Megacity Delhi atmospheric emission quantification, assessment and impacts (DelhiFlux)

Lead Research Organisation: UK Centre for Ecology & Hydrology
Department Name: Atmospheric Chemistry and Effects

Abstract

Inventories of emissions of pollutants to air form the basis for model predictions of air quality, visibility, human exposure, human health impacts, and climate change. They are further required to understand relationships between individual source locations or source types and targets. None of the model predictions and analyses can be better than the emission database on which they are founded. This project seeks to greatly improve the emissions inventory for the wider Delhi area, one of the most polluted conurbations globally. The emission inventory will be compiled at a 1 km x 1 km resolution with diurnal and seasonal temporal profiles. It will cover NOx, SOx, NH3, total volatile compounds with breakdown into its chemical profile, particulate matter in fine (PM2.5) and coarse (PM10) size ranges, together with the toxic metal components within, as well as CO2 and CO as combustion tracers.
To improve the emission inventory we will make laboratory-based measurements of emission factors and also measure, for the first time in India, the emissions from individual vehicles under real-world driving conditions to characterize the actual Delhi vehicle fleet. We will further perform the first micrometeorological flux measurements of these compounds above the city and study their enrichment along a transect. This will provide further information on potentially missing sources and serve as a direct assessment of the quality of the emissions inventory.
We will further apply a state-of-the-art chemistry and transport model to infer the concentrations that would be expected on the basis of the new emissions inventory for comparison against concentration data from air quality networks and the wider NERC-MRC-MoES-DBT programme.

ODA compliance:
By providing the emissions data required to assess human exposure and develop cost-effective solutions to combat air pollution in Delhi, the project will target poverty and development issues. Accurate knowledge of emissions is a key factor underpinning the development of mitigation strategies which will deliver improved public health, whilst further allowing economic growth. Both the UK and Indian research teams will benefit from their interaction and exploitation of complementary expertise. The project will leave a legacy beyond the project lifetime by increasing the research capacity of the Indian teams and providing the knowledge base which will allow the findings to be extrapolated to the rest of India. Thus, the project findings will continue to contributing to the improvement of life and welfare of more than a billion people.

Planned Impact

Mitigation of air pollution in Delhi and assessment of human exposure are both heavily dependent on a reliable, quantitative assessment of emission sources in the urban area and surrounding regions. By generating and evaluating an improved emissions database for the region, DelhiFlux will provide a firm foundation for local government decisions that will benefit public health and well-being and inform studies addressing air quality and its mitigation.

Who will benefit:

1. Policymakers: Urban and regional government departments and ministries responsible for air quality policy-making in Delhi and surrounding regions and for designing mitigation strategies. These include the Ministry of Science & Technology, the Ministry of Earth Sciences, the Ministry of Urban Development, and the Ministry of Environment and Forestry.

2. General Public: Residents of Delhi and the National Capital Region who experience the impacts of air pollution on health and quality of life first-hand.

3. Scientific Community: Researchers interested in emissions inventory development; air quality modellers; atmospheric composition and climate modellers; the Indian atmospheric science community; UK and Indian researchers contributing to other parts of the Indian Megacity programme.


How they will benefit:

1. Policymakers: Decisions on emission controls require a sound understanding of the contribution of different source sectors to poor air quality. DelhiFlux will provide a much improved and evaluated high spatial resolution emission inventory that includes information on temporal variations and covers a much larger number of pollutants than currently available. This provides decision makers with the detailed information they need to develop control measures and to support long-term control of key sources such as vehicle traffic and biofuel burning.

2. General Public: The public will benefit from new knowledge of the key sources of poor air quality in Delhi, raising awareness of the measures that could be taken to address it. They will also benefit from the more informed decision-making that arises from it through better air quality that benefits their health and economic well-being.

3. Scientific Community: New measurements and understanding of emission sources and region-specific emission factors will be of immediate value to researchers building emissions inventories for the Indian subcontinent. This will benefit the wider national and international communities involved in megacity air quality modelling and in global scale modelling of atmospheric composition and climate. UK and Indian researchers will benefit from sharing expertise in novel flux measurements, emissions assessment and modelling, and the emissions data will improve operational air quality forecasting capacity in India. Other contributors to the Indian Megacity programme will benefit directly from new emissions data for Delhi, allowing them to make more reliable assessment of air pollution processes, attribution of human exposure, and mitigation approaches.


Addressing ODA Objectives:

The emissions data generated during this project will contribute directly to the development of effective and efficient methods of addressing air pollution in Delhi. As a major development issue, improvements in air quality will lead to better health outcomes and improved quality of life, underpinning future economic development in India. The results will be applicable to other cities in India, and the techniques can be applied in other developing countries. Both UK and Indian research teams will benefit from their interactions and from sharing their complementary expertise. The project will leave a lasting legacy that increases Indian research capacity and contributes to the future welfare of more than a billion people.

