| The California Air Resources Board monitors
particulate matter pollutants to demonstrate attainment or
non-attainment of national and state ambient air standards.
Particulate monitoring can be divided into two main
categories: monitoring of particulate matter with an
aerodynamic diameter of 10 microns or less (PM10) and
monitoring for particulate matter with a diameter of
2.5 microns or less (PM2.5). PM2.5, of course, is a
constituent of PM10. The CARB particulate
matter monitoring programs under these two programs are
described below. |
|
| PM10
Monitoring |
| PM10
is a mixture of various substances. These substances occur in
the
form of solid particles or as liquid drops. Some
particles are emitted directly into the
atmosphere. Other
particles result from gases that are transformed into
particles
through physical and chemical processes in the
atmosphere. A
variety of emission sources and meteorological conditions contribute
to ambient PM10. |
| PM10 Mass - The
PM10 standards are expressed as a weight of PM10 particles per volume
of air (micrograms per cubic meter). The standards do
not
consider the size distribution or the chemical make-up of the
particles, although these are important factors in terms of
control strategies and of the health risks associated with PM10. |
| Ion Analysis - This
program is designed to measure some of the major secondary components
of PM10. Secondary PM10 is not emitted as
particles but
is formed through chemical reactions in the atmosphere. Knowledge of
the components of PM10 can indicate the source of the PM10 and
provide insight into how to control PM10. The inorganic ion analyses of
PM10 are performed at the request of the PTSD. Chloride,
nitrate,
sulfate, ammonium, and potassium are routinely measured from samples
collected in the network. |
|
| PM2.5
Monitoring |
| PM2.5
particulate matter, called "fine" particulate, is primarily a result of
combustion products emitted into the atmosphere
as well as
those particles that are formed in the atmosphere from gaseous
pollutants as a result atmospheric chemistry (secondary formation).
Generally, the fine particulate poses a greater health risk because
these particles can deposit deep in the lung and
contain
chemicals that are particularly harmful to health. In addition to
health impacts, these particles can reside in the
atmosphere
for long periods of time and are the main contributors to reduced
visibility. |
| PM2.5 Mass -
PM2.5 mass concentrations are measured to determine attainment status
for areas in California to the federal and state
ambient air
quality standards. Whereas PM10 mass is collected using a high
volume sampler and quartz fiber filters, PM2.5 mass is collected using
a low volume sampler (16.7 liters per minute) and a small (47
mm)
Teflon filter. Because much less of the mass is collected by
the
PM2.5 sampler, the samples are weighed to the nearest microgram (one
millionth of a gram) by special, ultra-sensitive balances
under
exacting conditions. Extreme care must be taken to insure accurate
results. Laboratories performing these analyses must be pre-qualified
and are monitored to insure acceptable performance. |
|
| PM2.5
Chemical Speciation Monitoring |
| The
U.S. EPA requires the monitoring of the chemical composition of PM2.5
particulate matter for use in health studies and to determine
appropriate control measures. Currently, the chemical
speciation
samples collected at the National Air Monitoring
sites (NAMS)
in California are analyzed by the EPA contract
laboratory.
The samples collected at the State and Local
Air Monitoring
sites (SLAMS) are analyzed by the CARB laboratory. Although additional
chemical constituents may be monitored (oxalic acid and
levoglucosan, for example), the minimum target list
identified by the EPA includes elemental analyses by
X-Ray
Fluorescence, ion analyses (nitrate, sulfate, ammonium, potassium and
sodium) and elemental / organic carbon. The CARB laboratory
was
the subject of an annual system
and performance audit by
the U.S. EPA to insure that produced data for this
program is
of acceptable quality. |
| Elemental Analysis -
After collection on a Teflon filter and determination of mass
collected, the samples are submitted for
X-Ray Fluorescence
analysis. This analysis determines the concentration of 28 elemental
constituents in the PM2.5. |
| Ion Analysis
- After nitric acid denuded collection on a nylon filter, the
water-soluble ionic constituents are extracted and analyzed by
ion
chromatography. |
| Elemental / Organic Carbon Analysis - After collection
on a cleaned quartz fiber filter, the determination of the organic and
elemental fractions of the carbon collected is made with
thermal-optical pyrolysis. The organic fraction of the carbon
is a result of direct emissions into
the atmosphere as well as organic compounds formed through
atmospheric reactions. The elemental carbon is solely a result of
direct emissions, usually from combustion sources. The determination of
the elemental and organic fractions is method dependent, so
careful control of the analysis conditions is
required. The CARB laboratory participates in round-robin exercises
with the U.S. EPA contract laboratory to insure continued data
comparability. |
|
| Sampling
/ Monitoring |
| Monitoring Activities
summarizes the network and the monitoring methods for PM10 and PM2.5.
