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Emission Inventory Special Studies
This page last reviewed August 2, 2010
The California Air Resources Board (ARB) gathers air quality data for the state of California, ensures the quality
of this data, distributes data sets to our stakeholders, designs and implements air models, and sets ambient
air quality standards for the state. The ARB also performs air quality and emissions inventory special studies.
Below, you will find listed areas of this web site which provide materials regarding special studies performed
by the ARB.
Mobile Measurement of Greenhouse Gas Emissions
Field research efforts to verify the California greenhouse gas (GHG)
emissions inventory, as instructed by Assembly Bill 32, are currently
underway using mobile measurement platforms. Two electric vehicles
outfitted with an extensive suite of analytical instrumentation
complete data collection experiments using several sampling
methodologies to assess the GHG emissions from a variety of source
categories. Measurements include GHG mixing ratios (CH4, N2O, CO2 and
CO), particulate concentration metrics (PM2.5 mass, PM1.0 number, and
Black Carbon), and meteorology metrics (wind speed, wind direction,
temperature and relative humidity). Active research collaborations with
industry and academia are fostered where available, and collocated data
collection events are pursued to enhance the power of each data set and
provide intercomparison. These field studies serve to develop and
refine measurement protocols to accurately ascertain the GHG source
emissions such that the existing emissions inventory values can be
validated and uncertainty in future values can be reduced. For more
information, please contact Mike FitzGibbon at (916) 323-2389.
Research Division's Pilot Methane Monitoring Network
The objective of this project is to establish a pilot methane (CH4)
monitoring network in California. Starting in May 2010, this network
will provide high quality measurements of CH4 concentrations at
selected monitoring stations. The design of this pilot CH4 monitoring
network is to install state-of-the-art analyzers at air quality
monitoring stations that will compliment the existing GHG measurement
sites in California. When the proposed pilot CH4 stations are
operational, it will become a high density CH4 monitoring network in
California (Figure 1 - PDF 62KB).
Currently, there are six GHG monitoring stations in the state. As shown
in Figure 1, there are no measurements in the San Joaquin Valley and
the Sacramento Valley where there are many CH4 emission sources such as
landfills, natural gas systems, rice paddies, dairies, waste water
treatment facilities, and other sources. The current proposed plan is
to set up to three stations in the San Joaquin Valley and two stations
in the Sacramento Valley at locations where they represent the regional
atmospheric compositions. The Research Division’s pilot CH4 monitoring
network is the first of its kind deployed at the regional level and
with a monitoring network dense enough to identify emission sources and
to true-up an already well developed anthropogenic CH4 inventory. If
the network is proven successful, over time it will provide data to
evaluate the effectiveness of California’s efforts to reduce CH4
emissions. For more information, contact Ying Hsu at (916)323-5774.
SARMAP Study Ozone Study
The development of the SARMAP Air Quality Model has been completed
and the model has been applied in central California which includes the
San Joaquin Valley and surrounding air basins, to prepare the 1994
State Implementation Plan. The model has been extensively tested and
evaluated using the rich database of the San Joaquin Valley Air
Quality Study. The model passed the model evaluation criteria of
U.S. EPA and the California Air Resources Board. The model has
many important attributes which include: map projection capability to
account for the curvature of the earth; telescoping grid capability; a
coordinate system that matches the coordinate system of MM5 to avoid
interpolation between the two models; grid nesting capability (both
one-way and two-way nesting is possible); a high resolution verticle
grid system (the thickness of the layer near the ground is about
10 m); two chemical mechanisms (Carbon-bond-IV and Statewide
Air Pollution Research Center (SAPRC)); a Plume-in-Grid module; and
three advection schemes. An aerosol module is being incorporated into the model. For more information, please contact Ajith Kaduwela at (916) 327-3955.
Central California Ozone Study
The Central California Ozone Study
is a project proposed to enhance existing tools and information
applicable for evaluating the scientific merit of various air quality
management activities. It will further the current understanding of how
major air pollution sources influence the existing 1-hour and new
8-hour federal air quality standard for ozone. The project will advance
model evaluation and the characterization of related uncertainties. The
proposed project will also enhance existing tools and information
applicable for evaluating the scientific merit of different air quality
management activities. The project will provide the information needed
for the development of a new State Implementation Plan for ozone by
2003 and particulate matter in central California by 2005 as required
by recent federal regulation. For more information, please contact Ajith Kaduwela at (916) 327-3955.
California Regional PM10 / 2.5 Air Quality Study
The California Regional PM10 / 2.5 Air Quality Study is a comprehensive
program of monitoring, emissions inventory development, data analysis,
and modeling. The study is intended to provide an improved
understanding of PM10 and PM2.5, establish a strong scientific
foundation for informed decision making, and develop and identify the
most efficient and cost-effective emission control strategies
to achieve PM10 and PM2.5 standards in Central California. The
study is funded and managed through an innovative cooperative
partnership between the public and private sector with completion
expected in 2003. For more information, please contact Karen Magliano at (916) 322-7137.
1995 Integrated Monitoring Study
The 1995 Integrated Monitoring Study (IMS95) was a preliminary field
program designed to collect PM10 and PM2.5 data to more effectively
plan the overall California Regional PM10/2.5 Air Quality Study. The
IMS95 had three primary components; a two week fall sampling
program in November 1995, a four week winter sampling program in
December 1995 and early January 1996, and a two-week fog sampling
program in January 1996. Data from the study are available at this
address. For more information, please contact Karen Magliano at (916) 322-7137.
1999 / 2000 Annual and Episodic Field Programs
The major effort of the California Regional PM10 / 2.5 Air Quality Study will involve annual and episodic
field programs designed to collect data to support modeling and data analysis of PM10 and PM2.5 in Central
California. The annual field program will commence in December of 1999 and continue through January of
2001. Fall and winter episodic monitoring will take place from September 2000 through January 2001. The
field programs will include comprehensive measurements of gaseous and particulate pollutants and meteorology both
at the surface and aloft. For more information, please contact Karen Magliano at (916) 322-7137.
Southern California Air Quality Studies
Southern California Ozone Study
In order to develop databases to support detailed photochemical
modeling and analysis for a better understanding of the processes
involved in the formation of high ozone concentrations in the
Southern California region, the ARB and several other groups
co-sponsored the 1997 Southern California Ozone Study -
North American Research Strategy for Troposheric Ozone
(SCOS97-NARSTO).
