To characterize the physical, chemical and oxidant properties of inhaled PM and establish which of these characteristics are critical determinates of adverse systemic and respiratory effects seen after PM exposures.

The project will be conducted in two phases. Firstly, a screening phase in 2007/2008, in which air pollution exposure is quantified at selected sites with expected contrasts in local source emission. Secondly, a health effect study in 2009, during which we will expose healthy volunteers at five different sites, selected based on the results of the screening phase. Exercise will be performed to increase inhaled doses of air pollution. Respiratory and cardiovascular health will be assessed before and after the exercise, with the difference in health status being the effect parameter for the study. Exposure will be characterized on-site, including collection of PM size fractions directly into fluid for further toxicological studies.

Air samples collected at the different sites will be assayed for their ability to induce oxidative stress and adverse effects on thrombosis and fibrinolysis in vitro. In addition, pro-inflammatory effects of PM will be studied in macrophages. Subsequent in vivo studies in animals will be conducted to determine the pro-inflammatory and pro-coagulant effects of ambient PM.

Other collaborations within the project:

• King's College London for assessing oxidative capacity measures in PM and plasma samples: Prof. dr. F Kelly, dr. I. Mudway and K. Godri (PhD-student)
• The University of Birmingham for characterization of PM: prof. dr. R. Harrison.
• Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht for the field of thrombosis and haemostasis: Dr. H. Spronk.