EPA Air Quality Designations for the 2010 Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standard—Round 3

On January 9, 2018, EPA published its final rule establishing the initial air quality designations for areas in the United States (U.S.) for the 2010 sulfur dioxide (SO2) primary National Ambient Air Quality Standard (NAAQS).  EPA identified and designated as nonattainment tow areas in Puerto Rico, San Juan and Guayama-Salinas.  The rest of the Island was designated as unclassifiable/attainment.  EPA has published a table that compares its intended designations with the state recommended designations. 




Furthermore, its designations are published in the Federal Register / Vol. 83, No. 6, page 1098 (January 9, 2018).






Designated area


San Juan, PR;

Ø  Cataño Municipality

Ø  Toa Baja Municipality (part)

§  Palo Seco Ward.

§  Sabana Seca Ward.

Ø  San Juan Municipality (part)

§  San Juan Antiguo Ward.

§  Santurce Ward.

§  Hato Rey Norte Ward.

§  Gobernador Pinero Ward.

Ø  Guaynabo Municipality (part)

§  Pueblo Viejo Ward.

Ø  Bayamón Municipality (part)

§  Juan Sanchez Ward.

Guayama-Salinas, PR:

Ø  Salinas Municipality (part)

§  Aguirre Ward.

§  Lapa Ward.



Rest of Territory




The SO2 designations become effective on April 9, 2018, triggering and 18 month time frame  for the Puerto Rico Environmental Quality Board (PREQB) to submit a State Implementation Plan (SIP) to EPA on how they will bring the nonattainment areas into attainment. The largest sources of SO2 emissions in these areas should be the main targets of the SIP to be proposed by PREQB.


These designations are also important because permitting requirements for the nonattainment areas will become more difficult since, among others things, nonattainment new source review (NSR) will require (1) the installation of the lowest achievable emission rate (LAER), (2) emission offsets, and (3) opportunity for public involvement.


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Carlos E. Colón Franceschi




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