Air pollution effects on
California mountain
forests
Andrzej Bytnerowicz, Michael Arbaugh and
Pamela Padgett
USDA Forest Service, Pacific Southwest Research
Station, Riverside, CA, USA
Air pollution is an integral
part of global climate
change
’
’
’
Elevated levels of CO2 and other
greenhouse-effect gases are mainly caused
by anthropogenic emissions
CFCs and other air pollutants causing
ozone hole are human-made air pollutants
Increase of background ambient ozone
concentrations and elevated levels of
atmospheric nitrogen deposition occur in the
entire Northern Hemisphere and have
strong effects on various ecosystems
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
(ozone, nitric acid, ammonia) at a large scale
Development of pollution distribution models in
complex terrains
Linking information on pollutant concentrations &
doses to the health of forests (trees and understory
vegetation)
Use of remote sensing sensing data for the large
scale assessments
Ultimate goal – development of pollution risk
assessment models for decision making
Another aspect of our
research - Smoke Monitoring
’
Development of low-cost, low maintenance,
robust samplers to monitor:
– Components of regional haze and fire smoke
– Ambient ozone and nitrogen concentrations and
deposition of ambient pollutants
’
Development of regional networks for:
– Evaluation of air pollutants from wildland and
prescribed fires
– Pollutant data needed for regional haze models
Big Bear Lake
N
Keller Peak
San Gorgonio Mt
Lake Arrowhead
Crestline
Passive samplers-2001
Redlands
Forest health-2000
Forest health-1973-1995
San Bernardino Mountains Gradient
Air pollutants
Nitric acid vapor (HNO3)
Ammonia (NH3)
Ozone (O3)
Nitrogen dioxide (NO2)
Nitrogen oxides (NOx)
50
64
70
115
60
97
(74)
60
(70)
61
(71)
(67)
52 63
85 (70)
56
60
(75)
30
(72)
(80)
60 (72)
(72)
Summer avg 2001 (Max. 2-wk)
July-Aug avg 1974-78
Ozone - 24h avg (ppb)
1
8
7
5
Nitrogen compounds
1
3
4
2 2
NO2 (ppb)
6
2
1
HNO3
(mg/m3)
9
4
2
4
5 4
2
2
6
5
3
4
4
2
3 3
NH3 (mg/m3)
2
2
Passive ozone sampler on
Turtleback Dome in Yosemite
National Park
First Step – understanding
spatial & temporal
patterns of ozone
distribution in the Sierra
Nevada
Collaboration between the
USDA Forest Service, US EPA,
National Park Service and the
Environmental Systems
Research Institute
Approach to the Problem
in the 1999 study
’
’
’
Deployment of passive ozone samplers in
the Sierra Nevada, mostly along the western
slopes
Evaluation of pine injury at the ozone
monitoring sites
Development of models of spatial and
temporal distribution of ambient ozone in the
studied areas – three different approaches
What have we learned from
the 1999 Sierra Nevada
study
’
’
’
Maps developed with the ESRI ArcGIS 8.1
Geostatistical Analyst, based on passive
samplers, active monitors & weather data
show high spatial and lower temporal
variability of ozone distribution
SW, W and E portions of the Sierra Nevada
experience long-lasting elevated ozone
exposures
The determined levels of ozone have a
strong phytotoxic potential and may affect
health of residents and visitors in Sierra
Nevada forests
Ozone Air Pollution in the
Sierra Nevada – Distribution and
Effects on Forests
’
’
’
’
Editors – A. Bytnerowicz, M. Arbaugh and R.
Alonso
Publisher: Elsevier Scientific – Developments in
Environmental Sciences, vol. 2
16 chapters on ozone distribution & effects, natural
history background, management issues, etc.
Publication date - April 2003
New research question – how do
polluted air masses get to
eastern Sierra Nevada and Lake
Tahoe Basin?
’
’
’
’
Passage across southern portion of the
Sierra Nevada from San Joaquin Valley
Passage along river valleys such as San
Joaquin River
Long-range transport from LA Basin
Local generation of pollutants (especially
Lake Tahoe Basin)
Approach to the
Problem
’
’
’
Deployment of passive samplers in the
Lake Tahoe Basin, along eastern Sierra
Nevada, and the San Joaquin River & Lake
Isabella transects
Evaluation of pine injury at the passive
sampling monitoring sites
Development of models of spatial and
temporal distribution in the studied areas
based on the 1999 & 2002 campaigns
2002 summer season field
monitoring campaigns
’
Ambient Air Transport and Dispersion
– Measured O3, HNO3 and NH3 along three
possible air transport corridors across
Sierra Nevada
– Developed a regional monitoring system
(combination of passive and active
monitors) for ambient O3 levels in
relationship to smoke emissions
Passive samplers for O3, HNO3 and NH3 at Agnew
Meadows, Inyo National Forest, Sierra Nevada
Lake Tahoe air pollution
monitoring – summer 2002
Other products from the
2002 study
’
’
’
’
Maps of ozone and nitric acid distribution
during seven individual 2-week long periods
for the Lake Tahoe area
Similar maps of ozone, nitric acid, and
ammonia distribution for the San Joaquin
River transect
Maps of ozone and nitric acid distribution for
the rest of the Sierra Nevada
Better understanding of effects of forest fires
on air quality (analysis of the McNalley fire
effects)
How did the McNalley fire affect
ambient air quality in the Sierra
Nevada in summer 2002?
Our newest study – Kings
River & Teakettle Projects
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 urban sprawl and
forest fires effects