Petrol/gas/diesel pollution

Bernard J. Goitein bjg at
Fri Jun 23 14:23:09 MDT 1995


On Fri, 23 Jun 1995, Ron Press wrote:
> Hi
> >>>>>>>>>>>>>>>>>>>>>>>>>>> From: Rahul Mahajan
> <rahul at
> Are you implying that unleaded gasoline is environmentally less
> sound than leaded because of higher production of aromatic
> polycyclics? That would be an interesting assertion -- I know
> nothing about it myself.
> 			     <<<<<<<<<<<<<<<<<<<<<<<<<<
> This is correct. Unleaded petrol without a catalytic converter is
> worse than leaded petrol in a normal car.

what about the environmental benefit of avoiding the airborne lead? I
would think that should outweigh the hazard implications of the "aromatic
polycyclics" (BTW, which hazards, of which aromatic polycylics ???).

 With a properly working
> catalytic converter it is better.
> However Diesel is worse than both from the point of view of
> particulates.
> Ron Press

yes, diesel is/was worse:  we are all used to seeing
diesel fueled busses belching black smoke (i.e., particulates).
But, in my own work, I have been evaluating data on some "alternative"
engine busses put in use in my area of Illinois these last few years.  We have
some special "low pollution" diesel engines, with a particulate trap to
capture the soot.

Very few particulates are in their emmisions- they are nearly as clean
 burning as the pure ethyl alcohol fueled engines (the ethyl alcohol engine
 busses are the main target of our evaluation study, with "normal"
(dirty) and several special diesel engine busses on the same bus routes used
as comparisons).

If diesel engines can avoid making heavy air pollution, unleaded gasoline
engines should too- the removal of lead from gas has been a big help to
reducing lead pollution levels in the US- i suspect unleaded petrol would
help in the UK, but i only have US data at hand.


To toss some petrol and gasoline on the flames of the
social science/natural science debate- is
there a difference?- I'm not finding a deep (or any) difference in my
conduct of the study-
my study looks at measured emmisions and recorded reliability differences
between engines (natural science), stated preference/attitude differences
between employees working with each engine type (social science), and sample
 survey stated attitude differences towards the different engines among the
general public (social science).

I will use the very same statistical inference techniques to decide if
 observed differences in the data measured -emmisions,
reliability, attitudes, preferences - are likely to
have happened by chance, or if they are so large that the probability of
that large (or larger) a difference happening by chance is less than 5%..

In practice, therefore, i am experiencing no *inherent* difference
between "doing" social science and "doing" natural science.

Further, I wonder if the suggestion of such an inherent difference is an
idealistic notion which won't go over well with materialist types,
even dialectical ones.

bernie goitein

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