01588780

Component

https://doi.org/10.3141/2570-13

Motor vehicle emissions include many different compounds that have different levels of toxicity in humans. Volatile organic compounds (VOCs) are components of motor vehicle emissions with varying effects on human health and cancer risks. Proportional emission rates among compounds can vary substantially by vehicle and fuel type. This study addressed the question of how traffic fleet composition affects the toxicity of VOC emissions. Using inhalation unit risk estimates from the U.S. Environmental Protection Agency, VOC risk profiles were quantified for vehicle–fuel type combinations, light-duty and heavy-duty vehicle fleets, and roadway facility types (on-network and off-network). Of 14 modeled VOCs, formaldehyde, benzene, naphthalene, and 1,3-butadiene contribute most to the cumulative risk of vehicle emissions. Formaldehyde and naphthalene are mainly emitted by diesel vehicles; benzene and 1,3-butadiene are mainly emitted by gasoline vehicles. Cumulative VOC risk generated per on-network vehicle mile is four times higher for a gasoline heavy-duty vehicle and eight times higher for a diesel heavy-duty vehicle than for a gasoline light-duty vehicle. Off-network, cumulative VOC risk generated per vehicle is twice as high for gasoline heavy-duty vehicles as for diesel heavy-duty vehicles or gasoline light-duty vehicles. A case study of lane management strategies demonstrated how traffic management can change a VOC emissions risk profile and that changes in VOC emissions risk are different from changes in VOC emissions mass.

01590543

16-6536

English

pp 118–126

2016

Transportation Research Record: Journal of the Transportation Research Board

9780309369923

Print

Figures (8) ; References (40)

Benzene; Butadiene; Diesel engine exhaust gases; Exhaust gases; Formaldehyde; Gasoline; Heavy duty vehicles; Highway traffic control; Toxicity; Vehicle fleets; Vehicle mix

Lane management; Light duty vehicles; Naphthalene; Volatile organic compounds

Energy; Environment; Highways; Vehicles and Equipment

TRIS, TRB, ATRI

Jan 12 2016 6:53PM

• Assessment of the Carbon Footprint Reductions of Tricycle Logistics Services
• Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications
• Comparison of Vehicle-Specific Fuel Use and Emissions Models Based on Externally and Internally Observable Activity Data
• Deriving Local Operating Distributions to Estimate Transit Bus Emissions Across an Urban Network
• Development of Macroscopic Emission Estimation Model Based on Microscopic Operating Modes
• Emissions Analysis for a Transit Corridor Under Different Improvement Strategies
• Emissions Modeling with MOVES and EMFAC to Assess the Potential for a Transportation Project to Create Particulate Matter Hot Spots
• Estimating Project-Level Vehicle Emissions with Vissim and MOVES-Matrix
• Evaluation of Light-Duty Gasoline Vehicle Rated Fuel Economy Based on In-Use Measurements
• Measuring Pedestrian Exposure to PM-2.5: Case of the Seattle, Washington, International District
• Microsimulation-Based Emissions Modeling for a Major Infrastructure Renewal Plan: Assessment of Network Attributes and Land Use Effects on Vehicular Emissions
• Modeling Criteria and Air Toxic Pollutants in Light-Duty Biodiesel Exhaust
• Operations and Emissions Characteristics of Light-Duty Vehicles on Ramps
• Optimized Adjustment of Speed Resolution and Time Alignment Data for Improving Emissions Estimations