The principle of air quality monitor is mainly based on the combination of a variety of sensor technologies and electronic technologies for real-time and accurate monitoring of pollutant concentration and air quality in the atmospheric environment. Here is a detailed explanation of the principle of the air quality monitor:
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. This sensor has high sensitivity and selectivity for specific gases such as sulfur dioxide, nitrogen dioxide, carbon monoxide, etc.
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 sensor uses laser or LED light source to illuminate particles in the air, particles will scatter light, 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 the assessment of air quality and the protection of public health.
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.
Ii. Data processing and analysis
Data collection:
The air quality monitor collects data on pollutants in the air in real time, including gas concentration and particulate matter concentration, through a built-in sensor network.
Data processing:
The collected data is 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 are calculated and analyzed by specific algorithms to derive key indicators such as the air quality index (AQI).
Results display and transmission:
The processed data can be displayed to the user through the display screen of the instrument in real time, or can be transmitted to the computer or other equipment through the data interface (such as USB, RS485, etc.) for further analysis and storage.
Other technical features
Automatic monitoring and alarm:
Air quality monitors usually have automatic monitoring functions, which can continuously monitor the 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, which can adjust the monitoring parameters and alarm thresholds according to the 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 and semiconductor gas sensors, and real-time monitoring and assessment of air quality can be achieved through the steps of data acquisition, processing and analysis. These technical characteristics make air quality monitors play an important role in environmental protection, pollution control and other fields.