Imagine having powdered sugar on your desk. What happens to it when the wind blows? Exactly the same as, for example, with sand or other “tiny” (a few micrometres in size) particulate matter on the ground, which can come from combustion processes, automobile transport, heating with poor quality solid fuels, or mining activities. Air is in constant motion in the atmosphere, and the movement of air relative to the Earth’s surface observed at a particular location on the Earth’s surface at a particular time is called airflow, or wind. When the wind blows strong and warm, it has great energy and “tiny” dust particles are blown hundreds to thousands of kilometres, depending on the strength and temperature of the wind. The composition of the dust is not constant, as it changes with the seasons and ‘travels’ between hemispheres from different areas of the world – from the deserts of East Asia, the Middle East and North Africa to the scrublands of Australia and North America. Where the dust comes from speaks volumes about its properties and composition.
What we could tell you about the dust you might have found on your car recently
Analysis of dust taken from the surface of a car in Trnava found that its main components were silicon and oxygen, suggesting that it was sand. Iron, potassium and other mineral constituents were also present in small amounts. Fortunately, no hazardous constituents were detected in the analyses. The fact that the sand is magnetic is due to the presence of iron, which could have reached it by wind picking up dust from, for example, opencast mines.
Could cornflakes also be magnetic?
Yes they can, because they contain iron oxide as a vitamin.
Are dust particles a few micrometres in size dangerous?
Particles smaller than 10 micrometers can reduce visibility and adversely affect climate, ecosystems and materials. They affect visibility by changing the way light is scattered and absorbed in the atmosphere. Particles of this size are also hazardous to human health as they can enter our lungs and cause serious health problems with prolonged exposure.
Author: Ing. Lenka Blinová, PhD., UIBE MTF
