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Investigating local and regional air pollution from shipping

Prof. James Lee (YDC), Dr Sarah Moller (YDC), Dr Jim Hopkins (YDC)

Contact email: james.lee@york.ac.uk

Summary

Shipping is a growing sector but one of the least regulated sources of emissions of atmospheric pollutants. It is also an important source of gaseous and particulate air pollution in coastal regions, causing up to 400,000 premature deaths per year globally. In the UK, it is estimated that between 2.0 and 4.6% of background nitrogen oxides (NO + NO2, NOx) NOx is attributable to local and regional shipping sources. It is therefore important to better understand the effect shipping has on UK air pollution, especially in coastal areas and in particular in ports.  Ships generally burn low-quality, high-sulphur fuel and the high temperature combustion in ship engines produce emissions high in NOx but low in other photo-pollutants such as carbon monoxide (CO) and volatile organic compounds (VOCs). It has been estimated that shipping accounts for between 12 and 17% of all NOx sources globally. Shipping emissions are particularly important because whereas most NOx sources are to be found over land, emissions from shipping occur within the marine boundary layer (MBL) and constitute the only large primary NOx source in these regions. The presence of NOx and VOCs in ship emissions means there is also effect an ozone (O3). Model studies have shown that shipping potentially contribute around 6% to the tropospheric ozone burden, which in turn leads to a radiative forcing increase of around 8% compared to pre-industrial times. It is therefore important to understand the chemistry that forms O3 in ship plumes.

This project aims to improve understanding of the effect of shipping on both local UK and regional air pollution through 3 specific objectives. 

1. Ozone production in ship plumes will be investigated using measurements of a range of chemical species made from the UKs large atmospheric research aircraft. Measurements of O3, CO, NOx, CO2, CH4, SO2 and a range of VOCs will be made in a series of ship plumes in both North Atlantic shipping lanes off the Iberian peninsula and in the English Channel. The measurements will allow O3 formation to be investigated in the plumes from close to source out to several hours downwind. Flights will be carried out in late 2019 and summer 2020 to allow investigation of the effect of the new sulphur emission regulation in international waters on the plumes. Modelling of O3 production will be carried out using a detailed box model in order to assess the dominant O3 formation pathways in the various plumes.  

2. The effect of shipping on remote NOx and O3 will be investigated using a 12 year time series of NOx and O3 taken at the Cape Verde Atmospheric Observatory (CVAO), a remote measurement site in the tropical North Atlantic Ocean. Regular spikes of NOx have been observed in the data with a possible source of these fluctuations being the presence of shipping in the area. Previous data will be investigated to assess whether there has been a change in ship originated peaks over the past 12 years and whether this coincides with any change in shipping patterns.

3. Measurements of NOx, SO2, O3, CH4, CO2, C2H6 and a range of other VOCs in coastal regions and around a series of UK ports to assess the impact of shipping on air quality. The Automatic Identification System (AIS) database (via the marine-traffic.com website) will be used to inform on ship traffic in the area and in the ports, which will allow background measurements to be made when ship traffic in the area is light or when ships are not in port. Different types of ports will be targeted (e.g. Felixstowe for container ships, Southampton for cruise liners and Grangemouth for oil tankers).      

The student will develop transferable skills in making atmospheric measurements (e.g. of NOx, O3, CO and VOCs for both ground and aircraft based measurements), the application and evaluation of chemical mechanisms, numerical and data skills associated with model/measurement comparison and analysis of long term trends of atmospheric gases using a variety of statistical techniques. They will also develop a wider view of what is important for local and global air quality, and the role of international policy in controlling local, regional and global air pollution.

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Related undergraduate subjects:

  • Atmospheric science
  • Chemistry
  • Computer science
  • Environmental science
  • Geochemistry
  • Geophysics
  • Geoscience
  • Mathematics
  • Physical science
  • Physics
  • Statistics