北京某小学室内外VOC浓度及有毒害物种识别

采用美国EPA推荐的TO14/15方法定量分析了北京市某小学室内外夏季观测的空气样品，得到82种挥发性有机物（VOCs）的浓度水平及组成特征，对其中可能危害儿童健康的有毒有害物质进行了识别.结果表明，室内总VOCs浓度高于室外，烷烃是含量最丰富物种，平均占室内外空气中定量VOCs总浓度的32.8%.室内外VOCs组成相似，异戊烷、苯、甲苯、丙醛、丙烯和二氯甲烷为浓度优势物种，受到室外源的影响较大，室内的对二氯苯、环己烷及间二氯苯较为特征，前2种物质室内/室外浓度比例平均值分别为65.8和10.5，间二氯苯室内平均浓度为2.02×10^-9（体积分数），而室外浓度低于检测限，这3种物质可能来自室内源. 1, 3-丁二烯、氯乙烯、苯和氯甲烷4种物质在学校室内、室外及儿童家中都超过1×10^-6的癌症风险值，平均风险值分别为1.3×10^-5、 6.4×10^-6、 5.1×10^-6和3.3×10^-6，小学室外、室内及儿童家中的累积癌症风险超过1×10^-6的癌症风险值24～39倍.丙烯醛未确认具有致癌性，但具有毒有害性，在室内外及儿童家中超过基准浓度13～72倍.

Identification of Air Toxics from Indoor and Outdoor Measurements of Volatile Organic Compounds in One Elementary School in Beijing

Concentrations and characteristics of 82 volatile organic compounds (VOCs) were measured in indoor and outdoor air in one elementary school of Beijing by method TO14/15 recommended by USEPA in 2007 summer. And the toxic VOCs for children's health were identified. The study illuminates that the concentration level of total VOCs were higher in indoor air than in outdoor air. Alkanes were most abundant VOCs species accounting for 32.8% of total measured VOCs on average. The chemical speciation of VOCs in indoor air was similar to the outdoor, and the dominant species were isopentane, benzene, toluene, propanal, propene and dichloromethane. In the indoor air, m/p-dichlorobenzene and cyclohexane likely came from indoor sources, proved by the indoor/outdoor concentration ratios of p-dichlorobenzene(65.8) and cyclohexane(10.5), and the large distance between the concentrations of m-dichlorobenzene in indoor air(2.02×10^-9) and outdoor(lower than the detected limit)air. 1, 3-butadiene, chloride vinyl, benzene and chloromethane, whose average cancer risk values were 1.3×10^-5, 6.4×10^-6, 5.1×10^-6 and 3.3×10^-6 respectively, exceeded the cancer risk value 1×10^-6 in all samples sites. The cumulative cancer risk in indoor air, outdoor air and children house were 24-39 times bigger than 1×10^-6. Acrolein was the only non-carcinogenic hazardous species which exceeded its benchmark concentration by 13-72 times in all sites.