Particulate matter is the name given to solids or liquids that
are distributed in a gas. In the workplace, most often the term
"particulates" refers to particles, dust, mist or fume that has
become suspended in the surrounding air. The hazard with
airborne particulates is that a person may breathe in the
chemical that, may have ill effects on an individual's health.
The diagram below shows the parts of the respiratory system. It
can divided in two systems - the upper airway passages and the
lower airway passages. The upper airway passages includes the
nose, nasal passages, mouth and the pharynx down to the vocal
cords in the larynx (voice box or "Adam's apple"). The lower
airway passages start at the vocal cords, extend down the
trachea (windpipe) and continue all the way down to the small
air sacs, (alveoli) at the end of every branch of the bronchial
tree. The bronchial tree includes the trachea, the bronchus
(branches of the trachea going to each lobe of the lung), and
bronchioles (branches of the bronchi)