Air Pollution: What, Where, How, Why?

Katy Swiere

Our air is increasingly becoming contaminated in both urban and rural areas around the world. Even if you don’t live in a city, you are affected by it. But why is it a problem, and how is it harmful? Let’s take a look at the science of air pollution.

What is pollution, really?

pollution-smoke Pollution consists of “gaseous and particulate contaminants that are present in the earth’s atmosphere,” according to the National Park Service. Our air is made of many gases, but the overwhelming majority is composed of nitrogen and oxygen. When other gases increase in concentration, they can easily become a threat to the environment and human health. There are many different types of air pollution, including sulfur dioxide, carbon monoxide, carbon dioxide, volatile organic compounds (or VOCs, carbon based chemicals which affect human health and are a part of the formation of smog), ozone (not to be confused with the good part of the atmosphere, this ozone plays a critical role in the formation of smog), particulates (sooty deposits of different sizes), gaseous heavy metals, and more.

Where does it happen?

Pollution is concentrated in cities. Delhi, India and Beijing, China are often put at the top of lists for being the most polluted in the world. Some cities like Beijing and Los Angeles, California, are particularly susceptible to the effects of pollution because of temperature inversion, influenced by neighboring mountains and oceans in which polluted air does not disperse to nearby areas but remains stagnant, building concentration. According to the World Health Organization, 90% of pollution related deaths happens in low- and middle- income countries, often where inefficient practices occur and medical practices are less available. In early January, Beijing and much of Northern China were put on “red alert” because of the concentration of fine particulates in the air. Pollution does not only affect the cities of these countries, however. Once it escapes into the atmosphere, it is a problem for us all.

How does it happen?


Air pollution is released into the atmosphere in many ways. Cars, the burning of fossil-fuels, industrial plants, and agriculture are just a few examples of the releasing of harmful additions to our atmosphere. Though much of it is human-related, there are also natural sources, such as volcanoes, wildfires, and dust storms. Air pollution can be carried by the wind in a process known as air transport, and does not only affect the area in which it is produced. Greenhouse gases, for example, affect the entire planet when emitted by trapping heat globally. It’s important to remember that air pollution is only one type of pollution– water, land, noise, and light pollution are also issues in our growing world.

Why should I care?

Of all global deaths, 11.6% were attributed to indoor and outdoor air pollution in 2012. This is a large-scale problem causing significant human health concerns which must be addressed. Pollution is a major health risk to everyone, but low-income communities, women, children, and the elderly are particularly susceptible. Lung damage, asthma, heart attacks, and cancers are just some of the health effects in humans. Significant effects are found on the environment as well, through phenomena such as acid rain, bio-accumulation (such as mercury building up in the food chain), and climate change. These can affect human health directly as well, but also contribute to other environmental issues like loss of biodiversity and desertification.

Thankfully, there is hope of a better future. Many of the agreements made in the Paris Climate Change Conference are predicted to lower pollution levels, and individual countries are taking action as well. More scientific research will be necessary (especially in developing countries) to monitor pollution and implement safe measures to curtail it. We still have a long way to go, so let us hope and take action to ensure that we keep moving forward.

Edited by: Daryn Dever and Ruby Halfacre