Evaluation of an in-duct bipolar ionization device on particulate matter and gas-phase constituents in a large test chamber

Zeng, Yicheng; Heidarinejad, Mohammad; Stephens, Brent

doi:10.1016/j.buildenv.2022.108858

Cited by 11 publications

(3 citation statements)

References 28 publications

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“…A summary of EAC installation details at each test location is provided in Table 1, followed by full experimental details in the following sections. For the chamber experiments in Chicago, IL, USA, many of the experimental methodological details are the same as those recently applied to performance testing of another EAC device; therefore, much of the methodological details provided in Section 2.1 of this paper are the same as those previously published, reprinted from [36] with permission from Elsevier. We utilize much of the same language herein to improve the readability of this paper without requiring reference to the other paper.…”

Section: Methodsmentioning

confidence: 99%

Experimental Evaluations of the Impact of an Additive Oxidizing Electronic Air Cleaner on Particles and Gases

et al. 2022

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Electronic air cleaning (EAC) technologies have garnered significant attention for use in buildings. Many EAC technologies rely on the addition of reactive constituents to indoor air to react with gas-phase compounds, enhance particle deposition, and/or inactivate microorganisms. However, limited data are available on the efficacy of many EAC technologies and their potential to form chemical byproducts during operation. Here we experimentally evaluate the indoor air quality impacts, specifically targeting particles and gases but not microbial constituents, of a commercially available additive oxidizing EAC that generates positive and negative ions and hydrogen peroxide (H2O2). Tests were conducted in a large unoccupied test chamber in Chicago, IL and an unoccupied laboratory in Portland, OR under a combination of natural conditions (i.e., without pollutant injection) and perturbation conditions (i.e., with pollutant injection and decay). A combination of integrated and time-resolved measurements was used across both test locations. Chamber tests at lower airflow rates demonstrated that operation of the EAC: (i) had no discernible impact on particle concentrations or particle loss rates, with estimated clean air delivery rates (CADRs) for various particle measures less than ±10 m3/h, (ii) was associated with apparent decreases in some volatile organic compounds (VOCs) and increases in other VOCs and aldehydes, especially acetaldehyde, although a combination of high propagated uncertainty, limitations in test methods (e.g., lack of replicates), and variability between repeated tests limit what quantitative conclusions can be drawn regarding gas-phase organics; (iii) did generate H2O2, assessed using a crude measure, and (iv) did not generate ozone (O3). Laboratory tests at higher airflow rates, which involved injection and decay of particles and a single VOC (limonene), both simultaneously and separately, demonstrated that: (i) pollutant loss rates for both particles and limonene were slightly lower with the EAC on compared to off, yielding slightly negative pollutant removal efficiencies (albeit largely within propagated uncertainty) and (ii) there was a change in observed concentrations of one potential limonene degradation product, m/z 59 (putatively identified as acetone), with steady-state levels increasing from 10 ppb (air cleaner off) to 15 ppb (air cleaner on). No increases or decreases beyond measurement uncertainty were observed for other analyzed gaseous limonene degradation products. Overall, both chamber and laboratory tests demonstrated negligible effectiveness of this device at the test conditions described herein for removing particles and mixed results for VOCs, including decreases in some VOCs, no discernible differences in other VOCs, and apparent increases in other compounds, especially lower molecular weight aldehydes including acetaldehyde.

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Section: Methodsmentioning

confidence: 99%

Experimental Evaluations of the Impact of an Additive Oxidizing Electronic Air Cleaner on Particles and Gases

et al. 2022

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“…The common ions produced from corona discharge are oxide ions (O2 -) [3]. Due to the aforementioned benefits of NAIs, more ionizers are incorporated in heating, ventilation, and air conditioning (HVAC) applications notably air purifying units and occasionally air conditioners nowadays [4][5].…”

Section: Introductionmentioning

confidence: 99%

The effect of air velocity and indoor ambient properties on the effective operating range of an air ionizer device

Karim¹,

Nagentrau²,

Ling³

et al. 2023

J. Phys.: Conf. Ser.

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Air ionizers are devices that purify the indoor air by artificially generating negative air ions (NAIs) which are proven to improve air quality and well-being of humans. Hence, more ionizers are being incorporated into heating, ventilation and air conditioning (HVAC) applications nowadays. . Every ionizer has its effective range of operation, which is the area inside a room that can potentially be covered by significant concentration of NAIs compared to the general concentration of ions naturally present in the room. This range may change depending on the indoor temperature, humidity and fan speed of the HVAC unit as preferred by the room occupants. Present research intends to design an experimental setup that could measure negative air ion (NAI) concentration at varying distances from an ionizer under different values of the aforementioned parameters. The experiment was conducted inside an indoor psychrometric test room to allow controlling of ambient temperature and humidity. Air velocity through the ionizer was varied from 1.5 m/s to 4.5 m/s, whereas the range of temperature and relative humidity were set from 25°C to 31°C and 60% to 80% respectively. To evaluate the ionizer’s operating range, NAI concentration was measured at every preset longitudinal (0 cm to 75 cm), lateral (-25 cm to 25 cm) and elevation (-15 cm to 15 cm) distance relative to the ionizer for 6 minutes using an ion counter named “Air Ion Counter Model AIC2”. The results reveal that the ionizer’s effective operating range increased with velocity, with the furthest range recorded at 4.5 m/s. Whereas a negative correlation was found between the ionizer’s effective operating range with temperature and humidity, with the furthest range recorded at 25°C and 60% respectively. The results also show that most ions were distributed in areas below and towards the right side from the ionizer’s perspective.

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“…They showed no O 3 byproduct production stating that the ionization energy provided by the device was lower than that required to ionize oxygen. 19,20 The scope of this study is to look at the effects of portable and built-in ionization devices used in vehicles. This study is the rst to use a consistent method of testing as developed in previous work for static in-cabin vehicle testing.…”

Section: Introductionmentioning

confidence: 99%

The effect of built-in and portable ionizers on in-cabin ozone concentrations in light-duty vehicles

Mendez-Jimenez

Lakey

Johnson

et al. 2022

Environ. Sci.: Processes Impacts

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Evaluation of an in-duct bipolar ionization device on particulate matter and gas-phase constituents in a large test chamber

Cited by 11 publications

References 28 publications

Experimental Evaluations of the Impact of an Additive Oxidizing Electronic Air Cleaner on Particles and Gases

Experimental Evaluations of the Impact of an Additive Oxidizing Electronic Air Cleaner on Particles and Gases

The effect of air velocity and indoor ambient properties on the effective operating range of an air ionizer device

The effect of built-in and portable ionizers on in-cabin ozone concentrations in light-duty vehicles

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