1、 Basic principles

This is an instrument that can simultaneously detect multiple gases. The principle is usually through the combination of gas sensors and gas selective adsorption materials, using the chemical or physical properties of gases, such as infrared absorption, chemical reactions, conductivity changes, etc., to identify and quantify the concentration of gases. It often integrates multiple sensors, each of which can respond sensitively to specific gas components, thereby achieving efficient monitoring of complex gas environments.

Common composite gas detectors use the following technologies:

1. Electrochemical sensing technology: By reacting gas with the electrolyte inside the electrochemical sensor, a change in current or voltage is generated for detecting gas concentration.

2. Semiconductor sensing technology: utilizing gas adsorption reactions on the surface of semiconductor materials, causing changes in semiconductor resistance, and detecting gas concentration through resistance changes.

3. Infrared sensing technology: Based on the characteristic of gas molecules absorbing infrared light, different gases have specific absorption peaks in different wavelength ranges. By detecting these absorption peaks, gas concentration can be inferred.

2、 Application in environmental monitoring

1. Air quality monitoring

Air quality monitoring is one of the widely used applications. With the increasingly severe air pollution, especially the rising concentrations of harmful gases such as PM2.5, sulfur dioxide, and nitrogen oxides, air quality monitoring has become particularly important. It can detect various harmful gases in the air in real-time and accurately, such as nitrogen dioxide (NO ₂), sulfur dioxide (SO ₂), ozone (O3), carbon monoxide (CO), etc., providing real-time data support. Through these data, relevant departments can take timely measures, such as limiting emissions, strengthening industrial supervision, etc., to reduce the release of pollutants, protect the environment and human health.

2. Industrial safety testing

In the industrial production process, especially in high-risk industries such as chemical, petroleum, and mineral industries, gas leaks and harmful gas emissions not only threaten the safety of workers, but may also cause serious environmental accidents. It can play a crucial role in these industries. For example, in petrochemical plants, detecting gas leaks and issuing timely alarms can effectively prevent accidents such as fires and explosions. By installing composite gas detectors in the production environment, the concentration changes of hazardous gases can be comprehensively monitored, providing strong guarantees for the safety production of enterprises.

3. Environmental pollution tracking

It also plays an important role in tracking and monitoring environmental pollution sources. For example, monitoring and identifying sources of exhaust emissions, tracking the sources of pollutants, and assessing the spread of pollution. It can quickly and accurately identify various pollutants in the air, especially gases with special odors or toxicity, such as ammonia, nitrogen oxides, etc. By monitoring these gases, scientific basis can be provided for environmental protection work, helping the government and environmental protection departments formulate more reasonable environmental protection policies.

4. Indoor air quality testing

With the improvement of people's quality of life, the attention to indoor air quality is gradually increasing. Especially during the winter heating season, indoor air pollution is particularly severe, with high concentrations of harmful gases such as formaldehyde and ammonia, affecting the health of residents. It can monitor the concentration of these harmful gases in real time, issue timely warnings, and remind people to take ventilation or other measures to improve indoor air quality. Especially in public places such as schools, hospitals, and office buildings, it can provide effective protection for indoor environmental safety.

3、 Future Development Trends

With the continuous advancement of technology, the technology of composite gas detectors is also constantly developing. From the sensitivity and stability of sensors to their detection range and response speed, their performance is constantly improving. In the future, it will be more intelligent and able to combine with IoT technology for remote monitoring and data analysis. Through the cloud platform, users can view real-time concentration data of various gases, and make data trend predictions and alarm processing.

In addition, with the increasingly strict environmental protection regulations, the demand for gas detectors will continue to increase, especially in areas such as urban air monitoring and industrial waste gas emission monitoring. In the future, it will not be limited to traditional gas detection functions, but will also expand to more intelligent monitoring and analysis functions, providing technical support for achieving more efficient environmental governance and safety protection.