RTEII: A new high-resolution (0.1° × 0.1°) road transport emission inventory for India of 74 speciated NMVOCs, CO, NO_x, NH₃, CH₄, CO₂, PM_2.5 reveals massive overestimation of NO_x and CO and missing nitromethane emissions by existing inventories

TY - JOUR

T1 - RTEII

T2 - 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

AU - Hakkim, Haseeb

AU - Kumar, Ashish

AU - Annadate, Saurabh

AU - Sinha, Baerbel

AU - Sinha, Vinayak

N1 - © 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) .

PY - 2021/6/20

Y1 - 2021/6/20

N2 - 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.

AB - 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.

KW - Acetaldehyde

KW - Air quality

KW - Emission inventory

KW - India

KW - Road transport

KW - VOC

UR - http://www.scopus.com/inward/record.url?scp=85108362180&partnerID=8YFLogxK

U2 - 10.1016/j.aeaoa.2021.100118

DO - 10.1016/j.aeaoa.2021.100118

M3 - Article

AN - SCOPUS:85108362180

SN - 2590-1621

VL - 11

JO - Atmospheric Environment: X

JF - Atmospheric Environment: X

M1 - 100118

ER -