Observations and modeling of the reactive nitrogen photochemistry at a rural site
- National Oceanic and Atmospheric Administration, Boulder, CO (USA) Univ. of Colorado, Boulder (USA)
- National Oceanic and Atmospheric Administration, Boulder, CO (USA)
- National Center for Atmospheric Research, Boulder, CO (USA)
- Washington State Univ., Pullman (USA)
Ambient concentrations of key trace gases were measured concurrently at a rural site in the eastern United States during the summer of 1986. The extensive data set allows the evaluation of certain aspects of photochemical oxidant models. A 4-day high-pressure period is chosen for a comparison of the model predictions with observations. The emphasis of this analysis is on the discussion of the photochemistry of the reactive nitrogen species and their role in shaping the ozone budget. Observations of the NO{sub 2}/NO ratio provide an estimate of the peroxy radical concentration at the site. The peroxy radical concentration so derived indicates a significant in-situ O{sub 3} formation which is in accordance with the observed diurnal variation of O{sub 3}. Isoprene, a natural hydrocarbon, is shown to be much more important than the anthropogenic hydrocarbons in this O{sub 3} formation. At this rural site NO, NO{sub 2}, HNO{sub 3}, and peroxyacetyl nitrate (PAN) account for 85% or more of NO{sub y} (the sum of the reactive nitrogen species). The diurnal cycle of the reactive nitrogen species and their partitioning is determined by transport and photochemical conversion. At night in the boundary layer defined by a low-level inversion, NO{sub x} is the major NO{sub y} species at this site. Nitric acid and PAN are suppressed by dry deposition and, in the case of PAN, thermal decomposition. During the daytime the NO{sub x} contribution to NO{sub y} decreases first as higher concentrations of HNO{sub 3} and PAN are mixed downward upon the breakup of the nocturnal inversion followed by NO{sub x} conversion to other NO{sub y} species in photochemical reactions.
- OSTI ID:
- 5512971
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:D2; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ATMOSPHERIC CHEMISTRY
BOUNDARY CONDITIONS
BOUNDARY LAYERS
BUDGETS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CLIMATE MODELS
DAILY VARIATIONS
DECOMPOSITION
DEPOSITION
DEVELOPED COUNTRIES
DIENES
ESTERS
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
ISOPRENE
LAYERS
MATHEMATICAL MODELS
NITRATES
NITRIC ACID
NITRIC ACID ESTERS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
OZONE
PEROXY RADICALS
PEROXYACETYL NITRATE
PHOTOCHEMICAL REACTIONS
POLYENES
RADICALS
RURAL AREAS
USA
VARIATIONS