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Unexpected large uptake of O 3 on sea salts and the observed Br 2 formation
Author(s) -
Mochida Michihiro,
Hirokawa Jun,
Akimoto Hajime
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl010927
Subject(s) - seawater , sea salt , troposphere , alkali metal , bromide , chemistry , inorganic chemistry , geology , oceanography , atmospheric sciences , aerosol , organic chemistry
Uptake coefficients of O 3 on various model compounds of sea salts at ambient temperature were measured using a Knudsen cell reactor coupled to a differentially pumped quadrupole mass spectrometer. Uptake of O 3 was below the detection limit (<1×10 −5 ) for pure alkali metal bromides, whereas reactive uptake with Br 2 formation was observed on two types of synthetic sea salts (Aqua Ocean and Instant Ocean) and commercial natural sea salt. Measured uptake coefficients were 10 −2 –10 −3 , (1.4±1.1) × 10 −3 and (9.7±4.6) × 10 −4 for Aqua Ocean, Instant Ocean and natural sea salt, respectively. These uptake coefficients were about three orders of magnitude larger than that on bulk bromide solution estimated from known liquid phase reactions. The results imply that minor components enhance reactivity of O 3 on synthetic and natural sea salts. This heterogeneous reaction is potentially an important Br source in the marine boundary layer on a global scale as well as in the polar troposphere.