Air Pollution 101 | National Geographic

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[Women Speaker] Air pollution consists of chemicals or particles in the atmosphere that pose serious health and environmental threats. But what causes air pollution? And what does it mean for our planet? Some air pollution comes from natural sources, like volcanic eruptions, wildfires, or allergens. But most air pollution results from human activities, such as energy used in agriculture.

There are different types of human-made air pollution. When we burn fossil fuels to produce energy, they release greenhouse gases into the air. These emissions, such as carbon dioxide, methane, nitrous oxide, and fluorinated gases, trap heat from the sun in Earth's atmosphere, leading to a rise in global temperatures. This creates a cycle where air pollution contributes to climate change, and climate change creates higher temperatures. In turn, higher temperatures intensify some types of air pollution.

For example, climate change increases smog because it forms in the presence of high heat and increased levels of ultraviolet radiation. More frequent extreme weather, such as flooding, contributes to damp conditions and therefore a rise in mold. Warmer weather also leads to longer pollen seasons, and therefore more pollen production.

Smog is a type of air pollution that reduces visibility and has serious health effects. Smog can be divided into two categories: sulfurous and photochemical. Sulfurous smog is made up of chemical compounds called sulfur oxides. It occurs when burning sulfur-bearing fossil fuels, such as coal.

Photochemical smog, also called ground-level ozone, is a result of the reaction between sunlight, nitrogen oxides, and volatile organic compounds. Nitrogen oxides come from car exhaust, coal power plants, and factory emissions. Volatile organic compounds are released from gasoline, paints, and many cleaning solvents.

Smog not only creates a brown haze that reduces visibility but also harms plants, irritates the eyes, and causes respiratory distress. Another category of air pollution is toxic pollutants. These are chemicals such as mercury, lead, dioxins, and benzene that are released during gas or coal combustion, waste incineration, or burning of gasoline.

In addition to adverse environmental effects, toxic air pollution can cause serious health problems, such as cancer, reproductive complications, and birth defects. While air pollution has many consequences for our planet, there are solutions. We can limit toxic pollutants, smog, and greenhouse gases by decreasing the use of fossil fuels, such as in transportation, manufacturing, and electricity generation.

Reducing air pollution not only contributes to a cleaner environment and better human health but can also slow the rate of global warming. (chime music)