Evolution of Vehicle Emission Factors in a Megacity Affected by Extensive Biofuel Use: Results of Tunnel Measurements in Sao Paulo, Brazil

Author(s)

Nogueira, Thiago ^[1] ; Kamigauti, Leonardo Yoshiaki ^[1] ; Pereira, Guilherme Martins ^{[2, 1]} ; Gavidia-Calderon, Mario E. ^[1] ; Ibarra-Espinosa, Sergio ^[1] ; de Oliveira, Guilherme Librete ^{[3, 1]} ; de Miranda, Regina Maura ^[4] ; Vasconcellos, Perola de Castro ^[2] ; de Freitas, Edmilson Dias ^[1] ; Andrade, Maria de Fatima ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, BR-05508000 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Escola Politecn, BR-05508010 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, BR-03828000 Sao Paulo - Brazil

• Document type: Journal article
• Source: Environmental Science & Technology; v. 55, n. 10, p. 6677-6687, MAY 18 2021.
• Web of Science Citations: 0

Abstract

Since 2001, four emission measurement campaigns have been conducted in multiple traffic tunnels in the megacity of Sao Paulo, Brazil, an area with a fleet of more than 7 million vehicles running on fuels with high biofuel contents: gasoline + ethanol for light-duty vehicles (LDVs) and diesel + biodiesel for heavy-duty vehicles (HDVs). Emission factors for LDVs and HDVs were calculated using a carbon balance method, the pollutants considered including nitrogen oxides (NOx), carbon monoxide (CO), and sulfur dioxide, as well as carbon dioxide and ethanol. From 2001 to 2018, fleet-average emission factors for LDVs and HDVs, respectively, were found to decrease by 4.9 and 5.1% per year for CO and by 5.5 and 4.2% per year for NOx. These reductions demonstrate that regulations for vehicle emissions adopted in Brazil in the last 30 years improved air quality in the megacity of Sao Paulo significantly, albeit with a clear delay. These findings, especially those for CO, indicate that official emission inventories underestimate vehicle emissions. Here, we demonstrated that the adoption of emission factors calculated under real-world conditions can dramatically improve air quality modeling in the region. (AU)

• FAPESP's process: 17/17047-0 - Aerosol and clouds life cycles in Amazonia: biogenic emissions, biomass burning and impacts on ecosystem
• Grantee: Paulo Eduardo Artaxo Netto
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 19/01316-8 - URBESP: levels, composition and source APPONTMENT of PM10 and PM2.5 in São Paulo
• Grantee: Guilherme Martins Pereira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/18438-0 - São Paulo Metropolitan Area, jointly tracking climate change and air quality - METROCLIMA-MASP
• Grantee: Maria de Fátima Andrade
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 18/07848-9 - Chemical and toxicological source profiling of particulate matter in urban air - SOPRO
• Grantee: Maria de Fátima Andrade
• Support Opportunities: Regular Research Grants