Characteristics of VOC Composition at Urban and Suburban Sites of New Delhi, India in Winter
Nidhi Tripathi
Physical Research Laboratory (PRL), Ahmedabad, India
Indian Institute of Technology Gandhinagar Palaj, Gandhinagar, Gujarat, India
Contribution: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing - original draft
Search for more papers by this authorCorresponding Author
L. K. Sahu
Physical Research Laboratory (PRL), Ahmedabad, India
Correspondence to:
L. K. Sahu and S. N. Tripathi,
Contribution: Conceptualization, Methodology, Writing - review & editing, Visualization, Supervision, Project administration
Search for more papers by this authorLiwei Wang
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Formal analysis, Investigation, Data curation
Search for more papers by this authorPawan Vats
Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
Contribution: Methodology, Investigation, Data curation
Search for more papers by this authorMeghna Soni
Physical Research Laboratory (PRL), Ahmedabad, India
Indian Institute of Technology Gandhinagar Palaj, Gandhinagar, Gujarat, India
Contribution: Software, Formal analysis, Investigation
Search for more papers by this authorPurushottam Kumar
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Now at Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
Contribution: Writing - original draft
Search for more papers by this authorR. V. Satish
Physical Research Laboratory (PRL), Ahmedabad, India
Now at Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
Contribution: Data curation
Search for more papers by this authorDeepika Bhattu
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Now at Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
Contribution: Writing - review & editing
Search for more papers by this authorRavi Sahu
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Contribution: Data curation
Search for more papers by this authorKashyap Patel
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Software, Formal analysis, Data curation
Search for more papers by this authorPragati Rai
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing
Search for more papers by this authorVarun Kumar
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Search for more papers by this authorNeeraj Rastogi
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Data curation, Writing - review & editing
Search for more papers by this authorNarendra Ojha
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Methodology, Software, Validation, Writing - review & editing
Search for more papers by this authorShashi Tiwari
Department of Civil Engineering, Manav Rachna International Institute of Research and Studies (MRIIRS), Faridabad, Haryana, India
Contribution: Writing - review & editing
Search for more papers by this authorDilip Ganguly
Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
Contribution: Resources, Data curation, Writing - review & editing
Search for more papers by this authorJay Slowik
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing, Visualization
Search for more papers by this authorAndré S. H. Prévôt
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing, Visualization, Supervision, Project administration
Search for more papers by this authorCorresponding Author
Sachchida N. Tripathi
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Correspondence to:
L. K. Sahu and S. N. Tripathi,
Contribution: Data curation, Writing - review & editing, Supervision, Project administration
Search for more papers by this authorNidhi Tripathi
Physical Research Laboratory (PRL), Ahmedabad, India
Indian Institute of Technology Gandhinagar Palaj, Gandhinagar, Gujarat, India
Contribution: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing - original draft
Search for more papers by this authorCorresponding Author
L. K. Sahu
Physical Research Laboratory (PRL), Ahmedabad, India
Correspondence to:
L. K. Sahu and S. N. Tripathi,
Contribution: Conceptualization, Methodology, Writing - review & editing, Visualization, Supervision, Project administration
Search for more papers by this authorLiwei Wang
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Formal analysis, Investigation, Data curation
Search for more papers by this authorPawan Vats
Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
Contribution: Methodology, Investigation, Data curation
Search for more papers by this authorMeghna Soni
Physical Research Laboratory (PRL), Ahmedabad, India
Indian Institute of Technology Gandhinagar Palaj, Gandhinagar, Gujarat, India
Contribution: Software, Formal analysis, Investigation
Search for more papers by this authorPurushottam Kumar
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Now at Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
Contribution: Writing - original draft
Search for more papers by this authorR. V. Satish
Physical Research Laboratory (PRL), Ahmedabad, India
Now at Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
Contribution: Data curation
Search for more papers by this authorDeepika Bhattu
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Now at Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, India
Contribution: Writing - review & editing
Search for more papers by this authorRavi Sahu
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Contribution: Data curation
Search for more papers by this authorKashyap Patel
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Software, Formal analysis, Data curation
Search for more papers by this authorPragati Rai
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing
Search for more papers by this authorVarun Kumar
