The principle of the air quality monitor is mainly based on the combination of a variety of sensor technologies and electronic technologies to monitor the concentration of pollutants and air quality in the atmospheric environment in real time and accurately.
I. Sensor technology
Electrochemical sensor:
Principle: Electrochemical sensors detect the concentration of a gas by measuring the current or potential change caused by the chemical reaction of the gas occurring on the electrode. The sensor has high sensitivity and selectivity for specific gases such as sulfur dioxide, nitrogen dioxide, and carbon monoxide.
Application: In air quality monitors, electrochemical sensors are widely used to detect a variety of toxic and harmful gases, providing important data support for environmental protection and pollution control.
Light scattering sensor:
Principle: Light scattering sensors use a laser or LED light source to illuminate particles in the air, the particles will scatter light, and the sensor calculates the concentration of particles by measuring the intensity of scattered light.
Application: It is mainly used to detect the concentration of PM2.5, PM10 and other inhalable particles, which is of great significance for air quality assessment and public health protection.
Semiconductor gas sensor:
Principle: The semiconductor gas sensor uses the characteristics of the resistance value of the semiconductor material to change when it comes into contact with a specific gas to detect the gas concentration. Such sensors have a certain response to a variety of gases, but require data processing by specific algorithms to improve accuracy and selectivity.
Application: In air quality monitors, semiconductor gas sensors can be used to detect a variety of volatile organic compounds (VOCs) and other harmful gases.
2. Data processing and analysis
Data collection:
The air quality monitor collects air pollutant data, including gas concentration and particulate matter concentration, in real time through a built-in sensor network.
Data processing:
The collected data are preprocessed by the processing unit inside the instrument, including filtering, denoising, and calibration steps to improve the accuracy and reliability of the data.
The processed data were calculated and analyzed by specific algorithms to obtain key indicators such as air quality index (AQI).
Results display and transmission:
The processed data can be displayed to the user in real time through the instrument display, or transmitted to a computer or other device for further analysis and storage through USB, RS485 and other data interfaces.
Other technical features
Automatic monitoring alarm:
Air quality monitors usually have automatic monitoring functions and can continuously monitor air quality. When the pollutant concentration exceeds a preset threshold, the instrument will automatically send an alarm so that timely measures can be taken to deal with the pollution event.
Portability and Flexibility:
Modern air quality monitors tend to have portable designs that facilitate mobile monitoring in different locations. At the same time, the instrument also has high flexibility, monitoring parameters and alarm thresholds can be adjusted according to actual needs.
Multi-parameter monitoring:
Some high-end air quality monitors can simultaneously monitor a variety of pollutant parameters, such as particulate matter, gas, temperature and humidity, to provide users with more comprehensive air quality information.
In summary, the principle of the air quality monitor is mainly based on the combination of various sensor technologies such as electrochemical sensors, light scattering sensors, semiconductor gas sensors, and through the steps of data acquisition, processing, analysis, etc., to achieve real-time monitoring and evaluation of air quality. These technical characteristics make air quality monitors play an important role in environmental protection, pollution control and other fields.