Dust Collection Performance using Dylos Meter

[Bob Antoniewicz]

Dr. Pan, this from Phil's first post on the Dylos -

"On returning to the shop, it was reading 53/4. You have to add "00" to the end of the readings, so 53/4 translates to 5300 particles total (per cubic foot), with 400 of them being larger than about 5 microns. So far, so good (looking at the table my reading was considered good)."

...

HTH... Steve

Thanks, thats what I was trying to ask (in my feeble way). Multiply that by 36.8 to get cubic meters. So your 53 turns into
(53 - 4) *100 * 36.8 = 180320 particles per m^3

That must be one heckuva counter on that there gizmo!

Bob A.

[Will Blick]

Wilbur, fabulous post, thank you for such a clear concise explanation.

So 1 micron and smaller particles, we have no built-in defenses system for, other than inflammation. Easily understood. But are you saying, these particles pass through the thin delicate membrane to our blood? Or do they simply remain lodged in the delicate membrane, causing constant inflammatory response?

I assume only gases can pass through the lung/blood membranes? Or maybe, if the particles are small enough, they too can pass through to the blood?

Air that is highly saturated with water vapor, such as a steam room, contains the smallest size water vapor particles as well. Therefore, I would assume a steam room still represent a good therapy to keep these small dust particles from remaining embedded in the tissue...as a much of the water vapor in in the steam will condense in all areas of the lungs, providing a "washing out" of the small particles - which we have no built-in defense against. I recently read something to this in a book on steam therapy. Your thoughts?

[michael osadchuk]

Thanks, thats what I was trying to ask (in my feeble way). Multiply that by 36.8 to get cubic meters. So your 53 turns into
(53 - 4) *100 * 36.8 = 180320 particles per m^3

That must be one heckuva counter on that there gizmo!

Bob A.

Bob, thanks for that conversion to particles per cubic meter......
.... does anyone know what the "accepted" conversion number from particles per m^3 to micrograms (ug) per m^3 is?......
.....because it's my understanding that in Canada (and I think also in the U.S.) "acceptable air quality" standards are based on this ug/m^3 calculation.... from a Toronto Star article Jan. 29/08 I understand that Environment Canada's acceptable air quality sets a limit of fine particulate matter of 30 ug/m^3....I'm not sure but I believe Environment Canada using PM 2.5 or the particulate size of 2.5 micron for this standard.....
for example, in Ontario, Toronto and Hamilton led the province of Ontario with the greatest number of days per year with 24 hour readings that exceeded that limit (28 and 16 days, respectively) while the median readings for those places are around 5-6 and 7, respectively....... the same article said downtown Beijing in 2001 had monthly average readings of 70

.....I received my Dylos monitor, a 1/5 micron unit, yesterday.... it seems to work fine; I like the monitor/sampling setting wherein it takes (and stores) an air quality reading once every hour...... I haven't taken it into the workshop yet but initial use in my 'living quarters' seems to emphasize how much human movement stirs up fine particulate after which the readings settle and stay down......

check out this item - HEPA filters may improve cardiovasular health - referencing February issue of the American Journal of Respiratory and Critical Care Medicine

http://www.cbc.ca/health/story/2008/...a-filters.html

..seniors living for 48 hours in an test environment with air filtration had a 8.1% improvement in blood flow, with researchers theorizing that "reduction of indoor air particles... most likely indicates a gerneral improvement in the function of the inner lining of small vessels, including those supplying the heart"

good thread

michael, newmarket, north of Toronto, Ontario

[Greg Funk]

.... does anyone know what the "accepted" conversion number from particles per m^3 to micrograms (ug) per m^3 is?......
.....because it's my understanding that in Canada (and I think also in the U.S.) "acceptable air quality" standards are based on this ug/m^3 calculation.... from a Toronto Star article Jan. 29/08 I understand that Environment Canada's acceptable air quality sets a limit of fine particulate matter of 30 ug/m^3....I'm not sure but I believe Environment Canada using PM 2.5 or the particulate size of 2.5 micron for this standard.....

