Investigating horizontal and vertical pollution gradients in the atmosphere associated with an urban location in complex terrain, Reno, Nevada, USA
Investigating horizontal and vertical pollution gradients in the atmosphere associated with an urban location in complex terrain, Reno, Nevada, USA
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DOI：
10.1016/j.atmosenv.2018.09.063
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发表时间：
2019
影响因子：
5
通讯作者：
A. Pierce;S. Loría‐Salazar;H. Holmes;M. Gustin
中科院分区：
文献类型：
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作者：
A. Pierce;S. Loría‐Salazar;H. Holmes;M. Gustin
一种新的统计方法，即象限法，用于帮助识别影响柱状气溶胶光学深度（τext）与颗粒物表面浓度（<2.5μgm−3in 空气动力学直径，PM2.5）之间关系的不同条件。本研究的主要目标是确定影响美国内华达州里诺市两个山谷地点（∼1370m）和一个高海拔地点（2515m）观察到的大气污染物梯度的空气污染源和大气过程。这两个山谷地点用于调查与高流量高速公路移动源相关的污染物的水平梯度。结果表明，距离主要高速公路 0.03 公里和 > 1 公里的两个山谷地点之间的标准空气污染物浓度存在统计显着差异。垂直梯度受到空气污染源的影响，包括局部和远程传输以及大气边界层稳定性。在 τext 和地表 PM2.5 浓度相关（即两者都增加）的时期，野火排放和充分混合的边界层中的当地污染物在这种关系中占主导地位。在无关联期间，稳定的边界层条件和高空污染造成了 PM2.5 浓度的垂直不均匀性。结果表明，为每小时数据开发的象限法可用于24小时PM2.5和气体数据，是识别空气污染源和大气物理驱动污染梯度的有用工具。
A new statistical method, the quadrant method, was used to aid in identifying different conditions affecting the relationship between columnar aerosol optical depth (τext) and surface concentrations of particulate matter (<2.5 μg m−3in aerodynamic diameter, PM2.5). The main goal of this study was to identify air pollution sources and atmospheric processes affecting gradients of atmospheric pollutants observed at two valley sites (∼1370 m) and a high elevation site (2515 m) located in and adjacent to Reno, Nevada, USA. The two valley sites were used to investigate the horizontal gradient of pollutants associated with mobile sources from high volume highways. Results indicated statistically significant differences in concentrations of criteria air pollutants between the two valley sites, located 0.03 km and >1 km from major highways. Vertical gradients were impacted by air pollution sources, including local and long-range transport, and atmospheric boundary layer stability. During periods when τextand surface PM2.5concentrations were associated (i.e. both increase), emissions from wildfires and local pollutants in a well-mixed boundary layer dominated the relationship. During periods of no association, stable boundary layer conditions and pollution aloft created vertical heterogeneity of PM2.5concentrations. Results showed that the quadrant method, developed for hourly data, can be used with 24 h PM2.5and gaseous data and that it is a useful tool for identifying air pollution sources and atmospheric physics driving pollution gradients.