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分析了珠江三角洲秋季VOCs在相对污染与清洁情况下的日变化特征.污染情况下的VOCs质量浓度可达清洁情况下的2.2倍,污染富集的是甲苯、二甲苯、乙苯、正丁烷、戊烷、丙烷、乙炔、乙烯等物种.自然排放的异戊二烯具有早晚浓度低而白天浓度高的日变化规律,体现植物的光合作用特征;而人类活动污染排放的甲苯其日变化规律基本反映了气象条件与污染源排放日变化的影响,在相对污染情况下早上出现明显的污染富集,午后出现污染低值.反应活性较强的物质主要是烯烃(反式-2-丁烯、异戊二烯、顺2-戊烯)与芳香烃(间对-二甲苯、甲苯);烯烃的质量百分比最低,却占最高的化学反应活性百分比.
The diurnal variation characteristics of autumn VOCs in the Pearl River Delta under the condition of relative pollution and cleanliness were analyzed.The concentration of VOCs under the pollution condition was up to 2.2 times of that in the case of cleanliness.The concentration of VOCs in the pollution was toluene, xylene, ethylbenzene, n-butane , Pentane, propane, acetylene, ethylene, etc. Naturally-emitted isoprene has the diurnal variation pattern of low morning and evening concentration and high daytime concentration, which reflects the photosynthetic characteristics of plants. The daily variation of toluene emitted by human activities Basically reflect the impact of meteorological conditions and diurnal changes of pollutant discharge, obvious pollution enrichment in the morning of the relative pollution and low pollution in the afternoon.The substances with strong reactivity are mainly olefins (trans-2-butene, Isoprene, cis-2-pentene) and aromatic hydrocarbons (p-xylene, toluene); the lowest mass percentage of olefins, but the highest percentage of chemical reactivity.