High and low volume sampling of particulate matter at sites with different traffic profiles in the Netherlands and Germany: Results from the HEPMEAP study

Within the EU project "Health Effects of Particles from Motor Engine Exhaust and Ambient Pollution" (HEPMEAP), ambient particulate matter (PM) was collected at sites, with varying traffic density and sources of PM emissions, in the Netherlands and Munich, Germany. In the Netherlands, measurements were conducted close to four schools which had participated 4 years earlier in a study on respiratory health of children attending schools near motorways. In Munich, measurements were conducted at a high traffic inner city and a suburban background (low traffic) site. Measurements were spaced over a period of approximately 1 year. Collection of PM was conducted using both high volume and low volume impaction methods. In addition to PM mass, PM-absorbance ('soot') and NO₂ were measured as indicators of fossil fuel combustion. PM_2.5 and PM₁₀ concentrations calculated from the high volume collections were highly correlated with PM_2.5 and PM₁₀ concentrations measured simultaneously by low volume samplers (R² 0.87-0.94). Both high and low volume measurements showed little difference in semi annual average PM mass concentrations between sites within each country, with PM concentrations at the highest exposed sites being only about 10-30% higher compared to the lowest exposed sites. Contrasts for PM-absorbance and NO₂ were significantly higher than for PM mass (70-90% in the Netherlands and 90-167% in Germany). This demonstrates a higher impact of traffic on these components compared to PM mass.