What is Photochemical Oxidation?

Oxidation is the process of combining oxygen with some other substance or a chemical change in which an atom loses electrons. Photochemical oxidation is oxidation caused by Ultraviolet (UV) radiation in the earth's atmosphere. This processes creates the free hydroxl radical (-OH). The high energy of UV radiation can also break the chemical bonds of water (H₂O) to yeild *OH and hydrogen (*H) radicals.

The rusting of iron is a common form of oxidation

Ultraviolet radiation is part of the electromagnetic spectrum which ranges from gamma rays at the most energetic end to radio waves at the less energetic end. Most people are familiar with UV radiation b/c it is what causes our skin to sunburn.

Home of the
Photochemical Oxidation/Products (POP) group and
the Atmospheric Radicals Studies Group

Mission

Perform measurements to address questions in three general research areas: photochemistry and sulfur chemistry.

Measurements include

Gas Phase: HO2, RO2, OH, H2SO4, MSA, DMSO, DMSO2, HNO3, NH3, ambient ion, and ion clusters.

Specific scientific questions of current interest

• How well is OH production and loss understood particularly in unique environments such as Antarctica and anthropogenic plumes?
• What are the remote marine oxidants responsible for the formation of gas phase sulfuric and methanesulfonic acids and DMSO at night?
• How do MS/sulfate ratios observed in the Antarctic ice depend on DMS oxidation chemistry and transport over the polar plateau?
• Does ammonia have a unique role in controlling particle growth?

New Research Thrusts

• Development of an aircraft based ammonia measurement capability
• Develop new chemical ionization ion trap mass spectrometric measurement technique for a broad range of oxygenated biogenic and anthropogenic compounds