SGER: Measurements of Nitrous Acid and Nitric Acid during BEARPEX 2009

这一探索性项目包括一种新仪器的开发和初步现场测试，该仪器采用长程吸收光度(LOPAP)方法来测量空气中的亚硝酸和硝酸。这两种酸都是氮氧化物的氧化产物。在某些条件下，亚硝酸被认为是羟基自由基的重要来源，而羟基自由基是最重要的大气氧化剂。硝酸的沉积是从对流层中去除氧化无机氮的主要原因。2009年夏季在加利福尼亚州布洛吉特森林进行的一项多调查者研究期间的实地测试(BEARPEX-09)，重点是生物排放及其对大气化学的影响，将包括通过并排比较和基于不同原理的方法调查测量中的潜在干扰。以前在高海拔和极地环境中对亚硝酸测量方法进行的现场相互比较得出了不同的结果，这表明测量人工制品的存在，而且它们可能与地点有关。在BEARPEX期间将获得大量其他痕量气体和气溶胶成分的数据，这将使我们能够在非常不同的森林环境中详细检查可能的HONO测量人工产物及其原因。更广泛的影响将包括更好地理解这两种酸的化学，进而更好地理解大气氧化化学和自由基预算。一名研究生和两名本科生将通过参与该项目进行培训。该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。

This exploratory project involves development and initial field testing of a new instrument employing the LOng Path Absorption Photometry (LOPAP) method to measure nitrous and nitric acids in air. Both acids are oxidation products of nitrogen oxides. Nitrous acid is thought to be, under some conditions, a significant source of hydroxyl radical, the most important atmospheric oxidant. Deposition of nitric acid is responsible for much of the removal of oxidized inorganic nitrogen from the troposphere. Field testing during a multi-investigator study focusing on biogenic emissions and their effects on atmospheric chemistry in Blodgett Forest, California in summer 2009 (BEARPEX-09) will include investigation of potential interferences in the measurements via side-by-side comparison with a method based on a different principle. Previous field intercomparisons of nitrous acid measurement methods in high-altitude and polar environments yielded differing results, suggesting that measurement artifacts exist and that they may be site dependent. The large array of data for other trace gases and aerosol composition to be obtained during BEARPEX will allow detailed examination of possible HONO measurement artifacts and their causes in the very different forest environment. Broader impacts will include better understanding of the chemistry of these two acids and, in turn, better understanding of atmospheric oxidation chemistry and radical budgets. One graduate and two undergraduate students will be trained through participation in the project. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).