Watch the video below once without sound. What do you notice? What do you wonder? As you watch, record a few of your observations, and your questions.
Pause the video halfway through, and reflect on the following questions:
- What did you notice about the colors in the video? How did they move?
- What do you think the red represents? What about the yellow? The gray?
- What information can you find on the bottom of the screen to help you interpret the colors in this video?
Now, watch the video again (and turn on the sound if you’d like to learn from the creators of this video). This is a video of a computer model of carbon dioxide (CO2) and carbon monoxide (CO) in the atmosphere, created using real ground-based air quality data. As you watch the video a second time, notice where carbon monoxide (dark gray and white), and carbon dioxide (blue, green, yellow, orange, and red) occur and how they move.
- Where did we see a lot of carbon dioxide being produced? Did it stay there?
- What about carbon monoxide?
- What does this model suggest about air pollution? Do you think air pollution travels?
The air around us is made of mostly nitrogen (78%) and oxygen (21%), which is great stuff to breathe. But other gases and particles get mixed into our air too, some of which can be harmful to breathe and contribute to global climate change.
Carbon dioxide occurs naturally in Earth’s atmosphere—it is used by plants and algae for photosynthesis—and is what most non-photosynthesizing organisms (e.g. animals) breathe out as a byproduct of respiration. Carbon dioxide is also formed when organic material is burned. However, CO2 is also an important greenhouse gas: It traps energy and heat from the sun in our atmosphere like a greenhouse. The rise of atmospheric CO2, and the resulting warming due to the greenhouse effect, is the primary cause of global climate change.
Unlike carbon dioxide, carbon monoxide (CO) is considered an air pollutant. An air pollutant is any substance that enters the air and is harmful to breathe. Like carbon dioxide, carbon monoxide is also a greenhouse gas, but it differs from carbon dioxide in that it is a poisonous gas that is dangerous to breathe, particularly in high concentrations. That makes it an air pollutant.
There are many different kinds of air pollutants that can make the air unsafe to breathe. Though many can have natural causes, most air pollutants come from human activities such as burning fossil fuels, agriculture, or manufacturing. Common air pollutants include particulate matter, nitrogen oxides, sulfur oxides, ground level ozone, volatile organic compounds, lead, carbon monoxide, and chlorofluorocarbons. The amounts of these pollutants in the air can change from place to place and over time, driven by weather and human activities. Poor air quality caused by air pollution is associated with a number of human diseases, including asthma, heart attack, stroke, pneumonia, and cancer, which is why air pollution is an important public health concern around the world.