Effects of temperature and relative humidity on laboratory air filter loading test by hygroscopic salts

Pei, Chenxing; Ou, Qisheng; Pui, David Y.H.

doi:10.1016/j.seppur.2020.117679

Cited by 21 publications

(15 citation statements)

References 38 publications

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“…[37] Depending on the temperature and relative humidity, changes in the morphology or state of the test pollutants may occur and should be considered. [38] Recently, a low-cost optical measurement for testing the efficacy of facemasks against expelled droplets during the speech was presented and applied to commercial masks and mask alternatives such as neck fleece and bandanas. [39] The evaluation of antimicrobial properties is usually ascertained by aerosol filtration and subsequent cell incubation or in liquid media, which can be problematic due to safety concerns.…”

Section: Model Pollutantsmentioning

confidence: 99%

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

Henning

Abdullayev

Vakifahmetoğlu

et al. 2021

Adv Energy and Sustain Res

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Particulate and gaseous air pollutants pose a threat to human health and contribute to climate change. By today, air filters, stationary and portable, are markedly improved and can often provide innocuous air pollution levels. After introducing the classification and standards on air filters, the influence of the processing route and its parameters on the resulting air filter properties and consequently its performance are discussed. Numerous tools are presented to adjust structural properties such as fiber or pore diameter, specific surface area, surface charge, hydrophilicity, or photocatalytic activity to achieve the desired performance in terms of high filtration efficiencies, sufficient mechanical stability, regeneration eligibility, antimicrobial and optical properties. In particular, inorganic and composite materials as well as nonfibrous structures are covered, which are currently holding an outsider position in an air filter community dominated by polymeric materials and fibrous structures.

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Section: Model Pollutantsmentioning

confidence: 99%

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

Henning

Abdullayev

Vakifahmetoğlu

et al. 2021

Adv Energy and Sustain Res

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“…This reduction in surface area of the particle deposits leaves large sections of the filter unloaded and free for the aerosol to pass through, which in turn leads to the observed low Δp and decline in separation efficiency. In other words, at almost the same Δp (here 80 Pa) the filter with exposure to higher humidity has a substantially higher mass loading (here by a factor of 16). An analysis of the SEM images of test filter B is provided in the Supporting Information and leads to similar conclusions.…”

Section: Analysis Of Deposit Structures Of the Test Filtersmentioning

confidence: 99%

“…Current testing standards specify a constant RH of, e.g., 45 ± 10 % according to ISO 16890 during testing, in order to prevent deliquescence and condensation. The need of revising current filter testing standards by including the filters' operating temperature and RH was previously stated by Wilcox et al and Pei et al [15,16].…”

Section: )mentioning

confidence: 99%

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Humidity Considerations in Filter Testing Based on Analysis of Filters from Gas Turbine Applications

et al. 2021

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Depth filters used in multistage filter systems adeptly clean the intake air of gas turbines, preventing damage and increasing performance. However, estimation of their service life is based on empirical data and/or standardized testing procedures, e.g., ISO 16890. By applying standardized synthetic test dusts at constant reference humidity, these testing procedures do not reflect application-typical loading conditions. Based on a direct comparison with field data, the influence of temporary exposure to high relative humidity on differential pressure and particle deposit structure is investigated. The results indicate that simulating humidity variations of the ambient atmosphere during filter tests leads to particle deposits, which more accurately reflect the actual behavior during operation.

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“…Specific ranges of relative humidity (RH) and temperature (T) govern the evaporation and condensation phenomena, producing efflorescences [ 37 , 38 ]. Phase transitions occur at a specific RH for each salt, at a given temperature and pressure, called equilibrium relative humidity [ 39 ]. In this sense, knowledge about the salt behavior, and if possible, the changes in T and RH conditions, is crucial [ 40 ].…”

Section: Introductionmentioning

confidence: 99%

Soluble Salts Quantitative Characterization and Thermodynamic Modeling on Roman Bricks to Assess the Origin of Their Formation

et al. 2021

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The environmental weathering and the formation of efflorescences on the brick walls are studied at the “Casa di Diana” Mithraeum at Ostia Antica archaeological site. Previous studies on subsoil, bedrock, hydrological systems and environmental conditions, and new ion chromatography analysis combined with ECOS-RUNSALT and Medusa-Hydra thermodynamic modelling software, had allowed us to identify the subsoil contamination related to soluble salts. The atmospheric acidic gases, CO2 and SO2, are determined as the main salt weathering species. A dry deposition after a subsequent hydration action from the shallow freshwater aquifer that reaches up to 1 m on the walls is identified as the mechanism of salt formation. An evaluation of potential sources such as the nearby Fiumicino airport, CO2-rich gases inputs from fumaroles and CO2 inputs was also debated. The risk level of contamination the surfaces of the materials should be considered mildly/very polluted with a medium/high risk of hygroscopic moisture due to the high concentration of sulphates.

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Effects of temperature and relative humidity on laboratory air filter loading test by hygroscopic salts

Cited by 21 publications

References 38 publications

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

Humidity Considerations in Filter Testing Based on Analysis of Filters from Gas Turbine Applications

Soluble Salts Quantitative Characterization and Thermodynamic Modeling on Roman Bricks to Assess the Origin of Their Formation

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