Negative ions offset cardiorespiratory benefits of PM _2.5 reduction from residential use of negative ion air purifiers

Abstract

Negative ion air purifiers (NIAPs), as a less costly alternative to the HEPA filtration, have been increasingly deployed in China and potentially elsewhere. While reducing indoor concentrations of fine particulate matter (PM2.5), NIAPs generate massive amounts of negative ions that may be of health concern. We performed week‐long interventions with NIAPs in the dormitories of 56 healthy college students living in Beijing. In a randomized order, each student underwent a true and a sham NIAP session. Cardiorespiratory outcomes were measured before and after each session. The use of true NIAPs reduced indoor PM2.5 concentrations significantly, while notably increased negative ion levels. Increases in PM2.5 and negative ion (NI) exposure were independently associated with increased urinary concentration of malondialdehyde, a biomarker of systemic oxidative stress, resulting in a null net effect of NIAP on malondialdehyde. Likewise, no significant net effects of NIAPs were observed for other outcomes indicative of lung function, vascular tone, arterial stiffness, and inflammation. Our findings suggest that negative ions, possibly along with their reaction products with the room air constituents, adversely affect health. The downsides do not support the use of NIAPs as a health‐based mitigation strategy to reduce PM2.5 exposure, especially in residences with PM2.5 concentrations that are not extremely high.

The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime

“…Some devices are known to produce by-products such as ozone so their effect on air quality should also be considered [99,110]. A recent study concluded that associated by-products other than ozone can also adversely affect the respiratory and cardiovascular systems [111].…”

Using circular economy principles to recycle materials in guiding the design of a wet scrubber-reactor for indoor air disinfection from coronavirus and other pathogens

“…1 ), require high inactivation efficiency, otherwise incubation of bacteria and viruses may take place ( Di Natale et al, 2018 , Ghosh et al, 2015 , Miaskiewicz-Peska and Lebkowska, 2012 , Soret et al, 2018 ). Negative ion air purifiers (NIAPs) have also been criticised for their adverse health effects ( Liu et al, 2020 ).

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Comparative Study of Computational Models for Reducing Air Pollution Through the Generation of Negative Ions

“…Inference and comparison of computational models electric field is high enough, a corona discharge occurs [12,13]. If a charged conductor or electrode has a type of needle with a sharp tip, the electric field around the tip will significantly be higher than elsewhere, and the air near the electrode can ionize and generate negatively charged particles [34].…”