AQ Programs

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.
DEQ 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 2017 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. DEQ 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 Nov. 22, 2017 and issued a Request for Information on Jan. 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 DEQ are from the more recent RFI process.


The Department’s contractor for this project, Eastern Research Group, Inc., presented the inventory findings during a public webinar on April 29, 2020. Below are the links to the slides, a recording of the presentation and the final report. 

Please email any questions or comments about this project to: