Carbon monoxide and ozone are two common air pollutants. They also studied rainfall data gathered by weather satellites in orbit over the Atlantic Ocean, and information stored in databases of Atlantic hurricane measurements. They found that weather on the East Coast of the United States is likely to be rainy on weekends and clear during the week. The dirt and dust, the solid parts of the pollution, tend to absorb heat. That makes the air around those parts warmer.
Warm air rises.
The seven-day week is a purely human creation. Balling and Cerveny also found a link between pollution patterns and hurricanes. Weekend hurricanes tend to be much weaker than storms that occur Monday through Friday. Cerveny and Balling only studied the Atlantic coast. As western cities grow, some people wonder whether or not their weekends might get wetter as well.