[Greenbuilding] Stale Air

[Shane ONeill]

Here is a posting from the Get Sust Newsletter released today on a
literature review relating to recent ventilation  studies in relation to
health.  One of the issues I note with research into indoor CO2 levels is
often the information tends to be rather out-dated in comparison to the
shift in what we are demanding from new construction.  Last year there was a
study carried out on Passive House school standards that placed most indoor
concentrations above 1,000ppm CO2.  I found this to be quite high for a
school; for a recent review on passive house schools I attach this link:
http://www.stadt-frankfurt.de/energiemanagement/english/Passive-house-school
-Riedberg.pdf

The issue on opening windows and ventilation rates is covered in section 2
of this PDF.

As a last note, when I was reviewing indoor CO2 concentrations the most
comprehensive current study was carried out by the US Navy where they
examined CO2 concentration levels in submarines, where these concentration
levels can go up to between 2,000-4,000 pmm.  

LA and Mexico City have, on average, 500-600 pmm as reading for their
external air concentrations.  If we are to move towards a low carbon
economy, I think that CO2 concentrations is an essential consideration and
standards based on preventing the perception of body odour should really be
placing greater concentration on CO2 as a serious pollutant for indoor
environments.  The German school mentioned in the above PDF mentions
concentration levels above 1,000 ppm for classrooms; this I think is too
high.  In part my consideration arises from the chemical changes that blood
undergoes when concentrations go above 427 ppm, which is the upper limit
that human blood can remain neutral to CO2 air concentrations.  After 427
ppm the blood begins (ever so gently) to become acidic... and blood acidity
leads to anxiety, an issue that is often not raised with indoor health
issues

Shane ONeill
See the Get Sust memo on the ventilation study below:


Better ventilation improves health

A team of international experts has recently published a comprehensive
review of the impact that ventilation rates can have on the health of
occupants, concluding that there is mounting evidence that higher
ventilation rates in offices reduces absenteeism and cuts sick building
syndrome.

The group assessed 27 papers published in peer-reviewed scientific journals
throughout 2005. They found considerable consistency across multiple
investigations and different epidemiologic designs for different
populations, suggesting that multiple health 'outcomes' are related to
ventilation rates. For example, higher ventilation rates in offices (up to
about 25l/s per person) are associated with reduced prevalence of sick
building syndrome (SBS) symptoms. The limited available data also suggest
that inflammation, respiratory infections, asthma symptoms, and short-term
sick leave increase with lower ventilation rates. In the home, ventilation
rates above 0.5 air changes per hour have been associated with a reduced
risk of allergic manifestations among children in a Nordic climate.

Overall, however, the review team conclude that further studies are needed
into the relationship between ventilation rates and health, especially in
diverse climates, in locations with polluted outdoor air and in buildings
other than offices.

Learn more

* 'Ventilation Rates and Health: Multidisciplinary Review of the Scientific
Literature', by Jan Sundell et al, Indoor Air, available online from 10
December via:
http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0668.2010.00703.x/abstract
(DOI: 10.1111/j.1600-0668.2010.00703.x)



-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of John
Straube
Sent: December-16-10 10:39 AM
To: John Bone
Cc: greenbuilding at lists.bioenergylists.org
Subject: Re: [Greenbuilding] Stale Air

In some ways John I am heartened to hear you have the same problems in the
UK as we do in Canada and the US.  Your quote could have been spoken with a
drawl or a twang and been completely authentic.

On 2010-12-16, at 10:39 AM, John Bone wrote:

> Yes, You are indeed correct I did mean to Type CO2 (Carbon Dioxide),...
and you are right to the expert air-conditioning and ventilation (fresh air)
are different thinks. But alas to many lay (ordinary folk) persons they
think an air-conditioner unit will replace the used up oxygen and remove the
human or combustion produced CO2 from aroom that is otherwise "sealed". In
35 year of being a building control officer (building code official) this
myth is still as dangerous as ever, even with some proffessional clients.
"Why do we neeed the opening windows when we ahce these air-con units...??""
> 
> John Bone
> 
> 
> On Thu, 16 Dec 2010 15:18:52 -0000, jfstraube <jfstraube at gmail.com> wrote:
> 
>> Hi John.
>> I hope you mean CO2. CO levels of 1500 ppm would kill students in 
>> about 2 hours :)
>> 
> Using Opera's revolutionary email client: http://www.opera.com/mail/
> 
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Dr John Straube, P.Eng.
Associate Professor
University of Waterloo
Dept of Civil Eng. & School of Architecture www.buildingscience.com


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