Water Sorption by Different Types of Filter Media Used for Particulate Matter Collection Under Varying Temperature and Humidity Conditions

Kamila Widziewicz-Rzońca,Malwina Tytła

doi:10.3390/ijerph17145180

Abstract

The present study describes the effects of temperature and humidity on the level of water absorption by filter blanks most popularly used for gravimetric analyzes of particulate matter (PM) and the effects of those on the accuracy of its weight measurements. The main parts of the research quantified the effect of temperature and humidity conditions on water contents quartz fiber (Q), fiberglass (G), PTFE, and nylon (N) filters. Supplementary studies were conducted to estimate the effects of temperature, humidity and material on mass loss/gain and the shape of water retention. All chemical analyses of water contents were performed by the Karl Fischer titration method. The results indicate that quartz filters are the most susceptible to the variations in water contents under changing humidity levels and therefore, less suitable to high accuracy determinations of PM mass compared to nylon or glass filters; PTFE performed the best due to their hydrophobicity. For PM water contents determinations, the best choice of filter media is PTFE. Although many other factors determine the choice of filter type for PM analyses, the present study is an important contribution to knowledge of assessing the suitability of different types of filter material for specific measurements.

Highlights

The World Health Organization (WHO) considers clean air a fundamental human need and defines this as “a basic requirement of human health and well-being” [1,2]
The only information given in a proper standard [23], regarding deviations in the mass of filter blanks under varying temperature/humidity conditions is that if differences between replicated gravimetric measurements of unsampled filters changed by less than 40 μg–in case of LVS– the unloaded filters can be treated as condition one and further measurements can proceed
The present work assesses the effects of the alteration of humidity and temperature on the weight of filter blanks made from different materials and analyzes the relations between variations in temp and relative humidity (RH)% on the amount of water sorption by those filters

Summary

Introduction

The World Health Organization (WHO) considers clean air a fundamental human need and defines this as “a basic requirement of human health and well-being” [1,2]. One of the most important pollutants regarding human health is particulate matter (PM). A standard method for its determination is based on sampling and weighing of the PM on filters and is defined by legislation (Council of the European Union, [3]). Public awareness has moved toward PM2.5 and PM1 particles, mainly due to the health effects posed by those fractions: mortality, respiratory and cardiovascular morbidity, and inflammatory airway response including asthma [4,5]. The Total Suspended Particles (TSP) and PM10 mass measurements are well standardized; but there are no recommendations for the instruments or techniques used for the investigation of ultrafine particles. Since ultrafine particles reach high concentrations but their mass is often very small, measurements of particles in ultrafine or even sub-micrometer ranges are more commonly based on particle number rather than mass concentration

Methods

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Discussion

Conclusion