RTEII: A new high-resolution (0.1° × 0.1°) road transport emission inventory for India of 74 speciated NMVOCs, CO, NOx, NH3, CH4, CO2, PM2.5 reveals massive overestimation of NOx and CO and missing nitromethane emissions by existing inventories

Haseeb Hakkim, Ashish Kumar, Saurabh Annadate, Baerbel Sinha, Vinayak Sinha*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


21 of 30 most polluted cities for particulate matter (PM2.5) are in India, yet the distribution, identity and emissions of volatile organic compounds (VOCs) from traffic, which are PM2.5 and ozone precursors, remain unknown. Here, we measured emission factors (EFs) of 74 VOCs from a range of Indian vehicle-technology and fuel types. When combined with 0.1 ° × 0.1 ° spatially resolved activity data for the year 2015, toluene (137 ± 39 Gg yr1), isopentane (111 ± 38 Ggyr−1), and acetaldehyde (41 ± 6 Ggyr−1) were top 3-VOC emissions. Petrol-2-wheelers and LPG-3-wheelers emitted the highest VOCs (EFs> 50 gVOC/L) and had highest secondary pollutant formation potential, so their replacement with electric vehicles would improve air quality. EDGARv4.3.2 and REASv.2.1 emission inventories overestimated total road sector emitted VOCs due to obsolete EFs and activity data, in particular over-estimating ethene, propene, ethyl benzene, 2,2- dimethyl butane, CO, NOx while significantly under-estimating acetaldehyde. Nitromethane emissions were missing from previous inventories and with isocyanic acid and benzene contributed significantly to toxic emissions (summed total ~41 ± 4 Ggyr−1). Knowledge of key VOCs emitted from the world's third largest road-network provides critical new data for mitigating secondary pollutant formation over India and will enable more accurate modelling of atmospheric composition over South Asia.

Original languageEnglish
Article number100118
Number of pages12
JournalAtmospheric Environment: X
Early online date20 Jun 2021
Publication statusE-pub ahead of print - 20 Jun 2021

Bibliographical note

© 2021 The Authors
Funding Information:
This research has been supported by the National Mission on Strategic knowledge for Climate Change (NMSKCC) MRDP Program of the Department of Science and Technology, India vide grant (SPLICE; grant no: DST/CCP/MRDP/100/2017(G) .


  • Acetaldehyde
  • Air quality
  • Emission inventory
  • India
  • Road transport
  • VOC

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