Characterization and Control of Fine Particles: Overview of NRMRL Research
Activities

C. Andrew Miller
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory
Research Triangle Park, NC 27711

Abstract
Research at the U.S. Environmental Protection Agency's (EPA's) National Risk Management
Research Laboratory (NRMRL) in the area of paniculate matter (PM) is designed to provide critical
information regarding emission rates, characteristics, and control approaches for PM 2.5 /urn in
aerodynamic  diameter and smaller (PM2.s). NRMRL researchers are also studying penetration of
outdoor particles into indoor environments as well as indoor sources of particles.

PM2.5 source profiles are being developed using a dilution sampling system to capture both
primary particles and particles formed by condensation of organic compounds. This research will
provide information needed by source receptor models to identify the contribution of different
sources to the ambient particle loading. Emissions characterization research is being conducted on
particle size and composition for residential wood combustion systems such as woodstoves and
fireplaces, for industrial combustion sources burning coal and heavy fuel oil, for diesel truck
engines during on-road operation, and for open burning of biomass. Emission inventory research
on ammonia from animal feeding operations and fugitive dust from construction activities will
improve understanding of PM2.5 sources and their impact on atmospheric chemistry and ambient
PM2.5 concentrations.  NRMRL researchers are studying innovative control technologies for
stationary sources.  The technologies being evaluated include improved primary particle collection
systems and multipollutant controls  such as fluid bed absorber systems. Research related to indoor
PM2.5 includes a study of the penetration rate of outdoor particles into indoor environments, as well
as research into methods of measuring the contribution of indoor particle sources to total indoor
PM2.5 concentration.

NRMRL researchers are also collaborating with health effects scientists to help link particle
characteristics to health effects, with atmospheric scientists to better understand the fate of particles
in the atmosphere, and with other organizations to create a base of broad scientific expertise and
interaction.

Introduction
Over the last several years, increasing numbers of studies have shown an association between
increases in ambient concentrations of particulate matter (PM) smaller than 2.5 /*m in aerodynamic
diameter (PM2.s) and increases in adverse health effects, including increased mortality rates. L2-3
These studies led to the revision of the National Ambient Air Quality Standard (NAAQS) for PM.
The NAAQS  revisions added two new primary PM2.5 standards: a 65 /ig/m3 24-hour average, and a
15 /ig/m3 annual mean. At the same time, the current 24-hour and annual standards of 150 and 50
/ig/m3, respectively, for PM smaller than 10 /im in aerodynamic diameter (PMjo) were retained.4

The U.S. Environmental Protection Agency's (EPA) Office of Research and Development (ORD)
has designed and is implementing a comprehensive research program to address the scientific
questions associated with PM2.5, including additional epidemiological studies to evaluate potential
subpopulations who may be more susceptible to increased levels of ambient PM^s, investigations
into the possible causes of the health effects associated with higher ambient PM2.5 concentrations,
enhanced ambient monitoring, improved atmospheric chemistry models, studies characterizing
emissions from different sources, including sources found indoors, and evaluations of air pollution

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 control technologies for new and retrofit applications. Emissions characterization studies and
 control technology development research are being conducted by ORD's National Risk
 Management Research Laboratory (NRMRL), and are the subject of this paper.

 NRMRL Research Activities
 In order to accurately model ambient concentrations of PM2.5, accurate inventories of source
 emissions of both primary particles and secondary particle precursors must be available as input to
 those models. Mass emission rates as a function of industrial or personal activities, species of
 compounds, and size distribution of particles are all important to understanding the atmospheric
 formation of secondary particles and the deposition rates of particles.  Such information is also
 important to health scientists who are seeking to identify specific ambient particle characteristics
 (such as size distribution and chemical composition) that may be linked to adverse health impacts.
 Implementation of the standards will require not only an accurate characterization of emissions, but
 also an understanding of what technologies can cost-effectively reduce such emissions. NRMRL
 PM2.5 research is characterizing particle emissions and improved methods for reducing those
 emissions to support the  Agency's goal of reducing risk associated with exposure to ambient
 concentrations of PM2.5.

