【摘要】 HONO作为大气OH自由基的前体物和重要贡献源，影响着大气中污染物的氧化降解，控制着对流层大气的自净能力，对灰霾和光化学烟雾形成起到重要作用，同时受污染排放特征、垂直传输和混合、非均相反应和大气光氧化等影响，HONO具有明显的垂直分布特征，因此探究大气中HONO的垂直分布特征对于了解大气灰霾和光化学污染的形成和控制都十分重要。MAX-DOAS作为一种被动遥感技术，能够快速有效地获取大气中污染物的立体分布特征。采用MAX-DOAS仪器对合肥市科学岛2017年12月冬季大气HONO和NO₂进行了立体探测，通过基于最优估算的气溶胶和痕量气体廓线反演算法PriAM获取了两种气体的垂直分布特征。研究结果表明，在观测期间NO₂在近地面10 m内体积混合比（VMR）和垂直柱浓度（VCD）的范围分别在0.51×10¹¹～20.5×10¹¹ molecules·cm^-3和6.0×10¹⁵～5.5×10¹⁶ molecules·cm^-2,在垂直方向上其浓度主要集中在1 km内，且在近地面浓度混合均匀。HONO的VMR和VCD分别在0.03×10¹⁰～5.1×10¹⁰ molecules·cm^-3和3.5×10¹⁴～7.0×10¹⁵ molecules·cm^-2之间，浓度高值出现在100 m内，浓度随高度的升高而明显下降。通过对HONO和NO₂的对比发现，HONO/NO₂比值在0.17%～16.0%（VMR）和1.0%～25.0%（VCD）之间，表明研究期间HONO主要来自于NO₂的转化。对冬季一次典型污染过程（2017.12.26—2017.12.31）分析，HONO/NO₂的比值大于5%,且HONO的浓度值升高(大于0.26×10¹¹ molecules·cm^-3),表明污染条件下NO₂向HONO的转化作用变强。结合风场信息研究发现，污染期间研究区域的NO₂和HONO浓度受到合肥市城区、安徽北部和西北部地区传输的影响。更多还原

【Abstract】 Nitrite（HONO）, as one of the sources of OH free radical in the atmosphere, plays an important role in the oxidative capacity of the atmosphere. Moreover, previous studies have shown that HONO plays an important role in generating atmospheric haze in winter. The conversion of NO₂ is considered one of the important sources of HONO. Therefore, researching the vertical distribution characteristics of HONO in the atmosphere has an important role in studying the formation and control of atmospheric pollution. Because of the important role of HONO in the atmosphere, currently, the methods of chemiluminescence and spectroscopy, as well as indirect methods, are mainly used to measure HONO in the atmosphere. MAX-DOAS method is a passive remote sensing technology that can quickly and effectively obtain the three-dimensional distribution of pollutants in the atmosphere. In this paper, the MAX-DOAS instrument was used for stereo detection of HONO and NO₂ in the winter atmosphere of the Science Island of Hefei in December 2017. The vertical distribution characteristics of those are obtained through the PriAM algorithm. The research results show that during the observation period, the NO₂ vertical mixed concentration（VMR） and vertical column concentration（VCD） in the range of 10 m near the ground were in the range of 0.51×10¹¹～20.5×10¹¹ molecules·cm^-3 and 6.0×10¹⁵～5.5×10¹⁶ molecules·cm^-2, respectively.The concentration was mainly concentrated within 1 km, and evenly mixed near the ground. However, the VMR and VCD of HONO were between 0.03×10¹⁰～5.1×10¹⁰ molecules·cm^-3 and 3.5×10¹⁴～7.0×10¹⁵ molecules·cm^-2, respectively. The upper level of concentration was within 100 m, and its concentration decreased significantly with the increase in height. The HONO/NO₂ ratio was between 0.17%～16.0%（VMR） and 1.0%～25.0%（VCD）, indicating that HONO was mainly derived from NO₂ conversion during the study period. Under a typical polluted episode（2017.12.26—2017.12.31）, HONO/NO₂ was greater than 5%, and the concentration of HONO increased(greater than 0.26×10¹¹ molecules·cm^-3), indicating that the conversion of NO₂ to HONO became strong. By combining the wind field changes to study the source of NO₂ during the pollution period, it was found that the transmission in the urban area of Hefei, northern and northwestern Anhui has a significant effect on NO₂ and HONO.更多还原