Lowerdust

Lowerdust is a term used in atmospheric science to describe the lowest layer of suspended particulates in the atmosphere that remains near the Earth’s surface after dust-raising events or in regions with persistent surface dust. It refers to a coherent, near-surface stratum of fine particles that can influence air quality, visibility, and microclimate conditions.

Definition and boundaries: The extent of lowerdust typically spans from the surface up to several tens of meters, depending on atmospheric stability, wind speed, and particle size. It is distinct from higher, lofted dust layers that can form during strong convection and from diffuse surface dust that remains mixed within the entire planetary boundary layer.

Formation and dynamics: Lowerdust forms when emissions from soils, vegetation, or human activity are entrained by near-surface winds, then dispersed by turbulent mixing. Moisture changes, temperature inversions, and surface roughness modulate its thickness and particle composition, which commonly include silicates, carbonaceous matter, and mineral dust. The layer can accumulate pollutants and allergens, altering chemical reactions in the lowest air layers.

Measurement and impact: Researchers study lowerdust with ground-based sensors, lidars, and satellite observations to assess air quality, visibility, and climate effects. The presence of lowerdust can reduce horizontal visibility, affect solar radiation at the surface, and influence respiratory health in nearby populations. It is an area of ongoing research in dust transport and boundary-layer meteorology.