Respirable Dust Size Per OSHA

Nuisance dust is defined as dust that contains less than 1 percent quartz. Because it is low in silicates, nuisance dust has little effect of the lungs. OSHA has set a list of standards for respirable dust that is categorized in nanometers.

Definition

• Respirable dust consists of dust particles small enough to penetrate the orifices of the body, most commonly the nose and the upper respiratory system. These dust particles can penetrate the respiratory system and are beyond the natural clearance mechanisms of the body.

Standards

• According to OSHA, respirable dust is the fraction of airborne dust that passes a size-selecting device having the following characteristics: 2.0 nanometers of dust have a 90 percent passing selector, 3.5 nanometers have a 50 percent passing selector and 10.0 nanometers of dust have a 0 percent passing selector.

Considerations

• Inhalable dust is defined by the Environmental Protection Agency (EPA) as the fraction size of dust that enters the body but is trapped within the nose, throat and upper respiratory tract. On average, the diameter of dust particles is about 10 nanometers.