| The poetry of reality|
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We will know.
|A view from the|
shoulders of giants.
Ozone (O3) or "trioxygen", is a triatomic molecule consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the usual diatomic allotrope, O2.
Ozone in the lower atmosphere is an air pollutant with harmful effects on the respiratory systems of animals and will burn sensitive plants. The ozone layer in the upper atmosphere is beneficial, preventing potentially damaging ultraviolet light from reaching the Earth's surface. Ozone is present in low concentrations throughout the Earth's atmosphere and is the key component of most atmospheric chemistry.
Atmospheric ozone levels are one measure of air quality. In the 1950s, a Stage 1 Smog Alert occurred when the ozone level rose to 0.5 parts per million, and a Stage 2 Smog Alert was declared at 1 part per million of ozone. (Today, 0.5 ppm of ozone would qualify as a Stage 3 Smog Alert.)
People in Victorian Britain would go to — indeed, were advised by physicians to go to — the seaside to "take the ozone". Fortunately, there's no more in sea air than there is anywhere else, or they'd have been coughing up blood. That characteristic seaside smell is dimethyl sulfide derived from rotting seaweed.