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Pollution from driven cars has fallen so fast it is now below that of parked cars in 1970

One small fact in my book has caught several readers’

Today, a car emits less pollution
travelling at full speed than a parked car did in 1970 from

My source for this remarkable statistic was Johan Norberg’s 2006
book När människan skapade världen. In a translation he
sent me it reads:

the average car today gives off one-tenth
as much pollution per kilometre as in 1970. The fact is that a car
travelling full speed causes less pollution than a parked car did
in 1970, because of leakages.

Recently Henry Payne gave some more details, quoting an
article in Autoweek — which is interesting, but a little confused
in one place:

The 1970 Ford
pollutes more parked in a driveway than a 2010
Mustang does traveling down the road…

The operating 2010 Mustang is 98.5
percent cleaner than the 1970 with its engine shut off, according
to Ed Kulick, an emissions regulatory planner in Ford’s vehicle
Environmental Engineering Department.

The ’10 Mustang has
demand-based fuel injection with no
return lines, hydrocarbon impermeable fluorocarbon gaskets and
evaporative emissions canisters that eliminate gasoline vapor
seepage, even during refueling.

The ’70 Mustang emitted the equivalent of
3.7 grams of hydrocarbon (HC) per mile sitting still, according to
Kulick. The ’10 is certified at 0.055 gram of HC per mile when
cruising the interstate at 70 mph.

The 1970 ‘Stang had Detroit’s first
rudimentary apparatus to control exhaust emissions It met federal
standards of 4.3 grams of HC, 39.6 grams of carbon monoxide (CO)
and 4.1 grams of oxides of nitrogen (NOx) per mile. The 2010
generates no more than 0.055 gram HC, 2.1 grams of CO and 0.070
gram of NOx, for reductions of 98.7 percent, 94.7 percent and 98.3
percent, respectively.

The confusion is this: a parked car cannot emit pollution `per
mile’, so `the equivalent of’ needs explaining. The key measure
would be `per minute’.  Can anybody shed light on this? I
cannot track down the original Autoweek article.



By Matt Ridley | Tagged:  rational-optimist