What is dust, fine dust, ultrafine dust
Dust is also called particulate matter (PM).
Dust is measured by mass concentration (particle mass per volume of air) or number concentration (number of particles per volume of air). The total amount of dust in the air is divided into several dust fractions. The basis for the division is the size of the dust particles and their separation behaviour in the human respiratory system.
All particles smaller than 10 micrometres (µm = 1 thousandth of a millimetre) are known as PM10 or as “fine particulate matter”. This limit was chosen because all particles smaller than 10 micrometres are breathed in. Fine particulate matter consists of a rough fraction with particles from 2.5μm to 10μm, as well as a fine fraction of 2.5μm, also called PM2,5.
These pass through the nasopharyngeal cavity and the trachea and enter the bronchi. The fine fraction contains the “finest” 1μm (PM1)and the “ultrafine particles” 0.1μm (UFP). These particles penetrate into the pulmonary alveoli (and further!).
The smallest dust particles are difficult to filter or trap. That is where physics helps – namely, through the ionisation of breathable air.
This is very easy to explain: understandably, dust particles large than 10 micrometres sink more rapidly to the floor than those which are finer and lighter. It is these particles which are the most dangerous. Remaining airborne for a long time, they are continuously inhaled.
The memonizer adds more positive and negative ions into the air, causing the fine particles to clump together. The growing individual particles form larger clusters, become heavier and sink more rapidly to the floor.