Over time, elevated ozone concentrations are associated with increased asthma attacks, hospital admissions, and deaths from respiratory and circulatory disease.
One small molecule, ozone, has both a very good and very bad reputation. On the one hand, we worry about areas in the stratosphere with ozone layer thinning, known as ozone holes. On the other hand, even trace amounts of ozone in our ground-level breathing zone are harmful to our health. To compound these mixed messages, we also hear about the odor-removing benefits of ozone indoors, yet air-cleaning devices that release ozone as a byproduct are harmful.
How can one molecule have so many actions? To make sense of this, let’s look more closely at the structure and chemical reactivity of ozone.