Dust Particles

Airborne dust particles matter.

(also called “particulate matter”, “PM”)

  • Testing:  identify individual particle types (mold spores, skin flakes, soil, fibers), and/or measure airborne concentration levels either by mass (weighing) or by total number (particle counting continuous monitor), often segregated by size range (like PM10 below 10 microns).
  • Sources:  Smoke, soot, soil, mold, dust, asbestos, lead paint, pesticides.
  • Effects:  Irritate eyes, nose, throat, lungs.  The smaller particles (PM-2.5), inhaled deep into our lungs, can cause the most problems.
  • Control:  Reduce the levels in the air with filters, in furnace or portable air cleaners.  Remove mold growth.  Vacuum clean carpets often, with air filters running or with open doors and windows.

Particle size matters

The bigger particles are stopped by the nose; the smalvery lest particles are inhaled deepest into our lungs, fine soot being the worst.  Some particle size ranges at more or less than certain diameters in micrometers (µm) (“microns”), descriptive words, regulatory standards, and typical sources are:


  • >100  stopped in the nose
  • <100  “Inhalable” (total suspended particulates, TSP)
  • <10   “Thoracic” or “Coarse” nuisance (PM10, including smaller <2.5) from crushing, grinding, abrasion, road dust, soil.
  • >5  “Large” [the larger size on the Dylos monitor] from pollen, etc.
  • <4  “Respirable” (PM4)
  • <2.5  “Fine” (PM2.5) from combustion soot
  • >1   “Small” [the smaller size on the Dylos monitor] from bacteria, mold, etc.
  • <0.4  “Very Fine”
  • <0.1  “Ultrafine”:  most of the soot particles (but most of the mass is in the larger sizes).

These “PM” standards (PM10, etc.) are limited to long-term compliance sampling, because they must collect enough mass to weigh.

see also Dust Monitoring.

>see also Soot.