I haven't seen an 'accepted' conversion but it is possible to convert from particle density (which the meter reads) to a mass density by making some assumptions. For 2.5 µm particles made from wood with a density of 530kg/m^3 a particle count of 10,000 particles/cu-ft (meter reading of 100) would correspond to a mass density of 1.5 µg/m^3 or .015 mg/m^3.

I'm not sure how applicable these air quality standards are as I believe they are dealing with considerably finer particles than we generate in the shop.

While the respirable particles you find in smog may affect lung function most of the dust generated in the shop is compriesed of larger size particles >10 µm in size. Most of these particles are inhalable but get trapped before they get to your lungs. They are also the ones that cause increased cancer rates amongst woodworkers.

Michael - do you have any indoor or outdoor readings to share?

thanks,

Greg

[Wilbur Pan]

How much does it matter what the composition is? Is, say, clay dust better than maple dust better than cocobolo dust better than asbestos? Is there a hierarchy, and what factors govern how bad different materials of the same size are?

I don't think that anyone knows why one type of dust is worse than others, except that things that are made of tough stuff that your body can't easily break down, such as silica, asbestos, or cellulose, or are of a shape that doesn't lend itself to being consumed, such as asbestos again because it's long and pointy, seem to be worse.

P.S. Can we go back to calling Dr. Pan, Wilbur? Otherwise we open the floodgates and will soon be using Sir, Professor, Commander, Your Highness, etc...

Yes, please. If I'm giving chemotherapy to your kid, then you can call me Dr. Pan. Here, I'm Wilbur, amateur woodworker. Emphasis on the amateur. Actually a better title would be, "Converter of Quality Cherry to Sawdust".

Wilbur, fabulous post, thank you for such a clear concise explanation.

So 1 micron and smaller particles, we have no built-in defenses system for, other than inflammation. Easily understood. But are you saying, these particles pass through the thin delicate membrane to our blood? Or do they simply remain lodged in the delicate membrane, causing constant inflammatory response?

I assume only gases can pass through the lung/blood membranes? Or maybe, if the particles are small enough, they too can pass through to the blood?

In a nutshell, yes. Once those small particles get down there, it's exceedingly difficult to get them out, and the inflammatory response just keeps going. Only gases get into the blood, and it's a good thing, because if 1 micron particles got into your blood stream, you'd have to worry about mini-strokes as they floated up to the blood vessels in your brain.

Air that is highly saturated with water vapor, such as a steam room, contains the smallest size water vapor particles as well. Therefore, I would assume a steam room still represent a good therapy to keep these small dust particles from remaining embedded in the tissue...as a much of the water vapor in in the steam will condense in all areas of the lungs, providing a "washing out" of the small particles - which we have no built-in defense against. I recently read something to this in a book on steam therapy. Your thoughts?

Unfortunately, that won't work. Steam or water vapor, once it gets down to very small particles, is just humidity. Besides, in the small airways of the lung, the air there already has a high humidity since it's surrounded by lung tissue, which is already wet. If there is a 1 micron wood dust particle lodged in a small airway, and you get 1 micron water droplets down there, it might become more wet, but it won't be any nearer to getting out of the lung. Remember, in this part of the respiratory tract, there isn't any cilia to clear foreign matter out, so the only way to clear foreign substances is by destruction or absorption by inflammatory processes, which in the case of asbestos or wood dust is difficult because of the nature of the materials involved.

If this worked, asbestosis would be curable by steam baths. As far as I know, there isn't even a case report of this.

[John Stevens]

While the respirable particles you find in smog may affect lung function most of the dust generated in the shop is compriesed of larger size particles >10 µm in size. Most of these particles are inhalable but get trapped before they get to your lungs. They are also the ones that cause increased cancer rates amongst woodworkers.

Hi, Greg. Would you mind elaborating a little about what you know about this and how you learned it? If I understand your post correctly, this is why I asked earlier about respirable vs non-respirable particles: I've seen nasal cancer listed as a risk of exposure to wood dust, and I was wondering if non-respirable particles could contribute to this risk.

