[Stoves] report with dissapointing results from cleaner cookstoves

Wed Dec 7 11:53:01 CST 2016

Dear Andrew

The message from the large scale investigation supports other observations:

The health impact of stove smoke has always been based on estimations that only apply to populations.

The health impact of stove smoke is over-estimated by those estimations.

The health impact estimates are based on several quirky things, one of which is that all particles of PM2.5 are equally toxic (the concept of equitoxicity). There is no factual foundation for such an assumption.

The health impacts are probably not concentrated on particular diseases.

You will often see quoted the idea that "The PM2.5 particles are the smallest and they get deeper into the lung..." with the idea that the smaller the particle, the more easily the cause 'disease' and the more easily they get into the lung, and the more easily and the deeper they go, the more effect they will have. Right? Is this a misrepresentation of the claims? I don't think so.

At the NESCAUM/NYSERDA meeting in Albany last week there was again a presentation on the 'ability' (or chance) that a particle of size x will get into the lung and cause a problem. It happens that the current thinking is focused on the head passages, not the deep lung. The coincident claims for the deep lung are COPD and pneumonia and particles. But small particles do not get into the deep lung so easily - the head passages are very efficient at getting small particles humidified, enlarged, and trapped by the mucous membranes.

This is the same idea they emphasized at the Brookhaven National Lab presentation by NYSERDA. It is not the deep lung that is the problem, they are worried about the smallest particles being trapped in the upper body and conducted via the opening in the skull, through the flesh, to the brain. They worried much more about trapping in the nose and communicating cell by cell to the brain where such particles have been found. That has little to do with getting them into the deep lung, into cells there, and thence to the red blood cells, which is also a current meme.

The efficiency with which small (10-20 nm) particles get trapped in the deep lung is quite low. The smaller the particle, the less the chance of being absorbed. One guy gave me a spirited defence of the potential for danger to the lung saying that diffusion of particles into the cells was a greater danger than 'being trapped'. Well, I will have to think about that mechanism. The main point, supported by charts of efficiency of trapping things, is that the upper head is the worry point, not the lungs.

So, it is not such a big surprise that the effects on disease occurrence was not detectable. Reducing PM to zero in the kitchen is not anything close to removing PM2.5 from people's lives. Witness the burning garbage, outdoor large scale cooking, grass fires, fugitive dust, smoky bus engines. There is a lot in the environment other than cooking fire smoke.

Nikhil has been at pains to try to communicate the change in the relative risk from a reduction or complete elimination of cooking smoke does not have a predictable effect on any individual because we don't know what their other risks are. The information simply doesn't exist to make such a calculation. Models of models of models have results in health impact estimates that have "false concreteness". The error is to treat an idea as if it is a real thing. The Global Burden of Disease is not a real thing, it is a way of discussing risks within a national cohort. One person in a population of 1 million does not have a fixed 'millionth' of the GBD.

The study proceeded on the basis that they do, and that changing one of the contributing factors would produce a particular, detectable outcome. If it had, such a correlation would have been spurious because it is based on a conceptual flaw at the root.

This definition of Fallacy of Misplaced Concreteness is sourced from here<https://web.cn.edu/kwheeler/fallacies_list.html>. Stove smoke impacts individuals. Reducing exposure impacts them individually. The impact of that change is also individual, even on average, is not susceptible to a calculation based on a GBD number. The GBD is an abstraction negotiated by a committee.

Regards

Crispin

Fallacy of Reification (Also called "Fallacy of Misplaced Concreteness" by Alfred North Whitehead): The fallacy of treating a word or an idea as equivalent to the actual thing represented by that word or idea, or the fallacy of treating an abstraction or process as equivalent to a concrete object or thing.  In the first case, we might imagine a reformer trying to eliminate illicit lust by banning all mention of extra-marital affairs or certain sexual acts in publications. The problem is that eliminating the words for these deeds is not the same as eliminating the deeds themselves. In the second case, we might imagine a person or declaring "a war on poverty." In this case, the fallacy comes from the fact that "war" implies a concrete struggle with another concrete entity which can surrender or be exterminated. "Poverty," however is an abstraction that cannot surrender or sign peace treaties, cannot be shot or bombed, etc. Reification of the concept merely muddles the issue of what policies to follow and leads to sloppy thinking about the best way to handle a problem. It is closely related to and overlaps with faulty analogy<https://web.cn.edu/kwheeler/fallacies_list.html#faulty_analogy_anchor> and equivocation<https://web.cn.edu/kwheeler/fallacies_list.html#equivocation_anchor>.

http://www.bbc.co.uk/news/magazine-38160671

It's a surprising result and I would like to know why the cleaner stoves used did not return a lower incidence of respiratory infections.

Is is because there are other vectors of the  illnesses linked to poverty?

The two  good results were that the cleaner stoves appear to be safer and more economical to use.

AJH

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