The air quality estimation tool for non-road mobile sources of emissions is the EPA developed NONROAD tool. This tool relies upon default values for equipment population counts and activity levels derived from surveys conducted by EPA as well as local knowledge when available. The tool’s ability to reflect emissions in any given geographic area is dependent upon the quality and specificity of the inputs provided.
The Department completed a thorough assessment of risk from toxic air pollutants in the Portland area in 2011 highlighting diesel as a prominent risk factor for elevated cancer risk from ambient exposure. Within the range of sources of diesel, non-road diesel powered construction equipment dominated the risk exposure. Locally sourced information about on-road vehicle operation (e.g., time, volume, location, speed, etc.) is well developed but similar information is lacking at the same level of quality for non-road equipment. A thorough analysis resulting in comparable levels of confidence would not only inform further modeling efforts but also allow more targeted and focused mitigation strategies to be implemented.
The 2009 Oregon Legislature appropriated funds to DEQ to use a third-party contractor to conduct a statewide and multi-sector inventory of non-road diesel engines. The purpose of this inventory is to inform and refine air quality models based on private and public fleets currently in use. To ensure the survey results are representative of the statewide inventory, data collection must be conducted using a mix of sampling techniques, including but not limited to whole fleet inventories (i.e., census style counts), representative sampling of fleets by fleet size, and industry surveying. Results and assumptions should be verified using existing relevant and complementary data, such as fuel use and business asset data collected by county tax assessors. The Department is to consult with interested stakeholders during certain phases of the inventory work including, but not limited to, prior to releasing the inventory request-for-proposal and upon the development of preliminary results.
The Department met with stakeholders on November 22, 2017 and issued a Request for Information on January 9, 2018 to further consult with stakeholders and gather input on the form of the Request for Proposals. The following stakeholder comments and responses
from the Department are from the more recent RFI process.