Control of Airborne Respirable Dust Hazards

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Control of Airborne Respirable Dust HazardsA
Training Program for Underground Coal Miners
Penn State
The Penn State Miner Training
Program University Park, PA 16802 Raja V.
Ramani, Ph.D., P.E, C.M.S.P. Mark C. Radomsky,
Ph.D. MPA, C.M.S.P. Joseph P. Flick, M.S.,
C.M.S.P.
March 31, 2003
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CENTERS FOR DISEASE CONTROL AND PREVENTION
NATIONAL INSTITUTE FOR OCUPATIONAL SAFETY AND
HEALTH
GENERIC MINERAL TECHNOLOGY CENTER ON RESPIRABLE
DUST
PENNSYLVANIA BUREAU OF DEEP MINE SAFETY
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RESPIRABLE DUST TRAINING PROGRAM

• Section 2
• HUMAN RESPIRATORY SYSTEM

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Breathing Process

• Breathing is essential for living
• Humans at rest breathe about 10 to 12 times per
  minute
• Air we breathe in mines
• must contain at least 19.5 Oxygen
• must not contain more than 0.5 Carbon Dioxide
• has limits on many other gases and dusts
• found in the mines

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Human Respiratory System

• Is a very complex system consisting of the nose
  and mouth, windpipe, bronchial tubes, lungs,
  bronchioles and alveoli. Alveoli are surrounded
  by arteries and veins where gas exchange takes
  place.
• Breathing substances that are harmful or in
  amounts not ordinarily encountered in the
  atmosphere can cause injuries to the system.

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The main function of the lungs is to provide
oxygen to the body, and eliminate carbon
dioxide. The average person breathes in about
eight liters of air per minute The average
person uses about 250 milliliters of oxygen per
minute
Liters
Milliliters
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Breathing Basics
Air In
Air is breathed in through the nose and/or mouth

• Air enters the windpipe (trachea)
• Air passes down the windpipe (trachea) to the
  lungs.

Trachea
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Breathing Basics
Bronchial Tubes

• The trachea divides into two bronchial tubes, and
  a bronchial tube enters each lung
• The bronchial tube in each lung divides and
  branches out many times forming progressively
  smaller bronchial tubes called bronchioles

Bronchioles
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Breathing Basics

• At the end of the bronchioles are small air sacs
  called alveoli
• There are millions of alveoli in the human lungs
• The alveoli are surrounded by very tiny arteries
  and veins
• This is where oxygen is given to the bloodstream

Alveoli
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Breathing Basics

• Oxygen is given to the blood stream to be used,
  and carbon dioxide enters the alveoli to be
  exhaled out of the body
• The oxygen given to the blood stream is carried
  to various cells and organs.
• This process is known as
• Oxygen Transport

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Without Oxygen

• Without oxygen transport,
• we would die in minutes

Carbon Dioxide out
Oxygen in
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Respiratory System Defensive Mechanisms

• Nose, Mouth, Trachea, and Bronchial Tubes
• all play a major role in evacuating inhaled
• dust and preventing it from reaching the
  alveoli
• Special Cells in Alveoli (Macrophages)
• engulf and try to digest the smallest particles
  that enter this region

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Respiratory System Defensive Mechanisms
The respiratory system has an elaborate defense
network to try and allow only clean air to reach
the lungs

• The nose regulates (warms/cools) the temperature
  of inhaled air
• The nose moisturizes inhaled air
• Small hairs in the nose trap particles for
  evacuation

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Respiratory System Defensive Mechanisms
The nose, trachea, and larger bronchial tubes
have cells with tiny hair-like fibers called
Cilia that sweep in an upward direction to try
and evacuate inhaled particles The nose,
trachea, and larger bronchial tubes are lined
with a mucus material which traps inhaled
particles. This mucus is moved by the cilia to
try and evacuate inhaled particles.
Cilia
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Respiratory System Defensive Mechanisms

• The process of the cilia and the mucus working
  together to sweep and transport inhaled particles
  upward is called the Mucociliary Escalator
• It works much like a
• human respiratory
• conveyor belt

Dust is Ingested or Evacuated
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Respiratory System Defensive Mechanisms

• There are special cells in the alveoli called
  Macrophages that engulf and try to digest the
  very smallest particles that have eluded all
  defense networks
• Some substances, like coal and silica, can damage
  the macrophages

Be kind to your macrophages! Dont overload
them with dust!
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Respiratory System Defensive Mechanisms

• Only the very smallest particles can actually
  enter the alveoli
• A small particle size is measured in microns. A
  micron is expressed as (u m)
• The smallest particle that the human eye can see
  is about 40 microns
• A human hair is about 50-70 microns thick

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Respirable Versus Visible Particle Size
Respirable dust lt1 micron to approximately 10
microns. Capable of being inhaled deep into the
respiratory tract and alveoli. Invisible to the
human eye.
lt10 microns
Visible dust approximately 40 microns.
40 microns
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The particles that can cause illness and
disease are so small that you can't see them!
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Proceed to Section 3 Health Hazards of Coal Mine
Dust