Ambient Air Quality Surveillance; CFR Correction

Federal Register: June 26, 2009 (Volume 74, Number 122)

Rules and Regulations

Page 30469-30470

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

DOCID:fr26jn09-6

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

These breakpoints

Equal these AQI's

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\)

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

\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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