The poor mice might have died from suffocation (no oxygen) rather than inhaling the ash particles. They also might have been crushed by the weight of three feet of ash.

Save the Mice!

I think that was Sue's point, more or less. Shoulda signed off as "Sarcastic Sue" this time.

Kinda reminds me of the "nazi scientist with the frog" skit from my youth. Scientist removes frogs legs one at a time, screaming and slapping the table next to frog after each amputation. On last round, frog no longer jumps when yelled at and table slapped. Conclusion: frog without legs becomes deaf.

I think many of these government funded studies work about the same way. Stuff 100 grams of splenda(or insert any other item here) down a mouse's throat 5 times a day until the mouse dies from asphyxiation, conclusion: splenda(or any other substance known to man) is bad for mice.

I'm not sure what's in the LA smoke, so as always YMMV.

For particulates, a half-mask respirator with P100 filters is the industrial-strength choice. Cartridges can be added for specific gases or a GME (gets most everything) cartridge can be used.

I am very happy with my MSA full-face respirator with P100s, FWIW, but that's because I get such a great seal with it.

Fit is everything. Not comfort fit, but a solid and reliable face seal. In industry, people go through a "fit test" with sophisticated monitoring equipment to find the size and type of respirator that really will protect them.

My two-cents' worth.

Yeah, the joke about the mice buried in ash was Sarcastic Sue speaking. I guess the mouse experiment sounded more plausible than Sue thought.

I think this discussion is confusing people. For wildfires, an N95 is decent protection. Working on "the pile" at Ground Zero day after day or being inside of a burning house full of thick smoke and poison gasses are completely different situations from simply being downwind of a wildfire. Until recently, I believe that even professional wildland firefighters rarely used more than a bandana. You see more of them using masks like Whiffs by Xcaper, but that's a fairly recent development, from what I can tell.

I didn't say useless, I said overkill.

That being said, I have no idea what wildland FF's are using. However, I think that the risks of breathing gunk in during the fires isn't too extreme. Why? Well, because of some simple "thought excercises." Smokers don't develop cancer overnight. Asbestos workers didn't get mesothelioma after their first shift. Coal miners don't get black lung in their first hours of work. What does this mean? That there is a dose/event curve. Sure, a few days of LA fires will make your snot black, and you might cough up some dark crud. Which is GOOD. That's what your body is supposed to do.

Another point here, just on the effectivness of N95's. As mentioned, they're good for filtering 95% of particulate matter, 3 microns or larger. According to my pathology book from medical school (Robbin's Pathologic Basis of Disease, 7th Ed., p 732) "The most dangerous particles range from 1 to 5 microns in diameter..." So, you only get partial protection (better than none) from a N95.

So, while it may be overkill to me, it still might be a good idea if A) you constantly live near some source of smoke, B) you have underlying lung disease, or 3) work in a profession with a prevalance towards developing lung disease. Or you smoke, in which case, you should consider the nearby fire a chance for you to save a few bucks by delaying your next pack. Stop smoking.

Actually the NIOSH definition for N95 uses a particle size of 0.3 micron or larger, not 3 microns.

Arney is correct (see my previous post). But there is more to it than that.

Now, in an ideal world the N95 is plenty good enough for filtering most harmful particles. In reality, especially if dealing with something like heavy air pollution (be it from a fire or something else) it won't last very long. The N95 is a DISPOSABLE, one-shot mask. Made of cheap materials that don't last long. What few people realize is that dust tends to be highly abrasive. It will degrade the cloth-like fiber structure quickly, clogging it at first then tearing it gradually on a micro level. All of which leaves you more and more exposed to the pollutants even though you won't know it and won't have any objective way of measuring it.

Second, the mask will degrade rapidly when in contact with sweat and body heat. Not such a big deal as long as you sit still but it becomes important if you are physically active. Moreover, strenuous activity will have a negative impact on the fit. Gaps will appear and once that happens you can forget about the 0.3 micron thing.

The N95 does what it was supposed to do pretty well but its real purpose is quite limited. Some folks seem to believe it's a quick fix for everything. Well, it's not. Also, it's called a disposable mask for a reason. Meaning that any situation that involves higher risk, longer duration exposure to irritant or harmful particles calls for a more complex and better made (and more expensive) mask.

OK, Tom and Arney are right, it is 0.3 microns.

Diddling around at 3M, apparently there are different "flavors" of N95. Interesting...

http://products3.3m.com/catalog/us/en001...ler/output_html

Haven't cruised through them all, but it appears some are designed for prolonged wear, oil vapors, etc.

As I read various local news articles after the fires, there were a few things that caught my interest. Points #2 and #3 seem to be specific to Yorba Linda.

• Even many homes with concrete roof tiles burned.
• Some fire fighting in a particular neighborhood was hampered by low/no water pressure in hydrants.
• Reverse 911 calls were too late.

I have concrete roof tiles so reading a fire captain mention that homes with concrete roofs also burned was a bit of a wake up call. Apparently the winds were strong enough to drive the embers into attic vents and under the eaves of roofs, so having a fire-resistant roof that could withstand having a burning ember land on it was less protection than expected in this situation. (Well, anytime strong Santa Ana winds blow, I suppose)

Sealing the eaves and putting fine mesh screens in the attic vents might have prevented some of the house fires. I imagine that radiant heat also set their next door neighbors' houses on fire, but I guess the point is that if you can prevent the first house from catching on fire from flying embers, then the radiant heat issue is less of a problem.

According to the water district, flames had destroyed a sensor somewhere which prevented them from detecting the loss of pressure. The fire fighting teams in that instance had to pull back from the hilltop areas to a lower elevation to find hydrants with enough pressure and make their stand there.

The reverse 911 problem seems to have been a human problem. It's not that the system wasn't functioning, it's because no one requested that the system be activated early enough. Someone quoted in one article says that the protocol to activate the system wasn't finalized when the fires hit. Some homes in the Yorba Linda area had already burned by the times the calls went out, and fire fighters had trouble speeding to the fire as panicked residents were told to evacuate at the last minute and were clogging the roads. I don't think my city has adopted a reverse 911 system yet, but this story is a bit worrying. As if often the case, it's the human factor that makes or breaks the system.