"I've always wondered why we pave our streets to begin with." Dramatic reduction in particulate air pollution. There have been programs to reduce air pollutio

"I've always wondered why we pave our streets to begin with." Dramatic reduction in particulate air pollution. There have been programs to reduce air pollution in towns along the US - Mexico border. Folks on the US side paid to have roads paved in Mexico so it would reduce pollution--it was cheaper than taking incremental steps on the US side.