Photostability of nitro-polycyclic aromatic hydrocarbons on combustion soot particles in sunlight
- Univ. of North Carolina, Chapel Hill, NC (United States)
Little is known about the stability of nitro-polycyclic aromatic hydrocarbons (NPAH) on atmospheric aerosols. In this study, the photostability of particle-associated NPAH was investigated under natural sunlight. Deuterated and native NPAH along with diesel exhaust or wood smoke particles were added to a 190-m{sup 3} outdoor smog chamber and permitted to age under sunlight in cold and warm temperatures. Ozone (O{sub 3}), nitrogen oxides (NO{sub x}), and volatile hydrocarbons in the gas phase were monitored. Rapid degradation of deuterated and native NPAH was observed in sunlight, over a temperature range of -19 to +38{degree}C. Deuterated 1-nitropyrene (d{sub g}-1NP) displayed the same behavior as native 1-nitropyrene (1NP), which indicated that it was reasonable to use deuterated NPAH as substitutes for native NPAH. The photolysis rate of NPAH was referenced to the NO{sub 2} photolysis rate in order to relate the observed decay of NPAH to the changing solar radiation. A photolysis rate of NO{sub 2} ({kappa}NO(2)4/=8.3x10{sup -3} s{sup -1} at noon on June 15, 1994, gave half-lives of 0.8 h for 1NP and 2-nitropyrene (2NP) and 1.2 h for 2-nitrofluoranthene (2NF), d{sub 9}-3-, and d{sub 9}-8-nitrofluoranthene (d{sub 9}-3NF and d{sub 9}-8NF)) on diesel soot particles. The half-life was 0.5 h for d{sub 9}-1NP, d{sub g}-3NF, and d{sub 9}-8NF on wood soot particles. 51 refs., 7 figs., 1 tab.
- OSTI ID:
- 226675
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 4 Vol. 30; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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