PHOTOCHEMISTRY OF FORMALDEHYDE
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Date
2003
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The $HO_{x}$ family (OH and $HO_{2}$) is central to the photochemistry of the atmosphere. Recent measurement campaigns have revealed $HO_{x}$ concentrations much greater than predicted by models using only water, methane and ozone chemistry. Formaldehyde is now recognized as an important source of $HO_{x}$ in the upper troposphere. The photodissociation of formaldehyde by sunlight can occur through two distinct and competing channels: $H_{2}CO + h\nu \rightarrow H_{2} + CO H_{2}CO + h\nu \rightarrow HCO + H$ The second channel produces radicals that, after subsequent reaction with $O_{2}$, form $HO_{x}$. This project investigates the $HO_{x}$ production from the photochemistry of formaldehyde. To achieve this high resolution absorption cross section data for formaldehyde and formaldehyde quantum yields for the production of HCO are needed over a wavelength range and conditions of temperature and pressure appropriate to the upper troposphere. The data are then introduced into atmospheric models to predict the importance of formaldehyde in the upper tropospheric region.
Description
Author Institution: School of Chemistry, University of Bristol