The October 2017 red sun phenomenon over the UK

On 16 October 2017 ex-hurricane Ophelia brought strong winds to Ireland and caused extensive damage. Over Wales, England and parts of Scotland a weak cold front associated with the system acted as a conveyor belt, bringing a mixture of Saharan dust and biomass burning smoke from Portugal and Spain and, for a time, turning the sky a muddy brown/orange colour and the Sun bright red. This analysis uses Copernicus Atmospheric Monitoring Service (CAMS) data to determine the fractionation of different aerosol types within the event and provide a comprehensive analysis for different cities across the UK. It also presents observations from the IASI satellite instrument of another pollutant, carbon monoxide, the concentration of which was greatly enhanced over Europe after the fire events.