Kalberer Group Projects

Composition and reactivity of organic aerosols

Approximately 30-50% of atmospheric aerosol particles are composed of organic material. Usually, these organic aerosol particles are formed within the atmosphere from gaseous organic precursors. 

Despite their dominance, the chemical composition, formation pathways, and atmospheric reactions and effects of these organic particles are poorly understood. This is mainly due to their incredibly complex composition - there are more than 10,000 organic compounds present in organic aerosol, covering a wide physical-chemical parameter space. 

The analysis of these highly complex mixtures at trace level concentrations is a main challenge in the study of atmospheric aerosols. To better characterise aerosol effects on climate and human health an improved understanding of aerosol composition, evolution and sources is needed, which is only possible through an improved knowledge of particle composition.

We are using a range of laboratory experimental techniques to study fundamental aspects of aerosols formation and composition and we are characterising aerosol and rain samples collected in the ambient atmosphere ranging from polluted urban to clean remote locations. Some of the research we have conducted in this area include:

1. Detailed, molecular-level analysis of organic aerosol composition 
2. Aerosol Extractive Electrospray Ionisation Mass Spectrometry (MS)
3. Criegee Intermediates
4. Particle reactivity and particle phase 

Reactive Oxygen Species (ROS) - a new aerosol toxicity metric and aerosol lung cell cultures studies

Epidemiological studies show consistently positive correlations between aerosol particle exposure and a range of adverse health effects. The World Health Organisation (WHO) even lists air pollution particles as the single most pressing public health issue - accounting for approximately 5% of all deaths worldwide.

Despite a large number of studies on atmospheric particle toxicity, the biological pathways causing the adverse health effects of particulate air pollution are poorly understood - there is no conclusive evidence as to which particle properties are causing their toxicity. Chemical particle components are likely a key factor, but are difficult to accurately define. Therefore, identifying health-relevant particle parameters, components and sources is crucial for improved and efficient air pollution mitigation strategies.

Atmospheric aerosol particles contain a range of oxidising aerosol components (i.e. Reactive Oxygen Species, ROS), which are potentially toxic as they can oxidise biological molecules at the liquid lung surface layer or generate oxidising components once deposited on the lung surface. From an analytical point of view it is highly challenging to quantify these oxidising particle components as some of them have short lifetimes requiring fast measurement techniques.

As part of our work into this area, our research includes:

1. Reactive Oxygen Species (ROS)
2. Peroxyacids synthesis
3. Nanoparticle - lung cell culture online deposition chamber

Other research: 

The Kalberer Group also has a number of research activities and interests in other areas, these include:

1. Analysis of organic tracers in ice cores
2. Selective analysis of plant surfaces 
3. MEMS-based aerosol mass detection

For more information on any of these projects, please refer to Professor Markus Kalberer's personal staff profile.