Vehicle Engines Produce Exhaust Nanoparticles Even When Not Fueled
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- 作者：Topi R?nkk? ; Liisa Pirjola ; Leonidas Ntziachristos ; Juha Heikkil? ; Panu Karjalainen ; Risto Hillamo ; Jorma Keskinen
- 刊名：Environmental Science & Technology
- 出版年：2014
- 出版时间：February 4, 2014
- 年：2014
- 卷：48
- 期：3
- 页码：2043-2050
- 全文大小：486K
- ISSN：1520-5851
文摘
Vehicle engines produce submicrometer exhaust particles affecting air quality, especially in urban environments. In on-road exhaust studies with a heavy duty diesel vehicle and in laboratory studies with two gasoline-fueled passenger cars, we found that as much as 20鈥?0% of the number of exhaust particles larger than 3 nm may be formed during engine braking conditions鈥攖hat is, during decelerations and downhill driving while the engine is not fueled. Particles appeared at size ranges extending even below 7 nm and at high number concentrations. Their small size and nonvolatility, coupled with the observation that these particles contain lube-oil-derived metals zinc, phosphorus, and calcium, are suggestive of health risks at least similar to those of exhaust particles observed before. The particles鈥?characteristics indicate that their emissions can be reduced using exhaust after-treatment devices, although these devices have not been mandated for all relevant vehicle types. Altogether, our findings enhance the understanding of the formation vehicle emissions and allow for improved protection of human health in proximity to traffic.