Resuspended dust is particulate matter (i.e., microscopic particles) that had been deposited on surfaces and that becomes airborne again as a result of wind or mechanical disturbances such as road traffic, some agriculture practices and leaf blowers. It can contain a wide variety of substances, including ultra-fine plastics, pesticides, fertilizer residues, dioxins, a variety of metals, radionuclides, and bacteria and viruses.
Resuspended dust caused by road traffic is a substantial, but often overlooked, component of urban air pollution and also of house dust. It varies according to a number of factors including traffic volumes and density, road surface conditions, and climate and weather.
There is a complex relationship between resuspended dust and climate change. For example, resuspended dust can both scatter and absorb sunlight, and thus it can have both cooling and warming effects. Climate change can exacerbate desertification, thereby resulting in increased dust emissions and resuspension, but increased dust can act as a nutrient source, thereby promoting plant growth and thus carbon sequestration.
The relationship between resuspended dust and human health is much more straightforward: that is, there is no evidence of benefit and it can only be harmful. The harm, which depends on its composition and its concentration in the air, occurs because it can penetrate deep into the lungs, and then into the bloodstream and other body organs.
For example, the particles can lead to, or aggravate, respiratory conditions such as asthma, chronic bronchitis and reduced lung function. The presence of metals such as aluminum and chromium can cause or contribute to cardiovascular diseases and lung cancer, and lead can cause behavioral problems and cognitive deficiencies in children. This harm can occur not only in urban areas but also in rural areas, and it can occur not only outdoors but also indoors.