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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
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© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 11 Dec 2019

Submitted as: research article | 11 Dec 2019

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A revised version of this preprint is currently under review for the journal ACP.

Quantifying burning efficiency in Megacities using NO2 / CO ratio from the Tropospheric Monitoring Instrument (TROPOMI)

Srijana Lama1, Sander Houweling1,2, K. Folkert Boersma3,4, Ilse Aben2,5, Hugo A. C. Denier van der Gon6, Maarten C. Krol3,7, A. J. Dolman1, Tobias Borsdorff2, and Alba Lorente2 Srijana Lama et al.
  • 1Vrije Universiteit, Department of Earth Sciences, Amsterdam, the Netherlands
  • 2SRON Netherlands Institute for Space Research, Utrecht, the Netherlands
  • 3Wageningen University, Meteorology and Air Quality Section, Wageningen, the Netherlands
  • 4Royal Netherlands Meteorological Institute, R&D Satellite Observations, de Bilt, the Netherlands
  • 5Vrije Universiteit, Department ofPhysics and Astronomy, Amsterdam, the Netherlands
  • 6TNO, Department of Climate, Air and Sustainability, Princetonlaan, the Netherlands
  • 7Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands

Abstract. This study investigates the use of co-located NO2 and CO retrievals from the TROPOMI satellite to improve the quantification of burning efficiency and emission factors over the mega-cities of Tehran, Mexico City, Cairo, Riyadh, Lahore and Los Angeles. Local enhancement of CO and NO2 above megacities are well captured by TROPOMI at relatively short averaging times. In this study, the Upwind Background and Plume rotation methods are used to investigate the accuracy of satellite derived ∆NO2 / ∆CO ratios. The column enhancement ratios derived using these two methods vary by 5 to 30 % across the selected megacities. TROPOMI derived column enhancement ratios are compared with emission ratios from the EDGAR v4.3.2 and MACCity, 2018 emission inventories. TROPOMI correlates strongly (r = 0.85 and 0.7) with EDGAR and MACCity showing the highest emission ratio for Riyadh and lowest for Lahore. However, inventory derived emission ratios are higher by 60 to 80 % compared to TROPOMI column enhancement ratios across the six megacities. The short lifetime of NO2 and different vertical sensitivity of TROPOMI NO2 and CO explain most of this difference. We present a method to translate TROPOMI retrieved column enhancement ratios into corresponding emission ratio, accounting for these influences. Except for Los Angeles, TROPOMI derived emission ratios are close (within 10 to 25 %) to MACCity. For EDGAR, however, emission ratios are higher by ~80 % for Cairo, 30 to 45 % for Riyadh and ~70 % for Los Angeles. The air quality monitoring networks in Los Angeles and Mexico City are used to validate the use of TROPOMI. Over Mexico City, these measurements are consistent with TROPOMI, EDGAR and MACCIty derived emission ratios. For Los Angeles, however, EDGAR and MACCity are higher by a factor 5 compared to TROPOMI. The ground-based measurements are consistent with a poorer burning efficiency in Los Angeles as inferred from TROPOMI, demonstrating its potential to monitor burning efficiency.

Srijana Lama et al.

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Srijana Lama et al.

Srijana Lama et al.


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Latest update: 05 Jul 2020
Publications Copernicus
Short summary
The rapid urbanization has increased the consumption of fossil fuel contributing the degradation of urban air quality. Burning efficiency is a major factor determining the impact of fuel burning on the environment. We quantify the burning efficiency of fossil fuel use over the mega cities using the satellite remote sensing data. City governance can used this result to understand the air pollution scenarios and to formulate the effective air pollution control strategies.
The rapid urbanization has increased the consumption of fossil fuel contributing the degradation...