Air Pollution Ozone
1. What is Ozone (O3)
is a gas that can form and react under the action of light and
that is present in two layers of the
stratosphere and the
In the stratosphere,
ozone forms a layer that
shields the Earth from ultraviolet rays.
However, in the
is the most important
There, it is a secondary pollutant formed when
precursor pollutants such
as nitrogen oxides
volatile organic compounds
react under the action of light.
Near strong emission sources of
where there is an abundance of NO,
ozone is “scavenged” as it
As a result its
concentrations are often low
in busy urban centres and higher in suburban and adjacent rural
areas. However, ozone is also transported long distances in the
atmosphere and is therefore
considered a trans-boundary problem.
Because the formation of
ozone requires light, ozone
depending on season and time of day, with higher concentrations
in the summer and in the afternoons.
Controlled exposure studies
on humans and animals have provided evidence that
ozone can cause
adverse health effects.
However, more research is needed, especially addressing the
spatial and seasonal patterns of ozone exposure and related
The same information on