Simultaneous Measurements of PM₁₀ and PM₁ using a single TEOM^#

Abstract

A time sharing, sequential scanning inlet system has been developed for a tapered element oscillating microbalance (TEOM) particulate matter (PM) mass measurement instrument, allowing quasi simultaneous measurement of ambient PM₁₀ and PM₁. Compared to running two separate instruments this approach eliminates systematic biases between the PM₁₀ and PM₁ data due to slightly different response functions of separate instruments. Furthermore, this approach reduces the costs of the measurements considerably. The system has been successfully tested during the winter 2005/2006 in Zurich, Switzerland and 24-hour average data have been compared to ambient concentrations measured with reference high volume sampler systems of the Swiss national air pollution monitoring network (NABEL) showing an excellent correlation. We demonstrate the use of our instrument for characterizing PM by showing the significant differences between PM₁₀ and PM₁ in their respective diurnal variation patterns as well as the increase in their concentrations during events of air stagnation.

Acknowledgments

We are grateful to Uwe Weers for technical advice. We thank the EMPA team for providing us with the data of the National Air Pollution Monitoring Network (NABEL). Also, we would like to thank an anonymous reviewer for very helpful comments and for providing an alternative explanation of the diurnal pattern of PM₁.