What is the Difference between a PM2.5 Monitor and a PM10 Monitor?

Monitoring particulate matter in the ambient air is more exciting than ever. The reason is a new public perception of the health effects of microscopic airborne particles. along with an increase in vehicles emitting such particles.

“PM” stands for particles. The numbers (usually 10 or 2.5) refer to the size of the particles tested, where PM10 refers to particles with a diameter of 10 micrometers or less, and PM2.5 refers to particles with a diameter of 2.5 micrometers, or It’s smaller than that.

Measuring process.

Technically, measure PM2.5 sample monitors and PM10 sample monitors look and work on exactly the same principle. Ambient air is forced through a special head inlet. (More about this below) Then it went through a fine dust filter. the net weight of the filter when the airflow is known and the weight of the filter after it has been exposed to the airflow for a period of time. You can calculate the weight per volume of the particles.

In a more original configuration, the filters are actually weighed by hand on the scale. But it is definitely labor intensive and causes a significant delay between the sampling and the measurement results. Many particle monitors use low-activity sources of beta radiation instead. Beta radiation weakens as it passes through matter. By measuring the amount of radiation passing through the sample before and after the sequence. You can calculate the mass of the filter before and after sampling. and consequently the mass of particles deposited on the filter.


The input header is a separate device between the sampled PM2.5 monitor and the sampled PM10 monitor. In both cases it consists of a carefully designed and manufactured tube and skid plate system. As air flows through the pipe and changes direction, the centrifugal force causes the heavier particles to collide and stick to the plate. This allows only small particles to pass through the head. Using (effectively) different sizes of tubes and plates, the “interface” diameter of the particles is determined. Only a fraction of the particles below the cross-sectional diameter will continue to flow through the air stream and collect in subsequent filters.

“Disqualification” is actually a bit misleading. There is no sharp edge where all particles above the threshold are rejected and all particles below are accepted. The PM number tells the particle diameter that 50% of the particles are rejected. Yet the standardized headline “segment curve” still looks like this. Human breathing body and it gives a good estimate of what the public has actually been exposed to.

Other types of PM monitors

There is also a group of PM monitors that work with a completely different technology. The laser beam is focused on a very small volume in the air stream. When a particle passes through the sound, some or all of the light is reflected or refracted. This is detected by the sensor as a short pulse of light. The intensity of the detected light refers to the size of the particle. by measuring the airflow and the concentration of the number of particles and the size over a period of time. PM10 and/or PM2.5 concentrations can be set. Some of these devices use the same “cut off” inlet head as the sample probe. Some machines have an “open” inlet head and the PM10 and/or PM2.5 fractions are simply derived by processing the signal from the detector.

Focus on PM2.5

Why are there two levels, both PM10 and PM2.5? Traditionally, PM10 was the measurement level to watch. the more damage you do. combined with modern automotive technology for air pollution. This yields smaller fractions than relatively longer larger particles. It has caused it to concentrate on particle fractions of PM2.5 or smaller. Today, there are measuring devices such as PM1 and even PM0.1 concentration. However, PM10 and PM2.5 monitors are still widely used devices today.

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