Emission characteristics and human health impacts of vehicle originated condensable particulate matter

Condensable particulate matter (CPM) represents airborne primary PM rapidly formed through condensation after being discharged to the atmosphere as gaseous pollutants. Compared to CPM produced by stationary sources such as coal-fired power plants, internal combustion engine vehicle originated CPM has not been spotlighted well, even though ICEVs can generate ultrafine CPM nanoparticles (< 100 nm). In addition, vehicle originated CPM contains hazardous materials (e.g., polyaromatic hydrocarbons), thus threatening human health in urban areas. In this study, CPM originating from 8 types of vehicles was characterized by a novel real-time CPM measurement system (PNU-CPM system) and off-line physicochemical analyses. Emission factors of CPM for the test vehicles were also derived from the measured real-time data. The diesel test vehicles (level 4 and 5) without post-treatment system emitted the largest amount of CPM and Total PM, whereas the gasoline GDI and LPG vehicles showed significantly lower emissions. The CPM emission factor in mass (EFM)-based percentages were about 63.2%, 8.2% and 58.8% for diesel level 4, GDI and LPG 2, respectively. The organic components of CPM were primarily composed of alkanes (∼53.5%) and esters (∼5.1%), varied depending on the type of ICEVs. In addition, the major water-soluble ions in CPM particles were SO₄^2- and Na⁺. The multiple-path particle dosimetry (MPPD) model simulation showed that the mass rate per weight of deposited CPM particles in lungs were increased for younger age groups. This shows that younger age groups receive higher particle deposition in the lungs per body weight, indicating greater respiratory risks for children.