Title: Studies of airborne ultrafine particles in polluted atmospheres Language: English
Invited speaker: Professor Roy M. Harrison, from the University of Birmingham and member of the IDAEA’s External Scientific Advisory Committee
Title: Studies of airborne ultrafine particles in polluted atmospheres
Date: 11th July 2023
Time: 11:30 pm.
Venue: Sala d’Actes IDAEA-CSIC. The talk will be also streamed online:
Link to the talk
Length: Long – up to 45min
Abstract:
Ultrafine particles (UFP), also referred to as nanoparticles, are defined as those with a diameter <100nm. They are a major focus of interest as they dominate the number count of particles in the atmosphere, and there is some, albeit limited, evidence for toxicity independent of the larger particles which account for most particle mass. A brief introduction to ultrafine particles will be given to place the topic in context. This will move on to studies of UFP in diesel engine exhaust and the roadside atmosphere, where both solid graphitic particles, and liquid particles comprised mainly of condensed lubricating oil are observed. Numerical models have been developed which simulate these particles in the urban atmosphere at resolution down to 10 metres. Recent work shows that diesel particle filters have been very effective in removal of the solid particles, but the liquid particles are largely unaffected as they pass through the filter as vapour, and condense as the exhaust cools on mixing with ambient air. Work airside at Heathrow Airport shows high concentrations of UFP, smaller than the majority of those from road traffic, and by using a fast response instrument, plumes from individual aircraft have been quantified. New particle formation in locations as diverse as Beijing and Antarctica has been a major focus of study, and comparison of roadside and urban background locations shows that nucleation events are typically less frequent at roadside, but both new particle numbers and growth rates are greater. Simulations of new particle formation in Beijing, where it can contribute significantly to haze formation, shows that projected emissions reductions will lead to a substantial reduction in new particle formation.
