Investigating local and regional air pollution from shipping

The PhD project will aim to improve understanding of the effect of shipping on both local UK and regional air pollution. To achieve this, there are three specific activities.


i.) Investigate ozone formation chemistry in ship plumes.

Measurements of gaseous of chemical species (O3, CO, NOx, CO2, CH4, SO2 and a range of VOCs) will be made in a series of ship plumes using the FAAM research aircraft (see picture above). Flights will take place 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 to several hours downwind (see panel above for an example taken from Chen et al. 2009). 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 content and O3 production in the plumes. Modelling of O3 production will be carried out using a box model based on the Master Chemical Mechanism (MCM) in order to assess the dominant O3 formation pathways in the various plumes. Tests will also be carried out on how effectively reduced mechanisms (such as those used in global models like GEOS-CHEM) can reproduce O3 formation in the plumes.


ii.) Examine the effect of shipping on remote marine boundary layer NOx and O3.

A 12 year and on-going time series of NOx and O3 has been taken at the Cape Verde Atmospheric Observatory (CVAO), a remote measurement site in the tropical North Atlantic Ocean managed by the University of York. Regular spikes of NOx have been observed in the data. One possible explanation for these is the presence of shipping in the area, with Cape Verde being close to a major shipping lane between Europe and South Africa - see figure above showing global NOx emissions with the Cape Verde area circled. 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. In addition, an instrument to measure SO2 (which is a marker for shipping emissions in a marine environment) has recently been installed at CVAO and this data will be used to ascertain whether shipping is indeed the source of the NOx spikes. The effect of any change in NOx attributable to shipping on O3 will also be investigated.


iii.) Investigate the effect of ship emissions on air pollution in UK ports.

The UK is surrounded by very busy shipping lanes and has a number of large ports (see picture to the right) ). The relative contribution of emissions from shipping is greater around the UK than elsewhere in Europe because of this. Measurements will be made using the University of York mobile laboratory (see picture to the right), in coastal regions and around a series of UK ports to assess the impact of shipping on air quality. The mobile laboratory will be equipped with instruments to measure NOx, SO2, O3, CH4, CO2, C2H6 and a range of other VOCs. 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). Using the mobile observatory allows observations to be made while moving and gives the much needed flexibility to enable individual ship plumes to be sampled while in or close to port.