“It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.”
—Dan Quayle

Recently I made a comment on a blog post about some of the polluting effects from the use of fossil fuels. Among other things, I referred to the harm caused by ozone. I didn’t specifically refer to the type of ozone, but at least one person was misled because he commented back to me that the Montreal Protocol from 1989 helped the problem of depletion of the ozone layer and questioned whether I really knew what I was talking about.

So to clear things up, let’s look at the different types of ozone we have on our planet. My comment wasn’t referring to the ozone layer as the reader was misled to believe. The ozone layer exists in the stratosphere and is, therefore, more properly referred to as statospheric ozone. It’s very high up, about 20 to 30 kilometres above Earth’s surface. Its concentration is very small, about 600 parts per billion on average. It forms when ultraviolet (UV) radiation strikes oxygen molecules (O2), splitting them into two separate oxygen atoms. Each separate oxygen atom can combine with another complete oxygen molecule, allowing ozone (O3) to form.

Decades ago concerns were raised about chlorofluorocarbons (CFCs) destroying the ozone layer which is known to be very protective from the harmful effects of UV radiation. This is because ozone is very good at absorbing UV energy. But CFCs break apart ozone molecules, depleting them from our atmosphere and allowing more UV to hit the Earth’s surface. The Montreal Protocol in 1989 helped to ban CFCs and in the decades since, we’ve seen a gradual increase in the ozone layer, demonstrating that we’ve made some progress in one component of protecting our planet’s atmosphere.

Ground level ozone is different. It exists in the troposhere and is, therefore, called tropospheric ozone. The troposhere is located from Earth’s surface up to anywhere between 12 and 20 kilmoetres up. Ground level ozone is formed from chemical processes. Molecules such as nitrogen oxides and carbon monoxide react in the presence of sunlight and go through a number of chemical reactions before leading to the formation of a molecule of O3.

The main ways we humans contribute to the formation of ground level ozone is through incomplete combustion of fossil fuels through motor vehicles and industry, and also through chemical solvents. In high concentrations, ground level ozone is a pollutant and a major factor in smog formation. When inhaled it irritates the respiratory system.

Ground level ozone can lead to the following:
—reduced lung function
—aggravation of asthma
—increased susceptibility to respiratory infections
—damage lung tissue which can be permanent

The World Health Organization estimates that in Europe alone, 21,000 premature deaths every year are attributed to ground level ozone. Canadian statistics estimate that 5.5 percent of cardiopulmonary deaths are attributable to ground level ozone, and unfortunately that number is on a slow but steady climb.

So from now on I promise to be more precise in my terminology. I also think tropospheric or ground level ozone is important to know about, but I believe few people have even heard of it. It’s not something strictly related to climate as much as pollution, but it has broad-sweeping implications to our health if it continues to increase as a problem.

Improved health and less pollution would be one of the many benefits—and a much more immediate one—if we were able to wean ourselves off of fossil fuels.