| 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
This table 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. |
2008
Monitoring Schedule for Three-Day, Six-Day, and Twelve-Day Sampling
The U.S. EPA sampling schedule for ambient air monitoring. |
|
| 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 Cliff Popejoy at cpopejoy@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 |
|
Particulate
Matter Audits
This
page 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 |
| Spreadsheets
for Estimating Monitoring Costs for PM2.5 - Excel and
QuattroPro spreadsheets developed by ARB staff to estimate the cost of settingup and operating a PM2.5 monitoring
network. The user enters specific information related to the size of the monitoring network, the frequency
of sampling and type the of analyses desired (e.g., mass, ions, elements). The spreadsheet returns summaries of
field and laboratory equipment and personnel costs. |
| California Air Quality Data Home Page - This site provides air quality data in a variety of electronic forms.
You can view air quality data interactively from the ARB air quality database, ADAM. Air quality data
is also available in summarized web format or you may request a free compact disk containing
a snapshot of 17 years of California air quality data. |
