Update: 2020-05-27 15:14 Source: LUFTMY
Is dust an atmospheric pollutant?Dust is a particulate floating material, or pm10, that is produced when a substance is burned.The dust particles are less than 10 microns in diameter, can float in the air for a long time, and can enter the human respiratory tract through breathing, which is very harmful to health.When the particle size is less than 2.5 microns, most of it can be deposited into the lungs through the respiratory tract, which is more harmful to the human body.Dust pollution is an important aspect of air pollution. The problem of dust pollution control has gradually attracted people's attention.
The impact of dust on air quality
Due to its small size, long floating time and wide range, dust keeps accumulating in the atmosphere.When it comes into contact with sulfur dioxide and oxygen in the air, sulfur dioxide converts some of it into nitrous oxide, which increases the acidity of the air and makes pollution levels progressively worse.In addition, small diameter airborne dust (PM2.5) also encourages oxygen to react with sulfur dioxide to form sulfur trioxide, a major source of acid rain.Dust is also the carrier and catalyst of many pollutants, which can absorb a variety of harmful and toxic substances that people discharge into the atmosphere.
The source of the dust
In general, the main sources of small diameter dust (PM2.5) are industrial production, vehicle exhaust emissions and other residues from combustion.The main source of PM2.5 is man-made emissions. Some gaseous pollutants emitted by human beings are converted into PM2.5 in the air. Direct emissions mainly come from the combustion process, such as the combustion of coal, gasoline and diesel, the burning of straw and wood, and the burning of garbage.
How to use PM2.5 sensor to detect dust
PM2.5 sensors, which are equipped with infrared light-emitting diodes and phototransistors, can be used to detect dust concentrations.When the light axis intersects, the dust will appear in the infrared light when the dust airflow passes through the intersection point of the light axis. The reflected intensity of the reflected light is proportional to the dust concentration.The infrared light emitting diode emits light and encounters dust to generate reflected light. The PM2.5 sensor detects the intensity of reflected light and outputs a signal. According to the strength of the output signal, the dust concentration is determined.