 Source Sampling and Source Profiles
 Conventional PM source sampling methods intentionally prevent the condensation of many organic
 compounds. However, ambient PM2.5 samples indicate relatively large amounts of organic carbon
 (OC), or carbon-containing organic compounds.  It is important to understand the contribution
 these compounds make to the total  ambient concentration for two reasons. First, urban ambient air
 samples contain 20-30%  or more OC, a significant fraction of the total ambient mass. Second,
 specific organic compounds may act as "marker" compounds that can be used to link specific
 source categories to their contribution to ambient samples. Therefore, it is important to conduct
 sampling operations in such a way that as much as possible of the condensible organic fraction of
 the exhaust gases is collected. NRMRL has constructed a modified version of the dilution
 sampling system pioneered by the California Institute of Technology to allow collection of these
 organic compounds.5 This sampling system is shown in Figure 1.

 Sampled flue gas passes through a cyclone to remove particles larger than 10 /*m in aerodynamic
 diameter, then through a heated sampling line into a U-shaped dilution chamber.  The flue gases
 (collected at a rate of 15-50 Lpm) are diluted with up to 1500 Lpm of clean dry air to achieve
 dilution ratios of up to 100:1 (air to flue gas). Cooled and diluted particle samples can be collected
 from a filter at the bottom of the dilution chamber, or a portion of the sample can pass into a
 residence time chamber that provides a longer residence time for additional condensation and
 chemical reaction to occur prior to sampling. Sampling ports at the bottom of the residence time
 chamber allow several measurement systems (scanning mobility particle sizing system, organic
 compound sampling system, or others) to collect samples simultaneously.

 Sources were chosen to be tested based on several criteria. The source category's national ranking
 as measured by total mass emissions, the lack of one or more known elemental markers, the
 presence of organic compounds, and the lack of previous source profile information were all taken
 into account when determining which source categories would be most strongly considered.
 Sources that have already been tested include open burning of biomass, residential wood
 combustion, and diesel trucks during on-the-highway operation.  Among the sources that are being
considered or planned for future tests are wood-fired industrial boilers, pulp and paper plant
 operations, and commercial jet engines.

PM from Stationary Combustion Sources
Work at NRMRL has identified some fundamental characteristics of particles generated by the
combustion of heavy fuel oil and pulverized coal.6,7 There is a large body of literature describing

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                              Dilution Chamber
                       Residence
                          Time
                        Chamber
           Probe with 3 Heated Zones
  PMio Cyclone
       ' • Stack Emissions Inlet
         15-50Lpm
Dilution Air
15001pm
Activated
 Carbon
   Bed
Fiber
Filter

                                                                            Sampling
                                                                            Device(s)
                  High
               Etficiency
               Particulate
               Air Filter
Figure 1. Schematic of NRMRL's dilution source sampling system for measuring
the characteristics of PM generated by the combustion of pulverized coal. However, much of this
work is relatively old and did not have access to modern measurement methods and equipment.

There is relatively less information available characterizing PM from residual fuel oil combustion.
For both heavy fuel oil and pulverized coal, NRMRL has been working collaboratively with EPA's
National Health and Environmental Effects Research Laboratory (NHEERL). This collaboration
has provided a significantly different perspective on what characteristics and constituents are of
interest. Previous work<> focused on measurement of trace metals that are considered to be
carcinogenic or toxic, while first-row transition metals (copper [Cu], iron [Fe], nickel [Ni],
vanadium [V], and zinc [Zn]) are of interest in the current NRMRL/NHEERL work. In addition,
factors such as ash melting temperature and resistivity, studied to improve operation and pollution
control system design, are less important from the perspective of understanding health effects. The
NRMRL/NHEERL studies have emphasized a loosely defined "bioavailability" that indicates the
propensity of a substance to be absorbed into the body or captured by the body's defense
mechanisms. A relatively simple surrogate for bioavailability is the solubility of a sample in
deionized water.

Recent tests at NRMRL measured the particle size distributions and the elemental compositions of
PM generated by the combustion of residual fuel oil and pulverized coal.6 These tests show  that
the water solubility of transition metals in oil fly ash is substantially higher than for the bulk  of
pulverized coal fly ash, as shown in Figure 2. This difference in solubility indicates that oil fly ash
is potentially more toxic than a coal fly ash containing a similar amount of transition metal due to a
higher bioavailability.  However, these tests have not yet been able to measure the solubility of the

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                     £0.4
                     0

                     | °-2
                     0
                     M-  0
                     -°  1
                     c
                     o
                     •-g 0.8
                     03
                     •^ 0.6
                     0

                     1 °'4
W. Kentucky coal
-•- Cu
-•- Fe
-a- Ni
-f- V
-e- Zn

                            Water
       HgBOg CHgCOOH
                                                           50% HF
                                           Solvent
Figure 2.  Cumulative fraction of elements in solution for particles generated by the combustion of
                               No. 6 fuel oil and three pulverized coals.

ultrafine (< 0.1 /urn) fraction of the pulverized coal fly ash.