Publications

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Chen Y (2021) Avoiding high ozone pollution in Delhi, India. in Faraday discussions

 
Description So far the analysis of our measurements in Delhi has led to the following preliminary insights:

1. Chlorine compounds in the gas and aerosol phase in Delhi's air make a large contribution to the pollution and its impact on visibility. Our data suggest that these are probably originating from incomplete combustion of plastics under non-controlled conditions. Overall, refuse burning appears to be a major contributor to air pollution, emitting directly harmful substances, but also substances that promote the formation of ozone and PM (both harmful to human health)

2. Local submicron organic PM emissions in Delhi are dominated by traffic sources, with smaller relative contributions from cooking-related activity than found in other megacities.

3. Unexpectedly large emissions of volatile organic compounds, which contribute to the formation of ozone and PM (both harmful to human health) are associated with CNG
powered vehicles, including three-wheelers. This may reflect combustion of lubricating oil rather than of fuel itself and thus stricter regular exhaust tests could have a large impact on the urban air quality.

4. Crop residue burning in the neighbouring states has been blamed as a key factor in the poor air quality experienced by Delhi during the post-monsoon season (Oct/Nov). Whilst crop residue burning makes a significant contribution to the concentrations, the relative contribution may not be as large as previously assumed. Analysis is ongoing.

5. Whilst emissions vary significantly between different parts of the city, air concentrations are much more similar. Thus, local traffic access control, e.g. in the so-called VIP areas, has limited impact on local air quality.

6. The combustion of dung cakes is much more polluting than the combustion of fuel wood and there is a potential here to reduce air pollution by controlling its use.

7. Current official emission inventories used to model and predict Delhi's air quality and test the potential impact of emission reduction measures greatly overestimate the emissions of NOx and black carbon, at least around our measurement site.

8. Due to the current chemical climate in Delhi future reductions in NOx emissions will need to be accompanied by reductions in VOC emissions to avoid an unintended increase in ozone.
Exploitation Route The results will help national Indian and local Delhi policy makers to make decisions on where to target emission reduction measures to maximise the benefit to society (human health) and the environment whilst minimising the impact on the economy and economical growth.
Sectors Environment,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology

URL https://www.urbanair-india.org
 
Description Delhi as other Indian cities continue to struggle with poor air quality, leading to a large number of premature deaths and thus greatly affecting society and economy. Poor visibility and the need for individuals to protect themselves against air pollution lowers the quality of life of those inhabiting these cities. It is vital to optimise interventions and emission reduction measures so that they are most beneficial for human health / society and the environment, whilst minimising direct costs and the impact on economic growth. The findings of this project will be communicated to policy makers so that they can be taken into account in future policy making. Because policy needs to be supported by robust evidence it is important that the findings are published in the peer-reviewed literature and papers from our work continue to emerge. Interaction with policy makers was hampered during 2020 and 2021 as joint meetings were cancelled. It will be very difficult to measure to what extent the findings will influence local and national environmental policy and what extent this may have on Delhi's air pollution and associated mortality and quality of life. We have also engaged in building capacity in Delhi. As part of the project work we have engaged with our Indian project partners to improve / establish higher-quality measurement approaches in India and train personnel. For example, we have trained a postgraduate student at the Indira Gandhi Delhi Technical University for Women (IGDTUW), India, in the operation of state-of-the-art instrumentation for the measurement of aerosol chemical composition. We have hosted postgraduate student groups at our IGDTUW supersite and have worked with NPL-India in assessing the ammonia monitoring technology used in Indian networks (SAFAR, NPL) for artefacts under Delhi conditions. This will assist NPL's mission as India's primary metrology institute as it is taking on an extended role in providing national standardisation for air quality measurements in India.
Sector Environment
Impact Types Societal,Policy & public services

 
Title High Resolution Time of Flight Mass Spectrometer measurements made at the Indira Gandhi Delhi Technical University for Women (IGDTUW) site during the DelhiFlux field campaigns 
Description Dataset of PM1 aerosol chemical composition measured by aerosol mass spectrometer during three seasons (pre-monsoon, monsoon and post-monsoon) in 2018 at the Indira Gandhi Delhi Technical University for Women site in Old Delhi, including the results of organic factor analysis by positive matrix factorisation 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact These data have supported a paper (https://doi.org/10.5194/acp-21-10133-2021) which has quantified the contribution of different sources to PM1 in Delhi across different seasons for the first time using high resolution mass spectrometry. In particular, it has been able to separate the contributions from waste combustion and agricultural residue combustion and identified new marker compounds for these combustion products. 
URL https://catalogue.ceda.ac.uk/uuid/5631c55a2caa4cd2bcdf1bf75365bcc8
 
Title VOC concentration measured in Old Delhi, India, during the APHH-India intensive measurement periods 2018 
Description Concentrations of a range of volatile organic compounds, measured during the APHH-India intensive measurement periods 2018 (June and Oct/Nov) using a PTR-Qi-ToF-MS. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact Unique dataset to assess concentrations and sources of volatile organic compounds in Delhi, India, used in a number of publications to date. 
URL https://data.ceda.ac.uk/badc/aphh/data/delhi/delhiflux/ceh-ptr-qitof-ms
 
Description Keynote lecture at UK-China International Particle Technology Forum VIII: The use of urban micrometeorological flux measurements for the quantification of local emissions and the study of aerosol dynamics 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Keynote lecture at UK-China International Particle Technology Forum VIII (vitual meeting) attended by 20+ participants mainly from China
Year(s) Of Engagement Activity 2021