[Stoves] Air pollution kills

Tue May 8 17:19:40 CDT 2018

Dear Xavier

Thank you for being skeptical. Science works on challenges, nullis in verba.

On the IAP matter in UB, there are generalisations one can make and specific circumstances worth noting. There is a study of the effect on indoor air pollution from the improved stoves (Korean study, available in English). The concluded that the improved stoves which reduce PM2.5 output by 90-98% increased indoor air pollution, which was so unbelievable that I bothered to investigate the study quite carefully.

What I found was that they did indeed measure an increase, on average, in IAP but: the difference was well inside their margin of error (a small fraction of the variations measured, rendering the conclusion meaningless.  Further, on those days when they were measuring, the ambient (outdoor) air pollution closely matched the claimed indoor air quality, save that in every case the IAP was lower than the OAP.  In short, all the Koreans measured was the effect on IAP from outside air.

The worst aspect of the paper was that they claimed a statistically significant difference: the new stoves provided worse IAP than the old stoves - which the numbers did not support at all. There was a difference in the averages, and the new stove measurements were higher, but the difference was a small fraction of the Sigma 1 of their numbers, which is to say, the difference was not statistically significant.

Decent chimney stoves with a correctly fitted chimney have very little effect on IAP. We have ample recent evidence of this in Kyrgyzstan if there was any doubt. Improper operation can lead to fugitive emissions from the stove - for example leaving the ash drawer open a bit 'to give more power' breaks the draft from the chimney and the top surfaces can leak smoke into the room as they are no longer under negative pressure.

There is correlation between OAP and IAP and infections, but they are associations, not causal relationships. We can ask Nikhil about which words to use exactly. The claim that 4.3m people 'die from air pollution' per annum is clearly false and a misrepresentation of the published evidence used to support the claims that air pollution shortens lives - by attribution (not medical evidence).

« Children in Ulaanbaatar, are taken bronchitis in 1.4-2.7 times and bronchitis asthma in 5.5-7.9 times more than children who are living in rural areas of less air pollution. » says Social Health institute. http://www.unoosa.org/documents/pdf/psa/activities/2006/graz/presentations/0102.pdf p 12.

Who simple is this statement? Did anyone measure IAP in the rural areas where they burn dung for heating and cooking? Many people in the rural areas are reasonably well fed and clothed. A lot of people in Ulaanbaatar were driven there by absolute poverty and live in desperate conditions, some depending on coal vouchers to obtain fuel. How did the temperature of the home affect the incidence, and what is the socioeconomic conditions of the families with high occurrence? Are there bronchitis epidemics in town that do not occur in rural areas because the possibility of transmission is so much lower? Yes the OAP is much lower in rural areas, but is their exposure to smoke, for example, lower or higher?

When the Kyrgyz villagers were keeping their homes free of IAP (with chimneys and non-leaking stoves) and 5 degrees warmer the incidence of bronchitis dropped to zero (51 homes, 2016-17 season). I interviewed parents in February in the Naryn region and they all said before they got the new stove the children were "sick all winter" before and "much sicker than this winter" and so on. Chronic cold spreads disease among children. Bronchitis is a bacterial infection. PM2.5 is sterilized. So you are looking for pre-dispositions caused by PM2.5, not 'causes'.

It is dusty pretty much everywhere. The city is definitely smokier, and it can be quite bad if the wind drops, because below -30 the city is colder than the mountains around, or communities at higher elevation such as nearby Nalaikh where the coal comes from.  Prof Lodoysamba confirmed the 'colder' hypothesis this winter using a pretty sophisticated monitoring station at his home in Nalaikh with thermometers at different heights above the ground. The city, below -30, is colder, smokier, has a poorer diet and more fugitive dust than rural areas. But a traditional stove burning dung can be pretty smoky, and we have zero measurement of IAP in rural homes.

«So we concluded that the level of urban air pollution in the capital city is clearly having an adverse impact on the pulmonary health of urban Mongolian children.»

They can conclude that but that is no proof. That is an association. It is why Nikhil keeps pointing out that you cannot make claims for causes and avoidances without knowing a heck of a lot about the sub-population you are examining.  Attributing something as a cause does not mean that removing the attributed cause avoids the problem. Suppose the attribution was in error by 80%?

Regarding proximity to highways: who lives next to noisy and polluted highways in California: the well fed and exercised with good medical treatment? Or poor people with poor health coverage, bad diets and no access to recreational facilities?  Correlation is not  causation.

"UNICEF says: « Outdoor air pollution is the most significant environmental risk faced by children in Ulaanbaatar."

Hmm...  Is alcohol an environmental risk? What about smoking?  The air pollution is awful on some days, and visible, and variable from place to place. There must be children for whom it is the worst environmental risk, and others for whom it is now. The point is that we can remove virtually all of it with improved combustion of the very same fuels they now use. The major impediment to achieving this is the parade of baseless claims that coal cannot be burned cleanly, and therefore they must ban it - the only fuel available at a price they can afford. The sheer stupidity of blaming the fuel for the performance of the stove cannot have a greater effect on the people. Those advocates of fuel bans based on the misbelief that the fuel is the problem, are partnering with the advocates of 'alternatives' costing multiple times as much and which provide no additional benefit save in some cases, convenience. Free electricity is lovely - if the nation can afford it. No nation I know of can, so how can Mongolia?  Other countries are now depending on the great progress made in coal stove designs from Mongolia. How is it possible that the Mongolians are deprived of the benefits of this work? Advocates, that's how. Advocators of heat pumps, subsidised electricity, dimethyl ether, natural gas, LPG, wood pellets, processed coal - every and anything that costs a lot, but not ultra-clean-burning coal stoves developed right up the road in a university-owned, government-supported stove development centre!

"For bronchitis, this study points to indoor smoking from parents as the main source of children's bronchitis cases:"

That is unbelievable. The "main source"? The cause? That is a clear claim that second hand smoke causes bronchitis.

"I didn't see anywhere that respiratory diseases were due to the cold in Mongolia."

Think about that. The record low for Ulaanbaatar is -54 C (2002). The annual average is -2C. Is it possible that people earning $2500 per year live in a chronically underheated home? Ya think??

« With 50 % of the ambient PM pollution (and more in the winter months) originating from household stoves for cooking and heating, this sector tops the list of the most opportunistic of the interventions for better air quality. »

That is 2013. Times have changed. The stove programme was in full swing in 2013. The % dropped from 88% (2010) in one district to an average of 45% in 2015 (in winter).  In summer the air is very clean (12 µg/m3, for example).

So, if « 7 million deaths » from WHO may be far fetched, it seems reasonable to me to call for cleaner stoves.
And, in the case of Ulan Bator, to sensitize people against indoor smoking: is it actually being done?

Preaching against smoking is everywhere. The number f people smoking in developing countries is increasing rapidly because they are targeted by vendors. The advertising has been driven out of developed country media. It is very reasonable to call for clean stoves. Very clean. Why not? The benefits are huge, but it is not the entire problem. Without doubt the strangest country I have worked in is Mongolia because the clean burning solutions were developed there, tested there, supported financially yet are maligned for political purposes. Everyone wants to blame others for "not solving the air pollution problem". After the stove replacement programme stopped at the end of 2015, air pollution was down 65%. Some say 45% depending on where you measure it. It was improved uuugely. Yet people popped up to say nothing was achieved by the programme. Short memories.

I am sure asthma attacks decreased because air pollution aggravates asthma. I do not have stats, however. It just seems likely. Now we need to address the low pressure boilers which are more and more common and burn 4 times as much fuel as the ger stoves, at least. They were not included in the ger stove programme. We are working on the at the moment.  Products were tested last week - efficiency was too high. I will reduce it.

In the meantime, Kyrgyzstan starts rolling out improved stoves (locally made) to 14,000 homes, slowly at first. The coal combustors are all based on the Mongolian developments. South Africa localised the design and we have a model ready for testing since last Monday. It is a beauty, and will incorporate lessons learned from the use of the plastic refractory materials in Ulaanbaatar last year. It is a game-changer.

Keep pushing! Rocks don't move by themselves.
Crispin

Hello Crispin,

So you say IAP wouldn't change much if stoves were electrical.
What about Outdoor Air Pollution (OAP)? Isn't most of it in Ulan Bator from stoves and cars?

I googled about the issue. I have to admit I was skeptical at first about the absence of farm animals being correlated to the frequency of asthma cases, or the importance of smoking indoor.
But actually, I couldn't find a lot of studies pointing very clearly at the relationship between OAP and respiratory infections.
Well, you probably know all the studies about Mongolia already.

« Children in Ulaanbaatar, are taken bronchitis in 1.4-2.7 times and bronchitis asthma in 5.5-7.9 times more than children who are living in rural areas of less air pollution. » says Social Health institute.
http://www.unoosa.org/documents/pdf/psa/activities/2006/graz/presentations/01-02.pdf<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.unoosa.org%2Fdocuments%2Fpdf%2Fpsa%2Factivities%2F2006%2Fgraz%2Fpresentations%2F01-02.pdf&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741366959&sdata=Fm90hzSdHMSOB8HvFKH9xxARTXfibqXZQN%2BIrk4GAeQ%3D&reserved=0>
p 12.

