APEX Environmental is well-resourced to perform source emission projects of any size and complexity. Our sophisticated state-of-the-art instrumentation, as well as a staff of experienced professionals, ensures a premier service for our clients. Some indicators of when stack sampling at an industrial source is conducted, include: STACK SAMPLING TEST METHODS Stack sampling test methods follow procedures and techniques described in US-EPA source testing codes. There are numerous recognised test methods for measuring industrial stack emissions, of which APEX Environmental uses the following: