香烟侧流烟中超细颗粒物释放及衰减特性

Analysis of ultrafine particle emission and sink characteristics from side-stream cigarette smoke

超细颗粒物(Ultrafine Particles,UFPs)能够进入人体肺泡组织进而危害人体健康,为了解香烟侧流烟中UFPs数浓度和表面积浓度释放及衰减特性,结合环境舱和现场实验结果对不同品牌香烟颗粒进行了分析.结果表明:燃烧过程中UFPs数浓度和表面积浓度峰值粒径分别为47.5~66.3 nm和85.6~100.5 nm,衰减2 h后,数浓度和表面积浓度峰值粒径仍小于200 nm;不同品牌香烟侧流烟中UFPs数浓度和表面积浓度释放速率分别为4.22×10^(12)~5.23×10^(12)个·min^(-1)和5.95×10^(10)~6.90×10^(10)μm2~·min^(-1),根据该释放速率模拟得到的不同换气率条件下UFPs数浓度衰减趋势与实验结果相符;通风和实验环境均会影响UFPs的衰减速率,随着换气率由0.7次·h^(-1)增至7次·h^(-1),侧流烟中UFPs的衰减时间由3 h降低至40 min,吸附作用的存在亦会加快UFPs的衰减速率.

Ultrafine particles（ UFPs） can penetrate deeply into the lung tissue and cause adverse health effects. In order to investigate the characteristics of concentration and size distribution of UFPs（ 20 - 600 nm） in side-stream smoke emitted from cigarettes,environmental chamber experiments and field experiments were carried out. The results showed that the count median diameters（ CMDs） and the surface area median diameters（ SMDs） during the combustion process were in the ranges of 47.5 - 66.3 nm and 85.6 - 100.5 nm respectively,and both of them were still less than 200 nm after 2 hours of decay after combustion. The number and surface area emission rates of different brands of cigarettes were in the ranges of 4. 22 × 10^12- 5. 23 × 10^12 particles·min^-1 and 5.95 × 10^10-6. 90 × 10^10μm^2·min^-1 respectively. Based on these experimental results,decay trends were modeled under various ventilation conditions. The decay rates of UFPs were affected by air exchange rates and environmental conditions. By increasing the air exchange rates from0.7（ ACH） to 7（ ACH）,the time required for the UFP concentration back to that of the background was decreased from more than 3 hours to less than 40 minutes. Moreover,the decay rate was further increased by the particle deposition as shown by the field experiments.