So, is it because of the OAP of the city, or the fact they live in the city and far from farm animals, and so built weaker immune systems? Or because of the cold (colder in Ulan Bator ?!), or dust (dustier ?).

Litterature seemed indeed to point that children build asthma defenses when they live close to farm animals (in rural regions). While when living in cities, there are more admissions in hospitals due to asthma.
https://www.ncbi.nlm.nih.gov/pubmed/17298344<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpubmed%2F17298344&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=uTSNM0lu%2Fjm8olkP6TMYdsM372%2BeoZQ0NB3TmM19NmY%3D&reserved=0>

This one attributes a bit quickly:
« Importantly the lung function of the children on the steppe was significantly better than those living in Ulaanbaatar. So we concluded that the level of urban air pollution in the capital city is clearly having an adverse impact on the pulmonary health of urban Mongolian children. »
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4043223/<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4043223%2F&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=uuilh%2B27MOwl44EFbbs5bAToviZpy1HlJrnI53A8g28%3D&reserved=0>

It also says:
« Similar patterns of adverse health risk such as asthma, obesity and autism in proximity to freeways and major roads have previously been well documented by us and our colleagues in Los Angeles, CA. »

The study seems to show that depending on the world region, different factors are involved in allergies:
https://pdfs.semanticscholar.org/7dca/35da8463d9c600f3651e1bb77ab3af259fc7.pdf<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpdfs.semanticscholar.org%2F7dca%2F35da8463d9c600f3651e1bb77ab3af259fc7.pdf&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=SVz%2Bq2FAfo9qqXNyAg9BrfJD34dHAOxrhRboVP%2FRGYg%3D&reserved=0>

For bronchitis, this study points to indoor smoking from parents as the main source of children's bronchitis cases:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4835771/<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4835771%2F&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=0z1a%2B7e%2B%2FowdVlBuP9oXh%2FbBWvMgBLqWDSm%2B4dP9vIQ%3D&reserved=0>  -> but it is in a rural area. It doesn't explain why there are more cases in Ulan Bator. Seems unlikely that people smoke more in urban areas?
It does not exclude the influence of IAP from stoves, and refers to a study saying that stoves contributes a lot to IAP.

This one, in Ulan Bator, points to both indoor smoking and air pollution:
https://www.sciencedirect.com/science/article/pii/S1323893015001586<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1323893015001586&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=wxr4wxDIRPYAQZhQ5o3tbzbwYM6LbdQ%2FAaWJwTekRmE%3D&reserved=0>

This one puts again indoor parental smoking and IAP from stoves as probable causes, and maybe outdoor air pollution:
https://journals.lww.com/epidem/fulltext/2011/01001/Indoor_Air_Pollution_in_Different_Mongolian.96.aspx<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fjournals.lww.com%2Fepidem%2Ffulltext%2F2011%2F01001%2FIndoor_Air_Pollution_in_Different_Mongolian.96.aspx&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=nQupZ%2F3mS0lt4As7KirDvg7SDncl8dqbWTMlOsVtzso%3D&reserved=0>

UNICEF says: « Outdoor air pollution is the most significant environmental risk faced by children in Ulaanbaatar. »
https://www.unicef.org/mongolia/Mongolia_air_pollution_crisis_ENG.pdf<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.unicef.org%2Fmongolia%2FMongolia_air_pollution_crisis_ENG.pdf&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=4ua91l%2Ba3SLco0Hu5W5jIsmYkWy9%2FtbxaeBzTGO5vm8%3D&reserved=0>
There seem to be a long list of medical studies (page 86) saying that air pollution has an effect on children's health, and even that OAP does:
https://www.unicef.org/publications/files/UNICEF_Clear_the_Air_for_Children_30_Oct_2016.pdf<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.unicef.org%2Fpublications%2Ffiles%2FUNICEF_Clear_the_Air_for_Children_30_Oct_2016.pdf&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=oeOdbJUbP9LoypDuN%2FiL91vKTTg19%2BMkwetn%2BHg74lg%3D&reserved=0>

There are studies correlating OAP and respiratory diseases in other parts of the world:
https://www.ncbi.nlm.nih.gov/pubmed/22871325<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpubmed%2F22871325&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741523205&sdata=RFATlX87u2v46ugKKXbQrULRf6HHzjKC%2BFU874Lgd1E%3D&reserved=0>
https://www.jacionline.org/article/S0091-6749(17)32516-2/fulltext<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jacionline.org%2Farticle%2FS0091-6749(17)32516-2%2Ffulltext&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=96r%2F94JgIyrymTsn6euDyjvPhvw08OxLQLdg79ev9Es%3D&reserved=0>

I didn't see anywhere that respiratory diseases were due to the cold in Mongolia.

