An Integrated approach of dispersed source mapping and hyperlocal monitoring for air quality management: A case study of hotspots in Delhi

Limited actionable data is one of the main constraints for urban local bodies and regulatory agencies to improve air quality. Emission inventories and source apportionment are important components of air quality management. However, they provide limited information about the location of pollution sources and how the sources are changing dynamically. To overcome these limitations, a field reconnaissance survey and hyperlocal monitoring through low-cost sensors were conducted for one of the hotspots in Delhi. Field reconnaissance survey helps identify and geolocate dispersed pollution sources (unpaved roads, road dust, biomass and waste burning, construction activities, etc.). The operation of the survey includes route planning, training of field surveyors, field survey, data quality control and analysis. Through the survey, 786 dispersed sources of 14 distinct types were identified. Construction and Demolition waste, potholes, road dust and garbage dumps constitute 40 % of the sources. The concerned agencies and sub-departments were mapped through consultation with stakeholders, and sources were prioritised based on factors like population density, predominant wind direction, etc. A network of low-cost sensors is also being deployed, taking the different land use categories within the hotspot into consideration to study the impact of tackling these dispersed sources. The present approach was found to be both cost as well time effective and has the potential to scale and can be used for other scientific applications like spatial bias correction in air quality models. The approach can also be used to develop targeted strategies for improving air quality and mitigating the negative impacts of air pollution on human health and the environment.