title: HONO and its potential source particulate nitrite at an urban site in North China during the cold season.
abstract: Characteristics and transformation of nitrous acid (HONO) and particulate nitrite were investigated with high time-resolution field measurements at an urban site in Ji'nan, China from Nov. 2013 to Jan. 2014. During the sampling period, averages of 0.35ppbv HONO and 2.08μgm(-3) fine particulate nitrite were observed. HONO and particulate nitrite exhibited similar diurnal variation patterns but differed in the time at which concentration peaks and valleys occurred. Elevated nocturnal HONO concentration peaks were mainly associated with primary emissions from vehicle exhaust and secondary formation via heterogeneous reactions of NO2. In fresh air masses dominated by vehicle emissions, the average HONO/NOx ratio was 0.58%. The nocturnal heterogeneous reactions of NO2 contributed to about half of the elevated HONO concentration peaks, with the conversion rates in the range of 0.05% to 0.96%h(-1). Meanwhile, a large amount of particulate nitrite, which greatly exceeded the concentration of the gas-phase HONO, was also produced through the heterogeneous reactions of NO2. The large yields of particulate nitrite were facilitated by abundant ammonia and particulate cations in urban Ji'nan. Notably, in the daytime, particulate nitrite acted as a potential source of HONO, especially in conditions of low humidity and acidic aerosols, which possibly has subsequent effects on photochemistry in the boundary layer.
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Liwei
authors: L
authors: Wang
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Liang
authors: L
authors: Wen
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Caihong
authors: C
authors: Xu
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China; School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors: Jianmin
authors: J
authors: Chen
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China. Electronic address: xinfengwang@sdu.edu.cn.
authors: Xinfeng
authors: X
authors: Wang
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China; School of Environmental Science and Engineering, Shandong University, Ji'nan 250100, China.
authors: Lingxiao
authors: L
authors: Yang
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Wenxing
authors: W
authors: Wang
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Xue
authors: X
authors: Yang
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Xiao
authors: X
authors: Sui
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Lan
authors: L
authors: Yao
authors: Environment Research Institute, Shandong University, Ji'nan 250100, China.
authors: Qingzhu
authors: Q
authors: Zhang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D002681:China; D004784:Environmental Monitoring; D009573:Nitrites / Q000032:analysis*; D009608:Nitrous Acid / Q000032:analysis*; D012621:Seasons
chemical_list: D000393:Air Pollutants; D009573:Nitrites; D009608:Nitrous Acid
keywords: HONO; Heterogeneous conversion; Particulate nitrite; Source identification; Transformation