[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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