Regarding dust: there are more diseases in Ulan Bator than in rural areas, yet the latter are more dusty (are they?). And Ulan Bator is far from the Gobi desert, correct?
https://www.ncbi.nlm.nih.gov/pubmed/21488467<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpubmed%2F21488467&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=ND3WFE9miFpYSLbx2AoZMCBOASHdCpZkgo6Bq6qtEXw%3D&reserved=0>

This study looks at all the sources of air pollution, among which dust and ash ponds. It still concludes:
« With 50 % of the ambient PM pollution (and more in the winter months) originating from household stoves for cooking and heating, this sector tops the list of the most opportunistic of the interventions for better air quality. »
http://www.urbanemissions.info/wp-content/uploads/docs/2013-09-AQAH-Ulaanbaatar-PM-Pollution.pdf<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.urbanemissions.info%2Fwp-content%2Fuploads%2Fdocs%2F2013-09-AQAH-Ulaanbaatar-PM-Pollution.pdf&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=xu0QoGtNeFL8DdT99xeJKTjPWyoUIih7ChaiO9NTKqI%3D&reserved=0>
You're quoted a bit below Crispin BTW.

Are there meta-analysis of medical studies on the correlation between OAP and respiratory diseases? It seems to me we don't know for sure to what extent each factor contributes to diseases and mortality. But we have good hints that the main factors may be:

  *   OAP and IAP from stoves
  *   indoor smoking

To me there seems to be only a handful of factors. That means that solutions are relatively straight-forward.
So, if « 7 million deaths » from WHO may be far fetched, it seems reasonable to me to call for cleaner stoves.
And, in the case of Ulan Bator, to sensitize people against indoor smoking: is it actually being done?

News are always alarmist. We see « 7 million deaths because of air pollution!!! » because we work in stoves, but in the news, there are also:
« 6 million deaths because of smoking!!! »
https://www.popsci.com/smoking-is-still-bad-for-you<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.popsci.com%2Fsmoking-is-still-bad-for-you&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=7BzPDe726CuQWpodlHquZn2OW85yW9Rd3%2FsK%2B%2BYEgK0%3D&reserved=0>
« Poor diet is a factor in one in five deaths !!! »
https://www.theguardian.com/society/2017/sep/14/poor-diet-is-a-factor-in-one-in-five-deaths-global-disease-study-reveals<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.theguardian.com%2Fsociety%2F2017%2Fsep%2F14%2Fpoor-diet-is-a-factor-in-one-in-five-deaths-global-disease-study-reveals&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=uUO9ArGmaQ7fUZ7UYfs4SjB1%2F9tv1y4aO7yTHb2BvHs%3D&reserved=0>

That's true, news tend to make us think that the main cause of mortality in Mongolia is air pollution. But if we go through a few articles, we see they actaully also talk about other causes:
https://www.mcc.gov/our-impact/story/story-preventing-mongolias-leading-killers<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.mcc.gov%2Four-impact%2Fstory%2Fstory-preventing-mongolias-leading-killers&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=K1s1NgrWk4kvzU3ksNTNVsWxag60xM4JancKcy6oLpM%3D&reserved=0>
https://www.theguardian.com/global-development/2017/nov/07/mongolia-liver-cancer-crisis-no-other-country-has-a-problem-like-this<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.theguardian.com%2Fglobal-development%2F2017%2Fnov%2F07%2Fmongolia-liver-cancer-crisis-no-other-country-has-a-problem-like-this&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=WUKaP0ZWLNurVZp3K9WyKg9d5pP3y1LlYQSNfruv3Gw%3D&reserved=0>
https://www.theguardian.com/world/2013/oct/20/ulan-bator-killer-winter-stoves<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.theguardian.com%2Fworld%2F2013%2Foct%2F20%2Fulan-bator-killer-winter-stoves&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=wcKXj4VdynBUzEcIg5OsdfrUGaVqKRsX5yBxyYk7qKU%3D&reserved=0>

News also talk more about respiratory diseases, because many children suffer from it.
http://time.com/longform/ulan-bator-mongolia-most-polluted-capital/<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Ftime.com%2Flongform%2Fulan-bator-mongolia-most-polluted-capital%2F&data=02%7C01%7C%7C913c931ab731422abf2308d5b526d449%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636614100741679462&sdata=AUciNXnWCxRu3Io9RPdGW8Xqr6VZBttnEpdPTU%2BPMyE%3D&reserved=0>
It is understandable that even if these diseases are not the major killer at the population level, they are still given a higher priority by public deciders, than, say, heart diseases which strike mostly adults.

