Life Cycle Inventory and Impact Analysis Framework for Nonroad Construction Vehicles and Equipment Based Upon In-Use Measurements (TSE03-L)

North Carolina State University, Raleigh NC

Investigators

Abstract

Construction vehicles contribute substantially to national emissions; however, their importance is difficult to quantify with existing tools. Key hypotheses are that: (1) vehicle/equipment energy use and emissions are episodic in nature; (2) in-use microscale data are required to quantify this; (3) new models are needed to explain such episodes and to identify opportunities for improvements; (4) fuel cycle energy use and emissions are not negligible compared to direct energy use and emissions of the vehicles/equipment; (5) there is substantial inter-vehicle variability and uncertainty in average emissions; and (6) there is a need for a new framework by which to design construction practices in order to prevent emissions and reduce energy use (thereby producing cost savings) in the face of uncertainty. The objectives are to: (1)Characterize second-by-second in-use emissions and energy use of nonroad construction vehicles and equipment and their uncertainty; (2)Develop a probabilistic life cycle inventory of conventional nonroad construction vehicles and equipment; (3)Identify and recommend methods for reducing energy use, emissions, and impacts. In Task 1, available second-by-second in-use data are supplemented by a field study to fill data gaps. In Task 2, a micro-scale Construction In-use Vehicle and Equipment emissions and energy use Model (CIVEM) is developed. A probabilistic life cycle inventory (LCI) model for construction equipment is developed in Task 3. The benefits of the approach are demonstrated via a detailed case study in Task 4. Results of the research are integrated into construction and air quality courses and disseminated to regional planning organizations. This work benefits the construction industry, environmental planners, and the general public. The industry can more accurately estimate its contribution to emissions, identify opportunities for reductions in energy use (cost) and emissions via modifications to current practices, and better prepare for future regulation and reduce exposure to liability for violations or fines. With the recent implementation of new stringent ambient air quality standards for ozone (for which NOx and hydrocarbons are precursors) and particulate matter, there will be more pressure on emitters of these pollutants to prevent or control their emissions. The scientific basis for improved emissions estimation developed in this work enables effective air quality strategies regionally and nationally.