increased use of catalytic convertors in cars around the world has
led to concerns about the increase in transport related nitrous
oxide emissions which might result.
However, although catalytic convertors in cars can
lead to an increase in nitrous oxide emissions of around 20 times
that of comaprable vehicles without catalytic convertors, global
emissions from this source are thought to be relatively small. Indeed,
advances in catalytic convertor technology have led to significant
reductions in nitrous oxide emissions in recent years.
Current estimates range from 110 to 240 thousand tonnes
of 'transport related' nitrous oxide-N emission per year, though
with rapidly increasing global car use, nitrous oxide emissions
from this source may rise in the future. Additional nitrous oxide
emissions arise from other forms of fossil fuel powered transport,
such as planes, boats and lorries.