The mechanisms governing particle formation suggest that the ultrafine fraction is formed by
nucleation of vaporized material, largely metals, and the chemistry of the combustion gases at the   .
nucleation temperatures is such that these metals have the potential to be in relatively soluble forms
based on their likely chemistry. Earlier work found that the ultrafine fraction of residual fuel oil fly
ash was largely composed of sulfate and metals,? and similar processes governing coal fly ash
particle formation would suggest that the ultrafine fraction of particles from pulverized coal
combustion may have characteristics similar to oil fly ash.  The presence of a distinct ultrafine mode
generated by nucleation processes has been identified in coal particles, in addition to a mode near 1
/urn and a larger mode typical of mechanical processes such as grinding (see Figure 3).  Further
work is being conducted at NRMRL to investigate the behavior of coal fly ash in more detail.

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                1.0e+6
                     0.01          0.1           1
                                        Diameter,
Figure 3. Particle size distributions measured for particles from the combustion of three different
         pulverized coals.

Source emissions tests have also been conducted to determine mass, size, and composition of
particles from residential wood combustion and open burning of biomass.  For both of these source
types, samples have been collected to determine the types and amounts of organic compounds that
are emitted to identify potential marker compounds.8

PM and PM Precursors from Mobile Sources During On-the-Highway Operation
NRMRL researchers have developed and employed several methods to measure pollutant emissions
from mobile sources during operation on the road. The majority of data for mobile sources is
collected using dynamometers with operating cycles designed to simulate actual operation. Because
these tests are simulations, they do not capture the full range of operating conditions that are
experienced during on-road operation. NRMRL's work has focused on determining emissions
while vehicles are operating on the highway under real-world conditions.

PMfrom Diesel Trucks
PM emissions from diesel engines has also been of concern, since they represent 77% of the
primary PM2.5 emissions from on-road sources and 11% of primary PM2.5 from non-fugitive
sources. These emissions also have characteristics believed to play significant roles in causing
adverse health effects, such as small particle size (almost entirely < 1 ju.m in aerodynamic diameter)
and high levels of organic and elemental carbon.

Among the most visible diesel sources are heavy-duty trucks.  Conventional emissions sampling
from these sources relies upon measurements taken while the engine is mounted to a stationary load
that can be varied to simulate actual driving conditions. A more realistic approach is to develop a
method that will measure actual emissions during on-highway operation. The on-highway
approach can then take measurements for a truck pulling varying loads, at varying road grades,
speeds, and acceleration rates. Ideally, one would sample directly from the exhaust plume, after the
pollutants had mixed with ambient air and cooled, allowing the natural nucleation and condensation

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 of gas-phase organic compounds. With this approach, source sampling would capture particles
 with essentially the same characteristics as those in the ambient atmosphere. However, because the
 plume moves and because the ambient air, especially along highways, contains pollutants from other
 sources, the next best approach is to sample in the exhaust stack and use a dilution chamber to
 simulate the plume.

 Current work at NRMRL is comparing results from a dilution sampling system with simultaneous
 direct plume sampling during on-the-highway operation of a heavy-duty diesel truck.  Sampling
 systems are placed in the truck cab and in the trailer (see Figure 4), and measurements are taken as
 the truck covers a predetermined route along different grades.  Engine and operational variables
 such as speed, acceleration, engine revolutions per minute (RPM), and exhaust temperature are also
 measured. Particle samples are collected with an electronic low-pressure impactor (ELPI) that
 quantifies PM sizes in 12 size bins from 0.032 to 10 /u,m in aerodynamic diameter at the rate of one
 measurement per second.

