Fact Sheet Final Data Requirements Rule for the 2010 1-Hour Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standard (NAAQS)

Fact Sheet
Final Data Requirements Rule for the 2010 1-Hour Sulfur Dioxide (SO2)
Primary National Ambient Air Quality Standard (NAAQS)
ACTION
• On August 10, 2015, the U.S. Environmental Protection Agency finalized requirements
for air agencies to monitor or model ambient sulfur dioxide (SO2) levels in areas with
large sources of SO2 emissions to help implement the 1-hour SO2 National Air Ambient
Quality Standard (NAAQS).
¦ This final rule establishes that, at a minimum, air agencies must characterize air quality
around sources that emit 2,000 tons per year (tpy) or more of SO2. An air agency may
avoid the requirement for air quality characterization near a source by adopting
enforceable emission limits that ensure that the source will not emit more than 2,000 tpy
of SO2.
¦ This final rule gives air agencies the flexibility to characterize air quality using either
modeling of actual source emissions or using appropriately sited ambient air quality
monitors. Modeling and monitoring are both appropriate ways to assess local SO2
concentrations, and this flexibility allows an air agency to select a cost-effective approach
that adequately characterizes each required area.
• This final rule establishes a schedule for air agencies to characterize air quality and to
provide that air quality data to the EPA. EPA expects to use this data to designate areas
across the country as meeting or not meeting the SO2 standard set in 2010. The EPA has
designed the implementation milestones in this data requirements rule to allow air
agencies to take into account compliance dates for achieving SO2 emission reductions
under other major national rules, such as the Mercury and Air Toxics Standards for
power plants and emission standards for boilers.
• The final rule for the 2010 1-hour SO2 standard lays out a common sense, orderly
approach for characterizing current air quality in areas with large SO2 sources. In
developing the rule, the EPA carefully considered stakeholder feedback obtained during
an extensive outreach process.
FINAL RULE IMPLEMENTATION TIMELINE
• By January 15, 2016, each air agency is required to submit to the relevant EPA Regional
Administrator a final list identifying the sources in the state around which SO2 air quality
is to be characterized. The list must include sources with emissions above 2,000 tpy of
SO2. The EPA Regional Offices or air agencies may include additional sources on this
list if they deem it necessary.
• By July 1, 2016, each air agency is required to identify, for each source area on the list,
the approach (ambient monitoring or air quality modeling) it will use to characterize air
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quality. In lieu of characterizing areas around listed 2,000 tpy or larger sources, air
agencies may indicate by July 1, 2016 that they will adopt enforceable emissions
limitations that will limit those sources' emissions to below 2,000 tpy.
• For source areas that an air agency decides to evaluate through air quality modeling, the
air agency must provide a modeling protocol to the EPA Regional Administrator by July
1, 2016. The modeling analysis must be submitted to the EPA by January 13, 2017.
• For source areas that an air agency decides to evaluate through ambient monitoring, the
air agency must submit relevant information concerning monitoring sites to the EPA
Regional Administrator by July 1, 2016, as part of its annual monitoring network plan
and in accordance with the EPA's monitoring requirements specified in 40 CFR part 58.
• The air agency must ensure that ambient monitors are operational by January 1, 2017.
Before then air agencies will need to identify appropriate sites to characterize peak 1-
hour SO2 concentrations, and may need to relocate existing monitors or install new
monitors.
• Air agencies will quality assure data from these monitors and submit them to the EPA Air
Quality System in the same manner as is currently done for existing SO2 monitors. The
first 3 years of data will be collected for calendar years 2017 through 2019.
• If an air agency adopts emission limits keeping sources' emissions below 2,000 tpy in
lieu of characterizing the areas surrounding sources, these limits must be adopted and
effective by January 13, 2017.
BACKGROUND
¦ On June 2, 2010, the EPA established a primary 1-hour SO2 air quality standard at a level
of 75 parts per billion (99th percentile value, averaged over 3 consecutive years). The
revised standard will improve public health protection, especially for people with asthma,
children and the elderly.
¦ In May-June 2012, the EPA held a series of stakeholder discussions with states, tribes
and other interested parties to refine the agency's approach for implementing the SO2
standard. The EPA also developed a White Paper which identified important monitoring,
modeling and implementation issues. The White Paper can be found on the EPA's
website at: http://www.epa.gov/airqualitv/sulfurdioxide/implement.html. Based on the
input on the White Paper, the EPA also developed an implementation strategy for the
2010 SO2 standard in February 2013. The strategy paper can be found at:
http://www.epa.gov/airquality/sulfurdioxide/implement.html.
• In July 2013, the EPA identified or "designated" as nonattainment 29 areas in 16 states
where monitored air quality showed violations of the 2010 1-hour SO2 standard. The
EPA based these nonattainment designations on certified air quality monitoring data
provided by the states, as well as an assessment of nearby emission sources, and weather
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patterns that contribute to the monitored levels. These areas are now taking steps to
reduce SO2 emissions and improve air quality, and this rule does not require further
characterization of sources in these areas, unless air agencies or the EPA Regional
Offices decide that further characterization is warranted.
• A March 2015 court order requires the EPA to complete designations for the 2010 SO2
standard for all remaining areas in the country in up to three additional rounds:
1. By July 2, 2016 --
¦ areas that have monitored violations of the 2010 SO2 standard based on 2013
- 2015 air quality data; and
¦ areas that contain any stationary source not announced for retirement that
according to EPA's Air Markets Database emitted in 2012 either (a) more
than 16,000 tons of SO2 or (b) more than 2,600 tons of SO2 and had an
average emission rate of at least 0.45 lbs SCh/mmbtu.
2. By December 31, 2017 - areas where states have not installed and begun
operating a new SO2 monitoring network.
3. By December 31, 2020 - all remaining areas.
For most areas, the data required by this final rule will be available in time to inform the
designations made under the Court ordered schedule.
FOR MORE INFORMATION
¦ To download a copy of this final rule, go to the EPA's website at:
http://www.epa.gov/airqualitv/sulfurdioxide/implement.html. The official version of this
rule will be published in the Federal Register.
¦ Today's Final Rule and other associated information are available either electronically at
http://www.regulations.gov, the EPA's electronic public docket and comment system, or
in hardcopy at the EPA Docket Center's Public Reading Room. (Docket ID No. EPA-
HQ-OAR-2013-0711)
¦ The Public Reading Room is located in the EPA Headquarters, Room Number 3334 in
the William Jefferson Clinton West Building, located at 1301 Constitution Avenue, NW,
Washington, D.C. Hours of operation are 8:30 a.m. to 4:30 p.m. eastern standard time,
Monday through Friday, excluding Federal holidays.
¦ Visitors are required to show photographic identification, pass through a metal detector,
and sign the EPA visitor log. All visitor materials will be processed through an X-ray
machine as well. Visitors will be provided a badge that must be visible at all times.
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