Filtration efficiency and loading characteristics of PM2.5 through composite filter media consisting of commercial HVAC electret media and nanofiber layer

Tang, Min; Chen, Sheng Chieh; Chang, De Qiang; Xie, Xiaofeng; Sun, Jing; Pui, David Y.H.

doi:10.1016/j.seppur.2017.03.040

Cited by 78 publications

(36 citation statements)

References 19 publications

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“…This range covered most of the ambient PM 2.5 , as indicated by the particle size distributions of Thielke et al [ 43 ]. The fractional efficiency was measured using monodisperse potassium chloride (KCl) particles with diameter of 30 nm, 50 nm, 80 nm, 100 nm, 150 nm, and 200 nm, as described by Tang et al [ 44 ], and polydisperse KCl particles ranging from 400 nm to 2 µm, as described in the following section.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Fibrillated Cellulose Nanofiber from Lyocell Fiber and Its Application in Air Filtration

et al. 2018

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Ambient particulate matter less than 2.5 μm (PM2.5) can substantially degrade the performance of cars by clogging the air intake filters. The application of nanofibers in air filter paper can achieve dramatic improvement of filtration efficiency with low resistance to air flow. Cellulose nanofibers have gained increasing attention because of their biodegradability and renewability. In this work, the cellulose nanofiber was prepared by Lyocell fiber nanofibrillation via a PFI-type refiner, and the influence of applying a cellulose nanofiber on filter paper was investigated. It was found that the cellulose nanofibers obtained under 1.00 N/mm and 40,000 revolutions were mainly macrofibrils of Lyocell fiber with average fiber diameter of 0.8 µm. For the filter papers with a different nanofiber fraction, both the pressure drop and fractional efficiency increased with the higher fraction of nanofibers. The results of the figure of merit demonstrated that for particles larger than 0.05 µm, the figure of merit increased substantially with a 5% nanofiber, but decreased when the nanofiber fraction reached 10% and higher. It was concluded that the optimal fraction of the cellulose nanofiber against PM2.5 was 5%. The results of the figure of merit were related to the inhomogeneous distribution of nanofibers in the fibrous structure. The discrepancy of the theoretical and measured pressure drop showed that a higher nanofiber fraction led to a higher degree of fiber inhomogeneity.

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Section: Methodsmentioning

confidence: 99%

Preparation of Fibrillated Cellulose Nanofiber from Lyocell Fiber and Its Application in Air Filtration

et al. 2018

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“…A multitude of factors can affect the actual penetrated urban aerosol PSD downstream of a filter, including: the type of filter (e.g. electret filter) (Tang et al, 2018), relative humidity (Pei et al, 2019), the filter installation method (which influences the bypass of particles around the filter), face velocity (Leung et al, 2010), aerosol morphological features (Wang, 2012), and the mechanical ventilation recirculation ratio.…”

Section: Urban Aerosol Psds: Implications For Indoor Air Quality and Aementioning

