Environmental Engineering Reference
In-Depth Information
Table 6.2
Some common anthropogenically produced ozone destroying chemicals
Source:
Compiled from data in Environment Canada (1989), MacKenzie (1992), Tickell (1992)
* ODP is a measure of the capacity of a chemical to destroy ozone, with the ODP of CFC-1 1 and CFC-1 2
as a base of 1 .0
foam used to improve home insulation. Polymer
foams are also included in furniture and car seats,
and, with the growth of the convenience food
industry, they were used increasingly in the
manufacture of fast food containers and coffee
cups. The gases are released into the atmosphere
from leaking refrigeration or air conditioning
systems, or sprayed directly from aerosol cans.
They also escape during the manufacture of the
polymer foams, and are gradually released as the
foams age. Halons are widely used in fire
extinguishers and fire protection systems for
computer centres, industrial control rooms and
aircraft. Although they are less abundant in the
atmosphere than CFCs, their ability to cause
ozone depletion may be 3-10 times greater
(Environment Canada 1989).
Advantages of CFCs and halons for such
purposes include their stability and low toxicity;
under normal conditions of temperature and
pressure they are inert—that is, they do not
combine readily with other chemicals nor are they
