| Secondary organic aerosol(SO A) attracts more and more attent ion o f scholars for its impact on atmospher ic visib ilit y, climate change and human healt h. The process and mecha nism of generatio n of SO A for matio n from aromat ic hydrocarbons are the focus of today’s atmospheric aerosol research as aromat ic hydrocarbon is an important anthropogenic source of SO A in urban air. The yie lds of SO A for mat ion fro m o- xyle ne, 1,3,5- trimet hylbenzene and the mixture of the two in a indoor smog cha mber with d ifferent init ial environmenta l factors are studied. Phtha lic acid and 1,3,5- benzene tricarboxylic acid are analyzed quant itat ive ly as the c haracterist ic component of the products from photo- oxidation o f o- xylene and 1,3,5- trimethylbenzene by BSTFA derivat izat ion- gas chromatography- mass spectrometr y to derive the contr ibut ion of SO A from o- xyle ne and 1,3,5- trimethylbenzene to PM2.5 in a tmospheric air.Referring to the Univers ity of North Carolina indoor smoke cha mber structure, a new indoor smoke chmber system is established. The wa ll loss, light transmitta nce of Teflon me mbrane, the analog characterizat ion of the sunlight and light leakage rate are characterized. The results(R e la t ive hum id it y = 3 0%, wa ll lo ss c oe ffic ie nt is 0.00 04 min- 1; RH =70%, w a ll los s co e ffic ie nt is 0.0006 min- 1, t he t ra ns mit t a nce o f Te flo n fi lm is abo ut 95 %, t he leaka ge ra te is ab o ut 1 0 %, t he ult ra vio le t light so urce w it hin t he ra nge o f 350 ~ 40 0 nm ha s good co inc ide nc e w it h s unli ght, t he re la t ive ra nge o f l ight int e ns it y d is tr ib ut io n in t he c ha mber is le ss t ha n 20 % in bot h t he ho r izo nta l a nd ve r t ica l d ire ct io ns) ind icate that the smog cha mber has a good perfor mance in all aspects to simulate the atmospher ic enviro nment as photo- oxidation plat form of aromat ic hydrocarbons. C ha mber experiments data can be corrected by the characterizatio n results to ensure the aut hent ic it y and accuracy of t he exper iments data.SO A yields are investigated b y varying the ratio of the init ia l concentrat ion of o- xyle ne and 1,3,5- trimethylbenzene in mixed system in different exper iments. The SO A yie lds of o- xylene and 1,3,5- trimet hylbenzene in mixed system were fo und to lower than the SO A yie ld of o- xyle ne and 1,3,5-trimethylbenzene single system, and the impact of 1,3,5- trimet hylbenzene on mixed syste m SO A yie ld is gteater than o- xylene.Phthalic acid and 1,3,5- benzene tricarboxylic acid in t he samp les from s mog chamber experiments and enviro nment are are quant ified. The results ind icate that: SO A mass concentration generate d fro m o- xylene and 1,3,5-trimethylbenzene together wit hin t he park HIT is about 1.91 μg/m3, account ing for the actua l atmosphere PM2.5 concentration of 2.15%, which is about 28.56% contr ibut ion fro m o- xyle ne and about 71.47% contrib ut ion from 1,3,5-trimethylbenzene. SO A mass concentration generate d from o- xyle ne and 1,3,5-trimethylbenzene together at a busy traffic intersection near Xili Rainbow is about 3.13 μg/m3, account ing for the actua l atmosphere PM2.5 concentrat ion of 2.73%, whic h is about 42.94% contr ibut ion from o- xylene and about 57.05% contr ibut ion from 1,3,5- trimet hylbenzene. SO A mass concentration ge nerated from o- xylene and 1,3,5- trimet hylbenzene together near Hart Avenue Hong Kong is about 1.82 μg/m3, about account ing for the actua l atmosphere PM2.5 concentrat ion of 6.55%, which is about 32.37% contr ibut ion fro m o- xyle ne and about 67.63% contrib ut ion fro m 1,3,5- trimethylbenzene. |
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