Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA.
Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, NV, USA.
Sci Total Environ. 2015 Oct 15;530-531:493-504. doi: 10.1016/j.scitotenv.2015.03.125. Epub 2015 Apr 4.
The current United States (US) National Ambient Air Quality Standard (NAAQS) for O3 (75 ppb) is expected to be revised to between 60 and 70 ppb. As the NAAQS becomes more stringent, characterizing the extent of O3 and precursors transported into the US is increasingly important. Given the high elevation, complex terrain, and location in the Intermountain West, the State of Nevada is ideally situated to intercept air transported into the US. Until recently, measurements of O3 and associated pollutants were limited to areas in and around the cities of Las Vegas and Reno. In 2011, the Nevada Rural Ozone Initiative began and through this project 13 surface monitoring sites were established. Also in 2011, the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX) began making routine aircraft measurements of O3 and other greenhouse gases in Nevada. The availability of aircraft and surface measurements in a relatively rural, remote setting in the Intermountain West presented a unique opportunity to investigate sources contributing to the O3 observed in Nevada. Our analyses indicate that stratosphere to troposphere transport, long-range transport of Asian pollution, and regional emissions from urban areas and wildfires influence surface observations. The complexity of sources identified here along with the fact that O3 frequently approaches the threshold being considered for a revised NAAQS indicate that interstate and international cooperation will be necessary to achieve compliance with a more stringent regulatory standard. Further, on a seasonal basis we found no significant difference between daily 1-h maximum O3 at surface sites, which ranged in elevation from 888 to 2307 m, and aircraft measurements of O3 <2500 m which suggests that similar processes influence daytime O3 across rural Nevada and indicates that column measurements from Railroad Valley, NV are useful in understanding these processes.
当前美国（US）的臭氧（O3）环境空气质量标准（NAAQS）（75 ppb）预计将修订为 60 到 70 ppb 之间。随着 NAAQS 变得更加严格，描述 O3 和前体污染物进入美国的程度变得越来越重要。内华达州由于海拔高、地形复杂，且位于山间西部，是拦截进入美国的空气污染物的理想位置。直到最近，O3 及相关污染物的测量才仅限于拉斯维加斯和里诺市及其周边地区。2011 年，内华达州农村臭氧倡议开始实施，通过该项目建立了 13 个地面监测站。同样在 2011 年，美国宇航局艾姆斯阿尔法喷气式大气实验（AJAX）开始在内华达州进行常规飞机测量 O3 和其他温室气体。在山间西部相对偏远的农村环境中，飞机和地面测量的可用性为研究导致内华达州 O3 观测的来源提供了独特的机会。我们的分析表明，平流层到对流层的传输、亚洲污染的长距离传输以及城市地区和野火的区域排放都会影响地面观测。这里确定的来源的复杂性以及 O3 经常接近修订后的 NAAQS 考虑的阈值这一事实表明，要达到更严格的监管标准，州际和国际合作将是必要的。此外，我们还发现，在季节变化的情况下，地面站点的每日 1 小时最大 O3（海拔从 888 到 2307 米）与飞机测量的 2500 米以下的 O3 之间没有显著差异，这表明类似的过程会影响整个内华达州农村地区的白天 O3，并表明内华达州铁路谷的柱测量值对于理解这些过程很有用。