confidence: 99%

Urban Aerosol Size Distributions: A Global Perspective

Wu¹,

Boor²

2020

Preprint

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Abstract. Urban aerosol measurements are necessary to establish associations between air pollution and human health outcomes and to evaluate the efficacy of air quality legislation and emissions standards. The measurement of urban aerosol particle size distributions (PSDs) is of particular importance as they enable for characterization of size-dependent processes that govern a particle’s transport, transformation, and fate in the urban atmosphere. PSDs also improve our ability to link air pollution to health effects through evaluation of particle deposition in the respiratory system and inhalation toxicity. To provide guidance for the evolution of urban aerosol observations, this paper reviews and critically analyzes the current state-of-knowledge on urban aerosol PSD measurements by synthesizing n = 793 PSD observations made between 1998 to 2017 in n = 125 cities in n = 51 countries around the globe. Significant variations in the shape and magnitude of urban aerosol number and mass PSDs were identified among different geographical regions. In general, number PSDs in Europe (EU), North America, Australia, and New Zealand (NAAN) are dominated by nucleation and Aitken mode particles. PSDs in Central, South, and Southeast Asia (CSSA) and East Asia (EA) are shifted to larger sizes, with a meaningful contribution from the accumulation mode. Urban mass PSDs are typically bi-modal, presenting a dominant peak in the accumulation mode and a secondary peak in the coarse mode. Most PSD observations published in the literature are short-term, with only 14 % providing data for longer than six months. There is a paucity of PSDs measured in Africa (AF), CSSA, Latin America (LA), and West Asia (WA), demonstrating the need for long-term aerosol measurements across wide size ranges in many cities around the globe. Inter-region variations in PSDs have important implications for population exposure, driving large differences in the urban aerosol inhaled deposited dose rate received in each region of the human respiratory system. Similarly, inter-region variations in the shape of PSDs impact the penetration of urban aerosols through filters in building ventilation systems, which serve as an important interface between the outdoor and indoor atmospheres. Geographical variations in urban aerosol effective densities were also reviewed. Size-resolved urban aerosol effective density functions from 3 to 10 000 nm were established for different geographical regions and intra-city sampling locations in order to accurately translate number PSDs to mass PSDs, with significant variations observed between near-road and urban background sites. The results of this critical review demonstrate that global initiatives are urgently needed to develop infrastructure for routine and long-term monitoring of urban aerosol PSDs spanning the nucleation to coarse modes. Doing so will advance our understanding of spatiotemporal trends in urban PSDs throughout the world and provide a foundation to more reliably elucidate the impact of urban aerosols on atmospheric processes, human health, and climate.

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“…The MPPS of the KC A20 and KC A30 fabrics, around 100 nm, tend to prove that these differences in protection efficiency are due to a particle collection enhancement by electrostatic effects. [32] This assumption is further reinforced by the manufacturer's technical specifications indicating a fiber treatment called "MICROFORCE. "…”

Section: Lsg and St 30 Fabricsmentioning

confidence: 99%

Filtering performances of 20 protective fabrics against solid aerosols

Wingert

Cloutier

Hallé

et al. 2019

Journal of Occupational and Environmental Hygiene

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Workers can be exposed to solid airborne particles in some occupational environments, and they might be required to wear chemical protective clothing to prevent skin exposure. Dedicated standards exist to certify the protective value of such clothing, but they are not informative enough to identify the main pathways of entry for solid particles nor to compare performances between different chemical protective clothing. In this work, 20 nonwoven fabrics used to make chemical protective clothing for solid particle protection were selected to be examined for both filtration and comfort performances. Nine were microporous fabrics (MP), 10 were multilayered nonwoven fibrous media (SMS) and one was a flash spun material (FS). To assess their filtration performances, fabrics were challenged in a benchtop wind tunnel with a 20-3,000 nm diameter sodium chloride aerosol at three low fabric face velocities (0.05, 0.15, 0.3 cm/sec). Airflow resistance and water vapor transmission rate were also measured to provide indications of comfort for the wearer. The penetration results led to the classification of the 20 fabrics into distinct groups of filtration efficiency. The data were analysed based on the porous media characteristics (thickness, fiber diameter, porosity, etc.). MPs were the most efficient fabrics, and SMSs showed a wide range of performances, mostly due to variations in the thickness of the filtering layer as well as to the fabric treatment. Measurements of airflow resistance and water vapor transmission rates revealed major differences between MPs and FSs and SMSs. This highlights the potential of some SMS fabrics to meet a compromise between protection and comfort.

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Filtration efficiency and loading characteristics of PM2.5 through composite filter media consisting of commercial HVAC electret media and nanofiber layer

Cited by 78 publications

References 19 publications

Preparation of Fibrillated Cellulose Nanofiber from Lyocell Fiber and Its Application in Air Filtration

Preparation of Fibrillated Cellulose Nanofiber from Lyocell Fiber and Its Application in Air Filtration

Urban Aerosol Size Distributions: A Global Perspective

Filtering performances of 20 protective fabrics against solid aerosols

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