Environmental Engineering Reference
In-Depth Information
have ensured that NO x formation has been reduced by nearly 50 per cent, despite
engine temperatures rising by approximately 300°C (Ruffles, 1998). Aircraft NO x
emissions, as well as UHC, smoke and CO, are currently regulated through the land-
ing and take-off (LTO) cycle, but the regulatory authorities are investigating the
possibility of extending this to cover NO x emissions during cruise.
F ACTORS AFFECTING DEVELOPMENT
Market growth
Average passenger air transport (revenue passenger kilometres) has been growing at a
minimum of 5 and 6 per cent over the last 40 years. Projections of future traffic indi-
cate growth rates for passenger traffic of around 5 per cent and higher for freight
transport (Rolls-Royce, 2000). This expected growth will impact upon a number of
areas, such as increased congestion at airports and the need to expand existing capac-
ity, but also operational issues such as flight path management and air traffic man-
agement systems. Communities local to airports are more involved in airport planning
procedures, and can be expected to increase their involvement in the future, perhaps
demanding restrictions on night-time traffic, local air quality assurances or improved
access to the airport before consenting to airport expansion plans.
The expected effect on the aviation growth rate by the revolution in electronic
communication is not yet clear. It could lessen the need for business travel through
Internet-based business transactions or, conversely, increase business travel because
web-based advertising reaches a wider target audience, resulting in more face-to-face
contact. Other transport systems such as high-speed rail and fast ships can offer alter-
native travel arrangements for some journeys currently undertaken by air, such as
short-haul flights.
Global climate change
Climate change is a major concern, and the Intergovernmental Panel on Climate
Change (IPCC) has accordingly issued the special report Aviation and the Global
Atmosphere (IPCC, 1999). This report highlights the major contributing factors to
climate change that are believed to result from aviation - factors that are discussed
in more detail elsewhere in Chapter 5. While it is understood that there remains
some considerable uncertainty about the radiative forcing effects of aircraft emis-
sions, it is clear that CO 2 , NO x and contrails play a significant part. As a result, exist-
ing international legislation covering emissions is likely to become more stringent,
and it is becoming clear that attention will focus not only upon emissions produced
during landing and take-off, but also at cruise, and will apply to both engine com-
bustion and acoustic emissions (Birch, 2000).
The reduction in fuel consumption and NO x over the past 30 years has been
driven by economic and environmental factors. However, the environment and,
more specifically, global climate change should have a significant effect on the future
development of the aviation industry.
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