Ozoning Regulations

Recently our local news in Michigan issued an air quality alert, which mentioned an increase in ozone levels. I was curious about this, since I know the ozone layer protects us from harmful UV light, and the hole over the South Pole is a major environmental concern. That hole was caused by certain pollutants, so I was surprised to hear increased ozone also being associated with poor air quality.

The key is where the ozone is in the layers of the atmosphere. The ozone layer that protects us is in the Stratosphere, while the one associated with poor air quality is in the Troposphere:

Wikipedia

The majority lies above 15-20 km and absorbs 97-99% of the UV light that comes from the Sun. The ground-level ozone results from byproducts of burning fossil fuels. Since ozone is made of 3 oxygen atoms, rather than the 2 that make up oxygen's breathable form, it's heavier, and so I wondered about the process that keeps it at those high altitudes. It turns out it's a continuous cycle, in which oxygen atoms bond and unbond in different configurations. The process is mediated by UV light, which is absorbed by ozone to break it into gaseous oxygen. Since it's absorbed up there, it doesn't make it to the troposphere to break up the ozone down here (or damage our DNA, so overall plus).

The benefits of ozone in the upper atmosphere, combined with its dangers in the lower atmosphere made me wonder if there were a way to transport it upward. Other people have wondered that, and unfortunately it doesn't work. Since ozone is heavier than oxygen, it won't naturally rise, and we'd need to carry it upward. That has its own problems though, since ozone corrodes many materials, so it would get expensive to keep making new containers. The other problem is that there just isn't a lot of ozone down here compared to what the upper atmosphere holds. It would be difficult to collect enough to make the process worthwhile. It seems our best bet is to stop making ground-level ozone in the first place, and to keep the upper-level ozone doing its job!