Article: Baldauf, RW; Isakov, V; Deshmukh, P; Venkatram, A; Yang, B; Zhang, KM; (2016) “Influence of Solid Noise Barriers on Near-Road and On-Road Air Quality”, Atmospheric Environment, 129; 265-276
Abstract: Public health concerns regarding adverse health effects for populations spending significant amounts of time near high traffic roadways has increased substantially in recent years. Roadside features, including solid noise barriers, have been investigated as potential methods that can be implemented in a relatively short time period to reduce air pollution exposures from nearby traffic. A field study was conducted to determine the influence of noise barriers on both on-road and downwind pollutant concentrations near a large highway in Phoenix, Arizona, USA.
Concentrations of nitrogen dioxide, carbon monoxide, ultrafine particles, and black carbon were measured using a mobile platform and fixed sites along two limited access stretches of highway that contained a section of noise barrier and a section with no noise barrier at-grade with the surrounding terrain. Results of the study showed that pollutant concentrations behind the roadside barriers were significantly lower relative to those measured in the absence of barriers. The reductions ranged from 50% within 50 m from the barrier to about 30% as far as 300 m from the barrier. Reductions in pollutant concentrations generally began within the first 50 m of the barrier edge; however, concentrations were highly variable due to vehicle activity behind the barrier and along nearby urban arterial roadways. The concentrations on the highway, upwind of the barrier, varied depending on wind direction. Overall, the on-road concentrations in front of the noise barrier were similar to those measured in the absence of the barrier, contradicting previous modeling results that suggested roadside barriers increase pollutant levels on the road. Thus, this study suggests that noise barriers do reduce potential pollutant exposures for populations downwind of the road, and do not likely increase exposures to traffic-related pollutants for vehicle passengers on the highway. Published by Elsevier Ltd.
Funding Acknowledgement: U.S. Environmental Protection Agency
Funding Text: This research study was fully funded by the U.S. Environmental Protection Agency, and relied on the collaboration and contribution of several partner organizations in the Phoenix area. We thank Ben Davis and the Maricopa County Air Quality Department for graciously providing storage and maintenance facilities for the air quality monitoring equipment. We also thank Wang Zhang and Vladimir Livshits of the Maricopa Association of Governments for traffic data on I-17 during the sampling period, and historical data on fleet mix characteristics for these sections of I-17 in Phoenix. In addition, we thank Darcy Anderson and Beverly Chenausky of the Arizona Department of Transportation for providing insights on sampling locations and assistance with permitting for access to the sampling locations. We also thank add Brian Eder of the U.S. EPA for providing meteorological forecasts to determine the best location for sampling each day. We finally want to thank Halley Brantley and Gayle! Hagler of the U.S. EPA for their assistance in data processing and quality assurance analyses.