Environmental Monitoring

Stack Emission Monitoring


Air is essential to life. It is the fundamental building block, apart from which life itself would not exist. Poor air quality is a great environmental risk to human health. Some of the common pollutants include particulate matter, Carbon dioxide (CO2), carbon monoxide (CO), Oxides of nitrogen (NOx) and Sulphur dioxide (SO2) Hydrocarbons (CxHy) and volatile organic compounds (VOCs) and ozone. Over a short period of time, exposure to the poor air quality causes an increased risk of heart disease, wheezing, coughing, and respiratory problems and skin, nose, and throat irritation. Chronic exposure causes respiratory diseases such as asthma, cardiovascular diseases and premature death. Lead exposure is linked poor brain development and thus reduces IQ in children. In Kenya, air pollution accounts for approximately 19000 premature deaths according to The State of the Global Air 2019 report. Apart from human health, pollutants such as sulphur dioxide and nitrogen oxides in air cause the formation of acid rain which damages buildings and cultural monuments, causes leaching of nutrients from the soil thus affecting agriculture and changes the composition of water bodies thus affecting aquatic life. Carbon dioxide, ozone and methane are known greenhouse gases which are responsible for global warming and climate change.

Forms of air quality

  1. Ambient air quality measurement

Ambient air pollution describes air pollution in outdoor environments. Poor ambient air quality occurs when pollutants reach high enough concentrations to affect human health and/or the environment.

Ambient air quality measurement is where the pollutant levels in the ambient atmosphere are measured.

  1. Stack emission monitoring

Stack emission monitoring also referred to as stack sampling, stack emission testing or source emission monitoring is the regular air monitoring of an emission point from industrial processes or plants.1,2 Where emission levels from an industrial process exceeds the set limits in permits and licenses this is considered a non-conformance. Therefore, with a reliable stack emission monitoring system, the relevant authorities monitoring the emission are able to take the necessary real-time action to ensure the emission parameters are within limits.

What is a stack?

Stacks are essentially large industrial chimneys that emit hot air, pollutants and particulate matter into the atmosphere at such a height that they do not cause danger to individual on ground. The pollutants emitted in the stacks could be in form of solid, liquid or gaseous state and include particles, dust, solvents and gases [Hydrocarbons, methane (CH4), CO2, carbon monoxide (CO), Oxides of nitrogen (NOX) and Oxides of Sulphur (SO2)]. If these emissions are not regulated they can have a detrimental effect on air quality.

Reasons for carrying out stack emission monitoring

  • Collect data for environmental impact assessment.
  • Assess the performance of pollution control devices.
  • Assess the process efficiency and process control.
  • To ensure compliance with environmental legislation

Approaches to monitoring stack emissions

Periodic measurements

In this approach, stack emission testing measurements are carried out periodically such as once in four months. Samples are withdrawn from the stack and either analyzed off-site or on-site using a transportable measuring system. Using this periodic stack emission monitoring approach, it does not allow concerned persons to take necessary action when required.4

Continuous measurements

Continuous stack emission monitoring on the other hand, involves automatic continuous monitoring of stacks enabling plant managers to monitor emission levels in real-time.1,4 While using this approach, whenever emission parameters exceeds permissible limits, the relevant authorities are able to take the necessary corrective action on time to ensure that parameters are within limits.

Stack emission monitoring from CSI International Ltd

Monitoring stack emissions is important in fulfilling your regulatory process control requirements. At CSI International Ltd we are able to carry out stack emission monitoring of all type of stacks from both small and large industrial plants. Our stack emission monitors include flow monitors, gas monitors and dust monitors. Our highly qualified technical team has a wealth of experience in undertaking this work to deliver a complete stack emission monitoring service to support your industry in fulfilling its regulatory requirements as per the Environmental Permitting Regulations.

We have our presence in Nairobi, Kenya and our laboratory is accredited by the Kenya Accreditation Service (Laboratory Number: KENAS/TL/48). CSI International Ltd has had its accreditation from 2017 allowing it to successfully complete stack monitoring testing using the most appropriate methods and analysis equipment. Depending on our client’s preference, we are able to offer either periodic measurements or continuous monitoring of stack emission to monitor a wide range of regulated pollutants including; Volatile organic compounds, particulate matter, metals, acid gases, hydrocarbons, metals and gases (such as O2, SO2, CO2, NOX and CO).

We aim to provide our unwavering support in Kenya and across the world.

CSI laboratory offers both stack emission monitoring and Ambient air quality measurement services to ensure our clients meet their environmental protection regulatory requirements

Contact us for your stack emission monitoring needs.


  1. What is Stack Emission Monitoring? - Machine Applications Corporation (macinstruments.com)
  2. Basic Information about Air Emissions Monitoring | US EPA
  3. Monitoring stack emissions: techniques and standards for periodic monitoring - GOV.UK (www.gov.uk)
  4. Stack Emission Monitoring | Logic Ladder



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