Reactive nitrogen oxides in remote regions: Atmospheric concentrations and atmosphere/biosphere exchange

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6539370

Bakwin, P S

Atmospheric concentrations and elements of the atmospheres/biosphere exchange of reactive nitrogen oxides (NO{sub y}) were measured in two disparate, remote ecosystems: the Amazon rain forest in central Brazil (wet season, 1987) and the moist tundra of southwestern Alaska (summer, 1988). Concentrations of total NO{sub y} and the NO{sub y} species NO and NO{sub 2} in both locations were found to be generally low compared to the few other remote continental regions where measurements have been made. In Alaska the concentrations of NO + NO{sub 2} (=NO{sub x}) were in the range (10-20 pptv) thought to be more typical of marine air masses. Occasional observations of higher concentrations, especially in Brazil, indicated that polluted air reached even these remote sites. The soils in both locations were modest sources of NO{sub x} to the atmosphere. In Brazil this source was approximately balanced, during unpolluted periods, by dry deposition of other NO{sub y} species to the forest canopy, while in Alaska the net flux of NO{sub y} was strongly downward. Diurnal variations in the NO{sub y} concentrations and fluxes at both sites suggest that dry deposition rates are controlled by the supply of reactive components such as HNO{sub 3} and that a significant portion of the observed NO{sub y} may consist of compounds with relatively long tropospheric lifetimes which are resistant to dry deposition.

• Research Organization: Harvard Univ., Boston, MA (USA)
• OSTI ID: 6539370
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION
AIR POLLUTION MONITORING
ALASKA
BRAZIL
CHALCOGENIDES
DAILY VARIATIONS
DEPOSITION
DEVELOPING COUNTRIES
ECOLOGICAL CONCENTRATION
FEDERAL REGION X
LATIN AMERICA
NITROGEN COMPOUNDS
NITROGEN OXIDES
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
POLLUTION
SOUTH AMERICA
USA
VARIATIONS