Exposure to ultrafine particles from combustion sources in the working environment

The overall aim is to quantify exposure levels to carbonaceous ultrafine particles (UFPs) at work places. The latest quantitative risk assessments of lung cancer due to diesel exhaust (where UFPs dominate the particle exposure) exposure suggest that only very low particle mass concentrations can be tolerated for acceptable
risks. EU recently decided on sharpened occupational exposure limits for diesel exhaust particles. However, a large number of workers in a variety of professions (airport workers, fire fighters, chimney sweeps, asphalt pavers etc) are today exposed to UFPs from other combustion sources than diesel, at incompletely known levels. We do not know if the risks from diesel exhaust may be extrapolated to other sources of UFPs.

Within nanotoxicology it has been shown that UFPs are more toxic per mass unit compared to larger particles of the same material. An important predictor of adverse health effects is solid particle surface area. There are reasons to suspect that exposure to UFP does not correlate well with exposure to known markers such as nitrogen oxides and particle bound PAHs. UFP exposure metrics need to be validated for sources beyond diesel exhaust.

In the project, a multidisciplinary group is formed with the specific aims to:
1. Determine emission factors and characteristics of ultrafine particles from common sources at a range of work places and validate novel exposure monitoring methods
2. Determine workers personal exposure levels in larger groups at two work places and validate novel exposure metrics for UFPs
3. Link UFP particle characteristics with reactive oxygen species (ROS) formation potential, a marker of oxidative stress and genotoxicity.
4. Collaborate with animal in-vivo studies and human exposure studies with the aim to identify effective, health relevant exposure metrics for UFPs

The results of the project will contribute to improved risk assessment of exposures to carbonaceous UFP’s in the working environment.