TY - JOUR
T1 - Investigation of organic hydrotrioxide (ROOOH) formation from RO
2 + OH reactions and their atmospheric impact using a chemical transport model, STOCHEM-CRI
AU - Khan, M. A. H.
AU - Holland, Rayne E T
AU - Bacak, Asan
AU - Bannan, Thomas J.
AU - Coe, Hugh
AU - Derwent, Richard G.
AU - Percival, Carl
AU - Shallcross, Dudley E
N1 - Publisher Copyright:
© 2025 RSC.
PY - 2025/3/6
Y1 - 2025/3/6
N2 - Incorporating the reactions of fifty peroxy radicals (RO2) with the hydroxyl radical (OH) into the global chemistry transport model, STOCHEM-CRI affected the composition of the troposphere by changing the global burdens of NOx (-2.7 Gg, -0.5%), O3 (-2.3 Tg, -0.7%), CO (-3.2 Tg, -0.8%), HOx (+2.1 Gg, +7.7%), H2O2 (+0.5 Tg, +18.3%), RO2 (-8.0 Gg, -18.2%), RONO2 (-19.4 Gg, -4.7%), PAN (-0.1 Tg, -3.4%) HNO3 (-7.4 Gg, -1.3%) and ROOH (-96.9 Gg, -3.8%). The addition of the RO2 + OH reactions have a significant impact on HO2 mixing ratios in tropical regions with up to a 25% increase, resulting in increasing H2O2 mixing ratios by up to 50% over oceans. Globally, a significant amount of organic hydrotrioxides (ROOOH) (86.1 Tg/yr) are produced from these reactions with CH3OOOH (67.5 Tg/yr, 78%), isoprene-derived ROOOH (5.5 Tg/yr, 6%) and monoterpene-derived ROOOH (4.2 Tg/yr, 5%) being the most significant contributors. The tropospheric global burden of CH3OOOH is found to be 0.48 Gg. The highest mixing ratios of ROOOH, of up to 0.35 ppt, are found primarily in the oceans nearby to the tropical land areas. The RO2 + OH reactions have a small, but noticeable, contribution to OH reactivity (~5%) over tropical oceans. Additionally, these reactions have a significant impact on RO2 reactivity over tropical oceans where losses of CH3O2, isoprene derived peroxy radical (ISOPO2) and monoterpene derived peroxy radical (MONOTERPO2) by OH can contribute by up to 25%, 15% and 50% to the total RO2 loss, respectively. The changes in RO2 reactivity influence the global abundances of organic alcohols (ROH) which are important species due to their crucial impact on air quality. The ROOOH generate secondary organic aerosol (SOA) by up to 0.05 µg/m3 which affects Earth’s radiation budget because of enhancing modelled organic aerosol by up to 5% and 2000% on land surfaces and the remote tropical oceans, respectively.
AB - Incorporating the reactions of fifty peroxy radicals (RO2) with the hydroxyl radical (OH) into the global chemistry transport model, STOCHEM-CRI affected the composition of the troposphere by changing the global burdens of NOx (-2.7 Gg, -0.5%), O3 (-2.3 Tg, -0.7%), CO (-3.2 Tg, -0.8%), HOx (+2.1 Gg, +7.7%), H2O2 (+0.5 Tg, +18.3%), RO2 (-8.0 Gg, -18.2%), RONO2 (-19.4 Gg, -4.7%), PAN (-0.1 Tg, -3.4%) HNO3 (-7.4 Gg, -1.3%) and ROOH (-96.9 Gg, -3.8%). The addition of the RO2 + OH reactions have a significant impact on HO2 mixing ratios in tropical regions with up to a 25% increase, resulting in increasing H2O2 mixing ratios by up to 50% over oceans. Globally, a significant amount of organic hydrotrioxides (ROOOH) (86.1 Tg/yr) are produced from these reactions with CH3OOOH (67.5 Tg/yr, 78%), isoprene-derived ROOOH (5.5 Tg/yr, 6%) and monoterpene-derived ROOOH (4.2 Tg/yr, 5%) being the most significant contributors. The tropospheric global burden of CH3OOOH is found to be 0.48 Gg. The highest mixing ratios of ROOOH, of up to 0.35 ppt, are found primarily in the oceans nearby to the tropical land areas. The RO2 + OH reactions have a small, but noticeable, contribution to OH reactivity (~5%) over tropical oceans. Additionally, these reactions have a significant impact on RO2 reactivity over tropical oceans where losses of CH3O2, isoprene derived peroxy radical (ISOPO2) and monoterpene derived peroxy radical (MONOTERPO2) by OH can contribute by up to 25%, 15% and 50% to the total RO2 loss, respectively. The changes in RO2 reactivity influence the global abundances of organic alcohols (ROH) which are important species due to their crucial impact on air quality. The ROOOH generate secondary organic aerosol (SOA) by up to 0.05 µg/m3 which affects Earth’s radiation budget because of enhancing modelled organic aerosol by up to 5% and 2000% on land surfaces and the remote tropical oceans, respectively.
U2 - 10.1039/D5EA00009B
DO - 10.1039/D5EA00009B
M3 - Article (Academic Journal)
SN - 2634-3606
JO - Environmental Science: Atmospheres
JF - Environmental Science: Atmospheres
ER -