Development of New Air Sampling Techniques for Semi-Volatile Chemicals (SVOCs)
We are developing novel techniques for sampling semi-volatile chemicals from air that are cheap, simple and require no electricity. In particular, we have developed a passive air sampler for semi-volatile organic compounds, which is based on styrene/divinyl benzene co-polymeric resin (XAD-2). We have characterized the uptake kinetics and capacity of the sampler through combinations of indoor and field calibration studies, flow field simulations and the measurement of adsorption isotherms onto the sampling sorbents. We have also used the samplers in numerous field deployments ranging in scale from the local to the global. Furthermore, we have developed a sampler that uses the wind to increase sampling rates (the so-called Flow-Through Sampler). Currently, we are working on a passive air sampler for gaseous elemental mercury.
Mechanistic Exposure Modeling
By combining environmental contaminant fate models on the regional and global scale that we have developed in the past with human food chain bioaccumulation models by Swedish collaborators we can now mechanistically link environmental emissions with contaminant body burden in humans. We are using these deterministic models to quantify and assign sources of variability in the observed human contaminant concentrations. This is done by first calculating longitudinal exposures for different human cohorts, which are then “sampled” to generate cross-sectional data. Currently, we are using that approach to shed light on the role of age, diet and body mass index on exposure to persistent organic pollutants. We are also developing bioaccumulation models for ionogenic organic substances
Contaminant Amplification Processes
We have wide-ranging research interests related to the environmental fate and transport of organic contaminants, with a particular focus on gaining a mechanistic understanding of contaminant enrichment processes through a combination of field work, laboratory experimentation and model simulations. In the past a focus was on the understanding of cold-trapping phenomena on the global scale and along elevation gradients in mountains. We have also worked extensively on amplification processes for organic contaminants during snow melt. Currently, we are exploring enrichment processes for organic contaminants in urban run-off.
Measurements and Estimation Methods of Chemical Properties
A prerequisite for virtually all investigations in environmental chemistry is the availability of data on a chemical’s basic physical-chemical and degradation properties such as vapour pressure or the air/water Henry’s law constant. In the past we developed and used simple and fast chromatography-based estimation techniques of physical-chemical properties and their temperature dependence. We also explored a common artifact in the measurement of the Henry’s law constant. Recent projects include the development of automated techniques for QSPR generation and the determination of the effect of inorganic salts on the partitioning of organic compounds into water.