Re: Air quality

["Neil Fuller" <neil@xxxxxxxxxxxxxxxxx>]

There are a number of technologies for measuring air quality. The problem
is
defining exactly what is meant by the term and exactly what you want to
measure.

There are several "Air Quality" sensors available commercially.
They tend to
be fairly expensive (Trend Controls AQ/S is GBP128 although Electro
Controls
EAQ (
http://www.electrocontrols.co.uk/htmlcatalogue/airqualityandgassensors.htm
)
is more reasonable at GBP50)

All of the technologies suffer from drift and their measurements are
relative - the air is relatively good or bad rather than the air is 23%
polluted!

Somewhere, I have a BSRIA guide to measuring air quality. It's aimed at the
HVAC industry. The subject was researched with a view to reducing the fresh
air requirements in mechanically ventilated buildings with low occupancy
density. The industry norm is to supply a minimum 10% fresh air in to a
building when an AHU is on 'full' recirculation. As conditioning outside
fresh air is fairly expensive under most circumstances, BSRIA were looking
at methods of measuring the quality of the extracted air and use that to
ensure that there is sufficient fresh air supplied in to the building.

IIRC, the conclusion was that the air quality sensors were not accurate
enough and different manufacturers sensors were sensitive to different
ranges of pollutants and therefore could not be relied upon.

One aspect that they did find was that (unsurprisingly) all the sensors
showed peaks in air quality (higher = bad) during the morning and evening
rush hour. The closer the building was to a road, the worse the air
quality.

If I can find the document, I'll happily pass it on to anyone interested.
It's in PDF mail me at work - nfuller at global-associates dot co dot uk
with BSRIA report in the subject if you want a copy or I could upload it
(if
I can work out how to do that!!!!!!)

Regards

Neil
----- Original Message -----
From: "Young, Jeff" <Jeff.Young@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Tuesday, May 25, 2004 1:01 PM
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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