Impact of roadside noise barriers on particle size distributions and pollutants concentrations near freeways

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Neelakshi Hudda
  • Nancy Daher
  • Winnie Kam
  • Jorn Herner
  • Kathleen Kozawa
  • Steven Mara
  • Constantinos Sioutas

Detail(s)

Original languageEnglish
Pages (from-to)3118-3127
Journal / PublicationAtmospheric Environment
Volume44
Issue number26
Publication statusPublished - Aug 2010
Externally publishedYes

Abstract

Increasing epidemiological evidence has established an association between a host of adverse health effects and exposure to ambient particulate matter (PM) and co-pollutants, especially those emitted from motor vehicles. Although PM and their co-pollutants dispersion profiles near the open freeway have been extensively characterized by means of both experimental measurements and numerical simulations in recent years, such investigations near freeways with roadside barriers have not been well documented in the literature. A few previous studies suggested that the presence of roadside structures, such as noise barriers and vegetation, may impact the decay of pollutant concentrations downwind of the freeway by limiting the initial dispersion of traffic emissions and increasing their vertical mixing due to the upward deflection of airflow. Since the noise barriers are now common roadside features of the freeways, particularly those running through populated urban areas, it is pertinent to investigate the impact of their presence on the particles and co-pollutants concentrations in areas adjacent to busy roadways. This study investigated two highly trafficked freeways (I-710 and I-5) in Southern California, with two sampling sites for each freeway, one with and the other without the roadside noise barriers. Particle size distributions and co-pollutants concentrations were measured in the immediate proximity of freeways and at different distances downwind of the freeways. The results showed the formation of a " concentration deficit" zone in the immediate vicinity of the freeway with the presence of roadside noise barrier, followed by a surge of pollutant concentrations further downwind at 80-100 m away from freeway. The particle and co-pollutants concentrations reach background levels at farther distances of 250-400 m compared to 150-200 m at the sites without roadside noise barriers. © 2010 Elsevier Ltd.

Citation Format(s)

Impact of roadside noise barriers on particle size distributions and pollutants concentrations near freeways. / Ning, Zhi; Hudda, Neelakshi; Daher, Nancy; Kam, Winnie; Herner, Jorn; Kozawa, Kathleen; Mara, Steven; Sioutas, Constantinos.

In: Atmospheric Environment, Vol. 44, No. 26, 08.2010, p. 3118-3127.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review