Quantifying Feedbacks between Pollution, Radiation and Dynamics in a Polluted Megacity

  • Jessica Slater

Student thesis: Phd


Air pollution is a major global health concern, contributing to an estimated 7 million premature deaths per year. 91 % of the world's population live in areas with unsafe air which is a particular issue in urban areas.This is due to high levels of anthropogenic emissions from sectors such as: industry, transport, heating and biomass burning. However, natural emissions from wildfires, volcanoes, sea spray and desert dust can also contribute to poor air quality. Pollutants in the atmosphere undergo physical and chemical changes which can greatly affect their physical and chemical properties. Furthermore, they can interact with radiation to impact the climate and cause changes in meteorology, which can enhance atmospheric pollution.Rapid urbanisation and industrialisation in countries like China and India has led to large populations living in urban environments with poor air quality. Beijing, a megacity in North Eastern China, is well known for its air quality problems. This is due to high anthropogenic emissions combined with unfavourable meteorology and topography. Despite policy interventions improving average annual air quality in Beijing, it still experiences extreme pollution episodes or haze. During haze episodes, aerosol particles accumulate in a shallow planetary boundary layer (PBL), to reduce visibility < 10 km. The interactions of aerosol particles with radiation in Beijing is believed to suppress turbulent motion, inhibit pollutant dispersion and allow for high aerosol concentrations to accumulate in a shallow PBL. This further increases the extent of aerosol-radiation interactions. The feedback between aerosols, radiation and PBL meteorology is believed to contribute significantly to the intensity and longevity of haze episodes in Beijing.However, quantifying this effect has proven difficult through observational and regional modelling studies alone. These studies struggle to fully characterise the urban PBL and directly elucidate some of the important processes and variables affecting the aerosol-PBL feedback mechanism. This work presents the development and use of a fully coupled LES-aerosol radiation model, which allows for isolation of processes and variables that impact the aerosol-PBL feedback. This has allowed for further understanding of the contribution of this process to Beijing haze episodes.
Date of Award31 Aug 2021
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorHugh Coe (Supervisor), Gordon Mcfiggans (Supervisor), Paul Connolly (Supervisor) & David Topping (Supervisor)


  • Planetary Boundary Layer
  • Air Pollution
  • Meteorology
  • Megacity
  • Aerosol
  • Atmospheric Modelling

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