## Technical Support Document (TSD) for the Response to the September

2010 Section 126 Petition from New Jersey Regarding SO 2 

## Emissions

from the Portland Generating Station
Docket ID No. EPA-HQ -OAR-2011 -0081 

# Summary of 1 -Hour SO 2 

# Monitoring Data from the Columbia Monitor in Warren County, New

Jersey

U.S Environmental Protection Agency

March 2011TSD for Columbia Monitor in Warren County, New Jersey

Air monitoring data collected at a newly established air monitoring site are consistent with our finding that emissions from the Portland P lant significantly contribute to nonattainment and interfere with maintena nce of the 1 - h ou r SO 2 NAAQS in New Jersey . New Jersey established the Columbia Site SO 2 monitor in Wa rren County in the Allentown - Bethlehem - Easton, PA- NJ Core Based Statistical Area ( CBSA) . The site is located approximately one mile from the Portland P lant, near the area predicted to exceed the 1 - hour SO 2 NAAQS based on the air modeling discussed in the preamble to this proposed rule and the modeling TSD . The majority of the collected data are still considered preliminary. Th e data appear in EPA’s AQS database and AIRNow database ( i.e. , AirNowTech) . Quality assured data have been uploaded to EPA’s Air Quality System (AQS) database from the monitor’s official starting date of September 23 , 2010 through the end of the third quarter on September 30 , 2010. The fourth quarter data for 2010 (October 1, 2010 through December 31, 2010) should be uploaded to the AQS by March 31, 2011. D ata in the AQS database have been fully quality controlled . T he data collected since January 1, 2011 have not been fully quality controlled or validated by the state, and are considered preliminary. Th is data appear only in AirNowTech, and will be uploaded into the AQS database after being fully quality controlled and assured by New Jersey . Additionally, the SO 2 data from the Columbia monitor have yet to be certified by the State . States typically certify their data in blocks of a calendar year at a time. EPA rules require 2010 air sampling data to be certified by the State by May 1, 2011 and 2011 data to be certified by New Jersey by May 1, 2012. The Columbia monitor is a Federal Reference Method monitor and uses the pulsed fluorescent method of analysis. The monitor meets the proper siting criteria as directed in P art 58 of the Code of Federal Regulations (Appendix E to Part 58 – Probe and Monitoring Path Siting Criteria for Ambient Air Quality Monitoring). T he primary SO 2 1 - hour standard is at a level of 75 parts per billion (ppb). The design value is calculated by taking the 99th percentile of the maximum daily 1 - h ou r averages for each of 3 consecutive years. These three 99 th percentile values are averaged together to get a design value for that monitor. If the design value is greater than 75 ppb, it is violating the SO 2 NAAQS. Since we do not have a complete 3 year data set, 75 ppb is used as a benchmark to determine whethe r there is a possibility of an SO 2 NAAQS violation. The monitor dataexceed ed the 75 ppb benchmark on ten days during the September 2010 – February

2011 time period . The top 10 maximum daily values and the date they were measured from the period September 23, 2010 through February 28 , 2011 are: Max (PPB) Date 183 10/30/2010 163 1/24/2011 136 9/24/2010 133 1/22/2011 111 2/13/2011 105 2/16/2011 92 9/29/2010 85 2/23/2011 83 12/30/2010 78 2/14/2011 Data for th e entire period can be seen in the chart below . The red line represents the level of the 1 - hour SO 2 standard (75 ppb).

0 20 40 60 80 100 120 140 160 180 200 

## Maximum 1- Hour SO 2 

## at Columbia Monitor

ColumbiaTh e chart below compares data from the Columbia monitor with all of the other SO 2

monitors in New Jersey. The Columbia monitor was set up to measure concentrations from a local source whereas the other SO 2 monitors in New Jersey were set up to measure concentrations from population centers. Again, the red line represents the 75 ppb standard.

0 20 40 60 80 100 120 140 160 180 200PPB

Date



## Maximum 1- Hour SO 2 

## in New Jersey Ancora State Hosptial Bayonne Brigantine Chester Clarksboro Columbia Elizabeth Elizabeth Trailer Jersey City Millville Newark Firehouse Perth Amboy