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GAS DETECTION lawmakers are getting on the same Page


While advances in technology and legislation - such as the 1956 Clean Air Act - have significantly reduced the appearance of lethal smog, the UK has still been in breach of its legal limits for key pollutants since 2010. And, with several factors driving emissions of gases and tiny particulate matter (PM2.5) - including an increase in wood burners caused by rising energy prices, and rising use of ammonia- based fertilisers - the government does not expect to meet these obligations until at least 2030. At the same time, it is planning to remove transparency laws as part of a post- Brexit cull of EU legislation. All of this means businesses have to lead


the way in tackling air pollution. And, as every business is responsible for at least some emissions throughout their supply chains, every business has at least some part to play.


Businesses can seize the oPPortunity


While the natural instinct of many in business is to view environmental targets and obligations as red tape, they should be seen as a way to improve transparency and efficiency. Through robust, transparent data collection, businesses can streamline supply chains and optimise operational workflows in ways that improve profitability while still meeting environmental obligations. In many industries, this


manifests as an increased focus on health, safety, environmental, and social policies, where any data


collected can be used to inform


improved ways of working. The sensing technology


required to achieve this is not some


far-off, futuristic concept - it is available today and is more affordable and accessible than ever. Any company - not just traditional polluters - can monitor its industrial


gas usage, emissions, or even just the general air quality around its workplace. The most powerful tool a business can use


to detect trace gases is laser absorption spectroscopy. It will prove vital for taking care of the ‘low hanging fruit’ – the emissions that have the biggest impact on climate change.


Carbon dioxide (CO2) and methane (CH4) are classified as greenhouse gases due to their ability to strongly absorb infrared light emitted from the Earth’s surface, which effectively traps infrared light emitted from Earth as heat and contributes to the warming of our atmosphere. However, infrared spectroscopy can be used to


exploit the infrared absorbing property of CO2 and CH4 and determine the atmospheric concentrations of these gases.


getting on the right wavelength


This type of spectroscopy is widely used when monitoring atmospheric greenhouse gases, pollution, and respiration processes. If needed, its scope can be focused down to the tiniest scale, where it can even be used to analyse the particulate matter in human breath. This can provide a detailed breakdown of the particles that enter and leave our lungs with every breath we take. This form of detection is based on how light is


absorbed as it passes through a medium. Emitters within the sensor generate beams of IR light which pass through a sampling chamber containing a filter. The filter only allows the required wavelengths - the ones reflected or emitted by the particles of gas being monitored - to make it past, meaning only those wavelengths can reach the detector. Different filters allow different wavelengths of light to reach the detector, which can, in turn, be used to detect different gases and distinct particles. Newer gas analyser instruments use a laser


diode mounted on a thermo-electric cooler to tune a laser’s wavelength to the specific absorption wavelength of its target molecule. They exploit their high-frequency resolution, which results in enhanced sensitivity - more significant levels of interaction between gas molecules and light in the order of parts per billion - and discrimination, as they are tuned


to specific gas compounds. This lowers the risk of false alarms, which can become a serious issue with other common gas detection technologies, providing greater clarity about the scale of air pollution in a given area. The benefits of these sensors include fast


response times and accurate results without using any additional gases to operate. Modern detectors can now continuously monitor for combustible gases and vapours within the lower explosive limit and provide alarm indications. These can be deployed within oxygen-deficient or enriched areas, require little calibration, and are immune to sensor poison, contamination, or corrosion.


Painting a clear Picture


Air pollution measurement instruments serve multiple purposes. They can help businesses comply with environmental legislation and keep their employees safe. However, they can also help provide detailed information that can be used to educate the public through warnings and emergency alerts, such as the Met Office’s daily air quality index (DAQI). The potential impact of improved access to


detailed educational resources on air quality should not be understated. It could help billions of people across the world to make tiny changes to their daily routines to add up to a big impact, just as they might work to reduce energy waste or recycle to help combat other factors harming our environment. And businesses can seize the opportunity to be the standard-bearers for this global transformation. By identifying what remains a largely


invisible problem, we can begin to mitigate and even eliminate harmful emissions from many industries. When so much of the environmental agenda is focused on our forests and seas, it is vital that we do not lose sight of our air quality. Action is needed on air pollution - that


much is clear. Laser absorption spectroscopy provides a path towards clearing the air - and the journey along that path must begin today.


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indUSTrial ComplianCe | aUgUST/SepTember 2023 29


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