[Stoves] PM emissions from engines

[Crispin Pemberton-Pigott]

Andrew sez:

"Okay, so far part of a good answer: so are you actually saying that indoor air pollution is not a quantifiable cause of bad health, yet we know respiring particulates is?‎"

Exactly. We can claim that indoor air pollution has a negative, if unquantified, impact on health. Quantifying that impact is expensive. 

The Malawi study and the Kyrgyzstan study are functionally the same: observe the health of HH members one by one in homes with and without the stoves claimed to be improved. ‎The Kyrgyzstan investigation also measured the exposure to which individuals were subjected which is about as good as it gets. 

The results were quite different. In Malawi the background PM overwhelmed any impact / reduction in exposure caused by the stove, at least on a macro-impact level. Child respiratory infections did not change in a statistically significant way. In Kyrgyzstan the needle moved to zero which is very significant. 

Was the disease in the unimproved stove homes caused by smoke? Low room temperature throughout the day? Cold at night? Gases not considered measurable PM?

It is clear the effect was produced by the stove system. In house after house the effect was seen, not just taken together and shown 'statistically'.

So we can take that as 'obvious and categorical evidence' that changing the stove improves health in specific ways. To claim that PM causes bronchitis is a stretch, however. PM is not a disease agent any more than a stove is a pill. Removing all PM from a chronically under-heated home ‎might have no effect at all. 

For all the noise usually made about how women do all the cooking and young children hang around them ‎getting exposed, the Kyrgyzstan project showed that men are more exposed to PM2.5 than everyone else. Put that in your corn-cobbie and smoke it!

In the Naryn region, Dr Sooronbaev says 100% of adults over 40 have COPD‎. That is probably caused directly by exposure to stove smoke indoors. 

Crispin