The Evolution of Gas Sensing

Author: Michael Krause, Sales Manager GAS, Axetris AG

Status Quo: A Fragmented Market in Transition  

Today’s gas-sensing market resembles a mosaic. A wide array of small specialist suppliers develops highly customized solutions for specific niches. For end customers, this fragmentation is a double-edged sword: on the one hand, there is a technical answer to almost every problem; on the other, it is virtually impossible to assess the “right” solution objectively. 

The consequence: because comparison standards are lacking, price often becomes the dominant purchasing criterion — instead of long-term measurement quality and operational reliability.  

Yet requirements differ dramatically from market to market: 

Environmental monitoring: Maximum sensitivity for greenhouse gases such as CO₂, CH₄ and N₂O at the lowest possible cost, so that large numbers of measurement stations can be operated worldwide. A broad range of methods is deployed to meet national and local requirements. International databases attempt to provide a unified picture, but a heterogeneous data model makes this challenging. 

Industrial safety: The oil, gas and chemical industries demand maximum robustness and explosion protection — often at the cost of selectivity, longevity and cross-sensitivity. The demand for millions of items of protective equipment and leak detectors has produced a multitude of concepts. For portable personal gas-protection devices, chemical and NDIR sensors have become established due to their low cost, but they require regular calibration or replacement because of limited service life. In leak detection, TDLS sensors are increasingly the technology of choice, as total cost of ownership, high accuracy and low cross-sensitivity are decisive for qualified detection.

Medical technology: In anesthesia and ventilation, NDIR systems have become the norm: the application is clearly defined, and hospital gas conditions (humidity, temperature, pressure) remain very stable, which allows a chosen technology to operate effectively. Breath-gas analyzers in doctors’ surgeries already require methods that are less sensitive to ambient influences. 

Agriculture: As one of the largest emitters of CH₄ and NH₃, agriculture is the focus of numerous research teams working to quantify emissions and develop mitigation strategies — with particular attention to storage and animal feed. Initial commercial TDLS-based devices are available worldwide and deliver reliable measurements. As with gas leaks, robust, accurate and portable instrumentation is essential for reliable outdoor measurement under varying weather conditions. 

Energy: Biogas plants are experiencing a revival: the CH₄ they generate is fed into local gas grids to reduce dependence on gas imports. Precise characterization of the gas mixture is critical in order to separate unwanted components, and the cross-sensitivity of the measurement system plays a central role. 

Core Technology: Tunable Diode Laser Spectroscopy (TDLS) 

To meet rising requirements for selectivity and the elimination of cross-sensitivities, TDLS has established itself as the gold standard. A tunable diode laser scans a precisely defined absorption line of the target gas, so that only the desired molecule is detected. The method’s sensitivity is primarily determined by the effective optical path length within the measurement cell. 

Compared with chemical sensors or NDIR systems, TDLS offers significantly higher spectral selectivity and long-term stability — without their drawbacks such as drift or sensitivity to interfering gases. At the same time, the technology is easier to handle and more cost-efficient to operate than high-precision FTIR or QCL systems. TDLS therefore represents the ideal compromise between performance, robustness and economy, and has become the preferred solution for industrial and safety-critical applications. 

The Three Most Important Measurement-Cell Concepts 

Detecting gases at the lowest concentrations (ppb range) requires the light beam to be folded within a small volume. The most common concepts are: 

The Vision: “Sniffing” the World

In the future, global standards must guarantee comparability of measurement data. Our vision is a networked world of sensors: 

Environmental Monitoring 

We want to measure not only that methane is present, but — via isotope analysis — where it comes from (e.g. fossil source versus biogas). This will make it possible to identify polluters unambiguously worldwide. The global concept of carbon credits — tradeable certificates representing the right to emit, or the saving of, one ton of CO₂ or CO₂ equivalent (CO₂e) — can become more refined and fairer, strengthening acceptance and raising environmental awareness even further. 

N₂O measurement in wastewater treatment plants will optimize processes and reduce emissions. Detecting harmful or hazardous gases in sewer networks will enable the early identification and localization of their sources. 

Infrastructure & Safety 

High-precision sensors monitor ageing pipelines. Instead of large-scale replacement, they enable targeted, predictive repairs by detecting the smallest changes in concentration. Mobile inspections can additionally capture other environmental gases, creating synergies between leak detection and environmental monitoring. 

Medical Technology: Predictive Breath Analysis 

Moving away from treating symptoms and towards early detection: portable TDLS devices analyze exhaled breath for biomarkers. AI models compare the results with an individual’s historical data to detect diseases before symptoms appear.

Smart Agriculture

Sensors in stables and on fields detect fermentation processes or diseases at an early stage. As in medicine, the analysis of historical data will enable significantly more efficient livestock farming, identifying changes and anomalies early on. Precise data from drones equipped with portable gas sensors allow fertilizer to be applied far more accurately where it is needed — enabling lower-impact, more sustainable agriculture. Biological waste is converted decentral into energy or compost, with decomposition and composting gases measured and captured precisely, creating a closed, significantly lower-emission cycle.

Conclusion – Central sensory organ of modern society

Gas sensing is evolving from a niche discipline into a central sensory organ of modern society. By standardizing suitable measurement methods with a focus on TDLS technology, we are laying the foundations for a better climate, greater safety and revolutionized preventive healthcare.

Would you like to learn how we can integrate TDLS technology specifically into your existing infrastructure? Get in touch with Axetris AG.