Aircraft emissions techie question

Date:         03 Dec 99 02:10:10 
From:         "Jack Pease" <Jack.pease@ifi.co.uk>
Organization: Nacamar Group Plc.
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Don't suppose anyone can help me with a technie question.

NOx emissions rise with engine power. NOx is saved if a pilot selects 85%
thrust on take off rather than 100% thrust, and presumably save fuel, so why
isn't this done all the time if the engines have enough in reserve??? Does
it reduce ambient noise if a plane shoots down the runway on 100% power then
thrusts down once over the airport boundary, or is it better to be 85%
thurst all the way but lower on the airport boundary?

Modern engines produce more NOx than old ones, but why do the authorities
claim that PM10 emissions are dropping hugely when it appears there are not
emission factors for this pollutant?

Why is SO2 considered irrelevent when if you plug in SO2 into the UK
national emissions database (http://www.aeat.co.uk/netcen/airqual/naei/ ) do
you get two dirty great red splodges over Gatwick and Heathrow? Where is
this SO2 coming from, given that avgas is a light distallate??

IS there anybody out there who can give an independent and authoritative
answer on these questions?

MTIA

Jack