Atmospheric Deposition Unit 4451 Research on Air Pollution Distribution and Effects in California Mountains Andrzej Bytnerowicz, Michael Arbaugh, Nancy Grulke, Mark Fenn and Pamela Padgett USDA Forest Service, Pacific Southwest Research Station, Riverside, CA, USA

Rationale Urban activities and forest fires cause emission of nitrogen oxides and volatile organic compounds (VOCs) promoting ozone and nitric acid vapor formation. Ozone, a criteria pollutant, affects human health and vegetation. Elevated levels of nitric acid vapor and ammonia contribute to particulate matter formation and loss of visibility. They are important components of atmospheric dry deposition of N to forests and other ecosystems.

Research Tasks Development of low-cost, low maintenance, robust samplers to monitor concentrations of ozone and nitrogenous air pollutants & N deposition Development of regional networks for evaluation of distribution of air pollutants caused by urban & agricultural activities and wildland & prescribed fires Evaluation of forest health from the point of view of interactive effects of ozone, N deposition and climate changes Evaluation of N deposition effects on soil and water contamination

Our approach to characterizing air pollution status & effects on forests at a landscape level Use of reliable, easy to use and inexpensive techniques allowing for monitoring air pollutants at a large scale Development of pollution distribution models in complex terrains Linking information on pollutant concentrations & doses to the health of forests Use of remote sensing data for the large scale assessments Ultimate goal – development of pollution risk assessment models for decision making

Performance comparison and calibration of air pollution samplers, RFL summer 2002

Ogawa Passive Samplers

New HNO 3 vapor passive sampler

Conclusions from the passive sampler comparisons and calibrations Ogawa passive samplers reliably and inexpensively measure ambient levels of O 3, NH 3, NO 2, NO x and SO 2. HNO 3 passive samplers developed by FS PSW provide reliable measurements (patent application).

Other accomplishments Instrument trailer for monitoring O 3, NO x and CO 2 has been tested and is available for future field campaigns (R. Musselman, USDA FS Rocky Mountain RS) Progress has been made in development of passive samplers for particulate matter IMPROVE Castnet

Application of passive samplers for understanding spatial & temporal distribution of ozone in the Sierra Nevada Collaboration between the USDA Forest Service, US EPA, National Park Service and the Environmental Systems Research Institute

What have we learned from the 1999 Sierra Nevada study? High spatial and lower temporal variability of ozone distribution throughout the Sierra Nevada SW, W and E portions of the Sierra Nevada experience long-lasting elevated ozone exposures Ambient ozone have a strong phytotoxic potential and may affect health of residents and visitors in Sierra Nevada forests

New research question: “Why are high levels of air pollutants present in eastern Sierra Nevada and Lake Tahoe Basin?” Crossing across southern portion of the Sierra Nevada from San Joaquin Valley? Passage along river valleys such as San Joaquin River? Long-range transport from the Los Angeles Air Basin? Local generation of pollutants (e.g., Lake Tahoe Basin)?

Passive samplers for O 3, HNO 3 and NH 3 on the San Joaquin River transect

Lake Tahoe air pollution monitoring – summer 2002

Ozone distribution in the Lake Tahoe Basin in summer 2002

HNO 3 distribution in the Lake Tahoe Basin in summer 2002

How did the McNalley fire affect ambient air quality in the Sierra Nevada in summer 2002?

Products from the 2002 studies Maps of ozone and nitric acid distribution during seven individual 2-week long periods for the Lake Tahoe area Maps of ozone, nitric acid, and ammonia distribution for the San Joaquin River transect Maps of ozone distribution in Eastern Sierra Nevada Better understanding of effects of forest fires on air quality (analysis of the McNalley fire effects)

2003 season research activities Monitoring of ozone and N pollutants on the San Bernardino Mountains and Kings River Project networks Testing of passive sampler systems for monitoring concentrations and deposition of gaseous & particulate matter Calibration of a new HNO 3 vapor passive sampler Monitoring NO 3 - and NH 4 + deposition in throughfall on the Sierra Nevada and San Bernardino Mountains networks with ion exchange resin samplers

Plans for the Future Continuation of the San Bernardino Mountains monitoring network - long-term effects of ozone, N deposition, and drought on mixed conifer forests Continuation of cooperation with the PSW Fresno Lab in the Kings River Project Sierra-wide evaluation of air quality mainly from the point of view of emissions resulting from urban sprawl, agricultural activities and forest fires

Collaboration within the PSW and San Joaquin AQMD – establishment of air pollution monitoring network for the Kings River and Teakettle Projects