汽油车非常规污染物排放特性研究

Unregulated Emissions from the Gasoline Vehicle

选择3种不同排量的典型汽油车,基于国Ⅲ标准的轻型车排放测试循环,用SKC采样泵和2,4-DNPH、TenaxTA采样管采集尾气中的非常规污染物,利用高效液相色谱仪和热脱附气相色谱质谱联用仪分析汽油车排放中醛酮类化合物和挥发性有机物的组成及含量,同时利用电子低压冲击仪研究了其颗粒物排放的粒径和质量浓度分布特征.结果表明,不同汽油车之间非常规污染物的比排放值有较大差异,3辆汽油车总醛酮比排放量分别为36.44、16.71、10.43mg/km,TVOC分别为155.39、103.75、42.29mg/km.排放的醛酮化合物中甲醛、乙醛、丙烯醛、丙酮和环己酮的检出含量较高,占总醛酮量的77.9%～89.7%,且绝大部分为有毒有害物质;废气中挥发性有机物绝大部分为芳香烃和烷烃,分别占总数的31.6%～39.2%和23.1%～27.9%,其中又以芳香烃类化合物甲苯、二甲苯和苯的检出含量最高,平均占TVOC的16.68%、16.87%和5.23%;其颗粒物排放以超细颗粒物(<100nm)为主,高速工况下排放的颗粒物明显多于低速和中速工况.

Based on the emission test cycle of China National Regulation Stage Ⅲ, the aldehyde and alkone emissions and VOCs emissions of three typical gasoline cars were studied with HPLC and TD-GC/MS and the exhausted particulates number and mass concentration were researched using ELPI. The results indicate that the unregulated emissions of different cars is diverse changed, the brake specific emission of the carbonyls in three cars are 36.44, 16.71 and 10.43 mg/km respectively and TVOC are 155.39, 103.75 and 42.29 mg/km respectively. Formaldehyde, acetaldehyde, acrolein, acetone and cyclohexanone are the main compounds in gasoline cars exhaust, which accounted for 77.9%-89.7% of total carbonyl compounds. Aromatic hydrocarbons and atkane are the main part of VOCs, the detected number of which is occupied 31.6 %-39.2 % and 23.1%-27.9 % of VOCs. Toluene, xylene and benzene have high concentration, which are occupied 16.68 %, 16.87% and 5.23% of TVOC in average. Ultra-fine particles （ 〈 100 nm） dominate the particulates emission. Exhausted particulate number of high speeds is higher than that of slow and medium speeds.