Regards,

John

[Bob Antoniewicz]

I haven't seen an 'accepted' conversion but it is possible to convert from particle density (which the meter reads) to a mass density by making some assumptions. For 2.5 µm particles made from wood with a density of 530kg/m^3 a particle count of 10,000 particles/cu-ft (meter reading of 100) would correspond to a mass density of 1.5 µg/m^3 or .015 mg/m^3.

Based on the above assumption, 1 particle would weigh:

530x10^3 x (2.5x10^-6)^3 = 8.3x10^-12 grams or 8.3x10^-6 micrograms

so a machine reading of 100 (= 10000 particles per cuft) translates to:

10000 x 36.8 x 8.3x10^-6 = 2.988 ug/m^3

And for anyone wanting a single conversion factor from machine reading to ug/m^3 :

36.8 x 8.3x10^-6 x 100 = .02988 ug/m^3 per machine count for the 2.5um particles.

For the 1 um particles the conversion is (1/2.5)^3 so:
(1/2.5)^3 x .02988 = .001912 ug/m^3 per particle per machine count

For the 5 um particles the conversion factor is (5/2.5)^3 so:
(5/2.5)^3 x 0.2988 = .239 ug/m^3 per particle per machine count

Bob A.

(YIKES!!! That means Greg's initial post reading of 6048/1941 (which as I understand it means the count of 4107 1um particles and 1941 5um particles) translates to 7.8 ug/m^3 of 1um particles and 464ug/m^3 of 5um particles!)

EDIT:

I was trying to remember what folks had said was allowable exposure. I searched and found the following page:
http://www.collinswood.com/M1_WoodPr..._Wood_Dust.pdf
which gives several numbers. The most conservative is 1 milligram/m^3 averaged over 8 hours for total dust from selected hardwood. There is also a 1mg/m^3 averaged over 8 hours for respirable dust (no particular wood mentioned).

So, maybe Greg isn't in real big trouble, but he only cut 23 14" strips of 1" fir.

[Greg Funk]

Based on the above assumption, 1 particle would weigh:

530x10^3 x (2.5x10^-6)^3 = 8.3x10^-12 grams or 8.3x10^-6 micrograms

so a machine reading of 100 (= 10000 particles per cuft) translates to:

10000 x 36.8 x 8.3x10^-6 = 2.988 ug/m^3

Bob,

My numbers were similar to yours but I assumed the particles were spherical rather than cubic.

Also, it is difficult to convert the larger particle counts to a mass density since the meter doesn't just count 5um particles but particles 5um and larger. So if the average diameter of particles was 20um that would give you a higher mass density than assuming the particles were 5um.

Greg

[Bob Antoniewicz]

Bob,

My numbers were similar to yours but I assumed the particles were spherical rather than cubic.

Also, it is difficult to convert the larger particle counts to a mass density since the meter doesn't just count 5um particles but particles 5um and larger. So if the average diameter of particles was 20um that would give you a higher mass density than assuming the particles were 5um.

Greg

You know, I thought that might be the case, but when I started typing and tapping the calculator, that totally left my mind. The other thing I was thinking is that the shape of the particle may not be solid, but curled shavings, etc. Or the machine might be measuring a splinter shaped particle by it's greatest dimension.

Also, I remember someone saying way back that below a certain size, any dust you inhale just blows back out again. But I don't know if that was vetted in any sense.

Bob A.

PS - I am really enjoying this thread - Thanks!

[John Stevens]

I was trying to remember what folks had said was allowable exposure.

Hi, Bob. You'll find some links in my first or second post on this thread, but keep in mind that just because a certain level of exposure is permitted doesn't necessarily mean it's harmless, as Wilbur has written from time to time. One of the problems we face, no matter what the OSHA levels are, is trying to make a good decision in deciding what our own exposure should be, assuming we can measure it accurately. For example, assuming this source is correct, even among white male smokers in the U.S., there's only an 8% chance of dying of lung cancer, if I understand this article:

http://www.journaloftheoretics.com/E...Vol-1/e1-4.htm

I'd like to find out if there's any way of making an apples-to-apples comparison between the lifetime risk of death from cancer of the respiratory tract for lifelong smokers versus career workers in, say, a sawmill or a cabinet shop. Another comparison that could put the "wood-dust-risk" in perspective might be the lifetime risk of death or disability from illness caused by exposure to airborne wood dust for U.S. sawmill workers or cabinet makers vs lifetime risk of death or disability in the total U.S. population due to being involved in a motor vehicle accident while driving or riding as a passenger. Perhaps any attempt at making such a comparison would be so loaded with assumptions that it might be useless, but maybe not.

