title: The effects of vegetation barriers on near-road ultrafine particle number and carbon monoxide concentrations.
abstract: Numerous studies have shown that people living in near-roadway communities (within 100 m of the road) are exposed to high ultrafine particle (UFP) number concentrations, which may be associated with adverse health effects. Vegetation barriers have been shown to affect pollutant transport via particle deposition to leaves and altering the dispersion of emission plumes, which in turn would modify the exposure of near-roadway communities to traffic-related UFPs. In this study, both stationary (equipped with a Scanning Mobility Particle Sizer, SMPS) and mobile (equipped with Fast Mobility Particle Sizer, FMPS) measurements were conducted to investigate the effects of vegetation barriers on downwind UFP (particle diameters ranging from 14 to 102 nm) concentrations at two sites in North Carolina, USA. One site had mainly deciduous vegetation while the other was primarily coniferous; both sites have a nearby open field without the vegetation barriers along the same stretch of limited access road, which served as a reference. During downwind conditions (traffic emissions transported towards the vegetation barrier) and when the wind speed was above or equal to 0.5m/s, field measurements indicated that vegetation barriers with full foliage reduced UFP and CO concentrations by 37.7-63.6% and 23.6-56.1%, respectively. When the test was repeated at the same sites during winter periods when deciduous foliage was reduced, the deciduous barrier during winter showed no significant change in UFP concentration before and after the barrier. Results from the stationary (using SMPS) and mobile (using FMPS) measurements for UFP total number concentrations generally agreed to within 20%.
authors.affiliation: Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Ming-Yeng
authors.initials: MY
authors.lastname: Lin
authors.affiliation: Office of Research and Development, US EPA, USA.
authors.forename: Gayle
authors.initials: G
authors.lastname: Hagler
authors.affiliation: Office of Research and Development, US EPA, USA; Office of Transportation and Air Quality, US EPA, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Baldauf
authors.affiliation: Office of Research and Development, US EPA, USA.
authors.forename: Vlad
authors.initials: V
authors.lastname: Isakov
authors.affiliation: Department of Radiation Oncology, William Beaumont Hospital, USA.
authors.forename: Hong-Yiou
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Division of Atmospheric Sciences, Desert Research Institute, USA. Electronic address: andrey.khlystov@dri.edu.
authors.forename: Andrey
authors.initials: A
authors.lastname: Khlystov
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control* / Q000706:statistics & numerical data; D002248:Carbon Monoxide / Q000032:analysis*; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D009657:North Carolina; D052638:Particulate Matter / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D002248:Carbon Monoxide
keywords: Carbon monoxide; Mobile measurement; Near-road; Ultrafine particle; Vegetation barriers