Impacts of monocyclic aromatics on regional and global tropospheric gas-phase chemistry
Abstract
Aromatic compounds in the troposphere are reactive towards ozone(O3), hydroxyl (OH) and other radicals. Here we present anassessment of their impacts on the gas-phase chemistry, using thegeneral circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). Themonocyclic aromatics considered in this study comprise benzene, toluene,xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehydeand lumped higher aromatics bearing more than 9 C atoms. On a globalscale, the estimated net changes are minor when aromatic compounds areincluded in the chemical mechanism of our model. For instance, thetropospheric burden of CO increases by about 6 %, and those of OH,O3, and NOx (NO + NO2) decrease between2 % and 14 %. The global mean changes are small partially because ofcompensating effects between high- and low-NOx regions. Thelargest change is predicted for glyoxal, which increases globally by 36%. Significant regional changes are identified for several species. Forinstance, glyoxal increases by 130 % in Europe and 260 % in East Asia,respectively. Large increases in HCHO are also predicted in theseregions. In general, the influence of aromatics is particularly evidentin areas with high concentrations of NOx, with increases upto 12 % in O3 and 17 % in OH. Although the global impact ofaromatics is limited, our results indicate that aromatics can stronglyinfluence tropospheric chemistry on a regional scale, most significantlyin East Asia.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- May 2020
- DOI:
- 10.5194/egusphere-egu2020-5114
- Bibcode:
- 2020EGUGA..22.5114S