 Dilution of the exhaust plume is determined by measurements of carbon dioxide (€62) in the stack
 and in the plume. The exhaust plume was sampled at different locations along the length of the
 trailer to evaluate plume behavior. These measurements were used to determine the dilution ratio
 and residence time for the diluted stack sample, so that the diluted stack samples would most
 closely simulate the actual exhaust plume  behavior. The stack sample is initially diluted with dry
 filtered air at a ratio of 7:1 (air to exhaust), with a residence time of approximately 3 ms to simulate
 the initial rapid mixing of the exhaust with turbulent air. A second stage further dilutes this mixture
 with a 10:1 ratio of dry filtered air to diluted exhaust, over a residence time of approximately 500
 ms, representative of the slower dilution along the length of the trailer.  A final stage of dilution is
 used to represent the rapid mixing of the plume and air at the end of the trailer. In this stage, the
 diluted plume is mixed with additional dry filtered air at a  ratio of 7:1 (air to diluted exhaust) in
 approximately 2 ms.

 Results of these tests to date indicate that stack sampling with the dilution system measures higher
 levels of PM than are measured in the naturally diluted exhaust plume (see Figure 4).  The size
 distributions are also slightly larger for the diluted stack sample than for the plume measurements.
 For several different operational test cases, the results consistently demonstrated a similarly shaped
 particle size distribution, with the peak of the mode near 0.2 /urn in aerodynamic diameter.
 Although additional work is required to more accurately represent the natural dilution of the exhaust
 plume, the results to date have shed light on  the mechanisms governing particle formation through
 nucleation and condensation, which may in turn have significant implications regarding the
 composition of the different particle sizes.9
   Slack Measurements
             Opacity
          Temperature
          Velocity Head
         Static Pressure

  Engine Measurements
     Exhaust Temperature
      Intake Temperature
          Speed, RPM
         Operational
       Measurements
       Truck Speed, MPH
      Acceleration, MPH/s
     Front-lo-Rear G-Force
   Exhaust Sample Measurements
       Oxygen, %      fttrtc Oxide, ppm
   Carbon Dioxide, %   NBrogen Oxides, ppm
Carbon Monoxide, ppm  Total Hydrocarbons, ppm
  Stack Instrumentation
 L Carbon Dioxide Monitor
1— Dilution Cnamber
  ELPI
Plume Instrumentation
ELPI
Carbon Dioxide
Figure 4.  Schematic of diesel truck instrumented for on-the-highway measurement of PM2.5-

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Ammonia from Passenger Automobiles
Ammonia emissions from automobiles, like emissions of carbon monoxide (CO) and nitrogen
oxides (NOX), varies as the driving conditions (such as acceleration and load) vary. Ammonia
(NHs) emissions are generated by high levels of nitrogen and low levels of oxygen in the exhaust,
which results in the formation of NHs in three-way catalysts. Measurement of ammonia emissions
during on-the-highway operation requires ammonia monitors that respond quickly to changes in
emissions, since the conditions that lead to NHs production occur rapidly. NRMRL researchers
have been examining different methods to quickly measure NHs emissions by simultaneously
measuring NOX and total nitrogen, and determining NHs by calculating the difference.  This work
has led to a better understanding of the engine and driving conditions that lead to NHs emission
peaks, information that can be used to generate improved emission inventories for mobile
sources. 10

Area Sources
The disperse nature of area sources such as construction activities, agricultural operations, and
fugitive emissions makes it difficult to quantify those emissions. Typical conditions can be difficult
to quantify, and inconsistent sampling conditions and the need to use unique sampling approaches
complicate the task. NRMRL has conducted several projects, in addition to the open biomass
burning project noted above, to quantify and characterize emissions from area sources.

Ammonia from Animal Feeding Operations
Animal feeding operations are relatively large sources of NHs due to the generation of waste from
the animals. In some cases, such as for hogs raised in some locations of the U.S., the waste is
collected in lagoons and may then be sprayed onto fields to provide a source of nitrogen.
Measuring NHs emissions from such large sources can be difficult because of the lack of a single
exhaust point and the variation in emissions as a function of meteorological variation. One
approach being tested at NRMRL is the use of open-path Fourier transform infrared (OP-FTIR)
sensing, which allows one to aim the instrument across the plume and determine the concentrations
of specific pollutants.  NRMRL researchers have measured NHs emissions from both a waste
lagoon and an animal feeding barn (the waste is generated in the barn and transported to the lagoon)
to determine the relative strength of emissions from both facilities.

