Re: Deaths from fossil fuel burning air pollution

[Bernard L Cohen <blc+@pitt.edu>]

On Wed, 22 Nov 2000, Otto G. Raabe wrote:

> At 09:04 AM 11/22/00 -0600, Prof. Cohen wrote:
> >
> >	--The key word here is "increases". As long as these increases
> >stay within the range of available data, I see nothing wrong with this and
> >I don't see why it should be called LNT. The problem with LNT as applied
> >to radiation is that it is *extrapolated* far outside the region where
> >there are data. In the case of air pollution, it is *interpolated*,
> >staying within the region where there are data.
> ***********************************************************
> 
> I believe that this use of air pollution data is actually similar to what
> has been done with atomic bomb survivor data. The RERF can claim that their
> regression fit to atomic bomb survivor data is similarly being interpolated
> since they have data at both ends of the fit. There are plenty of data for
> persons  receiving no (or very low) a-bomb radiation exposure as well as
> for persons receiving high exposure. The LNT model that is used for
> radiation effects is thus just an interpolation between available data.

	--By data in the region of interest, I mean several data points.
Other than the (0,0) point, there are no meaningful RERF data in the
region between 0 and 20 rem, which is the region of interest. Actuually,
the principal region of interest for radiation is between 0 and 5 rem.
	In contrast to this, in the Pope et al data on air pollution,
there are 151 data points scattered through the region of interest  

> The key is the shape of the dose-response curve. If a linear function is
> used for interpolation and the actual relationship is non-linear, the
> interpolation can lead to gross errors. This is what occurs when attempts
> are made to assign bodies to small increases in airborne particulate matter.

	--In the case of radiation, it is easy to imagine gross errors;
for example, there could be a threshold at 20 rem, or even a negative
slope below 20 rem. This would still be consistent with the RERF data.
	 But for air pollution, it is not credible that the
dose-response curve wandering through 151 data points can be so strange
that a linear interpolation within the region would give a gross error.
	

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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