Air Quality Monitor

Air pollution is a huge and serious issue in our daily life. A good air quality monitor will be an assisstant to help you understand the air floating around you. There are various types of air quality detectors for your option. These monitors can detect different varaibles based on models - dust (PM2.5/PM1.0/PM10), formaldehyde (HCHO), CO2, TVOC, AQI, temperature and humidity. With the help of the monitor, you will be able to easily check the air quality in your home, office, car or other indoor areas.

Working principle of air quality monitor

The air quality monitor is used to detect formaldehyde (HCHO), PM2.5, TVOC and temperature and humidity in real time. It is small and exquisite, easy to carry. Through the inner sensors, the monitor can accurately measure the concentration of pollutants, and calculate the air quality index AQI, and give an alarm when the concentration exceeds the standard.

The principle of the air quality monitor is to detect the signals of the front-end formaldehyde sensor, PM2.5 sensor, TVOC sensor and temperature and humidity sensor, amplify the weak signal of the sensors through an operational amplifier, remove the noise interference through the filter circuit, collect the signal through AD, use a high-precision CPU to process, and then convert it into a concentration value and display it on the LCD screen.

Working principles of air quality sensors

The air quality monitor is equipped with a variety of gas sensors, including formaldehyde sensor, PM2.5 sensor, TVOC sensor and temperature and humidity sensor, thus it can detect different varaibles. The below introduce the basic principle of these sensors.

Formaldehyde sensor

The air quality detector adopts a high-sensitivity electrochemical sensor. The HCHO sensor uses the scientific and effective electrochemical principles to sensitively and accurately detect the formaldehyde concentration in the air. When there is indeed formaldehyde existing, a low DC current will be generated. Combined with a high-precision amplifier circuit and AD sampling, the formaldehyde concentration will be measured.

PM2.5 sensor
The air quality monitor uses a high-precision laser sensor for PM2.5 detection. The laser sensor calculates the number and diameter of particles through laser scattering method, and finally accurately calculates the PM2.5 concentration of the measured environment, with a detection accuracy of 1 microgram/cubic meter.

Temperature and humidity sensor
In addition to formaldehyde and PM2.5 detection, the detector also has a built-in temperature and humidity sensor. When the temperature and humidity in the air change, the detector can immediately sense it and display the indoor environmental indicators more comprehensively.

TVOC sensor
The air quality monitor usually uses a semiconductor sensor to provide real-time monitoring of indoor TVOC concentrations for 24 hours a day, and provides warning alerts if the value exceeds the standards. Then, it is very suitable for home, office, and car applications.

Matters needing attention for using an air quality monitor

• Any sensor will be affected by some external substance when working, so please keep it away from alcohol, perfume, chemical volatile gas, smoke and so on.
• Indoor air is circulating, so the air that enters the monitor vent is different at different time, thus the formaldehyde content in the air may also be different. Therefore, it is normal that the detection value floats up and down.
• When using the air quality monitor, avoid the fan, heater and other strong winds blowing directly the monitor vent hole, which will interferes with the accuracy of the test results. The product should be placed in a relatively stable air circulation area, so as to make sure the accuracy of the detection.
• Before you use the device to monitor the HCHO and TVOC in the bedroom, living room, cloakroom and other rooms, it is better to seal the windows, doors for 24 hours. In addition, the average content of air is based on the average of multi-point test data in the room.

Why do our air quality monitors only need to calibrate HCHO and TVOC and not PM2.5 and AQI?

Our products are based on outdoor formaldehyde-free air sampling, and then taking the formaldehyde concentration in the indoor air as the comparison. Therefore, the new machine which is not used for a long time and the detection of ambient temperature changes requires calibration before testing. This calibration value has a great correlation with the subsequent detection accuracy. Calibration environment must avoid fragrances, perfumes, paints, cigarettes, air fresheners, alcohol and other chemical pollutants, so as not to damage the sensor.

Why is PM2.5 value different from the value posted online?

The location and conditions of the test are difficult to coordinate with the weather station, the weather station has several sampling points in the city, and the measurement data of each sampling point are also very different. The sampling points at this location are strictly required: 3 to 30 meters in height, good air circulation, not close to the chimney, furnace and other obvious sources of pollution. There are no tall buildings, trees or other obstacles that can hinder the flow of ambient air around the instrument.

Types and hazards of indoor air pollutants

Indoor air pollutants mainly come from decoration, decoration materials widely used in decoration, plate, paint, wall paint, glue, new furniture, adhesives and other easy to produce harmful to human health pollutants.

Formaldehyde (HCHO)

Formaldehyde is the main pollution from the decoration of new house. It is a kind of gas with irritating odor with release period as long as 3-15 years.

TVOC

What is TVOC? It stands for Total Volatile Organic Compounds. It contains hydrocarbon, halogenated hydrocarbon, oxygenated hydrocarbon and nitrogen hydrocarbon, and includes benzene series, organic chlorides, Freon series, organic ketone, amines, alcohols, ethesr, esters, acids and petroleum hydrazine compounds. The TVOC indoor mainly comes from the combustion of gas and natural gas, and the emission of construction and decoration materials, especially paints, coatings and adhesives=

PM2.5

In PM2.5, PM refers to particulate matter, namely the solid or liquid granular material in the atmosphere; 2.5 refers to particulate matter with an aerodynamic equivalent diameter of 2.5 microns or less in ambient air. Such matters can be suspended in the air for a long time, so the higher the concentration of PM2.5 in the air, the more serious the air pollution.

Indoor air detector is a great choice to quickly detect formaldehyde, benzene, ammonia, TVOC and other harmful pollutants in indoor air, so as to safeguard our health.