4 The record articles

ALL4’s: Is That Your Final Answer?

Posted: March 29th, 2011

Author: All4 Staff 

Last Month’s Answer and Winner:

We received several responses to our February edition of “Is That Your Final Answer” and George Woods was the first to provide the answer for which we were looking.  The performance standards apply to new, modified, or reconstructed emission units.  There are specific criteria that apply to the terms “new,” “modified,” and “reconstructed” and very often the applicability of these terms are not triggered even when a physical change is made to an emission unit.  However, under Section 111(d) of the Clean Air Act, if for a specific source category, U.S. EPA develops a performance standard for a pollutant that is not a criteria pollutant (e.g., SO2, PM, NOx, etc.) and that is not a HAP then U.S. EPA is required to establish an emission guideline for the emission source.  The emission guidelines are enforced via a state plan and apply to the source category after the state plan is approved by U.S. EPA.  The key difference is that the emission guidelines apply to an emission unit in the source category regardless or whether the emission unit is new, modified, or reconstructed.  For GHG, it is U.S. EPA’s plan to have NSPS emission guidelines apply to Subpart Da EGUs.


ALL4’s group of air quality modelers were conversing at the lunch table the other day and it seemed as if the entire conversation was in code with acronyms like PBL, ISC, NAD88, Deciviews, and AERMOD being used.  A project engineer overhearing the conversation finally was moved to ask, “Of all of the terms that I have heard in the last five minutes, AERMOD is the only term that I recognize.  What does AERMOD stand for?”  One of the air quality modelers replied, “Well actually, AERMOD is a contraction of an even longer acronym.  The full name of the AERMOD air dispersion model is…”  What did the air quality modeler tell the project engineer?


Please e-mail your answer to final.answer@all4inc.com.  Include in the e-mail your name, answer, and address (to receive your prize).

The final answer feature of 4 The Record is designed to test your knowledge across the environmental field, quiz you on the building blocks of air quality rules, stump you on ALL4 general trivia, and challenge you with brain teasers that have perplexed us.  The first correct answer e-mailed to us will qualify the respondent for free ALL4 gear and will enter the winner in our end-of-the year “Final Answer Championship.”  The subsequent month’s 4 The Record will identify the winner and the correct answer from the previous month’s question.  You must be an active subscriber of 4 The Record to win a monthly prize and be eligible for the championship prize.  ALL4 employees and family members are not eligible to compete.  Hope you enjoy this feature and good luck!


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