By Marlena Norwood
Recently, the American Lung Association ranked the 10 U.S. cities with the cleanest air. Leading the pack is Cheyenne, WY followed closely by Santa Fe, NM. To compute these rankings, two main criteria were used: amount of ozone and amount of particulate matter (PM) in the air. Ozone and PM are the main pollutants that harm the environment and our health. Let’s explore both.
(NOTE: Ozone as a pollutant is different than holes in the ozone layer. The atmosphere has good ozone and bad ozone. “Good” ozone that shields the Earth from UW rays can develop holes because of aerosol sprays. This is different than the “bad” ozone that is produced by human activity. Bad ozone, the pollutant, is closer to the ground.)
Ozone is a secondary pollutant, meaning it is produced by reactions of other pollutants. The ingredients for ozone are volatile organic compounds (products of industrial fossil fuel combustion) and nitrates (products of mainly vehicular emissions). When nitrates react with VOCs in the presence of heat, ozone is formed.
Ozone is a well-known pollutant, tightly linked to global warming science. Ozone acts as a “greenhouse gas” and traps radiation energy from the sun. As more radiation energy is trapped over time, Earth’s temperature rises. Global warming has countless harmful effects on the planet, its climate, human health, ecosystems, and endangered species.
Particulate Matter (PM)
In contrast to ozone, particulate matter (PM) is a primary pollutant – it is directly emitted, rather than the product of a reaction. PM is considered an aerosol because its tiny particles are dispersed throughout the air – similar to fog or hairspray. It results from the incomplete combustion of wood, diesel, and other organic compounds like fossil fuels.
There are many particles in the air that we breathe – but PM is the most hazardous of all because of its size. PM is “nano-sized” – so small that it can actually leave the blood and enter your cells by penetrating their membranes.
Although PM is nano-sized, it has a large surface area – similar to the microscopic villi in our small intestines. Harmful toxins and carcinogens in the air are able to bind to the surface of the PM. PM literally facilitates the transport of carcinogens and other toxins into our cells, which then wreak havoc on our DNA and cause harmful health effects like cancer. PM also can build up in the lungs, causing serious long-term health issues.
Babies in utero are the most at risk for health complications from PM. When pregnant mothers inhale PM in the air, the placenta provides no protection. Thus, babies in crucial developmental stages are directly exposed to dangerous carcinogens. PM also triggers asthma by inducing inflammatory responses in lung airways.
We all need air to survive. In order to live long and healthy lives, we need our air to be less polluted. Let’s clean our air. Here’s what you can do:
- Since both ozone and PM are results of combustion, limit the amount that you drive. Take public transportation, bike or walk to work, and look into buying electric or partially electric cars like the Nissan Leaf.
- Learn about your community’s primary sources of air pollutants from the EPA’s lists of activities: (1) industry, business & home, and (2) transportation sources.
- All the clothes, food, electronics, household items, etc. that we use most likely required the combustion of fossil fuels in the process. Recycle and reuse as much as possible to reduce your demand for products.