Mechanisms of Particulate Deposition and Filter Efficiency

The tendency of particles to settle out of suspension due to gravity. This is more common in larger airways.

The process by which particles are removed from an airstream due to collisions with the walls of airways, especially at bifurcations or if the fibers are curved.

The process by which particles are removed from an airstream due to changes in air direction. Larger particles are more likely to impact.

The movement of very small particles, smaller than 1 micrometer, caused by random bombardments from air molecules. It significantly influences deposition in the terminal bronchioles.

The removal of airborne particles by their attraction to oppositely charged surfaces.

The measurement of airborne particulate concentrations using specialized equipment to count and size particles.

A type of particle filter that captures a minimum of 99.97% of particles greater than 0.3 micrometers in size.

The most common sampling method for airborne particulates, where air passes through a filter, collecting particles for analysis.

The amount of air that flows through a sampler per unit of time, usually measured in liters per minute (lpm).

The total amount of air collected during a sampling event, calculated by multiplying the flow rate by the sampling time.

The weight of particulate matter collected on a filter, usually measured in micrograms (µg).

The concentration of particulate matter in the air, expressed as milligrams per cubic meter (mg/m3).

The fraction of aerosol particles that can be inhaled and reach the respiratory tract, typically up to 100 micrometers (µm) in aerodynamic diameter.

A sampling device designed to collect the inhalable fraction of airborne particulate matter. It mimics how particles enter the nose and mouth.

The fraction of aerosol particles that can reach the deep lung, typically particles less than 4 micrometers (µm) in aerodynamic diameter.

A device designed to separate particles based on their aerodynamic size, often used to collect the respirable fraction of air.

A standardized set of procedures developed by OSHA for sampling workplace air to determine compliance with permissible exposure limits (PELs).

A comprehensive manual developed by NIOSH providing detailed methods for sampling and analyzing workplace contaminants, emphasizing accuracy and reliability.