TY - JOUR
T1 - Atmospheric Nitrate Formation through Oxidation by Carbonate Radical
AU - Fang, Xiaozhong
AU - Liu, Yangyang
AU - Li, Kejian
AU - Wang, Tao
AU - Deng, Yue
AU - Feng, Yiqing
AU - Yang, Yang
AU - Cheng, Hanyun
AU - Chen, Jianmin
AU - Zhang, Liwu
N1 - Funding Information:
The authors gratefully acknowledge support from National Natural Science Foundation of China (Nos. 22006020 and 21976030), and the Natural Science Foundation of Shanghai (No. 19ZR1471200).
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/7/15
Y1 - 2021/7/15
N2 - The carbonate radical (CO3•-) has been proved to be of great significance in the water environment. However, a few studies concerned with its contribution to atmospheric heterogeneous chemistry. Here, we report the pathway for the first time for CO3•- generation by interfacial photogenerated hole/hydroxyl radical (•OH) transfer between the photoactive component and (bi)carbonate (CO32-/HCO3-) of mineral dust under atmospherically relevant actinic irradiation. By combining laboratory simulation, nanosecond transient absorption spectroscopy (NTAS), and field observation, we demonstrate that (bi)carbonate in the atmosphere not only has a pH buffering effect in the uptake of NO2 but more importantly directly participates in the photochemical reactions by generating CO3•- under irradiation. CO3•- can play an important role by facilitating nitrite transformation to nitrate, especially under a lower light intensity (15 mW/cm2) and a higher humidity (60% RH). Diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) was used to detect the surface species generated on simulated mineral dust. Under irradiation, the time-dependent reactive uptake coefficient for the first-order reaction of NO2 uptake on simulated mineral dust was found to be 2.817 × 10-8 × e-t/6559. These results highlight the important role of CO3•- in atmospheric photochemistry, which could act as a reactive radical and influence secondary aerosol formation.
AB - The carbonate radical (CO3•-) has been proved to be of great significance in the water environment. However, a few studies concerned with its contribution to atmospheric heterogeneous chemistry. Here, we report the pathway for the first time for CO3•- generation by interfacial photogenerated hole/hydroxyl radical (•OH) transfer between the photoactive component and (bi)carbonate (CO32-/HCO3-) of mineral dust under atmospherically relevant actinic irradiation. By combining laboratory simulation, nanosecond transient absorption spectroscopy (NTAS), and field observation, we demonstrate that (bi)carbonate in the atmosphere not only has a pH buffering effect in the uptake of NO2 but more importantly directly participates in the photochemical reactions by generating CO3•- under irradiation. CO3•- can play an important role by facilitating nitrite transformation to nitrate, especially under a lower light intensity (15 mW/cm2) and a higher humidity (60% RH). Diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) was used to detect the surface species generated on simulated mineral dust. Under irradiation, the time-dependent reactive uptake coefficient for the first-order reaction of NO2 uptake on simulated mineral dust was found to be 2.817 × 10-8 × e-t/6559. These results highlight the important role of CO3•- in atmospheric photochemistry, which could act as a reactive radical and influence secondary aerosol formation.
KW - carbonate radical
KW - heterogeneous uptake
KW - NO
KW - secondary nitrate aerosol
KW - transient absorption spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85110937618&partnerID=8YFLogxK
U2 - 10.1021/acsearthspacechem.1c00169
DO - 10.1021/acsearthspacechem.1c00169
M3 - Journal article
AN - SCOPUS:85110937618
SN - 2472-3452
VL - 5
SP - 1801
EP - 1811
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 7
ER -