With heat comes 'bad ozone'
Conditions will be ripe again Thursday for a harvest of ground-level ozone - not to be confused with the good stuff in the upper atmosphere that has become a perennial source of anxiety.
Conditions will be ripe again Thursday for a harvest of ground-level ozone - not to be confused with the good stuff in the upper atmosphere that has become a perennial source of anxiety.
For the first time this season, and on the first day that the official temperature nudged past 90 - the high was 91, just shy of the record for the date, 92, set in 1972 - the Environmental Protection Agency on Wednesday issued a "code orange" alert for so-called bad ozone.
With Thursday's high expected to hit 92 and Friday's due to flirt with 90, the region might be recording its first official heat wave of the season.
Heat is a catalyst for ozone, commonly called smog, an unpleasant respiratory cocktail brewed from sunlight interacting with motor-vehicle and other emissions.
Inhaling ozone can set up breathing problems for children, the elderly, and anyone with chronic lung conditions, such as asthma.
The ozone alert covers the entire region, including Delaware and all but a tiny portion of New Jersey. Studies have shown that Philadelphia is particularly ripe for bad ozone.
It is not to be confused with the benign layer in the upper atmosphere that helps screen out the sun's most-harmful rays. As Sean Greene at the Air Quality Partnership points out, people are prone to confuse ground ozone not only with the high-up stuff but also with pollen.
It so happens that tree pollen levels were reported "very high" in the Wednesday morning report from the Asthma Center. But as allergy sufferers well know, pollen constitutes a torment of a different stripe.
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