Investigators and Program Directors

Research Interests

Organic compounds and nitrogen oxides (NO_x = NO+NO₂) are emitted into the atmosphere by natural and anthropogenic sources. They play key roles in a variety of environmental processes such as ground-level ozone formation, stratospheric ozone depletion, acid deposition, and global climate change. My primary research objective is to determine quantitatively the kinetics, mechanisms, and products of homogeneous and heterogeneous atmospheric reactions related to organic compounds and reactive nitrogen species, NO_Y, where NO_Y is defined as the sum of NO_x and the atmospheric oxidation products of NO_x. Understanding atmospheric chemistry of organic compounds and reactive nitrogen species is vital to pollution prevention and control efforts.

In recent years, we carried out a series of research projects investigating the kinetics and photochemistry of homogeneous and heterogeneous atmospheric reactions related to aldehydes and nitric acid under the support of NSF. My group has determined the wavelength-dependent photolysis quantum yields of aliphatic aldehydes (propionaldehyde, n-butyraldehyde, i-butyraldehyde, n-pentanal, i-pentanal, t-pentanal, n-hexanal, and n-heptanal), aromatic aldehydes (benzaldehyde and 2-nitrobenzaldehyde), and saturated and unsaturated dicarbonyls (glyoxal, methylglyoxal, butenedial, 4-oxo-2-pentenal, and E,E-2,4-hexadienedial) in the actinic UV region by combining laser photolysis with cavity ring-down spectroscopy. My group, in collaboration with Dr. Liang Chu at the Wadsworth Center, has also applied cavity ring-down technique to study nitric acid and acetaldehyde photolysis on aluminum surfaces and on ice films. Using a novel variant of cavity ring-down technique, my group determined absolute absorption cross sections of adsorbed HNO₃ on fused silica surfaces in the 290-330 nm region. Since the determined 295 K UV absorption cross sections of surface-adsorbed HNO₃ are at least two orders of magnitude larger than those in the gas phase in the wavelength region studied, our results can account for the field-observed large differences between the nitric acid photolysis rates on the surface and that in the gas phase.

Contact Information

Phone: (518) 474-6846
Fax: (518) 473-2895
E-mail: zhul@wadsworth.org.