Semi-quantitative understanding of source contribution to nitrous acid (HONO) based on 1 year of continuous observation at the SORPES station in eastern China
Semi-quantitative understanding of source contribution to nitrous acid (HONO) based on 1 year of continuous observation at the SORPES station in eastern China
复制标题
基于中国东部SORPES站一年连续观测对亚硝酸（HONO）来源贡献的半定量认识
DOI：
10.5194/acp-19-13289-2019
复制
发表时间：
2019-10-28
影响因子：
6.3
通讯作者：
Ding, Aijun
中科院分区：
文献类型：
--
作者：
Liu, Yuliang;Nie, Wei;Ding, Aijun
抽象的。亚硝酸（HONO）是羟基自由基（OH）的重要前体，
长期以来被认为对大气层具有重要意义
化学，但其来源仍有争议。在这项研究中，我们进行了
2017年11月至2018年11月，
位于中国东部南京的SORPES站。年平均混合比
观测到的HONO为0.69±0.58 ppb，显示出对
OH相对于臭氧的平均OH产生速率为1.16 ppb h−1。到
估算了HONO燃烧排放的影响，
从55个新鲜烟羽（NO scinNOx> 0.85）中得到HONO到NOx的转化率，平均值为0.79%。在夜间，
发现HONO依赖于RH，NO_2在
气溶胶表面可能是HONO产生的原因。平均
测定夜间NO2-转化为HONO的频率（CHONO
在137例HONO形成病例中，为0.0055±0.0032 h-1。的
中午前后HONO来源的缺失似乎是光诱导的，
平均Punknown为1.04 ppb h−1，基于半定量
HONO预算分析。应用超定方程组，
获得夜间HONO源的月变化。除了
燃烧排放的HONO（约占总浓度的23%），
地面上不均匀形成的HONO对测量的HONO的贡献是
全年保持在36%左右。土壤
排放显示出明显的季节性变化，
在7月和8月观察了HONO。产生HONO的倾向更高，
气溶胶面出现在重度霾（占总浓度的40%，
一月）。我们的研究结果突出了HONO来源不断变化的贡献
并鼓励进行更长期的观察，以评估
各种来源。
Abstract. Nitrous acid (HONO), an important precursor of the hydroxyl radical (OH),
has long been recognized as of significance to atmospheric
chemistry, but its sources are still debated. In this study, we conducted
continuous measurement of HONO from November 2017 to November 2018 at the
SORPES station in Nanjing of eastern China. The yearly average mixing ratio
of observed HONO was 0.69±0.58 ppb, showing a larger contribution to
OH relative to ozone with a mean OH production rate of 1.16 ppb h−1. To
estimate the effect of combustion emissions of HONO, the emitted ratios of
HONO to NOx were derived from 55 fresh plumes (NO∕NOx > 0.85), with a mean value of 0.79 %. During the nighttime, the chemistry of
HONO was found to depend on RH, and heterogeneous reaction of NO2 on
an aerosol surface was presumably responsible for HONO production. The average
nighttime NO2-to-HONO conversion frequency (CHONO) was determined
to be 0.0055±0.0032 h−1 from 137 HONO formation cases. The
missing source of HONO around noontime seemed to be photo-induced, with an
average Punknown of 1.04 ppb h−1, based on a semi-quantitative
HONO budget analysis. An over-determined system of equations was applied to
obtain the monthly variations in nocturnal HONO sources. Besides the
burning-emitted HONO (accounting for about 23 % of the total concentration), the
contribution of HONO formed heterogeneously on ground surfaces to measured HONO was an
approximately constant proportion of 36 % throughout the year. The soil
emission revealed clear seasonal variation and contributed up to 40 % of
observed HONO in July and August. A higher propensity for generating HONO on
aerosol surfaces occurred in severe hazes (accounting for 40 % of the total concentration in
January). Our results highlight ever-changing contributions of HONO sources
and encourage more long-term observations to evaluate the contributions from
varied sources.