Reduced ultrafine particle levels in Sao Paulo's atmosphere during shifts from gasoline to ethanol use.

ABSTRACT: Despite ethanol's penetration into urban transportation, observational evidence quantifying the consequence for the atmospheric particulate burden during actual, not hypothetical, fuel-fleet shifts, has been lacking. Here we analyze aerosol, meteorological, traffic, and consumer behavior data and find, empirically, that ambient number concentrations of 7-100-nm diameter particles rise by one-third during the morning commute when higher ethanol prices induce 2 million drivers in the real-world megacity of São Paulo to substitute to gasoline use (95% confidence intervals: +4,154 to +13,272 cm^-3). Similarly, concentrations fall when consumers return to ethanol. Changes in larger particle concentrations, including US-regulated PM2.5, are statistically indistinguishable from zero. Th

SUBMITTER: Salvo A 

PROVIDER: S-EPMC5516031 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature