Ambient Ozone in Californian and
Central European Mountains
Andrzej Bytnerowicz1, Michael Arbaugh1
and Witold Frączek2
1USDA
Forest Service, Pacific Southwest Research
Station, Riverside, CA, USA
2Environmental Systems Research Institute, Redlands,
CA, USA
Why ozone?
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Ambient concentrations have been rising
since 1880s
Criteria pollutant toxic to humans and
vegetation
Levels of >30-40 ppb potentially toxic to
plants (NRC – need for ecologically-oriented
ozone secondary standard)
By 2050 ~60% of N. Hemisphere forests will
be affected by ambient ozone
Background O3 concentrations
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In a global and regional perspective, the
background region for atmospheric pollutants is
referred to as the area where the atmosphere is
not directly influenced by local and
anthropogenic sources. Such regions are limited
due to extensive human activities in most of the
continental areas and possible background may
be limited to the central Pacific, Middle Atlantic
and central Eurasia (Pochanart et al., 2003).
Continental background concentrations of
ozone, annual averages - 1
Location
Concentration
(ppb)
Reference
Asia
Mondy Mt (China)
43.5
Pochanart et al., 2003
Happo (Japan)
44.4
Pochanart et al., 2004
Mt. Abu (India)
48.1
Naja et al., 2003
37 - 46
Vingarzan, 2004
33.4
Naja et al., 2003
Pacific
Mauna Loa (Hawaii)
Indian Ocean
Mt. Abu data
Continental background concentrations of
ozone, annual averages - 2
Location
Concentration
(ppb)
Reference
Europe
Finland
30
Laurila & Lattila, 1994
Arosa, Swiss Alp
35
Pochanart et al., 2001
North America
US, inland
25 - 45
Altshuller & Lefohn, 1996
US, coastal
25 - 35
Ibidem
US, East
15 - 30
Liang et al., 1998
US, West
25 - 35
Ibidem
Canada
23 - 34
Vingarzan, 2004
CASTNET - Annual Mean O3 Concentrations (ppb) for 2002
CASTNET- Peak SUM06 Values (ppm-hr) for 2002
Our approach to characterizing air
pollution status in mountain terrain
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Use of reliable, easy to use passive samplers
allowing for monitoring air pollutants in remote
areas where electronic monitors cannot be used
In selected location, collocation of portable UV
absorption real-time monitors
Development of maps of ozone distribution with
geostatistical models
Ogawa Passive Sampler
Passive samplers for O3 and HNO3
vapor in Sierra Nevada
Advantages of using passive
samplers
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Low cost
Simple design and operation
Low maintenance needs
No need for electric power
Possibility for dense deployment
Reliable results
Integration of long-term exposure regimes
Limitations of passive
samplers
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No information on diurnal, real-time
concentrations (needed for
understanding toxic potential)
Changes in climatic conditions (wind,
temperature, RH) affect samplers’
performance
Need for calibration against real-time
monitors
ESRI Geostatistical Analyst
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Extension of ARC/INFO 8 generates
predictive surfaces from data points
using geostatistical tools and analyzing
error of the resulting estimations.
Numerous kriging and predictive tools
are the center of the extension.
Ozone distribution in the Sierra Nevada - 1999
Mountains as barriers for air pollution
transport – 2002 studies
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Hypothesis 1. River valleys are natural
corridors for moving pollutants across
mountain ranges.
Hypothesis 2. High mountain ranges
may be very effective barriers
preventing long-range transport of
polluted air masses.
2002
intensive
studies – Lake
Tahoe and the
San Joaquin
River transect
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ppb
Ozone on the San Joaquin River
transect in summer 2002
Ozone seasonal averages
100
90
80
70
60
50
40
30
20
10
0
Lake Tahoe air pollution monitoring –
summer 2002
hours
305
297
289
281
273
265
257
249
241
233
225
217
209
201
193
185
177
169
161
153
145
137
129
121
113
105
97
89
81
73
65
57
49
41
33
25
17
9
1
ozone (ppb)
2B Technology Monitor Real-time
Ozone Data
Fenced Meadow, 7/23/15:45 - 8/5/14:00/2003
120
100
80
60
40
20
0
Locations of the 32 Measurements Sites
Air quality in the Tatra Mountains is affected by
transport of polluted air masses from many
European countries
Distribution of ozone in complex
mountain terrain is difficult to predict
Information on ozone levels helps to understand risks to
sensitive plants such as ponderosa pine or Swiss stone pine
Elevated levels of ozone predispose trees to
drought stress and insect attacks
Conclusions - 1
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North America and European mountains
experience elevated levels of tropospheric O3
potentially toxic to humans and vegetation
Long-range transport, including trans-Pacific
transport from Asia, is responsible for significant
increases of ambient O3 levels
Better understanding of temporal and spatial
distribution of O3 in western mountains is needed
Conclusions - 2
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Polluted air masses can move across
mountain ranges along river valleys
(example - San Joaquin River drainage).
Mountain ranges can prevent
movement of polluted air masses acting
as pollution barriers (example –
Desolation Wilderness west of Lake
Tahoe)
Conclusions - 3
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Forest fires are important sources of VOCs
and NOx and promote O3 formation
Passive sampler networks can effectively
point to “hot spots” for ambient O3 and
other pollutants
There is a need for “translating” long-term
average O3 concentrations into real-time
values (models are already available)
Thank you !!!