Lee Ben H, Lopez-Hilfiker Felipe D, Schroder Jason C, Campuzano-Jost Pedro, Jimenez Jose L, McDuffie Erin E, Fibiger Dorothy L, Veres Patrick R, Brown Steven S, Campos Teresa L, Weinheimer Andrew J, Flocke Frank F, Norris Gary, O'Mara Kate, Green Jaime R, Fiddler Marc N, Bililign Solomon, Shah Viral, Jaeglé Lyatt, Thornton Joel A
Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA.
Now at Paul Scherrer Institute, Villigen, Switzerland.
J Geophys Res Atmos. 2018;123(19):11225-11237. doi: 10.1029/2018JD029284.
We present airborne observations of gaseous reactive halogen species (HCl, Cl, ClNO, Br,BrNO, and BrCl), sulfur dioxide (SO), and nonrefractory fine particulate chloride (pCl) and sulfate(pSO) in power plant exhaust. Measurements were conducted during the Wintertime INvestigation of Transport, Emissions, and Reactivity campaign in February-March of 2015 aboard the NCAR-NSF C-130 aircraft. Fifty air mass encounters were identified in which SO levels were elevated ~5 ppb above ambient background levels and in proximity to operational power plants. Each encounter was attributed to one or more potential emission sources using a simple wind trajectory analysis. In case studies, we compare measured emission ratios to those reported in the 2011 National Emissions Inventory and present evidence of the conversion of HCl emitted from power plants to ClNO. Taking into account possible chemical conversion downwind, there was general agreement between the observed and reported HCl: SO emission ratios. Reactive bromine species (Br, BrNO, and/or BrCl) were detected in the exhaust of some coal-fired power plants, likely related to the absence of wet flue gas desulfurization emission control technology. Levels of bromine species enhanced in some encounters exceeded those expected assuming all of the native bromide in coal was released to the atmosphere, though there was no reported use of bromide salts (as a way to reduce mercury emissions) during Wintertime INvestigation of Transport, Emissions, and Reactivity observations. These measurements represent the first ever in-flight observations of reactive gaseous chlorine and bromine containing compounds present in coal-fired power plant exhaust.
我们展示了对发电厂废气中气态活性卤素物种（HCl、Cl、ClNO、Br、BrNO和BrCl）、二氧化硫（SO）以及非难熔细颗粒氯化物（pCl）和硫酸盐（pSO）的机载观测结果。测量是在2015年2月至3月的冬季运输、排放和反应性调查活动期间，乘坐美国国家大气研究中心 - 美国国家科学基金会的C - 130飞机进行的。识别出了50次气团相遇情况，其中SO水平比环境背景水平升高了约5 ppb，并且靠近运行中的发电厂。每次相遇都通过简单的风轨迹分析归因于一个或多个潜在排放源。在案例研究中，我们将测量的排放比与2011年国家排放清单中报告的排放比进行比较，并展示了发电厂排放的HCl转化为ClNO的证据。考虑到顺风方向可能的化学转化，观测到的和报告的HCl:SO排放比总体上是一致的。在一些燃煤发电厂的废气中检测到了活性溴物种（Br、BrNO和/或BrCl），这可能与缺乏湿法烟气脱硫排放控制技术有关。在一些相遇情况中，溴物种水平的增强超过了假设煤中所有天然溴化物都释放到大气中的预期水平，尽管在冬季运输、排放和反应性观测期间没有报告使用溴化物盐（作为减少汞排放的一种方式）。这些测量代表了首次对燃煤发电厂废气中存在的含活性气态氯和溴化合物进行的飞行观测。
