Why Multi-Gas Sensors Are Essential for Smarter, Healthier Homes and Vehicles

Air is fundamental to our lives, and its quality has a direct impact on our health and well-being. Polluted air contributes to a wide range of health issues over time. This makes reliable air quality monitoring imperative, especially in enclosed spaces like homes, offices or vehicles. Traditional monitors that focus only on carbon dioxide (CO₂) fail to capture the full picture of air quality. This article explores how multi-gas sensors provide a more complete and accurate way to assess air quality in real-time, and discusses the features, applications and benefits of using ScioSense ENS16x series for air quality monitoring.

Importance of Indoor and In-Vehicle Air Quality

The air in the enclosed environments can contain a wide range of invisible pollutants, including volatile organic compounds (VOCs), carbon dioxide (CO₂), nitrogen dioxide (NO₂), formaldehyde, and particulate matter. Poor ventilation and airtight building designs further worsen their accumulation, making indoor air quality a significant health concern.

According to the World Health Organization (WHO) guidelines, VOC exposure is linked to respiratory irritation, allergic reactions, and even an increased risk of certain cancers. Moreover, these compounds can disrupt sleep, trigger headaches, and worsen symptoms for individuals with asthma or other chronic respiratory conditions. Children, the elderly, and those with pre-existing health issues are particularly vulnerable. The effects vary widely depending on the compound. For instance, benzene is linked to acute myeloid leukemia and genotoxicity, while formaldehyde can cause sensory irritation and has been associated with nasopharyngeal cancer and myeloid leukemia. Nitrogen dioxide is commonly emitted from gas stoves and combustion processes and can lead to respiratory symptoms, airway inflammation, and decreased immune defense. Similarly, even trace amounts of substances like trichloroethylene and tetrachloroethylene have been connected to organ damage and various forms of cancer. 1, 2 This shows the importance of comprehensive air quality monitoring in indoor spaces.

This air quality monitoring becomes even more important inside vehicles, as the situation is often worse due to the confined space and additional sources of pollutants. For example, engine emissions can seep into the cabin from outside, or the occupants themselves contribute to air quality degradation through exhaled CO₂ and water vapor. Given the frequency and duration of modern commutes, maintaining clean air in vehicles is a necessity for well-being and safety.

Multi-Gas Sensors for Smart Air Quality Monitoring

Traditional air quality monitoring systems often rely on single-parameter sensors like CO₂ sensors. However, this approach misses a critical aspect that harmful airborne substances like VOCs and oxidizing gases can be present even when CO₂ levels are low. Relying solely on CO₂ can lead to clean air false positives.

However, advanced multi-gas sensing technologies like the ScioSense ENS16x series overcome this limitation by delivering a holistic view of air quality. The ENS16x series uses TrueVOC® technology, which integrates advanced metal-oxide (MOX) gas-sensing elements with intelligent on-chip algorithms. TrueVOC® combines precise hardware design with proprietary data processing techniques to reliably interpret complex gas mixtures into accurate, actionable air quality metrics. This combination allows the sensor to detect complex patterns of VOCs and oxidizing gases with high sensitivity and precision. The embedded algorithms interpret raw sensor data to provide meaningful air quality indicators, such as equivalent CO₂ (eCO₂) and total VOC (eTVOC), without the need for complex external calibration or data processing.

Moreover, one of the key benefits of using multi-gas sensors is improved energy efficiency. For instance, in a real-world trial, a demand-controlled ventilation (DCV) system using a TVOC sensor in a gym operated 24% less time compared to a similar system using a CO₂ sensor. Despite the reduced operation time, the system maintained good air quality ratings from users and achieved a 60% reduction in total costs, which proves how VOC-based control can optimize ventilation performance without compromising user comfort. 1

Key features of ScioSense ENS16x Series

The ENS16x series from ScioSense comprises ENS160 and ENS161 models. These metal-oxide gas sensors are tailored for high-accuracy, low-power, and intelligent air quality monitoring. 

Multi-Parameter Air Quality Monitoring

The ENS16x series can measure several key indicators of air quality in real-time. It provides outputs for eCO₂, eTVOC, and air quality index values—both standardized (AQI-S) and UBA-based (AQI-U) , where UBA refers to the German Environment Agency (Umweltbundesamt) whose air quality guidelines are widely used across Europe. The eCO₂ metric estimates CO₂ concentration, whereas the eTVOC reading offers a general assessment of indoor air freshness by detecting a broad spectrum of volatile organic compounds. The AQI values, on the other hand, serve as intuitive indicators that simplify decision-making in air quality management systems. 

Embedded Intelligence with On-Chip Gas Algorithm

The ENS16x has been described as “the sensor with a brain” since, unlike traditional sensors that simply provide raw data, the ENS16x includes a powerful onboard microcontroller that runs a sophisticated gas algorithm. This embedded algorithm continuously interprets sensor readings in context, accounting for environmental factors and internal calibration data to generate meaningful air quality metrics. As a result, the sensor delivers ready to use data right out of the box. Developers don’t need to implement complex signal processing or spend time fine-tuning parameters, which accelerates time-to-market and also ensures a higher level of consistency and reliability across product lines.

