Irritant Gases
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þ Definitions
 - Fumes:  aerosol of solids (e.g., metal fume fever, organic dust toxic
   syndrome)
 - Vapors:  aerosol of liquids

þ Types:
 - acids, alkalis:  extreme pH changes.
 - how water soluble is the gas?
  + highly-soluble attack upper airway, immediate severe irritation, usually
    protects lower airways.
   - acid gas, ammonia, formaldehyde, chloramine gas (ammonia + Clorox), MIC
     (methyl isocyanate)
  + less-soluble gases attack lower airways
   - NO2, N2O4:  during drought: silo-filler's disease; red-brown haze with
     odor of bleach; around welding; and Zamboni ice-cleaning machines.
   - may not know of exposure until too late
   - over time, damage to alveoli may cause severe damage
   - bronchiolitis obliterans, but can sometimes be prevented by 60
     mg prednisone daily for several days.
   - phosgene:  AKA carbonyl chloride, heavy, low odor, smells like
     freshly-mown hay. used for making dyes, pesticides, resins; also
     welding may cut through plastics with chlorinated solvents in confined
     space.
  + mid-soluble gases can cause late sequelae
   - chlorine
   - acrolein
   - fluorine

þ How to detect type?
 - Hoarseness plus wheezing means lower airway damage
 - Also means admit, start steroids
 - If immediate upper airway irritation, no hoarseness or wheezing, got out
   right away:  OK to send home.
 - May present as delayed noncardiogenic pulmonary edema.