Biomaterial Database

Chemical Production of Oxygenated Volatile Organic Compounds Strongly Enhances Boundary-Layer Oxidation Chemistry and Ozone Production. 2021

Hang Qu, and Yuhang Wang, and Ruixiong Zhang, and Xiaoxi Liu, and Lewis Gregory Huey, and Steven Sjostedt, and Limin Zeng, and Keding Lu, and Yusheng Wu, and Min Shao, and Min Hu, and Zhaofeng Tan, and Hendrik Fuchs, and Sebastian Broch, and Andreas Wahner, and Tong Zhu, and Yuanhang Zhang

School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

Photolysis of oxygenated volatile organic compounds (OVOCs) produces a primary source of free radicals, including OH and inorganic and organic peroxy radicals (HO2 and RO2), consequently increasing photochemical ozone production. The amplification of radical cycling through OVOC photolysis provides an important positive feedback mechanism to accelerate ozone production. The large production of OVOCs near the surface helps promote photochemistry in the whole boundary layer. This amplifier effect is most significant in regions with high nitrogen oxides (NO) and VOC concentrations such as Wangdu, China. Using a 1-D model with comprehensive observations at Wangdu and the Master Chemical Mechanism (MCM), we find that OVOC photolysis is the largest free-radical source in the boundary layer (46%). The condensed chemistry mechanism we used severely underestimates the OVOC amplifier effect in the boundary layer, resulting in a lower ozone production rate sensitivity to NO emissions. Due to this underestimation, the model-simulated threshold NO emission value, below which ozone production decreases with NO emission decrease, is biased low by 24%. The underestimated OVOC amplifier effect in a condensed mechanism implies a low bias in the current 3-D model-estimated efficacy of NO emission reduction on controlling ozone in polluted urban and suburban regions of China.

UI	MeSH Term	Description	Entries
D009589	Nitrogen Oxides	Inorganic oxides that contain nitrogen.	Nitrogen Oxide,Oxide, Nitrogen,Oxides, Nitrogen
D010126	Ozone	The unstable triatomic form of oxygen, O3. It is a powerful oxidant that is produced for various chemical and industrial uses. Its production is also catalyzed in the ATMOSPHERE by ULTRAVIOLET RAY irradiation of oxygen or other ozone precursors such as VOLATILE ORGANIC COMPOUNDS and NITROGEN OXIDES. About 90% of the ozone in the atmosphere exists in the stratosphere (STRATOSPHERIC OZONE).	Ground Level Ozone,Low Level Ozone,Tropospheric Ozone,Level Ozone, Ground,Level Ozone, Low,Ozone, Ground Level,Ozone, Low Level,Ozone, Tropospheric
D004784	Environmental Monitoring	The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.	Monitoring, Environmental,Environmental Surveillance,Surveillance, Environmental
D000393	Air Pollutants	Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or materials. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.	Air Pollutant,Air Pollutants, Environmental,Environmental Air Pollutants,Environmental Pollutants, Air,Air Environmental Pollutants,Pollutant, Air,Pollutants, Air,Pollutants, Air Environmental,Pollutants, Environmental Air
D055549	Volatile Organic Compounds	Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.	Volatile Organic Compound,Compound, Volatile Organic,Compounds, Volatile Organic,Organic Compound, Volatile,Organic Compounds, Volatile