It includes sampling schedules, number of sites
operating in the State, methodology used by the ARB, U.S. EPA
reference method and data availability. |
The 2009 Monitoring
Schedule for Three-Day, Six-Day, and Twelve-Day Sampling is the U.S. EPA sampling schedule for ambient air monitoring. The U.S. EPA's 2010 Monitoring Schedule for Three-Day, Six-Day, and Twelve-Day Sampling for ambient air monitoring is available.
|
|
| Laboratory
Standard Operating Procedures |
|
Each
method used to generate laboratory data has a written SOP. These
procedures are followed each time the method is used
to produce
data for record. The following is a list of the SOPs
used
currently in the analysis of particulate pollutants. These SOPs can be
found at the Laboratory Standard
Operating Procedure page or contact
Michael Werst at mwerst@arb.ca.gov to request
a copy.
- SOP MLD005 - Acid Digestion
and Analysis of Metals from the Total Suspended
Particlates (TSP)
- SOP MLD007 - PM10 Anions (SO4,
NO3, Cl) by IC
- SOP MLD016 - PM10 Filter Mass
Analysis and Extraction for IC Analysis
- SOP MLD023 - PM10 Cations (NH4
and K) by IC
- SOP MLD033 - TSP Anions (SO4)
by IC
- SOP MLD034 - Metals by X-Ray
Fluorescence on Dichotomous and Xontech Filters
- SOP MLD055 - PM2.5 Mass in
Ambient Air by Gravimetric Analysis
- SOP MLD062 - Filter and
Canister Preparation for PM2.5 Speciation Samples
- SOP MLD064 - Anions and
Cations in PM2.5 Speciation Samples by Ion Chromatography
- SOP MLD065 - Organic and
Elemental Carbon Analysis of Exposed Quartz
Microfiber Filters
|
|
| Quality
Assurance |
|
The Particulate Matter
Audits presents information about the performance and system audits
conducted to ensure the accuracy of the particulate matter
pollutant data generated by the ARB and local air quality agencies. The
performance audit is a flow rate comparison using a NIST
traceable
transfer standard. The system audit is complete assessment of
the
entire monitoring program. Information is available
on the
following topics:
|
|
| Publications
and Downloadable Files |
| Evaluation of Fine
Particulate Samplers (PM2.5) in an Area of Volatile Constituents,
Jeff P. Cook and William E. Oslund.
Technical paper presented at the AWMA's International Specialty
Conference Particulate Matter: Health and Regulatory
Issues, Pittsburgh, Pennsylvania, April 4-6, 1995. |
| Abstract |
| A National Ambient Air Quality Standard (NAAQS) for
particulate matter equal to or less than 2.5 microns in
diameter is being considered by the United States Environmental
Protection Agency (U.S. EPA). Particulate matter of this size
is commonly referred to as PM2.5 or, more, generally, "fine"
particulate matter. PM2.5 matter found in California can be
volatile and water soluble, complicating sampling techniques.
In order to investigate potential sampling methodologies
for fine particulate, the U.S. EPA funded a
field study conducted by the California Air Resources Board (ARB)
between November 1994 and March 1995 in
Bakersfield, California. |
| Wintertime atmospheric conditions in Bakersfield
include persistent fog, temperatures in the near freezing
range, PM10 concentrations ranging up to 300 micrograms / m3 and predominant
concentrations of volatile compounds, such as ammonium nitrate
and carbon in the total PM10 mass measurements. |
| This paper presents the initial results of the
1994-95 Bakersfield winter particulate matter field study. A
total of 16 samplers representing a variety of existing, modified and
newly designated equivalent samplers, were sited in parallel and
results for both PM10 and PM2.5 measurements were compared. We found
that losses from evaporation and other mechanisms can lead to
significant particulate matter mass loss during and after sampling.
Understanding and addressing these losses are
critical to achieving a consistent measurement of PM2.5.
These factors must be addressed as the U.S. EPA proceeds to
identify reference or equivalent samplers for a
possible fine particle NAAQS. |
|
| PM10 Mass Analysis
System Audit Findings: A Prelude to PM2.5 (Fine) Mass Analysis, Thomas J.
Pomales. Technical paper presented at the AWMA's 90th Annual
Meeting and Exibition, Toronto, Ontario, Canada, June 8-13,
1997. |
| Abstract |
| During 1992, the California Air Resources Board's
(CARB) Monitoring and Laboratory Division initiated system audits
for laboratories conducting PM10 mass analysis as
data-for-record. The audits of the mass determinations
complement ongoing performance
audits of field samplers which began in1985
and provide a complete assessment of PM10 mass data.
