aerodynamic diameter less than 2. 5
microns (PM2.5).
With the changes to the ambient
air-quality standards, states and local
pollution control agencies made recommendations to the EPA for the classification of areas relating to the new standards. Attainment designations were
made in April 2004 with respect to the
8-hour ozone standard and in December
2004 for the PM2.5 standard. Many areas
that had previously attained the National
Ambient Air Quality Standards (NAAQS)
for ozone and particles found themselves
designated as non-attainment under the
new standards, and areas that were still
struggling to attain the older standards
continued to be designated as non-attainment under the new standards.
The Clean Air Interstate Rule
It is widely accepted that the precursors, or emissions, that contribute to
non-attainment of NAAQS can be transported great distances. (For more on
standards of criteria pollutants, visit
www.epa.gov/ttn/naaqs/). Recognizing
the impact of transport and the benefits
of a broad, regional solution, the EPA
published the Clean Air Interstate Rule
on March 10, 2005.
The Title IV annual SO2 program and
the NOx Budget Program were successful
at reducing emissions and achieving a
34 percent reduction in SO2 emissions
from the power sector from 1990 levels
and a 70 percent reduction in NOx emissions from 1990 levels. (For more, see
www.epa.gov/airmarkets/cmprpt/arp04
/2004report.pdf.)
The CAIR program builds on the
emission reductions realized under the
Title IV annual SO2 allowance program
and the NOx Budget Program, adding an
annual NOx allowance-trading program
to the existing ozone season program to
further achieve air quality goals. Compliance with the first phase of NOx reductions under CAIR is required in 2009,
and the first phase of SO2 reductions, in
2010. The second phase of reductions
under CAIR for both SO2 and NOx comes
into effect in 2015.
The emission-reduction requirements
under CAIR apply to certain electric-gen-erating facilities, including those with
generating capacity greater than 25 MW
for sale. Industrial boilers that do not
generate electricity for sale to the grid,
or which have a capacity less than 25
MW, are not affected by CAIR. (More
information on the specific unit applicability criteria is available at www.epa.gov/
interstateairquality/.)
The SO2 reductions under CAIR are
implemented through a reduction in the
‘face value’ of a Title IV allowance for
compliance. In 2010, affected utilities
are required to surrender two allowances
for every ton of SO2 emitted. In 2015,
the surrender increases to 2.86 allowances
for every ton of SO2 emitted. By integrating
the existing Title IV annual SO2 program
with the required SO2 reductions necessary to achieve the goals under CAIR, the
EPA has provided a mechanism by which
sources affected under both programs
(Title IV and CAIR SO2 program) can
continue to make investments in pollution control technology where such
investments make economic sense.
CAIR continues to implement the
ozone-season NOx reduction program
established by the NOx Budget Trading
Program to realize reductions necessary
to attain the NAAQS for ozone. In addition, CAIR establishes a year-around NOx
Figure 1. Map of U.S. States in CAIR Program.
reduction program to control emissions
that contribute to non-attainment with
the fine particle standards. Combustion
sources affected by the ozone-season-only program will be ‘rolled into’ state
programs necessary to implement CAIR,
including requirements for monitoring,
allowance allocation, recordkeeping and
electronic data reporting. (For more
CAIR continues to implement
the ozone-season NOx reduction
program established by the NOx
Budget Trading Program…
information on the SIP Call Transition,
visit www.epa.gov/airmarkets/cair/sip
calltrans.html.)
At full implementation, CAIR will
achieve a 70 percent reduction in SO2
emissions and a 60 percent reduction in
NOx emissions of from affected utility
sources in the CAIR region.
The model rules published by the
EPA for the allowance-trading program
establish statewide budgets for SO2 and/or
NOx (as shown in figure 1, not all states
kk
k
k
k kk
Source: U. S. Environmental Protection Agency.
In announcing the Clean Air Interstate Rule, then Acting-Administrator Stephen Johnson said “…CAIR
will result in the largest pollution reductions and health benefits of any air rule in more than a decade.
The action we are taking will require all 28 states [all states and the District of Columbia located east
of the Mississippi River except Rhode Island, Maine, New Hampshire and Vermont, as well as
Minnesota, Iowa, Missouri, Arkansas, Louisiana, and Texas] to be good neighbors, helping states
downwind by controlling airborne emissions at their source...” The map indicates the 28 states affected and what pollutants fall under the CAIR program in each state.
