Air Quality

Edmonds, Washington
The City of Edmonds wishes to reduce congestion and solve key safety issues for vehicles accessing SR 99 by providing protected left-turn phasing for both approaches and restricting left turns from SR 99 onto 76th Avenue W. The analysis examined CO concentrations using WSDOT’s Washington State Intersection Screening Tool (WASIST) and the results of this analysis demonstrate that carbon monoxide concentrations resulting from this project will not create new violations of the National Ambient Air Quality CO Standards (NAAQS). Therefore, this project met the transportation conformity requirements, and no additional air quality mitigation measures were required.

Renton, Washington
MM&A performed an examination of the air quality impacts resulting from the extension of the F-line Rapid Ride transit system, approximately 1.5 miles from its original terminus at the Renton Transit Center (Burnett Avenue S /South 3rd) Street in Renton, Washington. The analysis was based upon WSDOT and FHWA guidance and modeling in the Synchro software implementation of the Highway Capacity Manual. The results of the hotspot analysis demonstrated that the intersection would not meet or exceed the National Ambient Air Quality Standards for carbon monoxide.

Kelso, Washington
The analysis examined CO concentrations using WSDOT's Washington State Intersection Screening Tool (WASIST) and the results of this analysis demonstrate that carbon monoxide concentrations resulting from this project will not create new violations of the National Ambient Air Quality CO Standards (NAAQS). Therefore, this project met the transportation conformity requirements, and no additional air quality mitigation measures were required.

Shine, Washington
Three studies of the noise impacts of a large sand and gravel operation. The first was an extensive study of the noise impacts of an existing 1 million TPY sand and gravel operation. The second study was an analysis of the effects of the excavation activities moving to a new nearby area. The third study determined the noise impacts of building a ship-loading facility on Hood Canal. In the first two studies, simultaneous 24-hour measurements were taken at six locations and the results were compared to the King County Noise Code. To determine future noise levels when the mine’s working face is moved the 1/3-octave band noise signatures of the mining machinery were measured and input in the Environmental Noise Model. The third study (Pit-to-Pier Project) used the CADNA A noise model. All the studies indicated that the existing operations did not exceed state or county noise standards during periods of normal meteorology. In the second study, the proposal to relocate the working face was found to generate less noise than the current operations.

Seattle, Washington
A study of the air quality and noise impacts of system-wide changes to the City of Seattle solid waste trucking system. Air quality impacts are from changes in garbage truck vehicle-miles and dust control and filter systems for an intermodal solid waste transfer facility. Noise impacts are from changes in automobile traffic and truck traffic and the waste handling machinery used on site.

Vancouver, Washington
The Vancouver region is classified as a “maintenance area” for carbon monoxide and in “attainment” for ozone. Because of the low level of service at the intersection, a quantitative analysis was required. The analysis showed that overall, the intersection improvements will cause a slight decrease in vehicle emissions as the project will reduce vehicle delay at the intersection. This project is part of the 2007 Update of Clark County’s Metropolitan Transportation Plan (MTP), which has been found to meet Conformity requirements.

This study was an analysis of the impacts upon air quality resulting from improvements to the I-5 Nyberg Road interchange. This project will add two eastbound lanes to the Nyberg Road overpass and will make changes to the southbound and northbound off ramps. This report presented the results of air quality modeling which is based upon the use of air quality models developed by the US. Environmental Protection Agency (EPA) for predicting concentrations of carbon monoxide, the pollutant of most concern for transportation projects. Modeling was performed for both of the signalized off ramp intersections. They are currently operating at a LOS of C and D and are projected to operate at E and D in 2020 after the project improvements are built. No exceedances were found and no mitigation measures were required.