What is Particulate Matter and Suspended Particles and Why is it Dangerous?

What is particulate matter (PM)?

Particulate matter consists of microscopic solid or liquid particles that are either emitted directly into the air or are formed by pollutants that combine in the atmosphere. Particulate matter is typically measured in three size units: PM₁₀, PM_2.5, and PM₁.

The major sources of particle pollution in Hungarian cities are residential heating and transport. In many Russian cities, pollution from industry is also an important source.

PM₁₀ or coarse dust particles are particles 10 micrometers in diameter or smaller. They are at least 50 times smaller than the width of a human hair and they can evade our protective nasal hairs and be inhaled into our lungs. Sources of PM₁₀ are endowed with crushing/grinding functions, another source is dust picked up by vehicles. Dust, mold, and plant and insect particles are also considered PM₁₀.

In the European Union, the daily limit value for PM10 in the ambient air is 50 µg/m³, not to be exceeded more than 35 times per calendar year. The permitted annual limit value is 40 µg/m3. The World Health Organization recommends that the annual limit value should be 20 µg/m³.

PM_2.5 or fine particles have a diameter of 2.5 micrometers or less. Fine particulate sources are characteristic of all combustion, including in internal combustion engines of vehicles, power plants, wood burning, forest fires, agricultural waste incineration, and a number of industrial processes. While PM₁₀ enters your lungs, PM2.5 is more dangerous because it can travel from your lungs into your bloodstream. From your bloodstream, it can go anywhere in your body, and cause. serious pathological changes.
In the EU, there is no official hourly or daily limit value for PM_2.5; the annual limit value is 25 µg/m³. WHO recommends 25 µg/m³ as a daily limit value and 10 µg/m³ as an annual limit value.

PM₁ is particulate matter less than 1 micrometer in diameter. It is a major component of PM_2.5. They are extremely fine particles that are more likely to penetrate the human body deeper than PM_2.5 and from there go to any organ. PM₁ is caused mainly by emissions from residential heating, motor vehicles, construction work, and some factories.

There is no official limit value for PM₁ in ambient air.