UKC

I was listening to the radio the other day and was surprised to hear that inhalation of air pollutants has been linked to dementia. Apparently, when you breathe in certain particles, they can travel via your nose directly onto the brain, and this has been linked to degradation of the brain.

This got me thinking, as I was brushing chalk off holds in a stuffy bouldering wall yesterday...

We all know that chalk inhalation is bad for asthma sufferers, but what other effects can occur from breathing in so much chalk - mixed with sweat, dirt and bacteria?

It also really does make me want climbing wall owners and staff to think more about air quality. I visited my local bouldering wall twice over the last week due to rain, and despite intense humidity, on both occasions I had to ask for doors to be opened to increase the airflow. Over the winter, I remember looking around and seeing a mist of chalk hanging in the air; it was making me cough, and I don't have asthma.

Are we going to see all these young, bouncy people suffering dementia in 30 years?

Just food for thought.

In reply to C Witter:

When I was 17 I spent a week at Nottingham Uni on a course which was designed for those considering mining engineering. As a result I got to go down an active coal mine and crawl around behind the working face. The air was thick with coal dust. None of the miners wore masks and I asked about this. I was told that the dust you could see wasn't an issue, it was the stuff that was invisible that had wreaked havoc with the lungs of miners in the past. Machinery and procedures had evolved to drastically reduce the extremely small particles that caused pneumoconiosis. I think particulates have to be of molecular size to cross through from lungs into blood stream and then brain but I am, of course, no expert.

In reply to Lankyman:

Yes, I think they do have to be very small. I've no idea of the actual effects of chalk dust... but, feel it would be good to err on the side of caution! Above all, the radio story just made me realise that whatever effects can be longer term and delayed, as well as the short term annoyance. It's probably best not to be too alarmist, but when simple measures such as keeping windows and doors open could help so much, I really don't understand why practices are so often poor. It really doesn't feel like we learnt even basic lessons from covid...

In reply to C Witter:

If it's going to happen it will be happening already to those who worked in climbing walls 30-50 years ago, gymnastics or weight lifting coaches from before that and those exposed in employment (various industrial uses, previous generations of school teachers?).

A quick Google for "is chalk dust hazardous to health" suggests you are right about the risk but it is for lung disease rather than dementia.

In reply to C Witter:

https://www.alzheimers.org.uk/about-dementia/risk-factors-and-prevention/ai...

"Air pollution has been a focus of several studies on cognitive impairment and dementia risk. There is evidence that tiny air pollution particles can enter the brain, but at this time we can’t say if they play a role in the development of dementia. There is a strong case for further research into the effect of air pollution on brain health."

For a workplace, magnesium carbonate dust should currently be controlled by the following HSE EHO workplace exposure limit (WEL):

10 mg/m3 of 'inhalable' dust or 4 mg/m3 of 'respirable' dust

As a time-weighted average over an 8-hour period using this general sampling/testing method: https://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs14-4.pdf

The particle sizes of most concern for inhalation into lung would normally be considered to be PM-10 and the even smaller PM-2.5 (sum of <10 micrometre and sum <2.5 micrometre in size).  A human hair diameter is about 70 micrometres

In reply to C Witter:

I think pure chalk is generally considered safe as its water soluble however,  modern chalks might contain other drying agents in the mix which might be a different case.

In reply to C Witter:

This is a tricky kind of sentiment. On the surface it seems very reasonable and logical, but if you dig a little deeper, you realise that it can be an argument used as a substitute for evidence. To take a pre-emptive stance against something because one "feels" like something is a risk based on the "better safe than sorry" moniker and/or a dubious interpretation of a complex scientific study is not, in my opinion, a useful for helpful way to make progress.

Agreed. Just a shame it came before the word "but"

It is wrong to lump this into the argument. It is unrelated and is rather like having a debate about the health effects of olive oil consumption and someone bringing the harms caused by crude oil consumption into the argument.

