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

Abstract

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.

Keywords: garage pollution; particle lung deposition; ultrafine particles; vehicular emissions.

Figure 1

Overall schematic of this study. The three major steps were the collection of size-fractionated PM from a hospital garage, physicochemical characterization of the collected PM, and the assessment of the deposition in human lungs of the UFP fraction.

Figure 2

Time-integrated PM mass concentration as a function of aerodynamic size, as denoted for (a) each winter sampling campaign; (b) each summer sampling campaign; (c) comparison of average concentrations over the entire winter and summer sampling periods. The error bars denote ±1 standard deviation between concentrations obtained from individual HCCIs (n is the number of CCIs involved for each sampling period with n = 16 for winter, n = 18 for summer).

Figure 3

Real-time monitoring of PM particle number concentration as a function of size emissions in the garage conducted during winter and summer campaigns: (a) mobility size distribution utilizing a TSI Nanoscan SMPS and (b) aerodynamic size distribution using TSI APS. Error bars denote ±1 standard deviation.

Figure 4

Chemical characterization of the UFP size fraction of the PM sampled from the garage. The results are represented as percentages for (a) Inorganic Metal Analysis, (b) Elemental and Organic Carbon Composition Analysis and (c) Polycyclic Aromatic Hydrocarbons (PAHs) Analysis. The results are represented as weight over weight fraction percentages (w/w)%.

Figure 5

Deposition of UFPs in the head, tracheobronchial (TB), pulmonary, and total region of the human respiratory tract derived by MPPD model. Results represented in terms of (a) the percentage of UFP aerosol deposited in each region of human respiratory tract and (b) mass of UFPs deposited in each region of human respiratory tract during a typical work week (40 h) during winter (blue) ands (red).