Getting Started
Last revision 2026/01/14
This article provides a comprehensive guide on using an air quality sensor to monitor particulates like PM2.5, PM1.0, and PM10. It includes details on the sensor's laser scattering principle, installation guidelines, and best practices for ensuring accurate readings in various environments.
Introduction
As the most basic part of life, air is attracting more and more attention, for example, the most common PM2.5, PM1.0, PM10, etc. Keeping an eye on the quality of the air we breath is becoming quite important. This time, DFRobot brings you this Air Quality Sensor that can measure particulate matter like PM2.5, PM1.0, PM10. With easy-to-use Gravity interface, the air quality sensor works well with most main-controllers. And we provide you with relevant sample codes to help you quickly build up air quality monitoring projects.
Based on the principle of laser scattering, the PM2.5 air quality sensor employs a digital universal particle sensor that can continuously collect and calculate the number of suspended particles of different sizes in the air per unit volume, which is particle concentration distribution, and then convert to concentration and output via I2C interface. The sensor can be embedded in various instruments and meters or environmental improvement equipment related to the concentration of suspended particulate matter in the air to provide timely and accurate concentration data. It is typically suitable for smoking rooms, kitchens, hot springs, bathrooms and other environments.
Principle
How does the sensor work?
This sensor adopts the principle of laser scattering, that is, to make the laser irradiate the suspended particles in the air to produce scattering, and at the same time collect the scattered light at a certain angle, and obtain the curve of the intensity of the scattered light with time. Furthermore, the microprocessor, based on the MIE theory algorithm, obtains the equivalent particle size of the particles and the number of particles of different particle sizes per unit volume.
The block diagram of each functional part of the sensor is shown in Figure 1.
Precautions
Installation Note
- The metal shell is connected to the internal power ground. Be careful not to short-circuit it with other external board circuit or chassis shell.
- The best installation method is to connect the plane with air inlet and outlet holes with the user’s machine’s inner wall (where there are gas holes connect with the outside). If this method is impossible to use, make sure there is no obstacles within 2cm of the air outlets, and there should be a structure between the air inlet and the air outlet to isolate the airflow and avoid the airflow from the air outlet to the air inlet directly inside the user machine.
- The vent opening on the inner wall of the user machine for the air inlet should not be smaller than the size of the air inlet.
- When applied to purifier products, try to avoid placing the sensor directly in the air duct of the purifier. If it is unavoidable, set up a separate structural space and place the sensor in it to isolate it from the air duct of the purifier.
- When used with purifiers or fixed detection equipment, the sensor position should be more than 20cm above the ground. Otherwise, it may be contaminated by large dust particles or even flocs near the ground, causing the fan to wind and block rotation.
- When the sensor is applied to outdoor fixed equipment, the protection against sandstorms, rain and snow, and willow catkins, etc. should be completed by the equipment.
- The sensor should be an integral component, the user should not disassemble it, including the metal shielding shell, to prevent irreversible damage.
- The sensor can be fixed with M3 tapping screws.
Others
- This sensor data ensures the consistency between the factory individuals, and does not use third-party testing equipment or data as a comparison standard. If the user wants the final measurement result to be consistent with a third-party testing equipment, the user can perform data fitting based on the actual collected results.
- This sensor is suitable for ordinary indoor environment. If the user equipment is used in the following actual environments, corresponding protective measures should be added to the sensor, otherwise the data consistency may decrease due to excessive dust, oil, and water ingress:
- Places where more than 50% of the time, the dust concentration is greater than 300mg/m^3 or more than 20% of the time, the dust concentration is greater than 500mg/m^3, for example a smoking room.
- Oily fume environment, such as kitchen
- High vapour environment, such as hot spring, bathroom
- Outdoor
PM2.5 air quality international standard table
| Country/Organization | Annual average concentration（μg/m³） | 24h average concentration（μg/m³） |
|---|---|---|
| WHO guideline value | 10 | 25 |
| WHO transitional goal 1 | 35 | 75 |
| WHO transitional goal 2 | 25 | 50 |
| WHO transitional goal 3 | 15 | 37.8 |
| Australia | 8 | 25 |
| United States | 15 | 35 |
| Japan | 15 | 35 |
| European Union | 25 | None |
| China | 35 | 75 |
Correspondence table of air pollution index (AQI) and PM1.0, PM2.5 pollutant concentration value
| AQI index | Air quality level | Average PM1.0 concentration in 24 hours（μg/m³) | Average PM2.5 concentration in 24 hours（μg/m³） |
|---|---|---|---|
| 0~50 | Excellent | 0~50 | 0~35 |
| 51~100 | Good | 50~150 | 36~75 |
| 101~150 | Light pollution | 151~250 | 76~115 |
| 151~200 | Moderate pollution | 251~350 | 116~150 |
| 201~300 | Heavy pollution | 351~420 | 151~250 |
| >300 | Serious pollution | 421~500 | 251~250 |
SEN0460 Register Table
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