Influence of bromine and iodine chemistry on annual, seasonal, diurnal, and background ozone: CMAQ simulations over the Northern Hemisphere

TY - JOUR

T1 - Influence of bromine and iodine chemistry on annual, seasonal, diurnal, and background ozone

T2 - CMAQ simulations over the Northern Hemisphere

AU - Sarwar, Golam

AU - Gantt, Brett

AU - Foley, Kristen

AU - Fahey, Kathleen

AU - Spero, Tanya L.

AU - Kang, Daiwen

AU - Mathur, Rohit

AU - Foroutan, Hosein

AU - Xing, Jia

AU - Sherwen, Tomás

AU - Saiz-Lopez, Alfonso

N1 - This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy.

PY - 2019/9/15

Y1 - 2019/9/15

N2 - Bromine and iodine chemistry has been updated in the Community Multiscale Air Quality (CMAQ) model to better capture the influence of natural emissions from the oceans on ozone concentrations. Annual simulations were performed using the hemispheric CMAQ model without and with bromine and iodine chemistry. Model results over the Northern Hemisphere show that including bromine and iodine chemistry in CMAQ not only reduces ozone concentrations within the marine boundary layer but also aloft and inland. Bromine and iodine chemistry reduces annual mean surface ozone over seawater by 25%, with lesser ozone reductions over land. The bromine and iodine chemistry decreases ozone concentration without changing the diurnal profile and is active throughout the year. However, it does not have a strong seasonal influence on ozone over the Northern Hemisphere. Model performance of CMAQ is improved by the bromine and iodine chemistry when compared to observations, especially at coastal sites and over seawater. Relative to bromine, iodine chemistry is approximately four times more effective in reducing ozone over seawater over the Northern Hemisphere (on an annual basis). Model results suggest that the chemistry modulates intercontinental transport and lowers the background ozone imported to the United States.

AB - Bromine and iodine chemistry has been updated in the Community Multiscale Air Quality (CMAQ) model to better capture the influence of natural emissions from the oceans on ozone concentrations. Annual simulations were performed using the hemispheric CMAQ model without and with bromine and iodine chemistry. Model results over the Northern Hemisphere show that including bromine and iodine chemistry in CMAQ not only reduces ozone concentrations within the marine boundary layer but also aloft and inland. Bromine and iodine chemistry reduces annual mean surface ozone over seawater by 25%, with lesser ozone reductions over land. The bromine and iodine chemistry decreases ozone concentration without changing the diurnal profile and is active throughout the year. However, it does not have a strong seasonal influence on ozone over the Northern Hemisphere. Model performance of CMAQ is improved by the bromine and iodine chemistry when compared to observations, especially at coastal sites and over seawater. Relative to bromine, iodine chemistry is approximately four times more effective in reducing ozone over seawater over the Northern Hemisphere (on an annual basis). Model results suggest that the chemistry modulates intercontinental transport and lowers the background ozone imported to the United States.

KW - Background ozone

KW - Bromine

KW - CMAQ

KW - Iodine

KW - Ozone

UR - http://www.scopus.com/inward/record.url?scp=85067475507&partnerID=8YFLogxK

U2 - 10.1016/j.atmosenv.2019.06.020

DO - 10.1016/j.atmosenv.2019.06.020

M3 - Article

SN - 1352-2310

VL - 213

SP - 395

EP - 404

JO - Atmospheric Environment

JF - Atmospheric Environment

ER -