E9-15326. 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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Table 2—Breakpoints for the AQI

These breakpoints							Equal these AQI's
O3 (ppm) 8-hour	O3 (ppm) 1-hour 1	PM2.5 (μg/m3)	PM10 (μg/m3)	CO (ppm)	SO2 (ppm)	NO2 (ppm)	AQI	Category
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	4 150.5-250.4	355-424	15.5-30.4	0.305-0.604	0.65-1.24	201-300	Very Unhealthy.
(2)	0.405-0.504	4 250.5-350.4	425-504	30.5-40.4	0.605-0.804	1.25-1.64	301-400
(2)	0.505-0.604	4 350.5-500.4	505-604	40.5-50.4	0.805-1.004	1.65-2.04	401-500	Hazardous.
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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