Impacts of the 2013 “Aspen” and “Rim” Fires on Air Quality in Devils
Postpile National Monument, Sierra Nevada
Andrzej Bytnerowicz1, Monica Buhler2, Joel Burley3, Jennifer Chapman Varela3, Ricardo Cisneros4, Deanna Dullen2, Michelle Horn5, Mark McDaniel6, Donald
Schweizer4, and Barbara Zielinska6
Forest Service, PSW Research Station, Riverside, CA; 2Devils Postpile National Monument, Mammoth Lakers, CA; 3St. Mary’s College, Moraga, CA; 4USDA Forest Service, Region 5, Fresno, CA &
University of California, Merced, CA; 5Technical University of Munich, Freising, Germany; 6Desert Research Institute, Reno, NV
dramatically during the Aspen Fire period. This phenomenon could
have been caused by high concentrations of fine particulate (PM2.5)
scavenging gaseous organic species.
Abstract
Air pollutants with potential effects on human and ecosystem health
were monitored in summer 2013 at Devils Postpile National Monument
(DEPO), eastern Sierra Nevada. Measured species included ozone (O3),
ammonia (NH3), nitrogen oxides (NO and NO2), nitric acid (HNO3),
volatile organic compounds (VOCs), sulfur dioxide (SO2), and fine
particulate matter (PM2.5). The original objective of the study was to
develop a better understanding of how air quality at DEPO is affected
by locally produced air pollutants compared with those transported
from remote pollution source areas, such as the California Central
Valley and the San Francisco Bay Area. No major impacts of local
emissions on air quality were detected and generally, concentrations of
the monitored pollutants were low before the Aspen and Rim Fires.
Emissions from these fires drastically changed the air quality status at
DEPO. The highest impact of the fires was on PM2.5 which reached
the “unhealthy” level of the Air Quality Index (AQI) during the Aspen
Fire (3-h rolling averages >135 mg m-3) and the “unhealthy for
sensitive people” level during the Rim Fire (3-h averages >85 mg m-3).
Concentrations of NH3, NO and NO2 became elevated, while
concentrations of O3, HNO3 and SO2 did not noticeably change. In
general, concentrations of VOCs were quite low with a-pinene as a
dominating species. Concentrations of all VOCs dropped dramatically
during the Aspen Fire period. This phenomenon could have been
caused by high concentrations of fine particulate (PM2.5) scavenging
the gas phase organic species. Results of this study indicate potential
impacts of air pollution on human and ecosystem health of this
eastern Sierra Nevada receptor site and the importance of continued
monitoring of air quality at remote areas.
Aspen Fire
Location of the Rim and Aspen Fires 2013
Aspen Fire
Rim Fire
b
a
40
c
Fp
Mw
Fp – Flagpole site
Mw – Meadow site
35
Start date
July 22nd 2013
August 17th 2013
End date
August 11th 2013
October 24th 2013
Area
22,800 ac (9,227 ha)
257,314 ac (104,131 ha)
Fuel type
Mixed conifer forest and
chaparral
Chaparral, oak, and
conifer forest
30
25
20
15
10
Introduction
5
0
Methods:
EXP01
Air quality was evaluated with active monitors and passive samplers.
Ogawa passive samplers were used for determinations of ozone (O3),
ammonia (NH3), and nitrogen oxides (NO and NO2); USFS samplers
for nitric acid (HNO3) and sulfur dioxide (SO2); and Radiello samplers
for volatile organic compounds (VOCs). Passive samplers produced 2week average concentrations of the measured pollutants. Additionally,
hourly concentrations of O3 and NOx were determined with 2B
Technologies monitors, and real-time concentrations of fine particulate
matter (PM2.5) with E-BAM instruments. Air pollution monitoring
started on June 4 and ended on September 25, 2013.
EXP02
EXP03
EXP04
EXP05
EXP06
EXP07
EXP08
Ozone 14-day average concentrations at two DEPO
monitoring locations.
n-undecane
2.5
1,2,3-trimethylbenzene
n-decane
alpha-pinene
2
n-nonane
o-xylene
VOC (ppb)
In order to assess the overall air quality at Devils Postpile National
Monument (DEPO) and to gain a better understanding of various
factors influencing air pollution levels, a collaborative study between
the National Park Service; USDA Forest Service Pacific Southwest
Research Station and Region 5; Saint Mary’s College; Desert Research
Institute, and University of California – Merced was conducted there in
summer 2013. Volunteers from the Student Conservation Association
were actively involved in monitoring activities.
Rim Fire
1−hr and 3−hr rolling average PM2.5 (06/04−10/07, 2014).
