[Stoves] report with disappointing results from cleaner cookstoves

[Crispin Pemberton-Pigott]

Dear Xavier

>Again I ask: if you would design a health study to really understand the health impact of improved cookstoves, what would be your methodology?

At the moment the study we are conducting (we being 3 or 4 parties involved in the Kyrgyzstan stove pilot running this winter) can be attributed to fortuitous circumstances: the group that monitors indoor air decided to 'do it' just as others of us heard about their plan. We asked them to move the timetable forward and they did, just in time for the stove installations.

The study - quite detailed - is on the changes made in the home by the provision of an improved (normally highly improved) stove that has as its main claim, much better fuel efficiency. The side benefit is that such stoves almost always have far lower emissions because they are combusting things much more efficiently. Proper draft and ducting should reduce smoke in the room during refueling, we hope.

The study includes homes with no change, and they will monitor the PM occupants are exposed to during the winter. The other set of homes are substantially similar and will be monitored to find out what the effect of different stove models is on the home environment.

This is not a 'health study' it is an exposure study. We want to quantify the change in exposure, if any, and to find out under what circumstances that change takes place.

Will we be able to say what health impact any change will have on the occupants? Only if we also knew a great deal about their life until now and what it will be in future, which is to say, "No."

++++++++++

One of the worst cities in the world for smoke pollution used to be Ulaanbaatar, before the ger stove replacement programme. Prof Lodoysamba, who was measuring and reporting the level and sources of smoke in the city for over a decade, says that if one lives in an apartment in UB with one smoker, the PM2.5 exposure in the home is greater than living outdoors, even in one of the worst cities on record. One of the townships had an annual average concentration of 620 µg/m3. They are hollering in the news about Delhi at 200.

There is the view in the townships 31 Jan 2008 - this is stove smoke
[cid:image003.jpg at 01D25637.EFADA3D0]

And downtown (which is better than average) on 22 Dec 2010
[cid:image004.jpg at 01D25637.EFADA3D0]

Reducing the city air to 10-15 µg/m3 (typical summer levels) would not change the exposure a heck of a lot for the family of the smoker(s) who are exposed to a lot of tars and nitrosamines<https://en.wikipedia.org/wiki/Tobacco-specific_nitrosamines>.

That is why exposure numbers are very difficult to turn into health outcomes, save for generalisations applied at the national level for the total population based on a bunch of assumptions about risk and consequences, otherwise known as the GDB.

We can have national and international targets for exposure. Reduction is good. Claims that a particular response will be obtained are not valid for anyone in particular.

Regards
Crispin

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