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Search for more papers by this authorNeeraj Rastogi
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Data curation, Writing - review & editing
Search for more papers by this authorNarendra Ojha
Physical Research Laboratory (PRL), Ahmedabad, India
Contribution: Methodology, Software, Validation, Writing - review & editing
Search for more papers by this authorShashi Tiwari
Department of Civil Engineering, Manav Rachna International Institute of Research and Studies (MRIIRS), Faridabad, Haryana, India
Contribution: Writing - review & editing
Search for more papers by this authorDilip Ganguly
Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
Contribution: Resources, Data curation, Writing - review & editing
Search for more papers by this authorJay Slowik
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing, Visualization
Search for more papers by this authorAndré S. H. Prévôt
Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
Contribution: Writing - review & editing, Visualization, Supervision, Project administration
Search for more papers by this authorCorresponding Author
Sachchida N. Tripathi
Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, India
Correspondence to:
L. K. Sahu and S. N. Tripathi,
Contribution: Data curation, Writing - review & editing, Supervision, Project administration
Search for more papers by this authorAbstract
Simultaneous measurements of volatile organic compounds (VOCs) using two PTR-TOF-MS instruments were conducted at urban and suburban sites of New Delhi during the winter of 2018. The time series of VOC mixing ratios show substantial variations mainly influenced by local emissions and meteorological conditions. Mixing ratios of methanol (∼28 ppbv), acetaldehyde (7.7 ppbv), acetone (10.6 ppbv), isoprene (2.8 ppbv) and monoterpenes (0.84 ppbv) at the suburban site were higher than those at the urban site, while levels of aromatic VOCs were almost similar. The strong nighttime correlations of isoprene and monoterpenes with CO and benzene at the urban site indicate their predominant anthropogenic origin. Higher emission ratios of ∆VOCs/∆CO and ∆VOCs/∆benzene than those reported for vehicular exhaust suggest the contributions of other sources. In addition to vehicular emissions, episodes of biomass burning, industrial plumes and aged air strongly influenced the levels of VOCs at the suburban site. Despite the predominant primary anthropogenic emissions, the higher daytime enhancements of OVOCs/CO ratios indicate additional contributions of OVOCs from secondary/biogenic sources. The secondary formation of OVOCs in moderately aged air masses was noticeable at the suburban site. Using the source-tracer-ratio method, the estimated biogenic contributions of isoprene (71%) and acetone (65%) during daytime at the suburban site were significantly higher than those for the urban site. The photochemical box model simulations suggest that daytime ozone formation was under the VOC-limited regime. The present study highlights the impact of different emission sources, photochemical processes and meteorological conditions on the composition and concentration of VOCs in the Delhi region.
Key Points
-
Vehicular exhaust, episodes of biomass burning, industrial plumes and aged air strongly influenced the concentration and composition of VOCs
-
Higher enhancements of OVOCs in photochemically aged air masses reveal their significant secondary productions at the suburban site
-
The estimated biogenic contributions to ambient air isoprene for the suburban site were higher than those for the urban site
Plain Language Summary
Contributions of natural and anthropogenic sources of volatile organic compounds (VOCs) vary on local and regional scales. In recent years, emission from the use of fossil fuels is the main anthropogenic source of ambient air VOCs in the urban regions of developing countries. Other sources such as biomass/biofuel burning and biogenic emissions also influence urban air quality in tropical regions. The distinction between biogenic and anthropogenic contributions of VOCs in urban air is not straightforward because many VOCs are emitted from several co-located sources. In this study, we performed simultaneous VOC measurements using state-of-art instruments at the urban and suburban sites of New Delhi in the polluted Indo-Gangetic Plains of India during the winter season. Besides the impact of primary sources, we have also investigated the roles of photochemical secondary formation of oxygenated VOCs. Our findings will help policymakers develop strategies for controlling primary and secondary pollutants in this tropical urban region.
Conflict of Interest
The authors declare no conflicts of interest relevant to this study.
Open Research
Data Availability Statement
Data: The data (VOCs, CO, NOx, and O3) used in this study are archived at a public data repository at Figshare https://doi.org/10.6084/m9.figshare.12496169.v2 (Tripathi et al., 2021). The photochemical box model simulations were performed using the NCAR Master Mechanism (Madronich et al., 2006; Chen et al., 2021) version-2.5. We used ECMWF (Hersbach et al., 2018) for PBL and wunderground for weather parameters (Weather Underground, 2018). Software: Figures were made with Matlab 2019 (MATLAB, 2019), Sigma Plot 14 (SigmaPlot, 2018), and IGOR Pro 6.37 (IGOR, 2016).
Supporting Information
| Filename | Description |
|---|---|
| 2021JD035342-sup-0001-Supporting Information SI-S01.docx5.1 MB | Supporting Information S1 |
Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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