&EPA
www.epa.gov/airscience
science   in   ACTION
                                                                 CLEAN AIR  RESEARCH
                                                                 PROGRAM
      SCIENTISTS DEVELOP AND TEST MULTIPOLLUTANT
      CONTROL TECHNOLOGIES
      Issue:
      Historically, the U.S.
      Environmental Protection
      Agency's approach to regulating
      air pollutant emissions has been
      to target pollutants individually.
      For example, an industrial source
      may be subject to separate control
      requirements for nitrous oxide,
      sulfur dioxide, and hazardous air
      pollutant emissions.  As a result
      of these requirements, controls
      may be implemented and updated
      by different schedules for each
      emission component.

      These myriad regulations can
      yield inefficient control strategies.
      For example, the control
      technology that is most cost-
      effective for one particular
      pollutant may not be cost-
      effective in the context of other
      regulated pollutants. Thus, a more
      integrated, multipollutant
      regulatory approach may lead to
      more cost-effective and efficient
      control strategies.
             To this end, EPA is piloting an
             integrated, multipollutant
             approach that more
             comprehensively considers the
             various types of emissions,
             technology characteristics, and
             control options for specific source
             "sectors" such as cement
             production or power generation.

             Ultimately, a multipollutant
             approach is expected to lead to
             more streamlined regulatory
             requirements that achieve
             environmental and health goals
             more cost-effectively than
             traditional, single-pollutant
             approaches. Research is needed,
             however, to support the
             development of multipollutant
             regulatory strategies and
             applications.

             Scientific Objective:
             EPA's Clean Air Research
             Program in the Office of
             Research and Development is
             developing and testing new
             technologies and strategies for the
simultaneous control of multiple
pollutants. Research efforts are
underway and planned to:

• Evaluate the performance and
  benefits of various control
  technologies, including
  scrubbers and sorbents, in
  removing multiple air
  pollutants from coal-
  combustion systems.
• Determine the co-benefit
  efficiency of existing
  technologies for the control of
  other air pollutants.
• Develop modeling tools that
  will enable air quality managers
  to consider multipollutant
  reduction strategies and
  evaluate the economic and cost
  implications of various options.
• Determine the performance of
  novel and existing technologies
  for multipollutant control that
  have been developed for
  application in coal-fired
  electricity generating units to
  other industrial sectors (e.g.,
                                                                                    continued on back
       U.S. Environmental Protection Agency
       Office of Research and Development

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  &EPA
www.epa.gov/airscience
science   in   ACTION
       CLEAN  AIR  RESEARCH  PROGRAM
      continued f-omjront
         cement kilns, pulp and paper,
         etc.)
       In addition, EPA is developing
       computer models that will assist
       EPA and regulated industries in
       identifying cost-effective
       strategies for complying with
       multipollutant regulations.

       Key scientific questions being
       addressed include:

       •  What known technologies can
         be used to reduce multiple
         pollutants and are reasonably
         amenable to field application?
       •  How can existing technologies
         be modified to provide
         multipollutant control?
       •  Are there novel approaches or
         technologies that can be used to
         manage multipollutant risks?
       •  What are the relative costs,
         performance, and
         environmental implications of
         competing multipollutant
         reduction options?
       •  What are cost-effective control
         strategies by which specific
         industries can comply with
         multipollutant control
         requirements?

       Application and Impact
             EPA's Clean Air Research
             Program has been a leader in
             advancing air pollution
             prevention and control
             technologies for key industries,
             utility power plants, waste
             incinerators, indoor environments
             and sources of greenhouse gases.

             As EPA moves to a sector-based,
             multipollutant regulatory
             approach, the expertise in the
             research program is being tapped
             to develop new models and tools
             that can be used by risk assessors
             and air quality managers to
             develop more effective strategies
             to reduce air pollution.

             For example, EPA researchers
             have conducted bench- and pilot-
             scale work to provide
             multipollutant capacity to a wet-
             flue-gas desulfurization (FGD)
             scrubber used in coal-fired power
             plants. Through the optimized
             introduction of an oxidant
             additive, the scrubber can be used
             to reduce emissions of nitrogen
             oxides, mercury, and sulfur
             dioxides.

             EPA researchers have also
             developed a multipollutant, multi-
             sector emissions trading model to
analyze and evaluate various air
pollution reduction policy options
for industrial sectors. An initial
effort has focused on the U.S.
cement sector. The model enables
industries to evaluate their
emissions during the various
stages of the production process
and determine how to keep
operating costs down along with
associated air emissions. The
model is being expanded to
include additional sectors, such as
pulp and paper as well as iron and
steel.
REFERENCES
Hutson, N.D., Krzyzynska, R., Srivastava, S.K.,
Simultaneous Removal of SO2, NOX, and Hg
from a Simulated Coal Flue Gas using a NaClO2-
enhanced Wet Scrubber, Ind. Eng. Chem. Res.,
2008,47(16), 5825.

Staudt,J.E., Jozewicz,W. Performance and Cost of
Mercury and Multipollutant Emission Control
Technology Applications on Electric Utility
Boilers. US EPA Report EPA/600/R-03/110. 2003.
Washington, D.C.
CONTACT
Douglas McKinney, EPA's Office of Research and
Development, National Risk Management
Research Laboratory, 919-541-3006,
mckinney.douglas@epa.gov

Nick Hutson, Ph.D., EPA's Office of Research and
Development, National Risk Management
Research Laboratory, 919-541-2968,
hutson.nick(g!epa. gov

APRIL 2009
       U.S. Environmental Protection Agency
       Office of Research and Development

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