Dust is created during the drying, heating, and mixing of aggregates and asphalt. The dust primarily
results from the existing fine portions of the aggregate; is created by abrasion during mixing, blown
out by gases, or created by the air used for the burner; and comes from steam from the evaporation
of water from the aggregates. The dust is actually captured through a collecting mechanism and
prevented from polluting the environment. Air quality codes from regulatory agencies direct the
plants to test for particulate emissions in the exhaust gases from the plant to ensure the efficiency
of the dust-collecting system.