title: Summer-time distribution of air pollutants in Sequoia National Park, California.
abstract: Concentrations of air pollutants were monitored during the May November 1999 period on a network of forested sites in Sequoia National Park, California. Measurements were conducted with: (1) active monitors for nitric oxide (NO), nitrogen dioxide (NO2) and ozone (O3); (2) honeycomb denuder/filter pack systems for nitric acid vapor (HNO3), nitrous acid vapor (HNO2), ammonia (NH3), sulfur dioxide (SO2), particulate nitrate (NO3-), ammonium (NH4+), and sulfate (SO4(2-)); and (3) passive samplers for O3, HNO3 and NO2. Elevated concentrations of O3 (seasonal means 41-71 ppb), HNO3 (seasonal means 0.4-2.9 microg/m3), NH3 (seasonal means 1.6-4.5 microg/m3), NO3 (1.1-2.0 microg/m3) and NH4+ (1.0-1.9 microg/m3) were determined. Concentrations of other pollutants were low. With increasing elevation and distance from the pollution source area of O3, NH3 and HNO3 concentrations decreased. Ammonia and NH4+ were dominant N pollutants indicating strong influence of agricultural emissions on forests and other ecosystems of the Sequoia National Park.
authors.affiliation: USDA Forest Service, Pacific Southwest Research Station, Riverside, CA 92507, USA. andrzej@deltanet.com
authors.forename: Andrzej
authors.initials: A
authors.lastname: Bytnerowicz
authors.forename: Michael
authors.initials: M
authors.lastname: Tausz
authors.forename: Rocio
authors.initials: R
authors.lastname: Alonso
authors.forename: David
authors.initials: D
authors.lastname: Jones
authors.forename: Ronald
authors.initials: R
authors.lastname: Johnson
authors.forename: Nancy
authors.initials: N
authors.lastname: Grulke
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D002140:California; D017753:Ecosystem; D004784:Environmental Monitoring; D010316:Particle Size; D012621:Seasons; D014197:Trees
chemical_list: D000393:Air Pollutants