ABSTRACT

In the Southeastern U. S. there are Concentrated Animal Feeding Operations (CAFOs) that emit a variety of gases, including SO₂. Sulfur is emitted as reduced sulfur compounds and can react in the atmosphere to produce SO₂. It is expected that the concentration and spread of SO₂ emissions from these sources would differ between wet and dry periods. In this research, SO₂ emissions from locations representing CAFOs and its dispersion over the southeastern U.S. were simulated through sensitivity experiments using the Weather Research and Forecasting-Chemistry (WRF- Chem) model. Simulations were performed for dry periods and precipitation events that occurred over western Kentucky between July 7 and 13 July 2012.

The study found that spatial coverage of SO₂ dispersion originating from these locations was reduced during precipitation events and expanded during dry periods. The average concentration of SO₂ over the study area was also higher during the breaks between precipitation events than during precipitation. The highest concentrations of SO₂ exceeding 1,000 pptv remained within close range of the emission locations for the majority of the simulations, except for when local surface wind speeds were high. Most emissions from the locations remained limited to the surface and lower levels of the atmosphere (850 mb).

摘要

在美国东南部，有排放多种气体（包括 SO ₂ ）的集中式动物饲养作业 (CAFO) 。硫以还原硫化合物的形式排放，可在大气中反应生成 SO ₂。预计来自这些来源的 SO ₂排放的浓度和扩散在潮湿和干燥时期会有所不同。在这项研究中，使用天气研究和预测化学 (WRF-Chem) 模型通过敏感性实验模拟了来自代表 CAFO 的位置​​的SO _{2排放及其在美国东南部的扩散。}模拟了 2012 年 7 月 7 日至 13 日期间发生在肯塔基州西部的干旱期和降水事件。

研究发现，源自这些位置的 SO _{2扩散的空间覆盖范围在降水事件期间减少，而在干旱期间扩大。}研究区域内 SO ₂的平均浓度在降水事件之间的间歇期也高于降水期间。在大多数模拟中，超过 1,000 pptv的最高浓度 SO ₂保持在靠近排放位置的范围内，除非当地地表风速很高。来自这些地点的大部分排放仍然局限于地表和大气的较低层（850 mb）。