The particle counters of the PCE-PQC 1xEU series measure the concentration of particles such as dust, soot, pollen, and many other aerosols present in the air. These particle counters were developed to accurately determine the level of air pollution. Pollution is primarily generated by combustion, material processing, manufacturing, energy production, vehicle engine emissions, and the construction industry. With the help of the PCE-PQC 1x/EU series particle counters, the exact amount of dirt particles in the air can be measured. The level of air pollution with harmful particles, such as soot released by industry and especially by diesel vehicles without special filtration, is becoming increasingly important. Such dispersed particles are responsible for reduced visibility, inhalation of toxic substances, and consequently reduced work productivity. It has long been known that these particles also contribute significantly to many medical conditions, such as asthma, bronchitis, skin, and lung diseases. The particle counters were designed for easy and quick use. The PCE-PQC 1xEU series particle counters operate in various modes (Real-Time, Cumulative, Differential, Mass Concentration) and display the results until the device is turned off.