By measuring during  a range of meteorological conditions and with varying numbers of animals
present, the governing parameters can be examined to determine the most important factors
influencing emissions. Results to date indicate that the OP-FTIR method can be used to measure
NHs emissions from animal feeding operations, and that there is less variability with respect to the
number and size of animals present than was previously expected.11

Construction Dust
NRMRL has conducted several tests to measure the dust generated by certain construction
activities, in particular earth-moving operations using large construction equipment. 12 A series of
tests were conducted using ambient PM samplers placed downwind of diesel scraper-loaders
operating over a range of conditions (loading, unloading, transiting).  Soil moisture was also
measured to evaluate how dust generation was affected by changes in soil conditions.  The data
collected from these tests are still being analyzed.

Indoor Air Quality
Particle emissions do not only occur outdoors, but are also generated by indoor activities such as
space heating and cooking. Particles can also penetrate into buildings from the ambient
environment through open doors and windows and through heating and cooling systems. Research
at NRMRL is characterizing both indoor source emissions and penetration of ambient particles into
indoor environments.

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 Indoor Sources
 Using both a test chamber and a residential house dedicated to testing purposes, NRMRL
 researchers are measuring the particle concentrations generated by indoor activities such as cooking,
 space heating, and use of candles and incense.  Under certain conditions, some of these activities
 can generate significant amounts of PM2.s in relation to the volume of a room or a house, and
 under the appropriate conditions, can result in PM2.s concentrations higher than the PM2.5
 NAAQS. Particles generated by the use of candles also tend to be smaller than  1 /xm in
 aerodynamic diameter.  A particle size distribution measured using an electronic low pressure
 impactor (ELPI) for PM from a scented paraffin candle with three wicks is shown in Figure 5.
 Particle sizes during normal candle burning .and during smoldering are presented, and both
 demonstrate that a majority of particles from such activities are submicron in size. While
 smoldering tends to increase the particle sizes, the general shape of the distribution is similar to that
 for normal candle burning.13

 In order to accurately measure the particles generated by specific activities, indoor air quality
 researchers at NRMRL have also evaluated measurement methods using tracer compounds such as
 sulfur hexafluoride (SF^) and the potential for these compounds to break down  as they pass
 through high temperature regions in heating and cooking flames.14

 Penetration of Outdoor Particles into Indoor Environments
 Although the epidemiological studies noted in the introduction relate ambient particle concentrations
                         •G—  Normal Burn  -
                           Smoldering
             0

              0.01
     0.1                   1
Aerodynamic Diameter
Figure 5. Distribution of particle sizes from a normally burning (open symbols) and smoldering
        (solid symbols) scented paraffin candle.

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to adverse health effects, most people spend the majority, in many cases over 90%, of their time
indoors.  This is especially true for those who may be particularly susceptible to the effects of air
pollution, such as those with asthma or other pulmonary disease.  Even those indoors can be
exposed to ambient particles, however, since air passing through doors, windows, heating and air-
conditioning systems, or cracks can carry ambient particles. NRMRL is conducting research to
better understand the mechanisms governing the penetration of ambient particles into indoor
environments. Studies of the impact of particle size, differential pressure between outdoors and
indoors, and characteristics of cracks have led to the development of a model to predict the particle
penetration rate as a function of particle size for different conditions.15

Control Technology Development
In addition to emissions characterization research, NRMRL has also been evaluating improvements
to existing PM control technologies and development of new PM control technologies. New
technology development and testing has focused on multipollutant control capability to allow users
to minimize total cost and tailor the control system design to meet a number of pollution control
needs.

Electrostatic Fabric Filter Testing
In conjunction with Southern Research Institute and the Southern Company, NRMRL researchers
are conducting tests on an electrostatic fabric filter (ESFF) that improves collection of PM2.5
without significant increases in fan power requirements. This approach allows the installation of a
set of filters inside an existing electrostatic precipitator (ESP) housing so that existing particle
control systems can be upgraded without requiring additional space. The ESFF can improve
performance of either a conventional fabric filter or an existing ESP, particularly with respect to
removalof PM2.5-

The pilot-scale ESFF is a 0.3 MWe scale pulse-jet cleaned fabric filter fitted with an array of high-
voltage electrodes between the bags, as shown in Figure 6. The pilot-scale design has sixteen bags,
with a high-voltage array composed of nine corona electrodes suspended from the tubesheet with
insulators connected to the high-voltage source on the clean side of the tubesheet.

