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Open AccessArticle

Seasonal Trends of Formaldehyde and Acetaldehyde in the Megacity of São Paulo

Department of Atmospheric Sciences, Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG, Institute of Astronomy, Geophysics, and Atmospheric Sciences), Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, São Paulo—SP 05508-090, Brazil
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Atmosphere 2017, 8(8), 144; https://doi.org/10.3390/atmos8080144
Received: 5 June 2017 / Revised: 1 August 2017 / Accepted: 3 August 2017 / Published: 8 August 2017
(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)
The Metropolitan Area of São Paulo (MASP) is the largest megacity in South America, with 21 million inhabitants and more than 8 million vehicles. Those vehicles run on a complex fuel mix, with ethanol accounting for nearly 50% of all fuel sold. That has made the MASP a unique case study to assess the impact of biofuel use on air quality. Currently, the greatest challenge in terms of improving air quality is controlling the formation of secondary pollutants such as ozone, which represents the main air pollution problem in the MASP. We evaluated the temporal trends in the concentrations of ozone, its precursors (formaldehyde, acetaldehyde, and NO2), CO, and NO, from 2012 to 2016. Formaldehyde and acetaldehyde concentrations were frequently higher in winter than in other seasons, showing the importance of meteorological conditions to the distribution of atmospheric pollutants in the MASP. We found no clear evidence that the recent growth in ethanol consumption in Brazil has affected acetaldehyde concentrations, which are associated with emissions from ethanol combustion. In fact, the formaldehyde/acetaldehyde ratio remained relatively constant over the period studied, despite the change in the fuel consumption profile in the MASP. View Full-Text
Keywords: air quality; aldehydes; biofuels; carbonyl compounds; ozone precursors; pollution trends; volatile organic compounds (VOCs) air quality; aldehydes; biofuels; carbonyl compounds; ozone precursors; pollution trends; volatile organic compounds (VOCs)
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Nogueira, T.; Dominutti, P.A.; Fornaro, A.; Andrade, M.D.F. Seasonal Trends of Formaldehyde and Acetaldehyde in the Megacity of São Paulo. Atmosphere 2017, 8, 144.

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