Model-Based Fiber Diameter Determination Approach to Fine Particulate Matter Fraction (PM2.5) Removal in HVAC Systems

Marlena Drąg

doi:10.3390/app11031014

Abstract

Particulate Matter (PM) is a general term to classify air pollutants consisting of airborne particles. The particles vary in composition and size, and the sizes of particles range from 2.5 µm (PM2.5) to 10 µm (PM10). Anthropogenic activity (e.g., industrial processes or fuel/waste combustion) stands as the main emission source of PM. Due to the fact that indoor PM penetrates from the outside to indoor air, Heating, Ventilation, and Air-Conditioning (HVAC) filtration systems may play a significant role in decreasing air pollution indoors. The section of the respiratory tract affected by particulate matter depends on the particle size. The smaller the fraction, the more deeply it can enter into lungs and bronchi, causing a series of health problems. Conventional electret air filters applied in HVAC systems are not able to efficiently remove PM2.5 (e.g., huge gaps between thick fibers and unintentional elimination of electrostatic effects). The electrospinning process allows for the production of fibers of diverse diameters, including ultrathin yarns. The following work presents the axial length scale χχ estimation method for the given conditions and experimental results. According to this approach, it is possible to find out what parameters should be used to produce materials at certain fiber diameters and to capture fine particulate matter fractions (PM2.5). This research refers to poly(acrylonitrile) (PAN) fibers. The most important advantages, limitations, and challenges of the presented methodology are detected and discussed in this work.

Highlights

Nowadays, not everyone can breathe clean air [1]
Pollutants can get into human settlements through the filters assembled in the Heating, Ventilation and Air-Conditioning (HVAC) systems; the supply air can come entirely from the outside (European countries) or can be the mixture of the outside and recirculated air (USA) [6]
The results revealed that, depending on the particle size, different electrostatic mechanisms have different impacts on filtration enhancement; for particles of ≈20 nm, polarization force; for ≈100 nm, image force; and for ≈300 nm, Coulombic force

Summary

Introduction

Not everyone can breathe clean air [1]. Pollutants can get into human settlements through the filters assembled in the Heating, Ventilation and Air-Conditioning (HVAC) systems; the supply air can come entirely from the outside (European countries) or can be the mixture of the outside and recirculated air (USA) [6]. Even small amounts of pollutants can be dangerous due to long-term exposure [7]. The origin and characteristics of air pollution is varied and complex [8]. Particulate matter consists of both solid particles and liquid droplets, which are a mixture of organic and inorganic substances [9]. Two main fractions of particulate matter can be distinguished:

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Conclusion