The adsorption of peroxynitric acid on ice between 230 K and 253 K

Abstract

Abstract. Peroxynitric acid uptake to ice and snow has been proposed to be a major loss process from the atmosphere with impacts on the atmospheric oxidation capacity. Here we present results from a laboratory study on the interaction of peroxynitric acid with water ice at low concentration. Experiments were performed in a coated wall flow tube at atmospheric pressure and in the environmentally relevant temperature range of 230 K to 253 K. The interaction was found to be fully reversible and decomposition was not observed. Analysis based on the Langmuir adsorption model showed that the partitioning of peroxynitric acid to ice is orders of magnitude lower than of nitric acid and similar to nitrous acid partitioning behavior. The partition coefficient (K LinC ) and its temperature dependency can be described by 3.74 × 10 −12 × e (7098/T ) [cm]. Atmospheric implications are discussed and show that the uptake to cirrus clouds or to snow-packs in polar areas is an important sink for peroxynitric acid in the environment.

Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

“…Heating the synthesis gas to a temperature of 100 • C prior to sampling by the LOPAP allowed selective removal of HNO 4 from the gas mixture. The mixing ratios of HONO, NO 2 , H 2 O 2 , and O 3 that are present in the synthesis gas were independently monitored with a chemical ionization mass spectrometer (CIMS), which was calibrated by using several analysers as detailed in Ulrich et al (2012). An example of the mixing ratios of HNO 4 and HONO measured by CIMS and of the corresponding LOPAP signals in channel 1 and 2 is shown in Fig.…”

HO<sub>2</sub>NO<sub>2</sub> and HNO<sub>3</sub> in the coastal Antarctic winter night: a "lab-in-the-field" experiment

“…At 240 K, roughly the temperatures of our observations, Ulrich et al (2012), in their Fig. 4, show C s / C g ≈ 20 cm for HO 2 NO 2 and 8000 cm for HNO 3 .…”

“…For HO 2 NO 2 , the average H ads derived from our field data is −56 ± 1 kJ mol −1 which can be compared with the laboratory-derived value (Ulrich et al, 2012) of −59 kJ mol −1 . For both HO 2 NO 2 and HNO 3 , the agreement between laboratory and field-derived enthalpies of adsorption is remarkably good.…”

“…Both HO 2 NO 2 (Ulrich et al, 2012) and HNO 3 (BartelsRausch et al, 2002;Hudson et al, 2002;Ullerstam et al, 2005) have been shown in laboratory experiments to adsorb to ice surfaces. This conclusion is supported by field observations which have confirmed uptake of both HNO 3 and HO 2 NO 2 to snow surfaces Slusher et al, 2002), and of HNO 3 to cirrus clouds (Weinheimer et al, 1998;Popp et al, 2004;Ziereis et al, 2004).…”

“…Ulrich et al (2012) studied uptake of HO 2 NO 2 at low concentrations and temperatures between 230 and 253 K while BartelsRausch et al (2002) and Ullerstam et al (2005) studied the adsorption enthalpy of HNO 3 . Field studies carried out during the 24 h per day darkness of Antarctic winter provide optimum conditions for validating such laboratory-derived physical air/snow exchange parameters under "real-world" conditions.…”