Oil & Natural Gas Projects
Exploration and Production Technologies
Characterizing the Formation of Secondary Organic Aerosols
This project was funded through DOE's Natural Gas and Oil Technology Partnership
Program. The program establishes alliances that combine the resources and experience
of the nation's petroleum industry with the capabilities of the national laboratories
to expedite research, development, and demonstration of advanced technologies
for improved natural gas and oil recovery.
The goal of the project is to conduct experimental, analytical, and modeling
research to investigate secondary organic aerosols (SOAs) formation under actual
field conditions. The purpose is to establish a rich data set that will be analyzed
to characterize SOA formation from hydrocarbon emissions from a number of sources,
at the regional scale.
Lawrence Berkeley National Laboratory (LBNL)
Independent Petroleum Association of Mountain States (IPAMS)
Atmospheric aerosols from natural and anthropogenic processes have both primary
and secondary origins and can influence human health, visibility, and climate.
One key process affecting atmospheric concentrations of aerosols is the formation
of new particles and their subsequent growth to larger particle sizes.
A field study was conducted at the Blodgett Forest Research Station in the
Sierra Nevada Mountains of California from May through September of 2002 to
examine the effect of biogenic volatile organic compounds (VOCs) on aerosol
formation and processing. The study included in-situ measurements of concentration
and biosphere-atmosphere flux of VOCs, ozone, aerosol size distribution, aerosol
physical and optical properties, and meteorological variables. Fine-particle
growth events were observed on about 30 percent of the 107 days, with complete
size-distribution data. Average particle growth rates measured during these
events were 3.8 ± 1.9 nanometers per hour. Correlations among aerosol
properties, trace gas concentrations, and meteorological measurements were analyzed
to determine conditions conducive to fine-particle growth events.
Growth events were typically observed on days with a lesser degree of anthropogenic
influence, as indicated by lower concentrations of black carbon, carbon monoxide,
and total aerosol volume. Days with growth events also had lower temperatures,
increased wind speeds, and larger momentum flux. Measurements of ozone concentrations
and ozone flux indicate that gas-phase oxidation of biogenic VOCs occurs in
the canopy, strongly suggesting that a significant portion of the material responsible
for the observed particle growth are oxidation products of naturally emitted,
very reactive organic compounds.
This research will contribute to quantifying the portion of visibility degradation
attributable to natural sources by supporting the development of models used
to determine the aerosol loading resulting from biogenic emissions. The research
will provide sound science required for the equitable implementation of the
Regional Haze Rule. The results are important for the various regions of the
country where oil and gas exploration and production occur: the States and Tribes
in the Central Rocky and the Gulf Coast regions and Kern County, CA. This will
greatly improve the modeling of visibility that is important for implementing
the Regional Haze Rule and contribute to aerosol source apportionment, which
is necessary for permitting oil and gas operations. The research will be useful
to the Environmental Protection Agency and the Departments of Energy, Interior,
and Agriculture because of energy and environment concerns and their role in
implementing the Regional Haze Rule. The research sponsorship should be at the
federal level because industry sponsorship often is viewed as self-serving.
Anthropogenic aerosols from populated, industrial, and rural areas result in
regional haze that causes significant visibility degradation in areas valued
for their scenic beauty, such as the National Parks. These areas are designated
as Class I Areas in the Clean Air Act (CAA). Naturally and anthropogenically
derived aerosols are treated differently under the Regional Haze Rule.
The summarized visibility goals for the States and Tribes as laid out in Section
308 of the 1999 Regional Haze Rule of the CAA are:
- Prevent degradation of the 20 percent cleanest days.
- Determine a uniform rate of progress for each Class I area needed to return
the 20 percent dirtiest days to natural conditions by 2064.
- Establish a reasonable progress goal for each Class I area for 2018.
Implementing the Regional Haze Rule in the West and other parts of the country
requires that source apportionment of aerosols into natural (biogenic) and anthropogenic
source categories be accomplished. Carbonaceous aerosols are large contributors
to visibility degradation (extinction) in the West. The organic carbon (OC)
content of atmospheric aerosol has been increasing for the 20 percent dirtiest
day in the intermountain west and can be an important component of aerosols
in southeast and central California. SOA of biogenic origin can be a significant
fraction of this OC aerosol, particularly in heavily forested or rural regions.
