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Ambient Air Quality Surveillance

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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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Table 2—Breakpoints for the AQI

These breakpointsEqual these AQI's
O3 (ppm) 8-hourO3 (ppm) 1-hour 1PM2.5 (μg/m3)PM10 (μg/m3)CO (ppm)SO2 (ppm)NO2 (ppm)AQICategory
0.000-0.0590.0-15.40-540.0-4.40.000-0.034(3)0-50Good.
0.060-0.07515.5-40.455-1544.5-9.40.035-0.144(3)51-100Moderate.
0.076-0.0950.125-0.16440.5-65.4155-2549.5-12.40.145-0.224(3)101-150Unhealthy for Sensitive Groups.
0.096-0.1150.165-0.2044 65.5-150.4255-35412.5-15.40.225-0.304(3)151-200Unhealthy.
0.116-0.3740.205-0.4044 150.5-250.4355-42415.5-30.40.305-0.6040.65-1.24201-300Very Unhealthy.
(2)0.405-0.5044 250.5-350.4425-50430.5-40.40.605-0.8041.25-1.64301-400
(2)0.505-0.6044 350.5-500.4505-60440.5-50.40.805-1.0041.65-2.04401-500Hazardous.
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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