Ozone is the most abundant oxidant in the atmosphere of major urban
areas around the world. It is formed as a product of photochemical
reactions involving NOx and volatile organic compounds (VOCs).
Photolysis of ozone at wavelengthsb319 nm is important as the main
source of hydroxyl (OH) radicals, which largely determine the oxidative
capacity of the lower atmosphere [1–4]. Outdoor ozone levels, which are
lowin the early morning, normally increase until noon or early afternoon,
and decrease thereafter [2,3]. The concentration of ozone indoors depends
on a number of factors, including the outdoor ozone concentration, air
exchange rates, indoor emission rates, surface removal rates, and reactions
between ozone and other chemicals in the air [5]. A method for
quantification of ozone should therefore be able to identify concentration
fluctuations during the course of the day. This is important because at high
concentrations ozone can cause a range of adverse impacts on human
health, crops, natural vegetation and indoor materials [6–10].