Using satellites to map the spatial characteristics of urban air pollution from aerosols at a time of climate change, health choices and pandemics

Airborne particles play a critical role in environmental science with major implications for climate and air quality. Particulate matter (aerosols) is one of the most important factors for poor air quality and most of the estimated 4 million excess deaths per year stem from cardiovascular and respiratory diseases caused by particulate matter in the air. Correlations of high densities of aerosols (smog) with transmission and morbidity data from Covid-19 have suggested statistical links, at least, between pollution, Covid vulnerability (e.g. respiratory), urban density and disease transmission. However, aerosols are highly complex and variable, especially in cities, due to their diverse sources (vehicle exhaust, industry, fuel-burning etc.) and atmospheric reactions. Existing ground-based networks can provide an excellent temporal but only a very incomplete spatial view of urban aerosol distributions. For many cities, a new form of observation is required to provide aerosol air quality information to all and would transform our ability to assess aerosol distributions and their likely health impacts.
Optical instruments on satellites are an important resource to monitor aerosols from space. The recently launched Sentinel-2 can fundamentally change our approach to urban aerosols by allowing us to derive aerosol information on an unprecedented scale of tens of meters (potentially 10 m). This is the relevant scale to pinpoint different aerosol sources (roads, industrial facilities etc.), to diagnose aerosol variations across urban conurbations and the impact of transport pathways within a city.
In this project, the challenges of the science require new methods to derive the aerosol concentrations so the student will create a novel aerosol dataset with very high spatial resolution and use it to challenge our current understanding of urban aerosols. The exciting science that follows will be of great interest to other scientists, to the public and to policy makers. Results will be published in high quality journals and shared with government and local authorities, particularly through contacts in the Department for Environment, Food and Rural Affairs. CENTA partners have some great strengths in this type of research so the project will build links across CENTA.