Multi-criteria decision analysis for the selection of a near road ambient air monitoring site for the measurement of mobile source air toxics

In 2002, the Sierra Club legally challenged the US Federal Highway Administration and the Nevada Department of Transportation’s National Environmental Policy Act environmental document related to the proposed widening of US 95 in Las Vegas, Nevada, including the assessment of impacts of mobile source air toxics from the proposed project. To resolve the situation, Federal Highway Administration entered into a Settlement Agreement with Nevada DOT and the Sierra Club, wherein the Administration agreed to undertake a research effort to characterize the impact and behavior of particulate matter with aerodynamic diameter less than 2.5 μm and mobile source air toxics near highways. The US Federal Highway Administration and US Environmental Protection Agency determined that it would be in the best interest of both organizations to implement this project in a collaborative manner, allowing a more effective utilization of staffing and resources. One of the first steps of the project implementation has been the selection of a suitable ambient air monitoring site in or around Las Vegas, Nevada. This article presents the multi-criteria analytical steps taken to select the near road monitoring sites to provide air quality data needed to support environmental decision-making in this project.