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The PPM Blog

SO2 (NAAQS) and You

By: Paul Hansen, P.E.  – Project Engineer

During July 2010 the EPA published a “final” 1-hour SO2 National Ambient Air Quality Standard (NAAQS) potentially affecting many sources across our nation, most notably coal and oil fired sources. While the “final” rule has been pushed back many times since 2010, several compliance dates associated with the rule have not been moved. Beginning in January of 2016, Air Agencies must (1) identify sources to be characterized with monitoring data, and (2) provide modeling protocol for other sources.

To get a perspective on how a state agency may view this federal mandate, I met with the Alabama Department of Environmental Management’s (ADEM’s) Meteorological Section to get their perspective on what they foresee happening when the rule is actually finalized. ADEM has indicated that mid-year 2015 (yes, this year) the rule is to be finalized. Beginning in January of 2016 state agencies will identify who will have to monitor/model and meet with these facilities to brief each of them on what is required. Each site will have the option to either monitor or model. If a facility should choose to monitor then they will be required to provide a protocol stating their reasoning for the position of each monitor in relation to the facility. It is ADEM’s opinion that modeling/monitoring should be limited to those facilities above the threshold. While this could end up the case, EPA has built-in a loop hole to the rule by adding the language “…or any other source as deemed necessary by the administration or state.”

So, about these thresholds; the EPA is currently considering three options. These options are:

  1. Inside Core Based Statistical Areas (CBSAs) Greater than 1 million – 1,000 TPYOutside CBSAs Greater than 1 million – 2,000 TPY
  2. Inside CBSAs Greater than 1 million – 2,000 TPYOutside CBSAs Greater than 1 million – 5,000 TPY
  3. Inside CBSAs Greater than 1 million – 3,000 TPYOutside CBSAs Greater than 1 million – 10,000 TPY

It should be no surprise that the EPA prefers Option 1. ADEM will likely be pushing for Option 2. In any case, a facility may be able to use 2014 emissions to determine on which side of the threshold they fall. If a facility has made any changes to their operation, or experienced lower emissions during 2014 then it would be in their best interest to submit their emission estimates quickly this year!

ADEM will likely suggest that facilities should model first, as soon as possible, for several reasons. First, when you model and show compliance with the NAAQS then you have saved yourself a lot of headache. Turn in your results and celebrate! Should you model and show an exceedance then you have given yourself time to debate and implement your options – such as monitoring (developing your protocol) or taking a limit (Maximum Achievable Control Technology). Modeling before taking a limit may be in order to make sure that this step is even necessary. Each state may have their own guidance regarding how a facility can achieve compliance with the NAAQS.

As a word of caution before you model, there is no true way to “game” the system when it comes to modeling. Contrary to anything you may have read or been told, ADEM (or any other state agency) does not simply read your results. They are trained to read and write the code behind the graphical user interfaces (GUIs). If you attempt to try and pull one over on ADEM you could potentially land yourself in a messy situation with both ADEM and the EPA that will not only put you squarely in the regulatory agencies’ crosshairs, but create more work and costs for you. Beware of anyone who tells you they can make sure you model under the threshold. There are legitimate ways to achieve compliance. Remember, ADEM will be auditing EVERYONE!

During this coming year you can count on the professionals at PPM Consultants to keep you up to date and help you decide what options may best suit your facility. Should you have any questions regarding this matter, feel free to contact me and I will be happy to answer questions or find the answer you are looking for in a timely manner.


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