In reply to C Witter:

Sounds like you have been sniffing that special Colombian Chalk to me youth, stop thinking and go climbing.

In reply to Lankyman:

The rule of thumb is if you can see suspended dust particles, they are way big to penetrate to the deep lung.  They will lodge in your nose.  To get to the deep lung, ie, alveoli they need to be around 5 microns, and too small to see with the naked eye.  I think nano particles can track up the olfactory nerve directly into the brain.  Manganese also has a reputation of tracking via the olfactory nerve too.  
 

In reply to henwardian:

I take your point. But, interestingly, the US Climbing Wall Association states:

"The EPA is concerned about particles 10 micron or smaller because these particles are inhalable. These particles once inhaled can affect the heart and lungs and cause serious health effects."

"90% of chalk dust is estimated to be 5 microns or less, it’s very very small."

https://www.cwapro.org/blog/chalk-dust-mitigation-and-source-control

It recommends user reduction of chalk, because other methods of chalk reduction can be expensive.

An academic study on classroom use of chalk notes: "Aryal (2007) suggested that inhalation of a small amount of chalk dust does not cause acute illness, but breathing in it for a number of years can trigger respiratory diseases. Zhang et al. (2015) suggested that the chalk PM2.5 can also stimulate alveolar macrophages to produce reactive oxygen species and cause oxidative stress and cytotoxicity." It goes on to look at PM2.5 pollution from chalk in the classroom and recommends phasing chalk out of classrooms (https://asianjae.org/xml/22236/22236.pdf).

Think about how much less chalk there is in a typical classroom compared to a climbing gym!

Meanwhile, a 2021 critical review of the relationship between particulate matter pollution and cognitive decline notes: "Strong conclusions remain elusive, although the weight of the evidence suggests an adverse association between PM2.5 and cognitive decline." (https://pubmed.ncbi.nlm.nih.gov/34558969/).

See also this older (2020, https://pubmed.ncbi.nlm.nih.gov/33340865/) review: "The reported associations between a range of air pollutants and effects on cognitive function in older people, including the acceleration of cognitive decline and the induction of dementia, are likely to be causal in nature."

I'm not an epidemiologist and it's possible I'm missing certain factors, but it seems like:

a) there is evidence that fine (2.5.PM or smaller) particulate matter from chalk is a concern;

b) evidence is accumulating of a causal relation between fine particulate matter (2.5PM or smaller) and cognitive decline illnesses.

So, anyway, all those recommending a quick Google will set me straight: actually, it makes me feel that my wild speculation might have more basis in existing science than expected.

In reply to kipper12:

Manganese is a different element to magnesium

Magnesium carbonate is used in climbers chalk.

In reply to C Witter:

The risk is all about about the exposure time COMBINED with the concentration in the air being breathed.  People under 16 are also usually considered to be at more risk from compared with adults.

Students in the past when chalk was actually used, could well be in a classroom for 30 hours a week for 40 weeks a year from ages 5 to 18 = 13 years x 40 weeks x 30 hours =  15,600 hours.

The climbing wall staff are the ones to be concerned about, not casual wall users (225 days/year x 8 hours/day = 1,800 hours/year).

In reply to ChrisJD:

Indeed! Like bar workers before the smoking ban.

Although, a significant number are visiting the wall 3 or 4 days per week.... so, maybe 300 to 600hrs/year in an environment with... what? Triple the amount of chalk in the air?

Better ventilation + a move to liquid only chalk, and we could massively improve air quality.

In reply to C Witter:

Only with massively less evidence of harm.

In reply to C Witter:

During your googling did you pick up on the fact that climbing gym chalk and classroom chalk are two different substances?

Climbing chalk is mostly magnesium carbonate.  Blackboard chalk is probably gypsum, but might be calcium carbonate.  I have no idea what bearing that might have on dust particle sizes.

In reply to C Witter:

Challenge accepted!