Circulating Fluidized Bed Absorber
Use of a circulating fluidized bed absorber (CFBA) system for control of PM and PM precursors
such as sulfur dioxide (862) can reduce the total cost of pollution control for a plant, and has the
potential to fit within existing space in retrofit applications. NRMRL is conducting research  to
develop a computational model of a CFBA system to allow designers to determine size and
operating requirements for specific pollution control scenarios.  For instance, a high sulfur, low ash
coal may require one set of operating parameters, while a low sulfur, high ash coal may require
another. Plants that need the flexibility to switch fuels may wish to have a system that will allow
adequate capture of both PM and SC>2, and the potential need to control other pollutants such as
mercury can also influence operating parameters.  With the development of a computational model,
NRMRL researchers will be able to identify design and operational parameters that are optimized
for these and other instances.

Conclusions
Development of emission inventories, emissions characterization data for use in atmospheric
chemistry models, and performance of improved and new technologies are critical to being able to
gain a clear understanding of the sources, ambient concentrations, and effects of PM2.5-
NRMRL's research into source characterization, indoor air quality, and control technology
development will  assist the successful and cost-effective implementation of EPA's PM2.5 ambient
air quality standard.

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 High-Vollage
      Fram
                    Insulator
                                                                        Voltage
                                                                      Supply
                                         Bags

            Figure 6. Schematic of electrostatic fabric filter arrangment (plan view).
References
  1. U.S. Environmental Protection Agency, "Air Quality Criteria for Paniculate Matter," U.S.
    Environmental Protection Agency, EPA/600/P-95-001 (NTIS PB96-168224), National Center
    for Environmental Assessment, Research Triangle Park, NC, April 1996.

  2. Krewski, D., Burnett, R.T., Goldberg, M.S., Hoover, K., Siemiatycki, J., Jerrett, M.,
    Abrahamowicz, M., White, W.H., et al., Reanalysis of the Harvard Six Cities Study and the
    American Cancer Society Study of Paniculate Air Pollution and Mortality, Health Effects
    Institute Special Report, Part U, Health Effects Institute, Cambridge, MA, July 2000.

  3. Samet, J.M., Zeger, S.L., Dominici, R, Curriero, F., Coursac, I., Dockery, D.W., Schwartz, J.,
    and Zanobetti, A. National Morbidity, Mortality, and Air Pollution Study. Part U: Morbidity,
    Mortality, and Air Pollution in the United States, Health Effects Institute Report No. 94, Part
    H, Health Effects Institute, Cambridge, MA, June 2000.

  4. Federal Register, 62 FR 38652, July 18,1997.

  5. Hildemann, L. M., Cass, G.R., and Markowski, G.R. "A dilution stack sampler for collection
    of organic aerosol emissions: Design, characterization and field tests," Aerosol Science and
    Technology, Vol. 10, pp. 193-204,1989.
                                      10

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 6. Linak, W.P., Miller, C.A., and Wendt, J.O.L. "Comparison of particle size distributions and
    elemental partitioning from the combustion of pulverized coal and residual fuel oil," J. Air &
    Waste Manage. Assoc., Vol. 50, pp. 1532-1544, August 2000.

 7. Miller, C.A., Linak, W.P., King, C., and Wendt, J.O.L. "Fine particle emissions from heavy
    fuel oil combustion in a firetube package boiler," Comb. Sci. Tech., Vol. 134, pp. 477-502,
    1998.
 8. Champion, M., and Jaasma, D.R. "Degradation of Emissions Control Performance of Wood
    Stoves in Crested Butte, CO," EPA-600/R-98-158 (NTIS PB99-127995), National Risk
    Management Research Laboratory, Research Triangle Park, NC, November 1998.
 9. Brown, I.E., Clayton, M.J., Harris, D.B, and King, F.G.  "Comparison of the particle size
    distribution of heavy-duty diesel exhaust using a dilution tailpipe sampler and an in-plume
    sampler during on-road operation," J. Air & Waste Manage. Assoc., Vol. 50, pp.1407-1416,
    August 2000.

10. Shores, R.C., Walker, J., Kimbrough, S., McCulloch, R.B., Rodgers, M.O., and Pearson, J.R.
    "Measurement of ammonia emissions from EPA's instrumented vehicle," Visuals presented at
    the CRC On-Road Vehicle Emissions Workshop, San Diego, CA, March 27-29,2000.

11. Childers, J.W., Thompson, E.L., Jr., Harris, D.B., Kirchgessner, D.A., Clayton, M., Natschke,
    D.F., and Phillips, W.J. "Multi-pollutant concentration measurements around a concentrated
    swine production facility using open-path JKI1R spectrometry," Atmospheric Environment,
    accepted for publication.

