Investigation on lowering commuters' in-cabin exposure to ultrafine particles

Abstract To determine ways to reduce commuters’ ultrafine particle exposure, factors such as ventilation condition, mechanical airflow rate, driving speed, cabin air filter quality, and cabin air filter use are examined. The results show that the in-cabin to on-roadway ratio is reduced by 20% when the fan is set to recirculation-on versus when set to recirculation-off because fewer ultrafine particles are exchanged between the inside and outside of the cabin. Also, when the fan is set to recirculation-off, the ratio is reduced by 40% at lower mechanical airflow rates. The thickest cabin air filter resulted in a 30% in-cabin to on-roadway ratio decrease compared with the thinnest. Thus, driving conditions with the least UFP in-cabin to on-roadway ratio is when a vehicle is operating with a high efficiency cabin filter, the ventilation set to fan-on and recycling is recirculation on, and at a high ventilation airflow rate. Furthermore, recirculating in-cabin air through a high efficiency particulate air filter was found to significantly reduce in-cabin UFP exposure.

[1]  Dana B Barr.  2006 – A year to remember , 2007, Journal of Exposure Science and Environmental Epidemiology.

[2]  Lidia Morawska,et al.  Effect of cabin ventilation rate on ultrafine particle exposure inside automobiles. , 2010, Environmental science & technology.

[3]  P. H. Baker,et al.  Air flow through cracks , 1987 .

[4]  Wladyslaw W. Szymanski,et al.  Penetration of Monodisperse, Singly Charged Nanoparticles through Polydisperse Fibrous Filters , 2011 .

[5]  Paul Switzer,et al.  Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke , 2008, Journal of Exposure Science and Environmental Epidemiology.

[6]  Yifang Zhu,et al.  Effects of Vehicle Cabin Filter Efficiency on Ultrafine Particle Concentration Ratios Measured In-Cabin and On-Roadway , 2011 .

[7]  Yifang Zhu,et al.  Ultrafine particle penetration through idealized vehicle cracks , 2010 .

[8]  Yifang Zhu,et al.  Quantitative Analysis of the Parameters Affecting In-Cabin to On-Roadway (I/O) Ultrafine Particle Concentration Ratios , 2009 .

[9]  C. Sioutas,et al.  Predictive model for vehicle air exchange rates based on a large, representative sample. , 2011, Environmental science & technology.

[10]  Yifang Zhu,et al.  In-cabin commuter exposure to ultrafine particles on Los Angeles freeways. , 2007, Environmental science & technology.

[11]  Andrew Maynard,et al.  Recirculating Air Filtration Significantly Reduces Exposure to Airborne Nanoparticles , 2008, Environmental health perspectives.

[12]  Thomas Schroth.  New HEPA/ULPA filters for clean-room technology , 1996 .

[13]  Yifang Zhu,et al.  Ultrafine Particles Deposition Inside Passenger Vehicles , 2009 .