What I draw from the studies/reviews you linked is the following:

a) Particulate pollution can have adverse health effects.

b) Use of chalk can cause a high level of particulates.

The critical part that I think is missing is consideration of what the chemical nature of the particulates is. The studies that support a) above are referencing gases such as O3 and NOx, so it seems extremely likely that the particulates they are talking about are partially combusted hydrocarbons (i.e. all this stuff is coming from burning fuel in cars). Hydrocarbons are chemically completely different from chalk (like, really completely different), so I'm very dubious about the idea that chalk particles might cause the same effects as hydrocarbon particles (or plain carbon soot particles for that matter).

honestly sodium chloride particles would be a much closer chemical fit to chalk and we don't worry about breathing too many of them in when we go to the beach.

In reply to henwardian:

You're wrong.  Dust particles are inherently a hazard in their own right.

All dusts are regulated in the workplace by the HSE using WELs.  See my post near the start of this thread.

Many dust types also have their own specific WELs, e.g. Calcium carbonate dust

In reply to henwardian:

Don't get me wrong: I hope you're right and that the hazard is of low risk. And there is definitely more research to do. But, I think you're ignoring that some of the studies are specifically on the fact that excessive exposure to chalk is hazardous - even if the dementia angle is still very speculative.

Given what we already know about the risk of chalk to our lungs and the potentially negative effects of fine pm to our bodies, I think we should, as I said above, start taking the risk a little more seriously by doing what we can to improve air quality - esp the low hanging fruit: better ventilation and reduction  of chalk use. Especially as better ventilation would also be good for reducing airbourne virus transmission.

In reply to C Witter:

Here's an MSDS for magnesium carbonate 

Note how the dust control levels match the HSE WEL.

https://www.sigmaaldrich.com/US/en/sds/SIAL/M7179

In reply to C Witter:

I work in the field of Occupational Hygiene, if you can see the dust you are likely over the 10mg limit. Someone previously commented on visible dust being OK as it may only contain large particles, this is wrong, there will be small particles in the same air as the large particles.  I'd have to have a look through the research to confirm biosolubility of magnesium carbonate before commenting further.  Breathing dusts is never a good idea.  Fortunately we aren't using talc for climbing, as this is potentially contaminated with asbestos. 

In reply to C Witter:having lost a parent to dementia (all be it over a lengthy period) this is one of those things where the there are so many possible contributing factors that it’s impossible to say if climbing chalk is/could be impactful. It’s a bit like bacon and Diet Coke, in a large enough quantity, anything is possible.

what I will say however, having worked in enviro-tech for a while, is think of the opposite environment, one where chalk dust isn’t present. How much better might you climb without the pollutant in the air? There’s a study from the US where major league umpires were tested for their decision making reaction speeds under pressure.  Where the stadium was in the sticks their false calls/mistakes/ability to call the play was something like 11 times better than when the stadium was in a highly polluted city environment. Admittedly vehicle annd manufacturing emissions are far more complex and harmful than plain old chalk, you have additional VOC’s for a start. But if you think about it, clean air, it’s good for you whatever.

In reply to C Witter:

Found and had a quick look at the source 2008/2012 papers mentioned here https://www.cwapro.org/blog/chalk-dust-mitigation-and-source-control

The key takeaways from the papers (which you could have got to with common sense!) if you are concerned about dust levels:

- Climbing wall can be dusty and might well reach PM-10/PM-2.5 levels of (current) concern during peak wall use

- Use a wall with a good ventilation system

- Make sure it is on (the wall may not use the ventilation system during colder months)

- Go to the wall at quieter times

- If chalk type is unrestricted, use chalk balls and/or liquid chalk to do your part to reduce dust levels

(Pick and choose which intervention(s) to adopt based on your own level of risk tolerance, from none to all)

In reply to ChrisJD:

Reminds me when I got hold of some manganese metal and thought it would be a novelty to stick in to some electrochemistry practicals.  So I set up some cells and found it was very similar to magnesium.  Run away, run away! 

