Ozone Safety Warning!!!

[Randy Holmes-Farley]

An article in the NY Times yesterday reported on an EPA study that is to come out in April. It shows that even low levels of ozone contribute to premature mortality.

IMO, anyone that can smell ozone in their setup, and especially in rooms of their house, should be warned about is toxicity. The health risks are sufficiently high that some folks may decide to not use it for that reason alone.

I have some articles coming up in the next few Reefkeeping Magazines on ozone, and this section from the first one highlights some of the health issues with ozone.

Ozone's Effects in the Lower Atmosphere


0.003 to 0.010 ppm
Lowest levels detected by the average person (by odor).

0.08 ppm Latest EPA study (to publish April 2006) reports significantly increased risk of premature death in humans. Each 0.01 ppm increase results in a 0.3 percent increase in early mortality.

0.001 to 0.125 ppm
The natural ozone concentration in air.

0.1 ppm
The typical maximum allowable continuous ozone concentration in industrial work areas and public and private spaces.

0.15 to 0.51 ppm
The typical peak concentration in American cities.

0.2 ppm
Prolonged exposure of humans under typical work conditions produced no apparent effects.

0.3 ppm
The threshold level for nasal and throat irritation. Some species of plant life show damage.

0.5 ppm
The level at which Los Angeles, California, declares its Smog Alert No. 1.; can cause nausea and headaches.

1 to 2 ppm
The level at which Los Angeles, California, declares its Smog Alerts No. 2 (1.00 ppm) and No. 3 (1.50 ppm). Symptoms: headache, pain in the chest and dryness of the respiratory tract.

1.4 to 5.6 ppm
Causes severe damage to plants.

5 to 25 ppm
Lethal to animals in several hours.

25+ ppm
Likely lethal to humans in one hour.

[DrBDC]

Here are some other articals on the harmful effects and mostly bad information for owners of ozone generating air purifiers:


http://www.epa.gov/iaq/pubs/ozonegen.html

http://www.epa.gov/iaq/pubs/airclean.html

http://www.epa.gov/ozonedesignations/faq.htm

This one has a little info about marine ecosystems

http://www.epa.gov/ozone/science/effects.html

[boxfishpooalot]

what does ozone smell like? Similar to bleach?

[Randy Holmes-Farley]

Ozone has a sweetish smell. Not quite like bleach. Not that harsh. More pleasant.

[Reefugee]

If you have ever been close to an old laser printer or a copy machine - they give off a very distinct smell. That's the smell of ozone.

[Billybeau1]

I'm wondering if they make a device similar to a carbon monoxide detector that would detect O3 around a tank or in a room.

[Billybeau1]

Nevermind, I got the answer in a duplicate thread.

Randy, Step away from the coffee.

[Randy Holmes-Farley]

It seemed important.

[DrBDC]

The .003-.010 ppm that is the level to just notice it by smell is a pretty good tester. If I remember correctly they used to want the air purifiers set at .005. That would give a just noticable smell on the first sniff and not be able to notice on the second sniff. So in short, if you smell it, find the leak.

For a one time identification training, just lightly smell the the output tube but do not "huff" it. You'll know the smell after that.

[thrlride]

If inserting ozone to the skimmer is it safe to assume that the ozone will become airborne and possibly cause these health effects?

If so, how do you prevent that from happening?

[Randy Holmes-Farley]

If I send ozone into my skimmer, the whole basement smells of ozone.

To eliminate it, you need to pass the air/ozone through a bunch of GAC before it gets out. That isn't easy to do without hampering skimmer operation.

[thrlride]

So basically ensure all outlets of the skimmer go through carbon?

[Randy Holmes-Farley]

Yes. Putting any backpressure on the skimmer air flow may not be desirable, however.

[jay24k]

If you are running only a 50 mg/h unit at half capacity, what would the risks be? Currently it is in my living room with the back facing a wall and a vent above it. The room has good circulation and is about 16'x18' I just ordered mine so I'm just checking.

I have an ASM skimmer so couldn't I just port the return water into a filter sock with carbon?

