Assessment of real-world vehicle emissions in São Paulo

Vehicular emissions are the largest contributor to air pollution in the São Paulo Metropolitan Area (SPMA). Although the national Program for the Control of Air Pollution Emissions for Motor Vehicles (PROCONVE) drove down vehicle emissions and promoted cleaner vehicle technologies by setting emission limits, the SPMA’s annual average concentrations of nitrogen dioxide (NO2) and fine particulate matter (PM2.5) frequently exceed the 2021 World Health Organization guidelines. The SPMA also suffers from high levels of ground-level ozone (O3), a secondary air pollutant with serious health implications, which is exacerbated by strong sunlight and frequent high temperatures.

Light-duty vehicles (LDVs) in Brazil are predominantly flex-fuel vehicles (FFVs), which emerged in 2003 and are fueled by any mixture of ethanol and gasoline. For heavy-duty vehicles (HDVs), which are typically fueled by diesel, biodiesel blend is mandatory. These biofuels—ethanol and biodiesel—are produced mainly from domestic sugarcane and soybeans and their use has been widely promoted in Brazil to reduce reliance on imported fossil fuels. Currently, new LDVs and HDVs are required to meet emission limits outlined in the L8 phase (from 2025 onwards) and the P8 phase (from 2023 onwards), respectively, under the PROCONVE program.

This study, conducted under The Real Urban Emissions (TRUE) Initiative, provides insights into the real-world pollutant emissions from vehicles in the SPMA. Over 323,000 vehicle emissions measurements were collected from nine sites across the SPMA from May to July 2024. Remote sensing technology was used to measure emissions of carbon monoxide (CO), hydrocarbons (HC), ammonia (NH3), nitrogen oxides (NOX), and ultraviolet smoke (a proxy for particulate matter), in addition to evaporative emissions. This study offers a comprehensive analysis of passenger cars and trucks, which are responsible for a large share of pollutant emissions in the SPMA.