Which of the following is a secondary pollutant in the troposphere but beneficial component in the stratosphere?
A) ozone
B) nitrogen oxides
C) carbon monoxide
D) volatile organic compounds

In general, the
A) smallest particulate matter has the greatest impact on human health.
B) largest particulate matter has the greatest impact on human health.
C) EPA does not regulate particulate matter based on its size.
D) particulate matter released into the air drops out within 15 minutes and thus is quite safe

CFCs primarily contribute to the destruction of the ozone by
A) producing chlorinated gases that reflect back a significant amount of ultraviolet light.
B) releasing carbon monoxide into the stratosphere, which reacts with the oxygen in ozone.
C) releasing gases into the stratosphere that block the enzymes that create ozone.
D) contributing chlorine, which acts as a catalyst in the breakdown of ozone.