Impact of the heterogeneous hydrolysis of N₂O₅ on chemistry and nitrate aerosol formation in the lower troposphere under photosmog conditions

Abstract

[1] The impact of the heterogeneous hydrolysis of N 2 O 5 on tropospheric gas phase and particle phase chemistry was investigated by performing model simulations with two comprehensive model systems and taking into account recent findings on the heterogeneous reaction probability of N 2 O 5 . Hereby, we focused on photosmog conditions in the lower troposphere. Chemistry box model runs were carried out neglecting transport and deposition processes. The heterogeneous hydrolysis of N 2 O 5 leads to a decrease of ozone under low-NO x conditions and to a strong increase of ozone under high-NO x conditions. One-dimensional simulations were performed to take into account vertical mixing processes, deposition, and temporal changes of the emissions. The rate constant for the heterogeneous hydrolysis was determined depending on the simulated aerosol surface area density. A large impact of the heterogeneous hydrolysis on the nocturnal concentrations of N 2 O 5 , NO 3 , HNO 3 , and the surface area density and nitrate content of the aerosol is found. However, the effect of the hydrolysis of N 2 O 5 on ozone decreases considerably compared to the box model simulations. Three-dimensional simulations for a typical summer smog situation for the southwestern part of Germany and on the European scale, which cover a variety of atmospheric and emission conditions, confirm these findings. The impact of heterogeneous hydrolysis on ozone is small, but it causes remarkable changes in the nocturnal concentrations of nitrogen-containing species and on aerosol properties such as surface area density and nitrate content.

Production of N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> in summer in urban Beijing, China

“…The lower ClNO 2 /N 2 O 5 ratios during P2 compared with P1 can be explained by the "nitrate effect", which suppressed N 2 O 5 uptake (Mentel and Wahner, 1999) as P2 showed much higher nitrate concentrations than P1 (4.2 vs. 1.4 µg m −3 ). Note that the ClNO 2 /N 2 O 5 ratios were also characterized by a dependence on Org / SO 4 ratios in our campaign, similar to other studies (Evans and Jacob, 2005;Riemer et al, 2009). …”

“…Previous laboratory studies have shown a large variability of γ N 2 O 5 (0.0002-0.3) depending on the physical characteristics of the substrates (e.g., aerosol surfaces, water droplets, and ice and crystal surfaces), environmental conditions (e.g., acidity, relative humidity, and temperature), and chemical composition of aerosol particles (e.g., nitrate, sulfate, black carbon, and organic coating; Sander et al, 2006;Chang et al, 2011;Anttila et al, 2006;Cosman et al, 2008;Thornton and Abbatt, 2005;McNeill et al, 2006). To reveal the effects of each factor on N 2 O 5 /ClNO 2 chemistry, several parameterizations of γ N 2 O 5 and ø have been proposed during the last decade (Riemer et al, 2003;Evans and Jacob, 2005;Anttila et al, 2006;Davis et al, 2008;Riemer et al, 2009;Griffiths et al, 2009). For example, Bertram and Thornton (2009) constructed a parameterization of γ N 2 O 5 as a function of aerosol liquid water, nitrate, and chloride content based on the measurements of laboratory-generated internally mixed chloride-nitrate particles.…”

Long-range aerosol transport from Europe to Istanbul, Turkey

“…In recent years the formation of secondary particles from gaseous precursors and particle dynamics has been added to the physical and chemical processes handled in AQMs (Binkowski and Shankar, 1995;Ackermann et al, 1998;Binkowski, 1999;Schell et al, 2002, Riemer et al, 2003.…”

The sensitivity of aerosol in Europe to two different emission inventories and temporal distribution of emissions

“…The hydrolysis of N 2 O 5 on wet aerosol surfaces is an important pathway to convert NO x into HNO 3 (Dentener and Crutzen, 1993;Riemer et al, 2003;Schaap et al, 2003a, b):…”