Observations of gas phase hydrochloric acid in the polluted marine boundary layer

Abstract

Ship-based measurements of gas phase hydrochloric acid (HCl), particulate chloride (pCl À ), and reactive nitrogen oxides (NO y ) were made in the polluted marine boundary layer along the California coastline during spring 2010. These observations are used to assess both the rate of Cl atom production from HCl and the role of direct HCl emissions and subsequent partitioning as a source for pCl À . Observations of HCl made in coastal Southern California are broadly correlated with NO z (NO z ≡ NO y -NO x ), peaking at 11 A.M. The observed median HCl mixing ratio in Southern California is 1.3 ppb (interquartile range: 0.53-2.7 ppb), as compared to 0.19 ppb (interquartile range: 0.10-0.38 ppb) measured along the Sacramento River between San Francisco and Sacramento. Concurrent measurements of aerosol ion chemistry indicate that aerosol particles sampled in Northern California are heavily depleted in Cl À , corresponding to a mean pCl À deficit of 0.05 ± 0.03 (1σ) ppb for sub-10 μm aerosol particles. In comparison, aerosols measured in Southern California indicate that over 25% of particles showed an addition of Cl À to the particle population. Observations presented here suggest that primary sources of HCl, or gas phase chlorine precursors to HCl, are likely underestimated in the California Air Resource Board emissions inventory. These results highlight the need for future field observations designed to better constrain direct reactive halogen emissions.

Formation and emission of hydrogen chloride in indoor air

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Processes such as volcanic eruptions, biomass burning, coal combustion, and waste incineration emit HCl directly. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Processes such as volcanic eruptions, biomass burning, coal combustion, and waste incineration emit HCl directly.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Processes such as volcanic eruptions, biomass burning, coal combustion, and waste incineration emit HCl directly. 2,15,16 Although the subject of numerous atmospheric measurements and modeling studies, these sources are not well constrained. 2,15,16 Although the subject of numerous atmospheric measurements and modeling studies, these sources are not well constrained.…”

“…2,15 Due to the large relative abundance of reactants in polluted coastal regions, the reaction proceeds with ease. 2,15 Due to the large relative abundance of reactants in polluted coastal regions, the reaction proceeds with ease.…”

Reactions between Criegee Intermediates and the Inorganic Acids HCl and HNO3: Kinetics and Atmospheric Implications

“…[30] We estimate reactions with HCl and HNO3 contribute to atmospheric loss rates for CH2OO of 9.2 s -1 and 270 s -1 . Under all conditions of temperature and RH, HCl makes a minor contribution to the CH2OO loss rate.…”

“…[27] The inorganic acids HCl and HNO3 have both biogenic and anthropogenic sources (see Supporting Information) and are present in the troposphere at mixing ratios similar to organic acids and SO2 (ppbv to pptv), with peak concentrations found in coastal and polluted urban areas. [28][29][30] Here, we report direct measurements of rate constants for the reactions of the simplest CI with HCl and HNO3:…”