Is there a way to measure UV rays?

Question

Is there an easy way, or a tool that I can buy to measure UV rays (both UVA and UVB, preferably separately)? I'm interested in finding out how much UV rays my untreated window glass or tinted car windows are blocking. Or how much of there is outside in a day.

Answer 1

You want a UV radiometer.  They are not cheap however:

http://www.davis.com/catalog/product_vie...

If you want to save some cash and don't necessarily need it calibrated precisely, you could save a bundle by making your own.  You'll need some electronic skills and things like pliers, drills, soldering iron etc.  Although going with a discrete diode and external amplifier is cheapest, buying the amplifier and diode as an integrated package, like this:

http://www.eoc-inc.com/ifw/JIC_117_118_1...

is far easier.  Once this is hooked up, the output voltage will be proportional to the UV light incident on the diode.  So what you can measure is the relative intensity of the UV light.  So you would know that the UV light behind the window is 1/10 of that outside on a clear sunny day at noon.  

Since solar output is relatively constant, you can find what the UV light is in absolute terms for your latitude as a function of time of day and time of year and get an absolute calibration that way.