PM10: Comparison of TEOM-FDMS with Gravimetry Robert Gehrig, Christoph Hüglin, Beat Schwarzenbach Swiss Federal Laboratories for Materials Testing and Research CH-8600 Dübendorf Switzerland

TEOM (Tapered Element Oscillating Microbalance) Source: Baron/Willeke: Aerosol measurement

TEOM-FDMS FDMS = Filter Dynamic Measurement System Compensation for possible artefacts (humidity and loss of semi-volatile material)

TEOM-FDMS FDMS = Filter Dynamic Measurement System Compensation for possible artefacts (humidity and loss of semi-volatile material)

Dübendorf, Evaluation phase, FDMS Type B, 2006/2007

Lausanne PM10

Lugano (base and reference signal) ○ before spring 2009 ● after spring 2009 Base signal Reference signal

Dryer efficiency (%)

Zero Air Measurements (Laboratory)

Important observations Majority of TEOM-FDMS in NABEL showed poor comparability with gravimetry (too high values). While reference signal seemed to be plausible, base signal were too high. Poor performance seemed to be connected with low dryer efficiency. With new dryers comparability was often better for a short period, but got worse rather quickly. Filtered air gave not ± 0 μg/m3 signal (contribution from both reference and base signal).

Bern (good performance) TEOM – Grav. TEOM / Grav. ○ before spring 2009 ● after spring 2009

Lausanne (good performance) TEOM – Grav. TEOM / Grav. ○ before spring 2009 ● after spring 2009

Dübendorf (medium performance) TEOM – Grav. TEOM / Grav. ○ before spring 2009 ● after spring 2009

Zürich (medium performance) TEOM – Grav. TEOM / Grav. ○ before spring 2009 ● after spring 2009

AQUILA Recommendations (AQUILA = Air Quality Reference Laboratories in Europe) Recommendation 15 (November 2009) For measurements of the AEI exposure measurements of PM2.5 the standard reference method shall be used where possible.   Recommendation 16 (November 2009) AQUILA recommends to its members not to use new instruments for PM until the demonstration of equivalence is available. Recommendation 17 (November 2009) Current instrumentation may be used on the decision of the NRL/competent body and more rigorous QA/QC procedures shall be introduced as soon as possible.

Conclusions for EMEP Also within EMEP, the gravimetric reference method shall be used where possible for measurements of PM. In existing data base, correct documentation of metadata for PM (used method) is crucial. When comparing PM data from different sites or analysing long term trends considerations concerning data homogeneity are very important.