12. Cowherd, C., Jr., Muleski, G. E., and Masser, C. C. "Emission Measurements of Particle
    Mass from Construction Activities," presented at the A&WMA Emissions Inventory
    Conference, New Orleans, LA, December  10,1998.

13. Guo, Z., Mosley, R., McBrian, J.,  and Fortmann, R. "Fine Paniculate Matter Emissions from
    Candles," in Engineering Solutions to Indoor Air Quality Problems, Proceedings of a
    Speciality Conference, July 17-19, 2000, Raleigh, NC, Air & Waste Management Association,
    Pittsburgh, PA.

14. Guo, Z., Mosley, R., Wasson, S., Fortmann,  R., and McBrian, J., "Interference of SFe Tracer
    Gas with Characterization of Emissions from Indoor Combustion Sources," presented at PM-
    2000, Charleston, SC, January 25-28, 2000.

15. Mosley, R.B., Greenwell, D.J., Sparks, L.E., Guo, Z., Tucker, W.G., Fortmann, R., and
    Whitfield, C.  "Penetration of ambient fine particles into the indoor environment," Aerosol Sci.
    Technol., in press, October 2000.
                                     11

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 NRMRL-RTF-P-558
            TECHNICAL REPORT DATA
     (Please read Instructions on the reverse before completing)
i. REPORT NO.
   EPA/600/A-00/112
                           2.
                                                       3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
 Characterization and Control of Fine Particles:
 Cverview of NRMRL Research Activities
                                                       5. REPORT DATE
                                  6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)

 C. Andrew Miller
                                                       8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
                                                       10. PROGRAM ELEMENT NO.
 See Block 12
                                                       11. CONTRACT/GRANT NO.
                                                        NA (Inhouse)
12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Air Pollution Prevention and Control Division
 Research Triangle Park, NC 27711
                                   13. TYPE OF REPORT AND PERIOD COVERED
                                   Published paper;
                                   14. SPONSORING AGENCY CODE
                                    EPA/600/13
15.SUPPLEMENTARY NOTES Author Miller's  Mail Drop is 65; his phone number is 919/541-
2920.  For presentation at the Conference,  Tropospheric Aerosols: Science and
Decisions in  an International Community, Queretaro,  Mexico, 10/23-26/00.
         T The paper discusses particulate matter (PM)  research at EPA's National
 Risk Management Research Laboratory (NRMRL), designed to provide critical infor-
 mation regarding emission rates, characteristics, and control approaches for PM
 2. 5 micrometers in aerodynamic diameter and smaller (PM2. 5).  NRMRL resear-
 chers are also studying penetration of outdoor particles into indoor environments, as
 well as-indoor sources of particles.  PM2.5  source profiles are being developed
 using  a dilution sampling system to capture both primary particles and particles for-
 med by condensation of organic compounds. This research will provide information
 needed by source receptor models to identify the contribution of different sources to
 the  ambient particle loading.  Emissions characterization research is being conduc-
 ted  on particle size and composition for residential wood combustion systems, for in-
 dustrial combustion sources burning coal and heavy fuel oil, for diesel truck engines
 during on-road operation,  and for open burning of biomass. Emission  inventory re-
 search on ammonia from animal feeding operations and fugitive dust from construc-
 tion activities will improve understanding of  PM2. 5 sources and their  impact on at-
 mospheric  chemistry and ambient PM2.5  concentrations.   NRMRL researchers are
 studying innovative control technologies for stationary sources.
17.
                             KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
                                           b.lDENTIFIERS/OPEN ENDED TERMS
                                               c. COS AT I Field/Group
Pollution
Particles
Emission
Coal
Fuel Oil
Biomass
Organic Compounds  Ammonia
Combustion
Wood
Construction Ma-
  terials
Pollution Control
Stationary Sources
Indoor Air
Feed Lots
Fugitive Dust
13B
14G

07C
2 IB
11L
21D

08A
07B
13 C
18. DISTRIBUTION STATEMENT

 Release to Public
                      19. SECURITY CLASS (This Report)
                      Unclassified
                         21. NO. OF PAGES
                            11
                      20. SECURITY CLASS (This page)
                       Unclassified
                                               22. PRICE
EPA Form 2220-1 (9-73)

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