In-vehicle airborne fine and ultra-fine particulate matter exposure: The impact of leading vehicle emissions. (February 2019)

• Record Type: Journal Article
• Authors: Campagnolo, Davide; Cattaneo, Andrea; Corbella, Leonardo; Borghi, Francesca; Del Buono, Luca; Rovelli, Sabrina; Spinazzé, Andrea; Cavallo, Domenico M.
• Is Part Of: Environment international. Volume 123(2019)
• Page Start: 407
• Page End: 416
• Publication Date: 2019-02
• Subjects: PM particulate matter -- UFPs ultra-fine particles -- US EPA United States Environmental Protection Agency -- LV leading vehicle -- SV study vehicle -- PNCs Particle Number Concentrations -- CNG compressed natural gas -- OPC optical particle counter -- CPC condensation particle counter -- PTFE polytetrafluoroethylene -- DPF diesel particulate filter -- KW Kruskal-Wallis test -- MW Mann-Whitney test -- DPF vehicles diesel leading vehicles equipped with diesel particulate filter -- Non-DPF vehicles diesel vehicles not equipped with diesel particulate filter; Particle concentrations -- In-vehicle air quality -- Individual exposure -- Vehicle exhaust emissions -- Emission standard levels -- Diesel particulate filter; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2018.12.020
• Languages: English
• ISSNs: 0160-4120

Abstract

Abstract: Airborne particulate matter (PM) concentrations inside vehicle cabins are often extremely high compared to background levels. The present study was motivated by the fact that in the last few decades, the implementation of new emission standards has led to the reduction of vehicle particle emissions. This study addresses for the first time the relationship between leading vehicle (LV) emissions and in-cabin PM exposure levels in the immediately following vehicle (henceforth called the study vehicle - SV), with particular emphasis on the role of the LV's emission reduction technologies (e.g., diesel particulate filter-DPF) as an effective risk management measure. The study was performed using an instrumented study vehicle (always to be considered as the following vehicle) on a 26-km fixed route where 10 repeated tests were conducted during 60-minute trips. On-line monitoring of the fine 0.3–1 μm and 1–2.5 μm (PM0.3–1 and PM1–2.5 ) and ultra-fine particle (UFP) concentrations was performed inside the SV's car cabin with fixed ventilation settings (i.e., windows closed, air conditioning off, and recirculation fan off). Simultaneously, the license plate numbers of the LVs along the route were recorded to retrieve information pertaining to their fuel type and Euro emission standard category. The results clearly showed that the in-cabin PM levels were significantly affected by the LV's Euro emission standard. Regarding petrol-fuelled LVs, the median in-cabin particle exposure levels were statistically lower (e.g., −34% for PM0.3–1 ) when following vehicles with stricter emission standards (in particular, Euro 6) than when following a low-emission standard vehicle (i.e., Euro 0–2). Concerning diesel-fuelled LVs, a strong and significant decrease in the in-cabin median exposure levels (up to −62%, −44%, and −48% for UFPs, PM0.3–1, and PM1–2.5, respectively) was observed for recent-emission standards LVs (i.e., Euro 5–6) with respect to older-emission standard LVs (i.e., Euro 0–4). A specific analysis revealed that the in-cabin median exposure concentrations of PM were highly and significantly reduced by DPF-equipped LVs. For UFPs, this resulted in a 47% reduction compared to diesel-fuelled (non-DPF) LVs. For PM0.3–1, an approximate 80% reduction was observed compared to both petrol-fuelled and diesel-fuelled (non-DPF) LVs. For PM1–2.5, an approximate 38% reduction was observed compared to petrol-fuelled LVs and a 46% reduction compared to non-DPF LVs. Graphical abstract: Unlabelled Image Highlights: Leading vehicle (LV) emissions significantly affect in-cabin particle exposures. Euro 6 petrol LVs led to a decrease of fine Particulate Matter (PM) in-cabin levels. PM in-cabin exposure is greatly reduced starting from the Euro 5 diesel standard. Clear reductions of in-cabin PM exposures were linked to Euro 5 or 6 LVs. LVs fitted with diesel particulate filters highly reduced the in-cabin PM exposures.