Walden Employees Complete “Smoke School”

by | Sep 28, 2023

On September 13, four of Walden’s employees attended “smoke school” to certify or recertify in the United States Environmental Protection Agency (USEPA) Method 9 Air Opacity of Visible Emissions. Those who attended and were recertified include Ethan Lo, Cari Covell, and Jackie Bell. In addition, Cinthya Vidal, a new hire at Walden, obtained the certification for the first time!

“Smoke school” is another name for the visible emissions training that the USEPA requires individuals to take in order to become qualified observers of stationary emissions sources. Once certified, an individual can perform opacity tests like the USEPA Method 9.

Opacity testing is the observation of an emission plume using standardized procedures that include the observer’s distance from the emissions source, the height of the source, sun direction, and sun altitude. The opacity, or thickness, of the smoke is recorded to the nearest five percent on a scale from 0-100 percent. How much the opacity obscures background light from the observer’s point of view is also assessed. 

The Method 9 testing involves an hour-long observation. This observation is best done between one hour after sunrise and one hour before sunset, with the exception of midday, in order to minimize sun impedance. The observer stands in a location that keeps the sun to their back as best as possible and records the directions that they are facing and the location of the emissions point. During this test, wind speed and direction are also recorded; if a shift of the wind occurs, the observer may need to relocate.

A recording of the opacity is taken every 15 seconds for the duration of the hour. Once the time has concluded, an average is calculated. The average is compiled by using the highest percentage of opacity observed in consecutive two-minute time periods. In order to be in compliance with Federal limits and NYCDEP regulations, the average should not exceed 20 percent.

Walden can assist with and make recommendations to our clients regarding generator operations. Our staff is trained to read a stack with only a 15 percent margin of error. If you need assistance with opacity testing and other compliance requirements, such as air permitting and aboveground tank registration, contact Walden at 516-271-1948. Our certified operators are available for testing and permitting inquiries.

opacity, emissions, opacity test, smoke test, smoke school, generator, air permitting

If you need an opacity test (or if you have other air quality concerns), contact Walden at 516-271-1948 to connect with a member of our air team.