Question: How much carbon dioxide does a normal person exhale in a day, and does the increase in population have an effect on the carbon dioxide level in the atmosphere?
Answer: Each person exhales about 2-1/2 pounds of carbon dioxide a day, but the effect on the atmosphere is minimal. All the people on the planet contribute only around 3/1000 of a percent of the total amount of carbon dioxide in the atmosphere. So there's no need to worry that the population increase is contributing to the greenhouse effect -- at least not in terms of our exhalation. It's the other things that our large population does -- including driving cars and flying planes -- that add damaging levels of carbon dioxide to the atmosphere.