AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Seasonal Variations in Aerosol Emissions from Light- and Heavy-Duty Vehicles in the Fort McHenry Tunnel
ANDREY KHLYSTOV, David Campbell, Desert Research Institute
Abstract Number: 758 Working Group: Carbonaceous Aerosol
Abstract Vehicular traffic is one of the main sources of particulate matter and its precursors. Due to the introduction of increasingly stringent emission standards, significant advances in automotive technology and fuel formulations were made in recent years. We will present results of a study aimed to investigate real life effectiveness of emission controls and to update profiles of traffic-emitted air pollutants. The study was conducted in the Fort McHenry Tunnel in Baltimore, MD, during two one-week-long campaigns, one in winter (February 2015) and one in summer (August 2015). The tunnel passes under the Baltimore Harbor, carrying traffic of Interstate 95, approximately 55,000 vehicles per day. UFP size distributions were measured using scanning mobility particle sizers, while aerosol chemical composition was measured using filter-XAD pairs to capture both particle- and gas-phase semivolatile compounds. Filter and XAD samples were analyzed using gas chromatography – mass spectrometry for polycyclic aromatic hydrocarbons (PAH), alkanes, hopanes, steranes, and nitro-PAHs. Carbon monoxide, nitrogen oxides, and volatile organic compounds were also measured. Emission factors (EFs) of over 400 pollutants were determined separately for light dury (LD) and heavy duty (HD) vehicles during winter and summer seasons of 2015. Warm and cold season measurements allowed us to assess the effect of temperature on UFP size distributions and EFs of different pollutants. The EFs measured during this study will be compared with those from earlier real-world emission measurements in the U.S.A. in which EFs for LD and HD vehicles were reported separately, including a 1992 study conducted at the Fort McHenry Tunnel. The present study provides a check on whether emissions in the East Coast of the U.S.A. experienced similar emission reductions as California, where most past traffic emission studies took place. A comparison with predictions by the MOVES2014 model will also be presented.