[Randy Holmes-Farley]

Depends on the turnover of the room, how much is released, the half life of the ozone in the air, etc.

A room that is 16' x 18' x 8' holds about 2304 cubic feet, or 65,000 L. That contains about 81,000 grams of air (surprisingly large!).

So 25 mg is 25 mg/81,000 g = 0.3 ppm

I have an ASM skimmer so couldn't I just port the return water into a filter sock with carbon?

You need to pass the air over GAC too.

[Randy Holmes-Farley]

This other thread also has some useful discussion:

http://archive.reefcentral.com/forum...5&pagenumber=1

[thrlride]

how did you do that math Randy? I'm curious because the room my tank is in is roughly 40' x 14' (the entire length of the house consists of the family room, breakfast and kitchen. Nearby is the two story living room wide open to the upstairs.

My generator is a 200 mg/hr unit on a controller so 'shouldn't' be on 24x7.

How would you pass the air over GAC as well?

[Randy Holmes-Farley]

In my current ozone application, I have the air from an ozone reactor coming out of a thin plastic tubing that is stuck down a few inches into a vertical 4" PVC pipe packed with a foot of GAC. The water drains down into the tank, and the gas comes out the top or bottom. The water from the reactor also goes into this column of GAC, and out the bottom.

The only tricky part of the calculation above that isn't just a volume (l x w x h thing) is that 22.4 Liters (1 mole) of air weighs about 28 grams (that assumes it is all N2, the actual value is a tad higher due to heavier O2 in the air).

[jay24k]

Well I my room feeds into multiple rooms as well and my room is actually longer and cathedral ceilings. I'm not sure on turn over as the air is running due to the warm days and always have a fan on. I'll check the other thread.

If I may, what is GAC and do you have any pictures of how you have yours setup? I plan on using a luft pump and a t valve to have it get sucked into the intake air valve of my ASM skimmer.

What would you recommend on doing as I ordered everything this morning.

[Randy Holmes-Farley]

GAC is granular activated carbon. I use Marineland Black Diamond. No pictures yet.

[jay24k]

I apologize if I'm asking too much or just not getting it.

You have your outake of your ozone into a tube of GAC before it hits your skimmer? Does having it go into GAC before it hits my skimmer make it any less affective?

I could easily have all my water from my skimmer go into a filtersock with carbon but not sure on how to do the air portion unless it passes through carbon first but I'm not sure if that would affect the oxygen content.

[justinzimm]

Randy,

Thanks for the great info. I've got a question about the ozone levels you posted. I smell ozone sometimes at work so I know the smell and can notice it before allot of my friends. I've never noticed it outside work or even when I visited LA during heavy smog days. If I can smell O3 at .001 to .010 ppm why havent I noticed it in nature or even smoggy cities? Also, are these exposures over time or a one time dose?

Thanks,
Justin

[Randy Holmes-Farley]

You have your outake of your ozone into a tube of GAC before it hits your skimmer? Does having it go into GAC before it hits my skimmer make it any less affective?

GAC breaks down the ozone and certain ozone byproducts. So you want the GAC in the air and water after it leaves the skimmer. I agree that it is hard with the air, and also it is hard to get adequate contact time with the water since the flow rates are often very high.

[Randy Holmes-Farley]

I've never noticed it outside work or even when I visited LA during heavy smog days.

I never recall smelling it on smoggy days either, although at the time I lived there I did not know what it smelled like. One thing is that your nose can become accustomed to it. So asking if a person can smell 0.1 ppm when comparing it side by side to 0.00 ppm may be very different than asking if someone living in 0.1 ppm smells anything.

Also, are these exposures over time or a one time dose?

OSHA permitted levels for most chemicals have various time constraints, such as time weight over 8 hours, as well as instantaneous maxima.

[DrBDC]

Here is an interesting page. There are a lot of claims for ozone benefit but the one I find interesting is the one about breathing it after bubbling through olive oil. Different I must say.

http://www.geocities.com/ojoronen/OZ.HTM#100