DAVIS Health EnviroMonitor: Console - Manual (Page 46)

Weather Conditions Measured/Calculated
Health EnviroMonitor Manual Page 7
• Current Outside T-H Index (Alarm: Max)
• Current Outside T-H-S-W Index (Alarm: Max)
• Current Inside T-H Index (Alarm: Max)
• “Daily” High Outside T-H Index with time of occurrence (AutoClear)
• “Daily” High Outside T-H-S-W Index with time of occurrence (AutoClear)
• “Daily” High Inside T-H Index with time of occurrence (AutoClear)
UV Radiation
Energy from the sun reaches the earth as visible, infrared, and ultraviolet (UV)
rays. Exposure to UV rays can cause numerous health problems, such as sun-
burn, skin cancer and other skin damage, cataracts, and can suppress the
immune system. The Health EM can help analyze the changing levels of UV
radiation and can serve to warn of situations where exposure is particularly
unacceptable.
Be aware, however, that the Health EM’s UV readings do not take into account
UV reflected off snow, sand, or water, which can significantly increase the
amount of UV to which you are exposed. Nor does the Health EM take into
account the dangers of prolonged exposure to UV radiation and the readings
do not suggest that any amount of exposure is safe or healthful. Do not use the
Health EM to determine the amount of UV radiation to which you expose
yourself. Individual response to UV may vary widely. Scientific evidence sug-
gests that UV exposure should be avoided and that even low UV doses can be
harmful.
There are two scales in which UV is displayed. The first scale is MEDs. MED
stands for Minimum Erythemal Dose, which is defined as the amount of sun-
light exposure necessary to induce a barely perceptible redness of the skin
within 24 hours after sun exposure. In other words, exposure to 1 MED will
result in a reddening of the skin. You can determine the number of minutes of
sun exposure it will take to burn by dividing 60 by the MEDs per hour. Of
course, different skin types burn at different rates, a fact which is accounted for
by the use of skin factors, which are explained in “Setting Skin Factor” on
page 22.