Assessment of the Physicochemical Properties of Ultrafine Particles (UFP) from Vehicular Emissions in a Commercial Parking Garage: Potential Health Implications.

Vehicular emissions are a major culprit in the rise of urban air pollution. The particulate matter (PM) emitted from vehicular sources includes primarily ultrafine particles (UFPs) with aerodynamic diameters less than 0.1 µm (PM_0.1) and is linked to adverse respiratory and cardiovascular health effects. Despite this knowledge, few exposure assessment studies exist that detail the physicochemical properties of PM in parking garages. In this study, airborne PM emitted by vehicles in a parking garage of a hospital in New Jersey was sampled, during winter and summer seasons, and physicochemically characterized. The results indicate that the mass concentrations of the UFPs in the garage were 2.51 µg/m³ and 3.59 µg/m³, respectively. These UFPs contained a large percentage of elemental carbon and toxic elements. They also contained polycyclic aromatic hydrocarbons (PAHs), having deleterious health effects. An inhalation particle modeling revealed that 23.61% of these UFPs are deposited in the pulmonary region of the lung, translating to a dose of 10.67 µg for winter and 15.25 µg for summer, over a typical 40 h work week. These high deposited levels of UFPs and their complex chemistry levels further warrant the need for toxicological assessment of UFPs related to vehicular emissions.