So human lives are shortened by a number of diseases. There is a number of causes for these diseases. And we are working on one of these causes: stoves.

So I agree, there is no need to be alarmist, and to exagerate or misrepresent a truth which is, actually, already quite alarming. But the fact that the situation is a bit more complex than the one presented the WHO reports or the newspapers doesn't mean air pollution isn't a serious issue. And that we shouldn't be working on that issue with the highest possible energy.

Best,

Xavier

De : Stoves [mailto:stoves-bounces at lists.bioenergylists.org] De la part de Crispin Pemberton-Pigott
Envoyé : lundi 7 mai 2018 03:05
À : Discussion of biomass cooking stoves
Objet : Re: [Stoves] Air pollution kills

Dear Xavier

Let's take Ulan Bator. There are 1.5 million inhabitants.
If all of them were using electrical heating and cooking, and driving bicycles instead of cars:

  *   would we likely see less indoor and outdoor air pollution?
  *   would we likely see less cases of respiratory infections like bronchitis, pneumonias, etc.?
  *   would the respiratory infections cases likely be less acute?
  *   would there likely be less cases of deaths due to a respiratory infection?
  *   would the life expectancy of the population likely be higher?

     *   There isn't much air pollution now indoors so it would probably not be reduced. In a home where no one smokes and they have a typical Stove Programme stove, the majority of IAP is caused by smoking and cooking. In the case of IAP in gers (yurts) the indoor air is generally better than the ambient air outside.
     *   Respiratory infections are greatly influenced by the temperature in the home and seasonal flu. Assuming people would not be heating their homes any higher than they are now (which means 'chronically cold all the time') the rate would probably not change much. This was demonstrated in Kyrgyzstan when it was shown that increasing the average temperature 5 degrees and heating for more than 16 hrs per day instead of 2-6 there was a huge medical health benefit - nothing to do with smoke. Being chronically cold in a stove-smoke-free environment would help reduce eye irritation and asthma attacks, I think.
     *   I can't see the acuteness of the infections being much affected with an annual average PM2.5 of 160 microgrammes, if nothing is done to address the chronic underheating issue. Mostly children get sick, and they get sick because they are cold so much of the time, or are subjected to large changes in temperature all day from traditional stoves going from zero to 40 kW then back to zero. Electric heating would moderate that, presumable, but you described changing the energy source, not the temperature profile.
     *   About the deaths, this is the same as Q3 about acute problems. Remember that changing the energy sources for a few things doesn't change all the other sources of air pollution : ash ponds, the Gobi Desert, and vehicles. Using electric vehicles would remove about 50% of the PM2.5 downtown, but not the considerable fugitive dust created by those vehicles on dirt roads. Dust storms are 50 times worse than air pollution from people.  Construction dust is considerable. Stove smoke is only about 45% of the total. It used to be 88% in some areas.
     *   The life expectancy is affected negatively by a lot of things other than air pollution : alcohol is a big problem, the diet consists largely of meat and fat is appreciated, the average income is very low, there is a great reliance on traditional medicine. There are a great many car accidents and falls from horses.  Here are the top 25 causes of death in Mongolia (I don't have it for UB alone) :

[cid:image001.jpg at 01D3E65F.551C5C80]

Which of those are related to diet and what is the first on the list that might be contributed to by air pollution? A lot of people smoke and smoke indoors. Breathing the city air is on average like smoking a 1/28th of a cigarette per day - the same as Calcutta.

So how do Mongolian causes of death rank in the world?

[cid:image002.jpg at 01D3E65F.551C5C80]

Number 1 for liver cancer, stomach cancer and number three for suicide and stroke. Do you see any diet-related diseases there cause by consuming a large amount of meat and alcohol?

They have a very low global ranking for breast and prostate cancer and diabetes (all >170).

All things considered, it would be much better if there were no air pollution in the city, but is it a major killer, or the major killer? Doesn't look like it.

Bright side :

Improving the domestic combustion devices greatly reduces indoor and outdoor air pollution, saves money, increase the comfort level, being warm greatly reduces the incidence of bronchitis, and makes people a lot happier. Those are reasons enough to support stove programmes. Given the context, it is not going to make much difference to the premature death rate from ambient air pollution. Moving people from gers to heated apartments increases their IAQ problems because so many people smoke and the apartments have a low air change rate.  It is never simple and context is everything.

Never assume anything.
Crispin

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