Atmospheric HONO mixing ratios in indoor and outdoor environments span a range of less than a few parts per trillion by volume (pptv) up to tens of parts per billion by volume (ppbv) in combustion plumes. Previous HONO calibration sources have utilized proton transfer acid displacement from nitrite salts or solutions, with output that ranges from tens to thousands of ppbv. Instrument calibrations have thus required large dilution flows to obtain atmospherically relevant mixing ratios. Here we present a simple universal source to reach very low HONO calibration mixing ratios using a nitrite-coated reaction device with the addition of humid air and/or HCl from a permeation device. The calibration source developed in this work can generate HONO across the atmospherically relevant range and has high purity (> 90 %), reproducibility, and tunability. Mixing ratios at the tens of pptv level are easily reached with reasonable dilution flows. The calibration source can be assembled to start producing stable HONO mixing ratios (relative standard error, RSE ≤ 2 %) within 2 h, with output concentrations varying ≤ 25 % following simulated transport or complete disassembly of the instrument and with ≤ 10 % under ideal conditions. The simplicity of this source makes it highly versatile for field and lab experiments. The platform facilitates a new level of accuracy in established instrumentation, as well as intercomparison studies to identify systematic HONO measurement bias and interferences.

中文翻译：

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便携式，坚固，稳定且可调的气相亚硝酸校准源（HONO）

室内和室外环境中的大气HONO混合比的范围在燃烧羽流中的范围小于十亿分之几（pptv）。以前的HONO校准源已利用亚硝酸盐或溶液中的质子转移酸置换，其输出范围为数十到数千ppbv。因此，仪器校准需要大量的稀释流量以获得与大气相关的混合比。在这里，我们介绍了一种简单的通用来源，使用亚硝酸盐涂层的反应装置并从渗透装置中加入湿空气和/或HCl，可以达到非常低的HONO校准混合比。在这项工作中开发的校准源可以在与大气有关的范围内产生HONO，并且纯度高（> 90％），可重复性和可调性。合理的稀释流量可轻松达到数十pptv水平的混合比例。校准源可组装开始生产稳定HONO混合比（相对标准误差，RSE  ≤  2小时内2％），与输出浓度变化≤  25％以下的模拟运输或完全拆卸该仪器中并用≤ 在理想的10％条件。该源的简单性使其在现场和实验室实验中具有很高的通用性。该平台有助于将既定的仪器以及相互比对研究提高到新的准确性水平，以识别系统性的HONO测量偏差和干扰。