On the occurrence of nitrite in urban fogwater

Abstract

Nitrite was observed in fogwater samples 3 -52 pmol L', in a polluted source region in Germany. The fogwater contained high concentrations of various pollutants but only little or no acidity. The concentrations of oxidizable S(IV) were in the range 6 -290 pmol L-'.A two-phase chemical box model is used to interprete the chemistry. Fogwater N(II1) is found to be sensitive to gas-phase HNO, and also to HCHO (which were both not measured). From the distribution of S(IV) between oxidizable and non-oxidizable species (the latter is suspected to be dominated by the complex formed from S(IV) and dissolved HCHO), it is infered that HCHO most likely was low. The reaction between dissolved NO, and S(IV) was an important N(II1) source and could even explain the observed fogwater nitrite concentrations, if no gas-phase HNO, was fed into the fog. The comparison between observed and model predicted suggests that interphase mass transfer of NO, is characterized by a low mass accommodation coefficient.

Enhanced sulfate formation by nitrogen dioxide: Implications from in situ observations at the SORPES station

“…Meanwhile, HONO correlated very well with nitrite (Figure b). The chemical reactions and suggest that the aqueous‐phase oxidation of S(IV) by NO 2 produced nitrite, which was also reported by Lammel and Metzig []. The question is how the nitrite converted to gas‐phase HONO here?…”

“…However, Pandis and Seinfeld [] pointed out that for urban fog with high NO 2 concentrations, this reaction could be one important pathway for S(IV) oxidation, especially when the atmosphere has a sufficient neutralizing capacity. Lammel and Metzig [] did find that this mechanism is the main contributor to the occurrence of nitrite together with S(IV) oxidation in urban fog water.…”

Impact of emissions from shipping, land, and the ocean on stratocumulus cloud water elemental composition during the 2011 E-PEACE field campaign

“…Numerous other species follow in order of concentration: (i) crustal-derived elements including Mg, Si, Ca, and K (individual À was found to be best correlated with NSS Br À (r ¼ 0.81, n ¼ 71), with multiphase halogen reactions as a possible explanation (Enami et al, 2007). There are few recorded NO 2 À measurements in marine stratocumulus cloud water and its presence in clouds has previously been suggested to be due to dissolution of gaseous nitrous acid (HONO) and heterogeneous reactions of NO 2 in clouds (Lammel and Metzig, 1998).…”

Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation

“…Formate is also produced in the aqueous phase via hydroxyl radical (OH) oxidation of organic species such as hydrated formaldehyde (Chameides & Davis, ) and tryptophan (Bianco et al, ). Nitrite measurements in clouds are scarce due to its low concentrations and its fast oxidation (Acker et al, ), but it has been linked to continental emissions (Wang et al, ) and heterogeneous reactions of NO 2 in clouds (Lammel & Metzig, ). Air masses from continental emissions can enter the free troposphere and be transported long distances.…”