RE: Need Ozone

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Wood by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mike.wood-at-opennw-dot-com>

Hi Ralph

that's a very good point.  I didn't know either so I looked some stuff up.
I found some air quality standards:

Ozone levels are considered by the U.S. Environmental Protection Agency
(EPA) to be "unhealthful" and exceed the National Ambient Air Quality
Standard when they are measured at 125 parts per billion (ppb) or higher
under the one-hour standard or at 85 ppb or higher under the eight-hour
standard.

Exposure to extremely low concentrations of ozone initially increases the
reactivity of the airways to other inhaled substances (bronchial
hyperresponsiveness) and causes an inflammatory response in the respiratory
tissue. Exposure to ozone during exercise or work increases susceptibility
to this effect. Increased bronchial responsiveness has been observed
following 7-hour exposures to 0.08, 0.1 or 0.12 ppm (with moderate
exercise), or a 1-hour exposure to 0.35 ppm. This response occurs almost
immediately following exposure to ozone and persists for at least 18 hours. 

these are kind of in the same ballpark.  (I'm assuming EPA are using US
billions)


As to how much Mr Joe T Coiler might get exposed to, that's a bit more
tricky.  I did find a table showing exposure and health effects that has arc
welders occupational exposure at 9ppm (intermittent).  (The table references
"Occupational Hygiene Monograph #3 "The Toxicity of Ozone" published by
Science Reviews Ltd. Table 7, pp 14-17, 1979")


Apart from that, I'd have to go with pointing out that you only know there's
ozone present because you can smell it, and human beings just aren't
designed to detect odours at low concentrations.  I came across a couple of
measurements -

Ozone can be detected by its odour at concentration of about 0.04 ppm. The
nose, however, rapidly loses its ability to smell ozone. 

and CCOHS (Canadian Centre for Occupational Health and Safety) says:
Reported values [for sensitivity of smell to ozone] vary; 0.0076 ppm
(minimum perceptible value); 0.005 -2.0 ppm (detection threshold); 0.1 ppm
(recognition) 


So IMO it looks like the intermittent low(ish) levels coilers are probably
working around don't present much of a risk.  If you suffer from asthma or
something I'd say you should perhaps be a bit more careful, and I'll still
be making sure I work somewhere well ventilated.  But then I'm an outdoors,
fresh-air kind of person anyway!  I'd be much more cautious about working in
enclosed spaces, or generating ozone on purpose - for instance the CCOHS
site (http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/ozone/) is
really paranoid about that kind of thing.

Cheers anyway

Mike




-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: 03 April 2001 04:32
To: tesla-at-pupman-dot-com
Subject: Re: Need Ozone


Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Parpp807-at-aol-dot-com>

In a message dated 4/1/01 11:19:04 PM Central Daylight Time,
tesla-at-pupman-dot-com 
writes:

<< Also, many food crops are damaged by ground-level ozone each year.
  >>
Mike,

I wonder if you can offer any evidence for the above statement
This topic flares frequently on the Tesla list and is generally on-topic 
because ozone is readily produced by electrical discharge. 

Ozone is a powerful oxidizer and a very hazardous gas. But the one thing I 
have 
never heard in these discussions is what constitutes a hazardous 
concentration,
and especially, what levels of concentration may be expected in the
operation 
of Tesla coils. Ozone (O3) is so very reactive that most of it is quickly 
recombined with oxygen (O2)
as the O3 concentration rises. 

So IMHO, the important question of defining concentration
levels of interest to Tesla folk remains unanswered.

Happy day,
Ralph Zekelman