Why did recent rains result in dirty cars?

MINNEAPOLIS -- Waking up to rain overnight was a welcomed sight for so many of us. But what wasn't welcomed was seeing how dirty our cars were after the storm. So why was everything dirtier after it rained? Good Question.

The dust was actually from the central plains, where they've had strong winds just like us the past couple of days.

Luigi Romolo is a Minnesota State Climatologist. He explained the phenomenon to WCCO's Heather Brown.

"When it rains, dust get kicked up by the wind that precedes the rainfall, especially when you have a thunderstorm," Romolo said.

That dust then mixes with rain.

"It falls with the rain and lands wherever the water hit, whether it's a tree or your coat or your car," Romolo said.

There are other pollutants that could be in the mix as well, such as airplane or vehicular exhaust, seedlings, pollen, and other items.

Monday was especially dirty because it hadn't rained in awhile.

"If you get consecutive days of rainfall, you're going to wash that dust away and there's going to be less in the air," Romolo said.

The water in a car wash is cleaner than the rain. But what really gets the particles off your car is the soap. It adds something the dust can stick to and then slide off.