Review of HCFC-22 Distributed Emissions from the Global Emissions Inventory Activity (GEIA)

HCFC-22 (CHClF2, chlorodifluoromethane) is used primarily within refrigeration
and air conditioning systems as the working fluid. Some material is released
into the atmosphere when these systems are first filled but the bulk of the
losses occur subsequently during maintenance, or as the result of accidental
damage or when the equipment is finally removed from service and scrapped.
There are other minor uses in foam blowing and hermetically sealed systems.

As a consequence of the delay between first use and release, it is necessary to
calculate emissions from time series of data on production and sales into three
end-use categories having short, medium and long-term "banking times". The
calculation method is described in Midgley and Fisher (1993).

The calculated global emissions of HCFC-22 were distributed among countries
using the distribution of CFC-12, calculated in McCulloch et al. (1994), as a
surrogate. Within each country, emissions were distributed to individual
gridsquares using the population distribution in Li (1996).

Results are presented here as the percentage distribution among gridsquares,
with no cut-off at low values. Absolute emission from each gridsquare in 1990
should be calculated by multiplying global emission for 1990 in
"http://geiacenter.org/reviews/hcfc22.html" by the gridsquare percentages in
Table 2. For other years, the distribution in
"http://geiacenter.org/reviews/hcfc22.html" should be applied to the global
emission for the appropriate year. While global emissions change relatively
rapidly, distribution is affected only by relative economic activity and
population dynamics, which have slower rates of change with time. It is
expected that the distribution can be applied to the years 1985 to 1995 without
significantly increasing uncertainty but this has not been tested. It can be
applied to years beyond this range only with caution and new distributions for
more recent years are under development.

Taken from McCulloch et al., 2002 (itself compiled from AFEAS, 2001 and UNEP,
2002), the time series (1943 to 2000) of HCFC-22 emissions and their
uncertainties is shown in "http://geiacenter.org/reviews/hcfc22.html".

Future emissions will be governed by the controls required by the Montreal
Protocol and by the quantity of material currently in the "bank" (that is:
material which is in use but has not yet been emitted). A scenario for future
releases of HCFC-22 was described in Madronich and Velders (1999). This
scenario has been updated and will be published in Fraser and Montzka (2003).