UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 2 

290 BROADWAY 

NEWYORK, NY 10007-1866 

The Honorable Alejandro Garcia Padilla 

Governor of Puerto Rico 

BMB 110202 

Calle San Gustos 

San Juan, Puerto Rico 00901-1711 

Dear Governor Garcia Padilla: 

FEB - 6 2013 

Thank you for your recommendations of June 3, 2011 and March 26, 2012 on air quality designations 

for Puerto Rico for the 2010 revision to the primary National Ambient Air Quality Standard for sulfur 

dioxide (S02). Reducing levels of sulfur dioxide pollution is an important part of the U. S. 

Environmental Protection Agency's commitment to a clean, healthy environment. Exposure to S02 can 

cause a range of adverse health effects, including narrowing of the airways which can cause difficulty 

breathing and increased asthma. symptoms. This letter is to notifY you of the EPA's preliminary 

intentions regarding your recommended designations. 

On June 3, 2010, the EPA strengthened the health-based or "primary" standard for S02 by establishing a 

standard for 1-hour average S02 concentrations at a level of 75 parts per billion. The Clean Air Act 

requires the EPA to complete the initial designations process within two years of promulgating a new or 

revised standard. If the Administrator has insufficient information to make these designations, the EPA 

has the authority to extend the designation process by up to one year. On July 27,2012, the EPA 

announced that it had insufficient information to complete the designations for the 1-hour so2 standard 

within two years and extended the designations deadline to June 3, 2013. 

At this time the EPA is proceeding with designating as nonattainment most areas in locations where 

existing monitoring data from 2009-2011 indicate violations of the 1-hour S02 standard. The EPA 

intends to address the designations for all other areas in separate future actions. With input from a 

diverse group of stakeholders, EPA has developed a comprehensive implementation strategy for these 

future actions that focuses resources on identifYing and addressing unhealthy levels of S02. The strategy 

is available at: http://www.epa.gov/airquality/sulfurdioxide/implement.html. The EPA will continue to 

work closely with you and our other partners at the state, tribal and local levels to ensure healthprotective, common sense implementation ofthe 1-hour so2 standard. 

The EPA's review ofthe most recent monitored air quality data from 2009-2011 shows no violations of 

the 2010 S02 standard in any areas in Puerto Rico. Consequently, the EPA is not yet prepared to propose 

designation action in Puerto Rico and is therefore currently deferring action to designate areas in Puerto 

Rico. The EPA expects to be able to proceed with designation action in Puerto Rico once additional data 

are gathered pursuant to our comprehensive implementation strategy. In a separate future action or 

actions the EPA will notify you of our intended designations for these areas, and seek public comment 

on these actions, no later than 120 days prior to promulgating any final designations. 

Internet Address (URL) • http://www.epa.gov 

Recycled/Recyclable • Printed with Vegetable 011 Based Inks on Recycled Paper (Minimum SO% Postconsumer content) 
We look forward to a continued dialogue with you and your staff as we work together to implement the 

2010 primary S02 standard. For additional information regarding initial designations on the S02 

standard, please visit our website at www.epa.gov/so2designations. Should you have any questions, 

please do not hesitate to call me, or have your staff contact Richard Ruvo of my staff at 212-63 7-40 14 or 

ruvo .ri chard@epa. gov. 

cc: Ms. Laura Velez Velez, Chair 

Sincerely, 

~~~d~ 9'· -e,.e~e._ <::::._/ Judith A. Enck 

Regional Administrator 

Puerto Rico Environmental Quality Board 

Eliud Gerena, Advisor to the Chair 

Puerto Rico Environmental Quality Board 

Mr. Luis R. Sierra Torres, P.E., Acting Air Quality Area Manager 

Puerto Rico Environmental Quality Board 

Gina McCarthy, Assistant Administrator for Air and Radiation 

Stephen D. Page, Director, Office of Air Quality Planning and Standards