Now here's a question for any medical experts out there. From the early 20th century until about the 1990s, almost all brake shoes and brake pads on all vehicles on the road were made using asbestos. Inevitably, as the brake pad or shoe wears, whatever it is made from is released into the atmosphere as dust.
People living in large urban conurbations like say, for example, London, will have been exposed to truly vast quantities of this dust as each time a large vehicle like a London bus moved along the road on a dry day a cloud of invisible dust will have been stirred up into the atmosphere.
So, my question is this:
as asbestos is now considered to be deadly dangerous, how come the healthcare systems throughout the world are not seeing hundreds or even thousands of patients suffering from asbestosis and/or mesothelioma, given the vast amount of asbestos dust that all of us who lived in large towns and cities in that era will have inhaled?
@Paulos_the_fog I'm not a doctor but have an interest in vehicles (both modern and older) - other pollutants (especially lead in petrol) posed far more of a risk to town/city dwellers near busy traffic, whereas there was more asbestos exposure to those who worked on vehicles repairing brakes and other components containing asbestos, and more so in factories making the components (such as Ferodo, there is even a trust for the employees affected by asbestos exposure)
Asbestos is not 'toxic' in the same way as for example: lead, arsenic or cyanides. The silcate family that make up the overwhelming bulk of natural deposits of asbestos are chemically inert and generally completely insoluble in water or other solvents. However, so far as I can establish, it is the physical characteristics of asbestos that make it dangeous; notably the size and shape of the crystals which make it impossible for the human lungs to remove it using the same methods they use to remove the huge quantities of dust that all human beings inhale most days.
The thrust of my questioning is therefore given that asbestos causes its effect on the lungs through its crystalline structure, did the fact that brake dust was invariably ground to a very fine power render it harmless?
@Paulos_the_fog to an extent the harm might be masked by other factors such as cigarette smoking, higher alcohol and recreational drugs use which was common in my generation (X) and those Boomers who were part of the 1960s/70s counterculture (as these finished off people before asbestos got to them), so it took a while for the harms to be recognised (as well as corporates actively supressing warnings, as it was a useful material for many purposes)
You'd need to be a really shit doctor to conflate lung damage due to smoking with asbestosis or mesothelioma. In any case the "boomers" were far from being the 1st generation to be exposed to high asbestos content brake dust! Asbestos was the dominant materiel for friction linings/pads from the early 20th century. One would thus anticipate a high level of asbestosis and/or mesothelioma in workers on the deeper lines of the 'tube' in London and other enclosed underground railways as the dust released would be not only stirred up by the movements of the trains but would be contained within the underground tunnels thus concentrating the dust and trapping most of it within the tunnel system.
So far as I am aware there has been no such increase in those illnesses observed amongst such workers.
I would suggest that the answer is that asbestos is not toxic in the chemical sense (like arsenic, lead or cyanide) but does it's damage dues to its physical characteristics (size and shape of particles). I would therefore suggest that it is no more dangerous than any other inert powder if ground finely enough!
@Paulos_the_fog I expect brake dust would indeed be no more harmful than other particulates emitted by motor traffic - the major risk is for those who have to make the brake components - and also other workers exposed to asbestos in the course of their jobs, its also a risk to electrical engineers (including myself, as I have had to put various telecom and data cables in roofspaces, plant rooms and and risers of old buildings where there is almost certain to be asbestos around) >>