[Stoves] Top lit updraft combustors

[Nikhil Desai]

Andrew:

I see an opportunity here to explain my views differently.

You say, "I was thinking more about the simple metric of PM per kg or MJ of
fuel burnt, rather than a full blown test to simulate cooking, bearing in mind
the current concerns."

I agree with you that a full-blown test with simulated cooking may give
nothing for the purposes of prediction of PM exposures but the problem is
far worse than that.

What would PM per kg or MJ do? (It also has to have a time dimension and a
location/spatial dimension). What would such PM per kg per minute do for
whom and how? Under what theory of change in what else that may also change
in mere cooking fuel PM emission rates?

PM arises from different sources. PM emission rates from a cookstove (let's
stick to primary solid fuels, not processed fuels or charcoal for cooking)
vary according to combustion conditions, type and quality of fuel,
location, air flow. Other PM sources are often right around - from mud
floor and walls to animal husbandry sources, land, plants nearby.

The levels of concentrations "in" and "outside" - terms that do not have
uniform meanings worldwide, compared to US or UK rural single family homes
- homes vary, and so do exposures. There is no standard cook, standard
home, standard neighborhood with standard transport network and standard
land, trees, livestock, wind.

But let me stick to just fuel emission rates. Data on source, quality, and
cost of fuel have to be collected and cooking behavior modeled according to
not just the variables above but these economic signals. Which means a
"service standard"- a multi-dimensional practice, not just changing the
power level of a stove - has to be defined.

And to what objective? Emissions are not concentrations are not exposures
are not ingestions are not disease, but t hey can be modeled according to
relevant building types, meteorological conditions, baseline health and
nutrition conditions of the cohort.

None of this has ever been done for any locality that I know of. The
closest effort for quantification of reduction of HAP PM2.5, adjusted for
ambient PM2.5 and use of chimneys, that I know of is in Ajay Pillarisetti's
PhD thesis at Berkeley, signed off by Kirk Smith and Dan Kammen, whose work
I am familiar with.

But Ajay's model not only abstracts from many relevant variables, his list
of qualifications and assumptions is a convincing argument for NOT using
his model.

So what are we left with in terms of setting a PM2.5 emission rate or
emission load as a metric other than the very simplest ones -- eye
irritation, coughing, opacity?

Something our ancestors have done for millennia and last 20 years of EPA
theology has no relevance to household biomass cookstoves by the poor.

I hope I have conveyed to you that not only is the science of indoor air
pollution or HAP is very different from that of the science of ambient air,
by village or city, by county, by state, by air basin.

And the legal authority, professionalism, legislation and rulemaking, court
fights we have seen in US from at least 1973 all the way down today, 47
years, tell us that there are no simple miracles for getting clean ambient
air.

When it comes to air pollution from poor households' cooking, we know next
to nothing. There is no systematic data collection on fuels, emissions,
concentrations, exposures, diseases at all. And there is no force of law,
no vetting by professionals in the energy and environment industries or
even medical industry.

+++
Then you say,


"The thing is I can see official miles per gallon figures for my car and I
can take various journeys from full tank to full tank and compare them. I
see the official figures are not much use to me, I plainly drive
differently from the computer software doing the official test. Fuel
economy is but one part of choosing a car. So I can see a full cooking test
being fraught with difficulties but precision (repeatability) would be a
core issue. "


I assume Norbert is referring to EPA NSPS for residential heating stoves
and HOB (heat-only boilers) in the US. EPA had the authority to regulate
their emissions at least since 1971 if not earlier. It issued first set of
standards in 1986 or 1988, the second in 2015 or 2016, with full
implementation by 2020 if all states agree (instead of getting the Congress
to stop the implementation or going to Federal courts).

These NSPS for heating stoves and HOB took 30 years to develop and get a
broad agreement on. And that too because the fuel supply industry is fairly
reliable - delivering ordered quantities of high-quality wood on desired
schedules.

That is the equivalent of your "full tank". Whatever the standards, a home
user has some rough idea of how much he uses every month in winter, and
stocks up. Stove utilization rates vary from place to place, home to home,
one year to another.

Even for poor people's fuelwood for cooking, something similar goes on, at
least in the parts of India and Africa I am familiar with. Cutting and
stacking wood is part of the work cycle across seasons. Some wood is
obtained daily or weekly and some stored for winters and monsoons. They
know their wood requirements from years of cooking and heating practice.
Like you, they too think fuel economy is but one part of choosing a stove.

In short, the IWA is a top-down lie. The efficiency and PM2.5 hourly
emission ratings may do nothing for the customer until and unless they
accept the product in its entirety for other reasons,some of which cannot
be quantified by these scientists turned marketers. (I don't know who
represents whom, but we have GACC, Gold Standard, WHO in the game; what
experience do they have in air quality modeling or variations in fuels,
cooking preferences and the like?)

Whoever set IWA metrics had another agenda - not cookstove R&D but blowing
money on research useful to t he regulatory paradigm of EPA.

That is what regulatory bureaucrats are good at - spending money to justify
their controls. Except that in this instance, they invented GACC so they
didn't have to make claims about the rationale of TC-285 work.

Nikhil

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