4 research outputs found
Volatile organic compounds and ozone in Rocky Mountain National Park during FRAPPÉ
The 2014 Front Range Air Pollution and Photochemistry
Éxperiment (FRAPPÉ) aimed to better characterize summertime air
quality in the Northern Front Range Metropolitan Area (NFRMA) and its impact
on surrounding areas. As part of this study, measurements of
gas- and particle-phase species were collected in Rocky Mountain National Park (ROMO), located
in the mountains west of the urban northern Front Range corridor from
July to October 2014. We report on measurements of ozone from two locations in
the park and a suite of volatile organic compounds (VOCs) measured using a
continuous real-time gas chromatography (GC) system and a quadrupole
proton-transfer-reaction mass spectrometer (PRT-MS) at the ROMO Longs Peak (ROMO-LP) air quality
site. We also measured VOCs using canister samples collected along transects
connecting the NFRMA and ROMO. These datasets show that ROMO is impacted by
NFRMA emission sources, and high observed mixing ratios of VOCs associated
with oil and gas extraction (e.g. ethane) and urban sources (e.g. ethene and
C2Cl4) occur during periods of upslope transport. Hourly ozone
mixing ratios exceeded 70 ppb during six events. Two of the six events were
largely associated with VOCs from the oil and gas sector, three high ozone
events were associated with a mixture of VOCs from urban and oil and gas
sources, and one high ozone event was driven by a stratospheric intrusion.
For the high ozone events most associated with emissions from oil and gas
activities, we estimate that VOCs and NOx from sources along
the Front Range contributed ∼20 ppbv of additional ozone.</p
Impact of Front Range sources on reactive nitrogen concentrations and deposition in Rocky Mountain National Park
Human influenced atmospheric reactive nitrogen (RN) is impacting ecosystems in Rocky Mountain National Park (ROMO). Due to ROMO’s protected status as a Class 1 area, these changes are concerning, and improving our understanding of the contributions of different types of RN and their sources is important for reducing impacts in ROMO. In July–August 2014 the most comprehensive measurements (to date) of RN were made in ROMO during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ). Measurements included peroxyacetyl nitrate (PAN), C1–C5 alkyl nitrates, and high-time resolution NOx, NOy, and ammonia. A limited set of measurements was extended through October. Co-located measurements of a suite of volatile organic compounds provide information on source types impacting ROMO. Specifically, we use ethane as a tracer of oil and gas operations and tetrachloroethylene (C2Cl4) as an urban tracer to investigate their relationship with RN species and transport patterns. Results of this analysis suggest elevated RN concentrations are associated with emissions from oil and gas operations, which are frequently co-located with agricultural production and livestock feeding areas in the region, and from urban areas. There also are periods where RN at ROMO is impacted by long-range transport. We present an atmospheric RN budget and a nitrogen deposition budget with dry and wet components. Total deposition for the period (7/1–9/30) was estimated at 1.58 kg N/ha, with 87% from wet deposition during this period of above average precipitation. Ammonium wet deposition was the dominant contributor to total nitrogen deposition followed by nitrate wet deposition and total dry deposition. Ammonia was estimated to be the largest contributor to dry deposition followed by nitric acid and PAN (other species included alkyl nitrates, ammonium and nitrate). All three species are challenging to measure routinely, especially at high time resolution
Oil and gas impacts on air quality in federal lands in the Bakken region: an overview of the Bakken Air Quality Study and first results
The Bakken formation contains billions of barrels of oil and gas trapped in
rock and shale. Horizontal drilling and hydraulic fracturing methods have
allowed for extraction of these resources, leading to exponential growth of
oil production in the region over the past decade. Along with this
development has come an increase in associated emissions to the atmosphere.
Concern about potential impacts of these emissions on federal lands in the
region prompted the National Park Service to sponsor the Bakken Air Quality
Study over two winters in 2013–2014. Here we provide an overview of the
study and present some initial results aimed at better understanding the
impact of local oil and gas emissions on regional air quality. Data from the
study, along with long-term monitoring data, suggest that while power plants
are still an important emissions source in the region, emissions from oil and
gas activities are impacting ambient concentrations of nitrogen oxides and
black carbon and may dominate recent observed trends in pollutant
concentrations at some of the study sites. Measurements of volatile organic
compounds also definitively show that oil and gas emissions were present in
almost every air mass sampled over a period of more than 4 months