There is enough confusion between the two as it is so it did not come out.

I would want to limit my exposure to manganese dust to something resembling zero. Magnesium ions however are your best friend if you have cramp.  

In reply to ChrisJD:

Yes I know, I was just making a point that some substances can track directly along the olfactory nerve.

In reply to C Witter:

Further to previously linked research...

A 2012 study (https://pubmed.ncbi.nlm.nih.gov/22767051/) found "users of indoor climbing gyms are exposed to high concentrations (PM(10) up to 4000 μg m(-3); PM(2.5) up to 500 μg m(-3)) of hydrated magnesium carbonate hydroxide (magnesia alba)". Use of chalk balls has little effect on reducing these concentrations. Meanwhile, use of liquid chalk has a similar reduction effect as banning chalk.

A 2008 study (https://pubmed.ncbi.nlm.nih.gov/18449402/) found:
"it is concluded that solid particles of magnesia alba are airborne and have the potential to deposit in the human respiratory tract. The particle mass concentrations in indoor climbing halls are much higher than those reported for schools and reach, in many cases, levels which are observed for industrial occupations. [...S]ubstantial reduction of the dust concentration is required."

This 2015 study (https://pubmed.ncbi.nlm.nih.gov/25903174/) explores the mechanisms by which chalk causes negative effects on alveolar macrophages.

This 2016 paper (https://pubmed.ncbi.nlm.nih.gov/27837598/) explains two studies of the effects of chalk in gyms on climber's lungs. They both found a decline in lung function.

In reply to C Witter:

This is fascinating - chalk has always worried me, seems there are legitimate concerns. 

In reply to Eduardo2010:

I think it has to put in the context of general urban air pollution, smoking, life style, etc. Perhaps it's not the most acute danger... But, on the other hand, it does seem something we could do more to mitigate and manage.... I wonder if a move to liquid only chalk and more ventilation would be noticeably beneficial. Particularly for staff and for anyone with existing respiratory conditions...

In reply to C Witter:

Isn't it better just to get people to use less chalk? It's treated a bit like flour for rolling out bread dough, so all over hands, holds, everywhere. The newbies when a local bouldering wall opened were all wandering round with huge bags of loose chalk to climb V0.

The issue with liquid chalk is a lot of it contains colophony/rosin - "pof" - which a lot of people are allergic to (it's the same thing that causes allergy to plasters) and accumulates as a residue on holds that's difficult to remove. You'd have to mandate brands without colophony which would be very difficult to ensure. 

In reply to mik82:

I don't know how you'd practically do that though. A rule on 'liquid chalk only' is much clearer and easier to enforce.

I've always wondered if there is a technical alternative? If I had the time and energy I'd love to experiment with taking a microfibre towel and turning it into the shape of one of those plastic net shower sponge things, the thing with lots of folds. Wonder if the resulting product might be a good way of drying clammy hands as the folds would create a massive surface area and you could hang it from the back of your harness where the chalk bag sits? Not the same as chalk but perhaps might be helpful?

I have dry glassy hands so the opposite problem, no idea if this would work. 

In reply to Eduardo2010:

https://shop.thebmc.co.uk/product/metolius-eco-ball/

Not exactly what you were talking about but a similar idea. I tried it years ago and didn't much like it but it's better than nothing.

In reply to ChrisJD:

Are chalk balls better than lose chalk? To get though the mesh the dust is sieved fiinto a fine dust (especially with old saggy balls), I hate the things, find I have to use two hands and tap the chalk out (creating lots of airborne chalk dust), rather than with block chalk where I can just dip into the bag.

Main thing that creates huge clouds of dust is bouldering. Another argument for chalk bags to be kept off the mats, as huge plumes of dust can be released after a heavy landing.

In reply to Jenny C:

The papers I referenced seemed to think so.