Ultra-Low Power Consumption

The energy-efficient ENS16x series supports a variety of operating modes to suit different power budgets. In ultra-low-power configurations, the sensors can operate with an average current draw as low as 150 µA, which enables continuous monitoring even in battery-powered devices such as portable air quality meters. For applications that demand higher accuracy or faster response times, the sensors can switch to more active configurations dynamically to offer a balance between precision and power consumption. This flexibility allows product designers to fine-tune energy usage based on the specific needs of the end application.

Integrated Humidity and Temperature Compensation

Air quality readings can be skewed by environmental conditions like humidity, which affects how gases interact with the sensor surface. The ENS16x series tackles this challenge by incorporating built-in automatic humidity and temperature compensation. The sensor utilizes temperature and humidity reading from a companion sensor preferably ScioSense ENS21x to ensures accurate readings across a wide range of environments. This compensation is handled entirely on-chip, requiring no external sensors or manual corrections. 

Versatile Interface Options for Easy Integration

The ENS16x series offers flexible digital interface options, including both I²C and SPI, that allow it to connect easily to various microcontrollers and system-on-chip (SoC) platforms for consumer electronics, smart home hubs, HVAC controllers, or automotive ECUs. The dual-interface support also enables developers to optimize for system performance, whether they need higher-speed communication or minimal pin usage. This makes it easy for the ENS16x to drop into existing hardware ecosystems without extensive redesign, reducing development friction for embedded teams.

Compact Package with Surface-Mount Compatibility

The ENS16x sensors come in a compact 4 mm x 5 mm land grid array (LGA) package with a low profile, making them ideal for space-sensitive designs. Their surface-mount form factor supports automated pick-and-place assembly, which streamlines production workflows in high-volume manufacturing. 

Application in Smart Homes and Vehicles

In smart homes, multi-gas sensors like the ENS16x family integrate into home automation systems devices such as air purifiers, ventilation units, and thermostats and can react dynamically to the presence of harmful gases.

Real-time detection of VOCs enables appliances to modulate their activity based on actual pollutant levels rather than relying on time-based or manual triggers. For example, an air purifier can ramp up its performance when spikes in VOCs are detected after cleaning activities or cooking. Similarly, HVAC systems equipped with these sensors can preemptively increase airflow when indoor pollutant levels rise, especially in spaces with intermittent occupancy. The estimations of eCO₂ and eTVOC provided by the ENS16x series can be used by smart HVAC algorithms to balance air quality improvements with energy savings. These sensors can also be embedded into battery-powered or hardwired smart home devices without impacting system complexity or maintenance cycles.

Similarly, in vehicles, airtight cabins can trap pollutants from interior materials, external emissions, and passenger respiration. The ENS16x series improves in-cabin air quality by enabling HVAC systems to adjust airflow dynamically, ensuring a healthier and more comfortable ride.

Conclusion

The ScioSense multi-gas sensor ENS16x series, with its advanced features and capabilities, provides highly accurate, real-time air quality monitoring, enabling smarter automation and improved health outcomes. Their ability to detect a wide range of pollutants and translate that data into actionable outputs makes them ideal for smart, health-conscious products.

Original Equipment Manufacturers (OEMs) and engineers looking for cutting-edge air quality monitoring solutions should visit the ScioSense website to get more information about its advanced products.

References

1. Measure VOCs to maintain high indoor air quality [Online] ScioSense. Available at: https://www.sciosense.com/wp-content/uploads/2024/04/ENS16x-Technical-Article-Measure-VOCs-to-maintain-high-indoor-air-quality.pdf (Accessed on March 29, 2025)

2. World Health Organization. (2010). WHO guidelines for indoor air quality: Selected pollutants. WHO Regional Office for Europe. Available at: https://iris.who.int/bitstream/handle/10665/260127/9789289002134-eng.pdf (Accessed on March 29, 2025)

3. ScioSense Website. [Online] ScioSense. Available at: https://www.sciosense.com/ (Accessed on March 29, 2025)

4. ENS16x Digital Metal-Oxide Multi-Gas Sensor Family [Online] ScioSense. Available at: https://www.sciosense.com/ens16x-digital-metal-oxide-multi-gas-sensor-family/ (Accessed on March 29, 2025)

5. ENS160/ENS161 Evaluation board [Online] ScioSense. Available at: http://sciosense.com/wp-content/uploads/2025/02/ENS160-ENS161-Evaluation-Board-Application-Note.pdf (Accessed on March 29, 2025)

6. ENS160 Digital Metal-Oxide Multi-Gas Sensor [Online] ScioSense. Available at: https://www.sciosense.com/wp-content/uploads/2023/12/ENS160-Datasheet.pdf (Accessed on March 29, 2025)

7. ENS16x Versatile Digital Air Quality Sensors for Building Automation, Appliances & Consumer Applications [Online] ScioSense. Available at: https://www.sciosense.com/wp-content/uploads/2023/12/ENS16x-Factsheet.pdf (Accessed on March 29, 2025)

8. Intuitive air quality insights – ENS161: the sensor with a brain [Online] ScioSense. Available at: https://www.sciosense.com/intuitive-air-quality-insights-ens161/ (Accessed on March 29, 2025)