This paper presents the CARB's findings of the PM10
mass analysis system audits and highlights
the most common problems encountered by mid- to
small-sized organizations. Given the
discrepancies that we discovered and the possibility of new
and different requirements for a fine particulate
National Ambient Air Quality Standards (NAAQS), laboratories need to be
better prepared to meet the challenge of performing consistent
particulate matter mass weighings in the future. |
| The
system audits include an assessment of filter handling and storage,
standard weight checks, balance calibrations, equilibration techniques,
tare and gross weight checks (duplicate weighings) and data
management. They also include performance audits of the balances used
to weigh the PM10 filters. |
| This paper looks at the PM10 mass analysis system
audit requirements, history, description, findings and implications.
The paper identifies the most common problems
encountered by auditors, including poor recordkeeping;
inadequate filter equilibration (relative humidity and temperature);
and missing duplicate weighings and balance calibrations. These
deficiencies have resulted in the invalidation of several
years of valuable PM10 data. Avoiding these problems in the
early stages of the PM2.5 (Fine) mass analysis program is
critical and will prevent valuable data from being invalidated. |
|
| Effects of
Environmental Conditions on Particulate Nitrate Stability During Post
Sampling Phase, Gerhard H.
Achtelik, Jr. and Jim Omand. Technical paper presented at a
International Specialty Conference, PM2.5: Fine Particle Standard,
Long Beach, California, January 28-30, 1998. The
conference was cosponsored by the AW&MA, the U.S. EPA, and the
U.S. DOE. |
| Abstract |
| This
study was designed to evaluate the stability of PM2.5 particulate
nitrate during the post sampling period. Four samples
were collected per sampling run following instrument
guidelines
similar to those described in the particulate matter federal reference
method. One of the four samples was extracted on-site and was
used
to represent a "no losses" category against which one could
compare the effect of different post sampling environmental conditions.
The remaining samples were exposed to various environmental
conditions prior to extraction. The post sampling test
conditions
were storage temperature, storage time and
open versus
closed container. The post sampling test conditions were among
those permitted in the operating parameters for filter handling
described in the U.S. EPA's PM2.5 NAAQS regulations. The
nitrate values were evaluated by regression analysis for
similar
environmental conditions. This study suggests that particulate
nitrate losses occur if filters remain on samplers
for prolonged periods of time after sampling. Losses
increase
as the filters are exposed to increased temperature. The study suggests
that placing filters in closed containers and a cool
environment can significantly reduce
nitrate losses. |
|
| Voyager Data Files |
- Bakersfield
Particulate Data
- PKWare zipped file containing particulate air pollutants
data and meteorological data collected at the
Bakersfield -
California Avenue site from November 19, 1994 through March 31, 1995.
The principal objective of the Bakersfield Winter PM
Study
was to examine the performance of a variety reference
and non-reference PM10 samplers and several PM2.5 samplers in
an
environment and during a season that would challenge
any
sampler. In addition to a meteorological system, 12 integrated
particulate samplers and four continuous particulate monitors
were operated in the study. The integrated
sampling was
performed every
three days. The data were evaluated
in a paper published by the Air & Waste Management
Association
in; Particulate Matter: Health and Regulatory Issues,
VIP 49, "Evaluation of Fine Particulate
Samplers (PM2.5)
in an Area of Volatile
Constituents."
(bak_pm25.zip, 571K)
- Statewide
Particulate Data
- PKWare zipped file containing Size Selective Inlet
(SSI) High Volume Sampler
mass and ion data and
Dichot mass data for a period from October 1990 to March 1994.
The
file contains SSI chloride, nitrate, sulfate,
ammonium,
potassium and total mass data (total is measured); and Dichot fine,
coarse and total mass data (total is sum of
fine and
coarse). (pm10_s-d.zip, 91K)
- Statewide
Particulate and PAMS HC Data
- PKWare zipped file containing preliminary data for
air
pollutants and pollutant precursors sampled at seven
California
sites from June 1, 1993 to October
30, 1993. The
Voyager file was used as a quality
assurance tool to review the hydrocarbon data for
year zero
of the U.S. EPA mandated Photochemical Assessment Monitoring Stations
(PAMS) program. The data taken
during the Summer of
1993 will be used to assess the California
Air Resources Board's monitoring capability and
preview the
ambient hydrocarbon patterns. (sum93.zip, 185K)
|
|
| Related
Links |
| PM Home Page - ARB's Main
Website for Dissemination of PM 2.5 Information |