Note elevated levels to “unhealthy” during the Aspen Fire
and “unhealthy to sensitive people” during the Rim Fire.
Ozone (ppb)
1USDA
styrene
1.5
m&p-xylene
ethylbenzene
n-octane
1
toluene
n-heptane
cyclohexane
0.5
benzene
n-hexane
isoprene
0
EXP01
Fp
EXP01
Mw
EXP02
Fp
EXP02
Mw
EXP03
Fp
EXP03
Mw
EXP04
Fp
EXP04 EXP05
Mw
Fp
EXP05 EXP06
Mw
Fp
EXP06 EXP07
Mw
Fp
EXP07
Mw
EXP08
Fp
EXP08
Mw
1,3-butadiene
VOCs concentrations during 8 monitoring periods
10
9
Air quality monitoring
equipment consisted of
various passive
samplers and real-time
electronic monitors.
The National Park Service, US Forest Service and Student
Conservation Association members of the research team
During the monitoring campaign, smoke from the Aspen and Rim fires
affected air quality in the Sierra Nevada, including DEPO. The ongoing
monitoring provided real time information on air quality and the
information on concentrations of fine particulate matter (PM2.5)
helped in an ad hoc warning system for the public to plan their
recreation activities.
Experimental
Study location
The study was conducted at Devils Postpile National Monument
(DEPO) which is located in the Middle Fork of the San Joaquin River
drainage close to the Sierra Nevada crest (latitude: 37.6293oN;
longitude: -119.5678oW).
7
6
NH3-N μg/m3
5
4
NO2-N μg/m3
3
NO-N μg/m3
2
HNO3-N μg/m3
1
SO2-S μg/m3
0
EXP01
Fp
Monitoring
Period
1
2
3
4
5
6
7
8
Duration
June 4 – 19, 2013
June 19 - July 3, 2013
July 3 - 17, 2013
July 17 – 31, 2013
July 31 – August 14, 2013
August 14 – 28, 2013
August 28 – September 11
September 11 – 25, 2013
Results and Discussion
Smoke from the Rim Fire (left) and Aspen Fire (right)
Concentration (μg/m3)
8
No major impacts of local emissions on air quality were detected and
generally, concentrations of the monitored pollutants were low before
the Aspen and Rim Fires. Emissions from these fires drastically
changed the air quality status at DEPO. The highest impact of fires
was on PM2.5 which reached the “unhealthy” level of the Air Quality
Index (AQI) during the Aspen Fire (3-h rolling averages >135 μg m-3)
and the “unhealthy for sensitive people” level during the Rim Fire (3-h
averages >85 μg m-3). Concentrations of NH3, NO and NO2 became
elevated, while concentrations of O3, HNO3 and SO2 did not noticeably
change. In general, concentrations of VOCs were quite low with apinene as a dominating species. Concentrations of all VOCs dropped
EXP01
Mw
EXP02
Fp
EXP02
Mw
EXP03
Fp
EXP03
Mw
EXP04
Fp
EXP04 EXP05
Mw
Fp
EXP05 EXP06
Mw
Fp
EXP06 EXP07
Mw
Fp
EXP07
Mw
EXP08
Fp
EXP08
Mw
Nitrogenous pollutants and SO2 during 8 monitoring periods
Conclusions
1. Before the Aspen and Rim Fires, air quality was good with low
concentrations of O3, NO, NO2, NH3, SO2, VOCs and PM2.5 which
are typical for the North American remote areas.
2. The Aspen and Rim Fires caused a serious deterioration of air
quality with PM2.5 concentrations above the federal health
standards.
3. At the initial stage of both fires, NH3 and NO2 concentrations were
elevated.
4. While the Aspen Fire did not affect O3 concentrations, the Rim Fire
caused O3 increase.
5. A drop of VOCs concentrations during the Aspen Fire was
surprising and warrants further investigation.
6. This study shows importance of ambient air quality monitoring for
better understanding of impacts of air pollution on human and
ecosystem health.
7. Long-term air quality monitoring should be an integral part of
management of the Sierra Nevada public lands.
8. Real-time information about air quality is of high importance for
informing the public on current and anticipated conditions.
Acknowledgements: study was funded by USDA Forest Service
Pacific Southwest Research Station and National Park Service.
References: a) Google 2014. Google Maps, https://www.google.com/maps/ms?ie=UTF8&oe=UTF8&msa=0&msid=208523333872813891131.0004e850f6b1674b3c43b&safe=on , April 15 th 2014
b) InciWeb 2013. Aspen Fire, http://inciweb.nwcg.gov/incident/3552/ , April 21st 2014
c) InciWeb 2013. Rim Fire, http://inciweb.nwcg.gov/incident/3660/ , April 21st 2014