1 Technical Support Document for 2008 Ozone NAAQS Designation for Puerto Rico



### Puerto Rico Area Designations f or the
20 08 Ozone National Ambient Air Q uality Standard s

No areas of Puerto Rico violate the 2008 National Ambient Air Quality Standards for ozone (2008 NAAQS). Two monitors constitute the EPA

- approved ozone network in Puerto Rico and both have design values well under the 0.075ppm NAAQS.

Technical A nalysis for Puerto Rico

Since the air quality from the EPA

- approved network is attainment at al l the sites in Puerto Rico, the only factors to review are 1) the air quality data and 2) whether Puerto Rico impacts any nonattainment

areas.

In a February 4, 2009 letter to the USEPA, Puerto Rico recommended that all of Puerto Rico be designated as atta inment for the 2008 ozone NAAQS b ased on air quality data from 2006

- 2008. These
data are from Federal Reference Method ( FRM ) monitors sited and operated in accordance with 40 CFR
Part 58

. .

After considering Puerto Rico’s recommendation and b ased on EPA 's technical analysis described below, EPA intends to designate all of Puerto Rico as attainment/unclassified for the 20 08 o zone NAAQS

.

Factor Assessment



### Factor A : Air Q uality D ata

For this factor , we considered 8

- hour o zone design values (in ppm ) for air quality monitors in Puerto
Rico based on data for the 2008

- 2010 period (i.e., the 2010 design value, or DV) , which are the most

recent years with fully

- certified air quality data

. A monitor’s DV is the metric or statistic that indicates
whether th at monitor attains a specified air quality standard. The 2008 o zone NAAQS are met when the
annual f ourth

- highest daily maximum 8

- hour average concentration, averaged over 3 years is 0.075 ppm or less

. A DV is only valid if minimum data completeness crite ria are met. See 40 CFR part 50 App endix P . Where several monitors are located in a county (or a designated nonattainment area or maintenance area ), the DV for the county or area is determined by the monitor with the highest level.

The 2010 DVs for the o zone NAAQS for counties in Puerto Rico a re shown in Table 2

.

Table 2 . Air Quality Data

. Location 2008

- 2010 Design Value ( ppb )

Catano 40

Juncos 402 Data for these two sites meet EPA’s completeness requirements and are well under the 75ppb ozone

NAA QS. See the attached report from EPA’s Air Quality System for the data used for this table.

PR-VI O3.pdf



### Factor B : Impact on other areas

As part of EPA’s evaluation of Section 110 ozone transport State Implementation Plans, EPA
det ermined that Puerto Rico is too far from any other nonattainment areas to cause to contribute to violations of the ozone NAAQS in these areas. The nearest nonattainment areas are in the eastern portion of the continental United States, over a thousand m il es from San Juan, Puerto Rico.

PR_110(a)(2)(D)(i) letter_Nov 29.pdf



### Conclusion

Based on the assessment of factor s described above

, EPA has preliminarily concluded that Puerto Rico
has met the CAA criteria attainment of the 2008 ozone NAAQS, all monitors in its EPA

- approved ozone network show attainment of the ozone standard. In addition, Puerto Rico is far enough from other ozone nonattainment areas that is does not cause or contribute to any nonattainment for the 2008 ozone NAAQS.