.Materials and methodsTaking PAHs, amines, and biogenicterpenes as examples, in order to improve the understanding on health damage of SOA pollution, this article brie fl y reviewed the formation and bio-toxicity effects of speci fi c group of SOA, and focused on the rising toxicity of the products comparing with their parent compounds.Results(1) Polycyclic aromatic hydrocarbons (PAHs). Because of the mutagenic, teratogenic and carcinogenic properties, PAHs has focused a great deal of attention from scienti fi c researchers and is considered as one of the most important organic pollutants in the atmosphere. Parent PAHs in the aerosols can undergo a photo-oxidation or nitration reaction with gas oxidants in the air to form oxygenated-PAHs (OPAHs) or nitrated-PAHs (NPAHs), and thus the toxicity and health hazard are enhanced. Parent PAHs and their derivatives can absorb light energy to reach the photo-excited states, and then react with molecular oxygen, medium, and coexisting chemicals to produce reactive oxygen species (ROS) and other reactive intermediates, which can induce lipid peroxidation and DNA damage. (2) Amine: Organic amines are derivatives of ammonia in which one or more of the hydrogen atoms replaced by an alkyl or aryl group. They are strong alkaline compounds and play a very important role on secondary aerosols formation. The gaseous aliphatic amines can undergo rapid acid-base reactions to form salt particles in the presence of atmospheric acids (such as HCl, HNO3, H2SO4). Other multiphase reactions of amines include carbonyl-amine interaction and particle-phase oxidation reactions. Particulate alkyl amine can also react with nitrite to form carcinogenic nitrosamine. All these secondary products have signi fi cantly adverse effects on human health, such as skin allergy, respiratory diseases, and cancers etc., and thus would alter the biological effect of aerosols in the atmosphere in return. (3) Terpenes: Terpenes is one of the most important biogenic volatile organic compounds (BVOCs) in the atmosphere. In indoor environment, terpenes can be easily emitted from many consumer products such as furnitures or clothes. On the other hand, some gaseous oxidants like ozone and NOxcan also present in the indoor air because of the in fi ltration from outdoor environment or emission by some of fi ce and consumer equipment. Thus, the indoor health effect of secondary organic aerosol formation of terpenes with other gaseous oxidants is a popular issue in recent researches. Some of the gaseous products formed are irritating to biological tissues, while the condensed-phase products have received attention due to their contribution to ambient fine particulate matter and its respective health signi fi cance. Although the biochemical mechanism of terpenes to human body remains unclear, but nearly all the related studies can prove that the secondary products of terpenes have some harmful effect to human epidermis or respiratory system.DiscussionAt present, many researches were focused on the bio-toxicity effects of fi ne particles in the atmosphere, however, rare studies referred to the toxicity change of secondary organic aerosols formation in the atmosphere.ConclusionsMore speci fi c areas in which improvements and advances could be made for toxicological studies of secondary organic aerosols in the atmosphere in the future.Recommendations and perspectives(1) Comprehensive study combining the chemical and bio-toxicity properties of secondary organic aerosols; (2) Research on bio-toxicity of secondary organic aerosols from speci fi c pollution sources.

secondary organic aerosols (SOA); toxicity; polycyclic aromatic hydrocarbons (PAHs); amines; terpenes

CAO Junji, E-mail: cao@loess.llqg.ac.cn

10.7515/JEE201605001

2016-06-02；錄用日期：2016-08-02

Received Date:2016-06-02;Accepted Date:2016-08-02

中國科學(xué)院戰(zhàn)略先導(dǎo)性專項（XDB05000000）

Foundation Item:Strategic Pilot Project of Chinese Academy of Sciences (XDB05000000)

曹軍驥，E-mail: cao@loess.llqg.ac.cn