I haven't been able to find any data comparing rates of diseases like lung cancer, nasal cancer and emphysema in the general population vs persons who have spent a career working in occupations that expose them to high levels of wood dust. Such a comparison would be interesting, although it might overstate the risk for woodworkers who are non-smokers. If I understand what I've read about asbestos and lung cancer, smoking has a synergistic effect, such that the rates of lung cancer among smokers exposed to asbestos is higher than if you were to simply add the rate of cancer for smokers in the general population to the rates of cancer for non-smokers who are exposed to similar levels of asbestos. If the same holds true for persons exposed to wood dust, then the risk of lung cancer from occupational exposure to wood dust for non smokers would be lower than the risk of lung cancer from all persons whose occupations exposed them to wood dust. I suspect that persons in occupations that expose them to wood dust are more likely than the general population to smoke. If correct, I think that that would further increase the difference in rates of cancer between all persons whose occupations exposed them to wood dust and non-smokers who are exposed to similar levels of wood dust wood dust.

Or perhaps I've just had too much coffee and not enough sleep. I'd appreciate feedback from anyone who's tried to understand my ramblings.

Regards,

John

[Will Blick]

John, I sure appreciate your desire to get a better grip on this wood dust problem...... more specifically, how it relates to the big picture, i.e. those who smoke, live in smog filled cities, etc. It would be a very interesting exercise.

My initial guess is.... it would be impossible to get the data required to do such a calc. For example, for ww's who have had extreme dust exposure for many years, which caused severe respiratory illness till the end of their life....but yet, the person died from a heart attack, which could have been the result of complications from the respiratory illness.... well, this person would defy the statistic.

My suspicion is, these respiratory illnesses can destroy the quality of life for many years, and yet a persons cause of death will often be listed as something else. Probably because our lungs are so over-designed, they rarely become the final weak link in the chain of death. (just speculating here)

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan. Of course, this is just theoretical equations trying to pull together all the factors.... I question if they got it right.


Another interesting factor regarding this is.......those who live with constant exposure to radiation. For example, japan has kept meticulous records of the nuclear exposure from the two bombings. Interestingly enough, the people who survived the blast might have had on going health problems, but in the end, they lived several years longer than Japanese people of the same class, gender, social class, etc. A very startling statistic. 1945 was 60+ years ago....those who were 30 then, are 90 now.

In the high elevation of the rockies here in the USA, people are exposed to every high levels of radiation vs. people living near sea level. Most of the radiation from the Rockies comes from the radioactive rock itself.....in addition, at such altitude the suns radiation is much higher... I can't recall the exact numbers, but the difference is quite staggering. Lifelong exposure to such radiation would suggest shorter lifespans, but yet again, the opposite is true.

Also, with smoking, many of the carcinogens are in a gaseous state, which will enter into the blood, unlike wood dust. So smoking IMO is not a good apples to apples comparison, as it relates to particle levels.

Using my Dylos, I am really starting to see where the dust hazards lie. IMO, carpeting might be a bigger dust hazard than ww, at least for the hobbiest who don't spend 50 hours a week in the shop. From my initial experiments, the rooms I have plush carpeting has very high particle counts vs. those rooms with wooden floors. The areas are isolated, so I can get a good read.... I would suggest a 8x increase in particle count on average. Vaccuum cleaners seem to be the culprit.... a beater brush on a vacuum will continually produce micron and sub micron particles.... very similar to sanding wood.... in addition, the suction is pulling all the settled micron particles out of the carpeting.... then, with a very poor vacuum filtration filters, these small micron particles are dispersed back in the air. Combine this with the interesting fact stated earlier in this thread is.... these small micron particles take a long time to settle, from days to weeks. So by vacuuming once a week or every two weeks, we assure a continuous supply of small micron particles will remain airborne in our living environments - sort of, a perfect storm. Many of us breathe our house air more than any other air in our lives. I was shocked to see my house values 5x higher than my shop (at rest), which is not ultra clean to begin with.

