[Federal Register Volume 74, Number 122 (Friday, June 26, 2009)]
[Rules and Regulations]
[Pages 30469-30470]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-15326]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58


Ambient Air Quality Surveillance

CFR Correction

    In Title 40 of the Code of Federal Regulations, Parts 53 to 59, 
revised as of July 1, 2008, on page 271, in appendix G to part 58, 
Table 2 is corrected to read as follows:

Appendix G to Part 58--Uniform Air Quality Index (AQI) and Daily 
Reporting

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[[Page 30470]]



                                                            Table 2--Breakpoints for the AQI
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                                                 These breakpoints                                                            Equal these AQI's
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                                                                       PM10
            O3 (ppm) 8-hour             O3 (ppm) 1-   PM2.5 ([mu]g/   ([mu]g/    CO (ppm)    SO2 (ppm)   NO2 (ppm)     AQI              Category
                                          hour \1\        m\3\)        m\3\)
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0.000-0.059...........................  ...........        0.0-15.4      0-54      0.0-4.4  0.000-0.034      (\3\)       0-50  Good.
0.060-0.075...........................  ...........       15.5-40.4    55-154      4.5-9.4  0.035-0.144      (\3\)     51-100  Moderate.
0.076-0.095...........................  0.125-0.164       40.5-65.4   155-254     9.5-12.4  0.145-0.224      (\3\)    101-150  Unhealthy for Sensitive
                                                                                                                                Groups.
0.096-0.115...........................  0.165-0.204  \4\ 65.5-150.4   255-354    12.5-15.4  0.225-0.304      (\3\)    151-200  Unhealthy.
0.116-0.374...........................  0.205-0.404      \4\ 150.5-   355-424    15.5-30.4  0.305-0.604  0.65-1.24    201-300  Very Unhealthy.
                                                              250.4
(\2\).................................  0.405-0.504      \4\ 250.5-   425-504    30.5-40.4  0.605-0.804  1.25-1.64    301-400
                                                              350.4
(\2\).................................  0.505-0.604      \4\ 350.5-   505-604    40.5-50.4  0.805-1.004  1.65-2.04    401-500  Hazardous.
                                                              500.4
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\1\ Areas are generally required to report the AQI based on 8-hour ozone values. However, there are a small number of areas where an AQI based on 1-hour
  ozone values would be more precautionary. In these cases, in addition to calculating the 8-hour ozone index value, the 1-hour ozone index value may be
  calculated, and the maximum of the two values reported.
\2\ 8-hour O3 values do not define higher AQI values (>= 301). AQI values of 301 or greater are calculated with 1-hour O3 concentrations.
\3\ NO2 has no short-term NAAQS, and can generate an AQI only above the value of 200.
\4\ If a different SHL for PM2.5 is promulgated, these numbers will change accordingly.

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[FR Doc. E9-15326 Filed 6-25-09; 8:45 am]
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