1 Ozone Depletion and Refrigerant Environmental Impacts Free Online FlashCards

Where is most atmospheric ozone found?

About 90% of atmospheric ozone is in the stratosphere.

What is the ozone hole?

It is a region of unusually low ozone, not an empty hole; it is most pronounced over Antarctica in spring.

What can result from reduced stratospheric ozone?

Less stratospheric ozone allows more UV-B to reach Earth, raising risks such as skin cancer and cataracts and harming some plants and marine organisms.

How can CFCs and HCFCs contribute to ozone loss?

Ultraviolet light breaks them down in the stratosphere, releasing chlorine atoms that participate in ozone-destroying reactions.

Why can one chlorine atom destroy more than one ozone molecule?

A chlorine atom can take part in repeated ozone-destroying reactions, so its effect is not limited to one ozone molecule.

How does the ozone-depletion potential of HCFCs compare with CFCs?

CFCs generally have high ozone-depletion potential; HCFCs have nonzero but generally lower potential. HCFC-22 has an ODP of about 0.055.

At what stages can refrigerants escape into the atmosphere?

Releases can occur during manufacture, equipment leaks, servicing, and disposal.

What does ozone-depletion potential (ODP) measure?

ODP compares a substance’s ozone-depleting effect with CFC-11, which is assigned an ODP of 1. An ODP of zero means it does not deplete stratospheric ozone.

Why does zero ODP not mean an HFC has low climate impact?

HFCs have zero ODP because they contain no ozone-depleting chlorine or bromine, but some have high GWP; HFC-134a has an approximate 100-year GWP of 1,470.

What environmental feature can make some HFOs lower-impact alternatives?

HFOs generally have zero ODP and break down more readily in the lower atmosphere than many conventional HFCs; some, such as HFO-1234yf, have very low GWP.

What ozone impact do natural refrigerants such as ammonia have?

Ammonia, hydrocarbons, and carbon dioxide do not deplete stratospheric ozone; their direct climate effects are generally low compared with many high-GWP fluorinated refrigerants.

How do direct and indirect refrigerant-related climate impacts differ?

Direct emissions come from refrigerant escaping; indirect emissions come from the energy used to operate the system.