I have been investigating true HEPA vacuum cleaners, but this entire field of vacuum cleaners is so scammed based, it's hard to get reliable information. One unit in particular seems to have addressed the problem with a large HEPA filter on the exhaust. But, can't find any independent non biased test results. AS with most new areas of research, we generate more questions than answers :-( Ok, now I am the one rambling on....

[John Stevens]

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan.

Will, with that in mind, here are a few selected paragraphs from something I read recently:

Healthy Aging Health Center

It’s Never Too Late to Live Healthily
Even After Age 70, Healthy Habits Pay Off by Helping
You Live Longer

By Jennifer Warner
WebMD Medical News
Reviewed by Louise Chang, MD

In the first study, published in the Archives of
Internal Medicine, researchers followed 2,357 men who
were part of the Physicians' Health Study. The men
were evaluated when they started the study at about
age 72 and were surveyed at least once a year for the
next two decades.

Overall, 970 men survived to age 90 or beyond.
Researcher Laurel B. Yates, MD, MPH, of Brigham and
Women's Hospital, and colleagues estimated that a
70-year-old man who did not smoke, had normal blood
pressure and weight, no diabetes, and exercised two to
four times a week had a 54% chance of living to age
90.

But for each of these common health risk factors, the
chances of living to age 90 were reduced as follows:
• Sedentary lifestyle, 44%
• High blood pressure, 36%
• Obesity, 26%
• Smoking, 22%
Having three of these risk factors drastically reduced
the odds of surviving to age 90 to 14%, and having
five risk factors dropped the chance to just 4%.

Interestingly, it seems as if a smoker reaches age 70 but exercises and avoids obesity and medicates for high blood pressure, his chance of living to 90 is only 22% less than a non-smoker with otherwise-equivalent risk factors.

As for quality of life, the article continued:

In the second study, Dellara F. Terry, MD, MPH, of the
Boston University School of Medicine and Boston
Medical Center, and colleagues studied 523 women and
216 men aged 97 or older.
Researchers split the participants into two groups
based on gender and the age they developed diseases,
such as heart disease, diabetes, high blood pressure,
dementia, stroke, chronic obstructive pulmonary
disease (COPD), osteoporosis, and Parkinson's disease.

If they developed disease at age 85 or older, they
were considered "delayers," and those who developed
disease at a younger age were called "survivors."

The results showed that 32% were survivors and 68%
were delayers. But researchers found that those who
developed heart disease or high blood pressure before
age 85 and still survived to 100 had similar levels of
function as those who developed disease later.

Food for thought?

Regards,

John

[John Newell]

I don't think that anyone knows why one type of dust is worse than others, except that things that are made of tough stuff that your body can't easily break down, such as silica, asbestos, or cellulose, or are of a shape that doesn't lend itself to being consumed, such as asbestos again because it's long and pointy, seem to be worse.

Thanks - do we know what makes tropical hardwoods (or some of them) toxic? Presumably something wholly apart from the size of the sawdust particles?

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan. Of course, this is just theoretical equations trying to pull together all the factors.... I question if they got it right.

Using my Dylos, I am really starting to see where the dust hazards lie. IMO, carpeting might be a bigger dust hazard than ww, at least for the hobbiest who don't spend 50 hours a week in the shop.

Jogging in NYC or LA always puzzled me... ...I hear you on the vacs, but I wonder if the stuff that lurks and recirculates is as bad as wood dust?

Then again, look at the nationwide epidemic (I use the term loosely in the presence of MDs) of asthma. When I was in school in the 60s and 70s I never knew anyone with the disease. The number of kids in my boys' classes with the disease is truly shocking.

[John Stevens]

My initial guess is.... it would be impossible to get the data required to do such a calc.

