Water - a great matter of aerosol mass uncertainty

Gravimetric mass of PM continues to be an important surrogate of regulatory importance linking particulate pollution to health and environmental impacts. For this reason methods of PM measurement have become essential in the preparation of strategies directed to human health protection. Filter weighing is a key part of this process, since PM mass and its concentration give a measure of air quality. Next to the manual weighing a robotic weighting systems have been developed to catch even microgram-level PM mass. In comparison to traditional weighing these systems provide more repetitive and accurate results regarding PM mass and eliminates human factor as the reason of measurement errors, making them more cost-effective and compliant with the EN 12341:2014 standard. This project will give an evaluation of the performance of a traditional manual weighing vs robotic weighing in the repeated measurements of mass as a comparative measure. To the date a coherent scientific view of the effects of PM-bound water on uncertainty in mass measurements has yet to be established. In this research I will define the uncertainty in gravimetric measurements of PM due to water species occurrence, and finally find out to which extent this uncertainty can be reduced to get most precise mass results. Different PM fractions (PM1, PM2.5, PM10) will be collected in three locations differing regarding the type of emission sources. The reference samplers will be used. To know, whether and to which extent filter type influence deviations in weighing precision different types of filter media will be used. The PM mass will be measured with a typical microbalance and newly developed weighing robot. The impact of the weighing technique on the deviations of PM mass measurements will be determined. An influence of the particle mass loadings collected onto filter on the accuracy of the gravimetric measurements will be also determined. The ultimate goal of this study is to obtain a better understanding of mechanisms regulating variation in mass of particulate matter due to atmospheric water content as well as the impact of this uncertainties on human health, when determining PM concentration.