The reaction of nitrogen dioxide with sea salt aerosol
- Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry
It is estimated that sea salt is the largest source of tropospheric aerosol particulate matter with 10{sup 12} kg introduced into the atmosphere from wave action over the oceans each year. Recently, considerable attention has been given to heterogeneous reactions between salts and nitrogen oxides and their possible roles in atmospheric chemistry, primarily as potential sources of tropospheric halogens. The reaction of sea salt aerosol with NO{sub 2} under ambient conditions was explored using particles that were generated by atomizing an aqueous solution of synthetic sea salt. The aerosol at 9--30% relative humidity, was mixed with 1--3 mbar of NO{sub 2} and then passed through an optical cell where reactants and products were monitored by infrared spectroscopy. The duration times of the reaction, partial pressure of NO{sub 2}, and relative humidity were systematically varied in order to explore the aerosol heterogeneous chemistry. Infrared spectra of the aerosol revealed that a substantial fraction of the particulate Cl{sup {minus}} was replaced by NO{sub 3}{sup {minus}} and that there was a significant production of ClNO, consistent with the stoichiometry 2 NO{sub 2} + Cl{sup {minus}} {yields} NO{sub 3}{sup {minus}} + ClNO. The rate of the reaction was found to increase both with NO{sub 2} pressure and relative humidity. The infrared spectra also revealed that, even under arid conditions, the sea salt aerosol particles contain more water than can be explained by the various hydrates in sea salt, suggesting that the particles possess a complex structure. This complex structure involves microcrystalline and amorphous regions with pockets for water inclusions.
- OSTI ID:
- 682165
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 25; Other Information: PBD: 24 Jun 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetic Study of Heterogeneous Reaction of Deliquesced NaCI Particles with Gaseous HNO3 Using Particle-on-Substrate Stagnation Flow Reactor Approach
A diffuse reflectance infrared Fourier transform spectroscopic (DRIFTS) study of the surface reaction of NaCl with nitrogen oxides