To properly apportion the effects of organic aerosols on visibility, it is
necessary to quantify the fraction due to primary emissions and to apportion
the SOA into that fraction due to anthropogenic and biogenic precursors. Because
the atmospheric chemistry that leads to SOA formation is highly complex and
non-linear, the only way to predict and apportion SOA is to build and use models
that accurately describe the formation of SOA from precursor emissions.
Formation of SOAs is important because they contribute significant particle
mass in urban and rural areas. SOAs are derived from volatile and semi-volatile
hydrocarbon emissions from the biosphere, fuels and their combustion products
from mobile sources, and operations concerned with oil and gas exploration and
production. SOAs and their precursors influence atmospheric processes at the
urban, regional, and global scales and potentially affect visibility, ozone
chemistry, ambient PM2.5 (particle mass having diameters of 2.5 microns or less)
concentrations, actinic flux, global climate, and human health. There is a need
to improve our scientific understanding of SOA formation to build more-robust
models for particles, ozone, and visibility. These models must be representative
of actual atmospheric conditions that involve the transport and transformation
of emissions over urban and regional scales.
In response to this need, the researchers are conducting experimental, analytical,
and modeling research whose objective is to investigate SOA formation under
actual field conditions to establish a rich data set that will be analyzed to
characterize SOA formation from hydrocarbon emissions from a number of sources,
at the regional scale. The understanding of SOAs derived from these studies
will contribute to model development and model benchmarking.
Current Status (October 2005)
The project performers have requested a no-cost extension for FY 2006 and plan
to apply to DOE for future funding involving flux measurements.
Lunden, Melissa, Black, Douglas, Brown, Nancy, Lee, Anita, Schade, Gunar, and
Goldstein, Allen, Fine Particle Formation and Processing in a California Pine
Forest, American Association of Aerosol Research, October 2003.
Lunden, Melissa, Black, Douglas, and Brown, Nancy, Characterizing the Formation
of Secondary Organic Aerosols, Interim Report to DOE, February 2004. Also: LBNL
Report No. 54446.
Lunden, Melissa, Black, Douglas, Brown, Nancy, Lee, Anita, Schade, Gunar, McKay,
Megan, and Goldstein, Allen, Aerosol Growth Observed in a Sierra Nevada Pine
Forest and its Relationship to Biogenic Volatile Organic Compounds and Anthropogenic
Pollutants, Poster No. A41A-008, American Geophysical Union, San Francisco,
CA, December 2004.
Lunden, M.M., Black, D.R., McKay, M., Revzan, K.L., Goldstein, A.H., and Brown,,
N.J., Characteristics of Fine-Particle Growth Events Observed above a Forested
Ecosystem in the Sierra Nevada Mountains of California, accepted for publication
in Aerosol Science and Technology, 2005. Also: LBNL Report No. 58135.
Project Start: March 27, 2002
Project End: April 26, 2005
Anticipated DOE Contribution: $650,000.
Performer Contribution: $150,000 (in-kind, IPAMS).
Other Government Organizations Involved
California Air Resources Board
National Science Foundation
National Aeronautics and Space Administration.
NETL - Rhonda Jacobs (email@example.com or 918-699-2037)
LBNL - Nancy J. Brown (firstname.lastname@example.org or 510-486-4241)
The tower at the Blodgett Forest field site. The boxes mounted on the tower
contain the aerosol equipment. The adjoining schematic shows the locations of
the aerosol instrumentation on the tower: (1) 2.5 mm cyclone inlet, (2) aethalometer,
(3) condensation particle counter, (4) scanning mobility particle scanner, (5)
optical particle sizer, (6) nephelometer, and (7) filter samplers.
Size distribution measured as a function of time for (a) a typical day when
a growth event occurred and (b) a day when no event occurred. The curves that
overlay the images are the results of the bimodal fitting procedures with the
larger and smaller modes indicated by the dotted and solid lines, respectively.