RE: Air quality

["Ward, David" <DAvid.Ward@xxxxxxxxxx>]

AFAIK the way it is done professionally is with filters of varying grades
fitted over filter paper. Air is drawn in through the filters using a
littl=
e
calibrated pump. Results are given by examining the filter paper
Not very automation friendly... though a few automation possibilities exist

Maybe you could try a different approach, similar to the roadside fog or
particulate smoke detector

Fix a light source at one of a tube and a light detector at the other.=20
Shield the whole lot from ambient light, but allow the air with
particulate=
s
to enter the tube
The amount of attenuation of the detected light would give an indication of
the amount of particulate in the air=20
Of course this would depend on the wavelength of light used, area of cross
section and length of tube

My guess is you'd need a long tube and a sensitive detector, perhaps with a
'reference' detector at the light source end too


I'm sure I've gone off on a tangent again and that somebody will point out
that Laser or similar have an X10/USB device for =A350 that does the job
;-=
)

Still that's the real beauty of this list, diversity and some very clever
people who are generous with their time


HTH

Dave=20
=20=20=20

-----Original Message-----
From: Young, Jeff [mailto:Jeff.Young@xxxxxxx]
Sent: 25 May 2004 13:02
To: 'ukha_d@xxxxxxx'
Subject: [ukha_d] Air quality


Anyone know of a way of monitoring levels of polution in the air?  I live
fairly near a main road and I've been thinking for some time of monitoring
the level of rubbish in the air and possibly providing the results on a web
site.

Thanks in advanced.  Jeff


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