Will, I have no expertise in the areas of industrial hygiene, medicine, public health, actuarial science or statistics. But I'm sure that data exists regarding the rates of various cancers in the general population and in various occupational groups that are exposed to airborne wood dust. After all, the "permissible exposure levels" established by OSHA and recommended by NIOSH and ACGIH are based upon models that attempt to reach certain projected rates of such illnesses in these occupational groups. I'm not sure how those projected rates compare with the rates for the general population--I assume the projected rates are higher, but I don't know this for sure. I do know that they're modeled on assumptions like no more than 10 hours' exposure per day and 40 hours exposure per week, and, IIRC, a 40 year career. I know there was some debate on how the model should handle the additional risk caused by smoking, but I don't know what decisions were made by OSHA, NIOSH and ACGIH, respectively, in reaching their final sets of assumptions.

A comparison of these rates of illnesses (actual and projected) could be interesting, although I'm not sure how you'd look at factors such as particle levels, particle sizes, hours per day, hours per week, and lifetime hours exposure of, say, a career sawmill employee, and then try to compare that to a hypothetical hobbyist who is exposed to different levels of all of those factors.

Regards,

John

[Will Blick]

JohnS.... interesting article indeed.... From what I gather, it all comes down to the critical risk factors, i.e., the ones that are most closely related to being fatal. I often thought, many who smoke, don't over-eat due to the appetite suppression the nicotine causes. Its possible the smoking is less fatal than the potential obesity brought on by ceasing to smoke. I am not suggesting smoking is a health tonic.... but I think obesity could possibly be more lethal over many years. Of course, some common sense must come into play...if you need to smoke 4 packs a day to cut appetite, its probably counter productive....but if you smoke 10 cigs a day, maybe then, the obesity avoidance becomes more beneficial.

Of course the article you posted discusses people who have already made it to a certain age (70).... lots of men never make it to this age. It stands to reason if you made it this far, there is a good chance the deck is stacked in your favor.


John N, there does seem to be a lot of mystery about why some woods produce more toxic dust than others.... i.e., its not just particle size here.... I too wish there was more data available....but from the data we do have, there seems to be some woods that have proven to be more toxic than others through experience. then factor in how different we all react to allergens, and it can be a bit of a crap shoot. IMO, I will wear a respiratory, and continue to move air, while watching my Dylos.... if I can eliminate 95% of the problem, I will be better off.... and at this level of reduction, if I react to a given wood noticeably, its time to stop using that wood. However, the wild card here is those woods that are sesnitizers, which make you sensitive to woods you previously were not sensitive too. Jims story about his locksmith in a previous thread sure drove this point home. So being cautious is prudent IMO. But then again, I am one of those people who already have a lot of sensitivities. I see others who seem to be immune to whatever to thrown at them.


> Jogging in NYC or LA always puzzled me

yeah.... when living in LA, I really began to notice the effects of smog, while jogging on smoggy days, I really noticed severe asthma type reactions, which I NEVER had in my life, and was always very physically fit.... of course, I monitored air quality before exercising after these experiences. But, I wonder how much better the air quality is inside health clubs, which ultimately get their air from the outside...then often the added dust from people, carpets, etc. And I agree with the asthma epidemic of kids today.... obviously, we are passing thresholds of what the body can handle vs. when we were younger.


> But I'm sure that data exists regarding the rates of various cancers in the general population and in various occupational groups that are exposed to airborne wood dust.

this is very possible.... but my point was.... if cancer was predominate outcome of wood dust exposure, then I would agree.... this certainly was the case with asbestos....but not so sure its true with wood dust, specially for the hobbiest vs. the lifelong mill worker.


All in all.... this topic has really introduced a health variable I have completely overlooked in my life.... as mentioned previously, because we don't see it, its easy to dismiss it as a health risk. If micron particle wood dust casted a fluorescent glow at all times, many of us would have been suspicious long ago of its potential risks. The Dylos makes these particles visible, so once again Kudos to Phil for bringing this to light, and working the deal that got many members to buy the meter. I think we will all learn a lot in the months ahead with this tool....