Road transportation has contributed to increased emissions of conventional air pollutants and, consequently, to the increase in problems associated with the environment and human health, depending on the type of pollutant and the concentration of it. To support the development of public policies aimed to decrease total tonnes of emissions, we used a bottom-up approach to estimate the amount of air pollutants, such as carbon monoxide (CO), total hydrocarbons (THC), nitrogen oxides (NO,), particulate matter (PM), and aldehydes (RCHO), that are emitted by road transportation in the state of Rio de Janeiro (RJ) from 1980 to 2010. The results from 2010 show that cars are responsible for 55% of CO emissions, 61% of THC emissions, and 93% of RCHO emissions. Due to the use of hydrated ethanol and compressed natural gas (CNG) instead of petroleum based fuels during the period analyzed, 1,760,370 t of air pollutant emissions were avoided. Compared to Brazil, in 2010, RJ had a quantity of emissions per vehicle from 12% (CO) to 59% (PM) smaller than the national average. As strategies to reduce air pollutant emissions, we consider reducing the intensity of use, with a proportional reduction in emissions, and increased the use of biodiesel. (C) 2012 Elsevier Ltd. All rights reserved.