Answer: Here are some factors on why the Carbon Levels are lower in this months. The main factor why is because it's around the summer time, and a lot of plants grow at this time of year. With the more plants grown, the more Carbon is out of the air, and the less levels there are in the air. The second factor why this is happening is because many people are on vacations. They are resting in Florida, or chilling in Italy. You may be like, What? But this is a reason. When they are chilling on the beach, there vehicle isn't in use, and it lowers the levels as more people are doing this. And In these times, people are staying home, so they aren't using their car, which added, increases the carbon rates. And in Winter, the plants die, so the carbon goes up, and cars burn more petrol to keep it in use in the cold, which also increases the carbon levels in the air. I hope this helps. :)