Satellite Evidence for Glyoxal Depletion in Elevated Fire Plumes

Abstract

Vegetation fires can have a very large impact not only on ecosystems but also on atmospheric composition and therefore on air quality (e.g., Voulgarakis & Field, 2015) with associated adverse consequences on health (Grant & Runkle, 2022). Fires directly emit large amounts of aerosols and gases, including carbon dioxide (CO 2 ), carbon monoxide (CO), nitrogen oxides (NO x ), volatile organic compounds (VOCs) and many other species. Subsequently, photochemical processing of these emissions often leads to enhanced levels of ozone and secondary organic aerosols (SOAs) (Majdi et al., 2019;Palm et al., 2020), thereby affecting the global radiative balance (Chang et al., 2021;Jiang et al., 2016). This environmental issue is becoming more acute as the intensity and frequency of wildfires are increasing due to hotter and drier conditions (di Virgilio et al., 2019;Pausas & Keeley, 2021;Senande-Rivera et al., 2022;Xu et al., 2020). Furthermore, the large number of megafires injecting material in the upper layers of the atmosphere raises concerns on their impact on the stratospheric composition and the ozone layer in particular (Das et al., 2021;Schwartz et al., 2020;Solomon et al., 2022).Satellite measurements provide invaluable information on the global distribution of atmospheric trace gases and aerosols on a daily basis. Therefore, they are well-suited to characterize the spatial and temporal evolution of biomass burning plumes. In this context, the Tropospheric Monitoring Instrument (TROPOMI) in operation since October 2017 on board of the Sentinel-5 precursor platform (Veefkind et al., 2012) is of particular interest as it allows measuring column densities of a suite of key trace gases present during fire events, such as nitrogen dioxide (NO 2 ), carbon monoxide (CO), nitrous acid (HONO), formaldehyde (HCHO), glyoxal (CHOCHO), in addition to the absorbing aerosol index (AAI) (e.g.,

Satellite Evidence of HONO/NO2 Increase With Fire Radiative Power

“…Thus, covariations in UVAI will also affect these relationships to some degree. The Australian Black Summer produced multiple pyrocumulonimbus plumes which exhibited UVAI values above 8 at high altitudes in the atmosphere (Lerot et al., 2023; Peterson et al., 2021). Only 114 of the Australian TROPOMI pixels we sampled had a UVAI greater than 8 (<3% of samples) and thus do not affect our fits.…”

Analyzing the Impact of Evolving Combustion Conditions on the Composition of Wildfire Emissions Using Satellite Data

“…TROPOMI measurements were used in Fredrickson et al. (2023) to study the ratio between HONO and NO 2 for intense wildfires with high average FRP. In contrast, we observed wildfires with lower average FRP to study the transition from mainly flaming to mainly smoldering combustion by comparing the ratio between NO 2 and CO.…”

“…The ratio between NO 2 and CO from TROPOMI has been used as a proxy for wildfire combustion efficiency (van der Velde et al., 2021). Additionally, TROPOMI has been used to detect HONO enhancement in fresh wildfire smoke (Theys et al., 2020), and the ratio between TROPOMI HONO and NO 2 has been found to increase with increasing fire radiative power (Fredrickson et al., 2023).…”

Comparison of Gas–Particle Partitioning of Glyoxal and Methylglyoxal in the Summertime Atmosphere at the Foot and Top of Mount Hua

“…The former study indicated that the bleaching of Gly–ammonium sulfate BrC was predominantly driven by OH oxidation, while that of mGly–ammonium sulfate was driven by direct photolysis [ 9 ]. Moreover, the high water solubility of low-molecular-weight carbonyl compounds makes them more easily adsorbed on aerosol particles or tiny droplets for liquid-phase chemical reactions [ 10 , 11 ]. Aromatics and biological hydrocarbons with acid-catalyzed heterogeneous reactions produce Gly and mGly [ 12 ].…”