Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

Ricardo Cisneros, Andrzej Bytnerowicz, Donald Schweizer, Sharon Zhong, Samuel Traina, Deborah H Bennett

Research output: Contribution to journalArticle

24 Scopus citations


Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O3, 1.0-3.8 μg m-3 for HNO3, and 2.6-5.2 μg m-3 for NH 3. Calculated O3 exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha-1 for maximum values, and 0.4-8 kg N ha-1 for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O3 human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O3.

Original languageEnglish (US)
Pages (from-to)3261-3271
Number of pages11
JournalEnvironmental Pollution
Issue number10
StatePublished - Oct 2010



  • Air pollution
  • Critical loads
  • Human health
  • Nitrogen deposition
  • Ozone
  • Phytotoxicity

ASJC Scopus subject areas

  • Pollution
  • Health, Toxicology and Mutagenesis
  • Toxicology

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