Ozone forms naturally in the upper atmosphere surrounding the Earth
and protects life from the damaging ultraviolet light emitted by the
sun. At ground level, the same ozone is harmful to living things; it
is an air pollutant that damages human health, vegetation, and many
man-made materials. Ground-level ozone is the key ingredient of urban
smog. Ozone is mainly a daytime problem during the summer months because
more sunlight and higher temperatures enhance ozone formation.
||Ozone is not
emitted directly into the air, instead it is created when gases
called oxides of nitrogen (NOx) and volatile organic compounds (VOCs)
react in sunlight and heat. Emissions of NOx are produced when fossil
fuels are burned in motor vehicle engines, power plants, and industrial
boilers. There are hundreds of thousands of VOC sources including
automobile emissions, gasoline vapors, chemical solvents, and consumer
products like paint.
your health when it is inhaled. Even at low concentrations, ozone
can cause respiratory problems and aggravated asthma in children,
people with respiratory diseases, and even otherwise healthy adults
who are working or exercising outside on smoggy days. Children are
most at risk from exposure to ozone because they are often active
outside during the summer and their lungs are not fully developed.
Long-term exposure to ozone may lead to premature aging of the lungs
and chronic respiratory illnesses. Ground-level ozone is also responsible
for 1 to 2 billion dollars of crop damage in the United States each