Atmospheric formaldehyde at El Teide and Pic du Midi remote high-altitude sites

Abstract

Formaldehyde (CH2O) is a tracer of the photochemical activity of the atmosphere. Linked to air quality, CH2O is an ozone (O3) precursor and serves as a proxy for natural and anthropogenic reactive organic emissions. As a product of the photooxidation of methane (CH4) and other hydrocarbons (e.g., isoprene), CH2O represents an important source of radicals in the remote free troposphere. This work aims at improving the characterization of this part of the troposphere where data are scarce. In particular, this study assesses the presence of CH2O at two high-altitude remote sites: El Teide (TEI, 3570 m a.s.l., Tenerife, Canary Islands, Spain) and Pic du Midi (PDM, 2877 m a.s.l., French Pyrenees).