It is also essential to know the chemical composition of particles to interpret their impact on health and the environment, particularly in polluted urban environments, and to understand how particles are chemically changed over time.
Water is ubiquitous in our environment and largely regulates the composition of atmospheric aerosol. However, many chemicals are not soluble in water. This is particularly true for many pollutants such as polycyclic aromatic hydrocarbons, which are considered to be carcinogenic and mutagenic, and for many of the agrochemicals that are used in crop production. Such chemicals may be very soluble and become concentrated in organic liquids.
A key theme of our work is to understand the properties of aerosol droplets that contain both water soluble and insoluble chemicals, and to understand how chemicals can dissolve into the organic phase within an aerosol. Indeed, many of the organic components may undergo chemical reactions in our environment and we are exploring the chemistry that can occur in aerosols and how chemical reactions influences aerosol properties. We are also exploring how aerosols can be used to drive chemical transformations, using aerosol droplets as sub-picolitre reaction vessels.