Brazilian researchers determine ultrafine particles in air falls with more ethanol use

In Brazil, the concentration of ultrafine particles less than 50 nanometers in diameter rose by one-third in the air of São Paulo, Brazil, when higher ethanol prices induced drivers to switch from ethanol to gasoline, according to a new study by a Northwestern University chemist, a National University of Singapore economist and two University of São Paulo physicists.

The research team also found when São Paulo drivers—some two million of them—switched back to ethanol because prices had gone down, the concentration of ultrafine particles also went down. This lockstep movement illustrates a very tight correlation between fuel choice and nanoparticles in the air.