yellow tree

Choosing the lowest priced stack sampling contractor may lead to low accuracy, non-compliance, and fines. We would love you to partner with Yellow Tree and in so doing to have the Peace of Mind that we provide in the following ways:

All our Stack Scientists are Chemical Engineers

You will be served by Scientists who obtained at least 70% for their National Diploma in Chemical Engineering, or who possess a BSc or MSc in Chemical Engineering.

We follow ISO17025 systems

Your work will follow our ISO17025 systems (accreditation in progress), giving you peace of mind.

we will meet you

We will meet you afterwards

We will meet you digitally or in person to explain your results and to recommend solutions.



Strong relationships with Air Quality Officers (AQO’s)

Because of our focus on integrity and accuracy, the authorities trust our results. We aim to help you establish a strong relationship with your AQO.

Your report will be professional and easy to read

Your report will be written simply so that even your financial director will understand the emissions results and required actions.

Consolidated results across all your sites

If you have many sites, governed by a head office, we can perform the stack sampling at all sites and consolidate the results to help you make decisions at head office level.

abatement equipment

We will inspect your multi-cyclones' internals

If you have boilers, we will use a special camera to do this. Watch this video to see what we mean.


We will perform a mass balance over your boiler

If you have boilers, we will calculate how much sulphur is in the fuel so that you can hold your fuel supplier to account. We will also calculate the excess air and evaluate whether your boilers are being operated efficiently.

Short lead times

Unless we are sampling metals, halides, PAH’s or Dioxins and Furans, our report lead time is typically 10 working days from completion of site sampling.

certified calibration gas

Certified calibration Gas

We place our gas analysers on certified calibration gas every morning before starting work, so you know your results are highly accurate.

peace of mind

Peace of Mind

The Peace of Mind that legally compliant and highly accurate stack testing brings, can save you from millions of Rands of fines and imprisonment.


If you need assistance with an Atmospheric Emissions License (AEL) Application, Greenhouse Gas (GHG) report, or Carbon Tax, we can support you with these services too. Click here to view our consulting services.