Radiocarbon based fossil fuel CO 2 observations in megacity Delhi

Temporal variations and effect of Covid-19 restrictions

Bibliographic Data

ID21378599
AuthorsRajveer Sharma (0000-0003-0454-4753, Inter-University Accelerator Centre, corresponding author), Ravi Kumar Kunchala (0000-0002-3212-6068, Indian Institute of Technology Delhi, corresponding author), Sunil Ojha (0000-0003-2240-6813, Inter-University Accelerator Centre), Pankaj Kumar (0000-0002-5625-8145, Inter-University Accelerator Centre), Satinath Gargari (Inter-University Accelerator Centre), Sundeep Chopra (Inter-University Accelerator Centre)
Year2026
Pages1-15
Publication date2026-07-08
Open AccessYes
TypeARTICLE
VenueRadiocarbon (JOURNAL)
Journal identifiersISSN: 0033-8222 • E-ISSN: 1945-5755
PublisherCambridge University Press (CUP) (PUBLISHER)
DOI10.1017/rdc.2026.10223
OpenAlexW7167706867
LanguageEN
References cited52

This study employs radiocarbon measurements (Δ 14 C) to detect fossil fuel CO 2 (CO 2ff ) in the megacity Delhi from 2018 to 2022, offering unique insights into fossil fuel emissions. Our measurements reveal varying Δ 14 C values ranging from −56.2‰ to 7.5‰ and CO 2ff values ranging from 0.3 ppm to 25.2 ppm. We observed a distinct seasonality in Δ 14 C and CO 2ff , with higher CO 2ff (lower Δ 14 C) values during winter and post-monsoon seasons and lower CO 2ff (higher Δ 14 C) in summer and monsoon seasons. We have determined emission ratios (R CO and R NOx ), and compared them with other studies worldwide. Our study also examines the impact of the COVID-19 lockdown periods on CO 2ff and observed a notable decrease of 5.6 (4.8) ppm during the pandemic’s first (second) waves. These findings enhance our understanding of CO 2 emission inventories in megacity Delhi

Fossil fuel · Megacity · Monsoon · NOx · Radiocarbon dating · Seasonality · Atmospheric and Environmental Gas Dynamics · Atmospheric chemistry and aerosols · COVID-19 impact on air quality

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