🚀 go-pugleaf

In article <1dc71cINNa48@iskut.ucs.ubc.ca> arnett@unixg.ubc.ca (Bill Arnett) writes:
>In article <schuck.720989040@sfu.ca> Bruce_Schuck@sfu.ca writes:
>>Some very interesting emissions research is being done in Colorado.
>>The professor who has done this research has also come up with a
>>gadget that can be set up on the road side to measure emissions of
>>cars going by. It uses a TV camera to record license plate #'s and is
>>relatively cheap. It is not as accurate as the Air Care type stations,
>>but that isn't important because the 2 out of 10 cars pollute much
>>more than the other 8.
>
>This sounds ludicrious to me.  How the heck is this device going to
>measure emissions quickly enough to photograph the offender?   It takes
>time for gases to travel to the sensor!  In my case the tail-pipe is
>on the left side of the car so the gases would have to travel 8 feet
>before they reached the sensor.  The car is going to be travel a *long*
>way before the gases reach the sensor.
>

perhaps not. It might use some kind of spectrometry technique, where 
the gases abosrb different amounts of light, and radiate according to
the gas spectra of the pollutants. (some chemist can sya whether it would
be emmission or absorption spectra...)

>Besides this, wind direction, wind speed, and air turbulence would all
>have to factored in in order to decide which car produced the emissions
>and how dispersed the gases were by the time they got to the sensor.
>A certain error factor were be tolerable since an additional test would
>be performed, but I can't beleive that this could do much better than
>50% accuracy.

Well, astronomers can estimate helium on the sun, methane and ammonia 
concentrations on Venus or Jupiter. I don't think the probes sent down
little flasks to sample the atmosphere directly.

I think you are looking at it from the intuitive (direct sampling) but
wrong angle.
>
>Bill "the skeptic" Arnett.
>-- 
>Bill Arnett                            Internet: arnett@unixg.ubc.ca


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__________________________________________________________________________
 John Paul Morrison                     |  
 University of British Columbia, Canada |  
 Electrical Engineering                 |   .sig file without a cause
 jmorriso@ee.ubc.ca              VE7JPM |  
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