Narrator: This is Science Today. When one thinks of air pollution, images of smoggy cities with lots of combustion come to mind. While a day in the country may seem like a respiratory respite - there's pollution in rural areas too. Lara Gundel, a staff scientist at the Lawrence Berkeley National Laboratory, says it's just from another source.

Gundel: Country and rural areas have a different mix of particles. Can have a lot more soil dust for example. Unpaved roads, agricultural operations that will generate usually bigger particles that'll be brown rather than gray or black, like we see in urban air because of their mixture of soil.

Narrator: There's also smaller particles of pollution in rural areas that have dramatic health impacts.

Gundel: Pesticide application for example will generate a lot of gas phase pollution that when it rains, will allow these pesticides to be picked up into particles and water droplets. And so, there are actually high levels of pesticides in the rural particles and not quite so much influence of combustion. So they're different kinds of problems.

Narrator: For Science Today, I'm Larissa Branin.