Glossary / FAQs / LexiconParticulate Matter (PM)

Particulate matter, also known as PM, consists of small particles in the air that can have health effects because of their tiny size. PM10 includes particles with a diameter of 10 microns or less, while PM2.5 includes particles with a diameter of 2.5 microns or less. PM10 and PM2.5 values indicate the mass of particulate matter per volume, typically in micrograms per cubic meter (µg/m³).

The Air Quality Index is a numerical value that summarizes the air quality at a specific location. It is based on several pollutants such as particulate matter, ozone, sulfur dioxide and nitrogen dioxide. The AQI provides information about how harmful the air can be to the health of the population. The composition of the pollutants included in the AQI can vary, making it difficult to compare values from different sources.

A particulate separator is a device designed to remove particulate matter from the air. There are several types of particulate collectors, including filters, electrostatic precipitators, and cyclone collectors.

Emission sources are the origins of particulate matter in the air. They can be natural (e.g. volcanic eruptions, forest fires) or anthropogenic (e.g. traffic, industry, heating).

A limit value for particulate matter indicates the maximum concentration of particulate matter in the air that is considered safe for human health. The EU has set limit values for PM10 and PM2.5 in directives. In addition to specifying the limit value for particulate matter concentration in µg/m³, the directives also specify the permissible number of days per year with higher particulate matter levels. Separately, there are Air quality guidelines from the World Health Organization (WHO).

In contrast to emission, immission describes the sum of air pollutants affecting humans from different sources

Particle size distribution describes, in addition to the total amount of particulate matter in the air, the proportions of different particle sizes. The size distribution can provide information regarding the origin of particles and their potential health effects.

A temperature inversion is a meteorological condition in which the typical decrease in air temperature with altitude is reversed. This condition impedes the exchange of air with higher layers, leading to the accumulation of pollutants, including particulate matter, near the ground.

A particle monitor is an instrument used to measure the concentration of particulate matter in the air. There are several methods for measuring particulate matter, from traditional methods such as depositing particles on a filter to light-scattering technology.

Traditional method filter method:
Measurement by depositing particles on a filter.
Daily filter change and laboratory weighing.
Determines the amount of particles in micrograms per cubic meter of air.
Does not provide information on chemical composition.

Continuous measurement of particle concentration by light scattering:
Real-time measurements, taking into account particle size distribution.
Does not provide chemical composition.

Advanced particle measurement system from Thies CLIMA:
Particulate Matter Hygro-Thermo-Baro Sensor Compact:
Advanced particulate monitor, measures PM1, PM2.5, PM4 and PM10 fractions.
Provides accurate meteorological base information.
Continuous real time measurements with RS485 interface.

Particulate matter measurements are critical for environmental protection, especially in heavily polluted urban areas. Continuous and distributed monitoring allows the identification of sources and the development of measures to reduce particulate pollution. Modern, low-cost sensors, such as the Particulate Matter Hygro-Thermo-Baro Sensor Compact, enable a dense distribution of measurement points for a comprehensive knowledge of local air quality.

Particulate Matter Hygro-Thermo-Baro Sensor Compact:
Advanced particulate monitor, measures PM1, PM2.5, PM4 and PM10 fractions.
Provides accurate meteorological base information.
Continuous real time measurements with RS485 interface.