title: Photolysis of Nitric Acid and Nitrate on Natural and Artificial Surfaces.
abstract: Photolysis of nitric acid and nitrate (HNO3/nitrate) was investigated on the surfaces of natural and artificial materials, including plant leaves, metal sheets, and construction materials. The surfaces were conditioned in the outdoor air prior to experiments to receive natural depositions of ambient HNO3/nitrate and other atmospheric constituents. The photolysis rate constant (JHNO3(s)) of the surface HNO3/nitrate was measured based on the production rates of nitrous acid (HONO) and nitrogen oxides (NOx). The JHNO3(s) values, from 6.0 × 10(-6) s(-1) to 3.7 × 10(-4) s(-1), are 1 to 3 orders of magnitude higher than that of gaseous HNO3. The HONO was the major product from photolysis of HNO3/nitrate on most plant leaves, whereas NOx was the major product on most artificial surfaces. The JHNO3(s) values decreased with HNO3/nitrate surface density and could be described by a simple analytical equation. Within a typical range of HNO3/nitrate surface density in the low-NOx forested areas, photolysis of HNO3/nitrate on the forest canopy can be a significant source for HONO and NOx for the overlying atmosphere.
authors.affiliation: Wadsworth Center, New York State Department of Health , Albany, New York 12201, United States.
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Ye
authors.affiliation: Department of Environmental Health Sciences, State University of New York , Albany, New York 12201, United States.
authors.forename: Honglian
authors.initials: H
authors.lastname: Gao
authors.affiliation: Department of Environmental Health Sciences, State University of New York , Albany, New York 12201, United States.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Wadsworth Center, New York State Department of Health , Albany, New York 12201, United States.|Department of Environmental Health Sciences, State University of New York , Albany, New York 12201, United States.
authors.forename: Xianliang
authors.initials: X
authors.lastname: Zhou
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D007700:Kinetics; D009566:Nitrates / Q000528:radiation effects*; D017942:Nitric Acid / Q000528:radiation effects*; D009589:Nitrogen Oxides / Q000528:radiation effects; D009608:Nitrous Acid / Q000528:radiation effects; D010782:Photolysis / Q000528:radiation effects; D010944:Plants / Q000528:radiation effects; D013472:Sunlight; D013499:Surface Properties
chemical_list: D009566:Nitrates; D009589:Nitrogen Oxides; D017942:Nitric Acid; D009608:Nitrous Acid