# Air-fed cold atmospheric plasma device as a safe and effective anti-SARS-CoV-2 air filter

## TL;DR

A new air filter using cold atmospheric plasma effectively inactivates SARS-CoV-2 and appears safe for daily use based on rat studies.

## Contribution

Development of an air-fed cold atmospheric plasma device that inactivates SARS-CoV-2 with demonstrated structural and safety effects.

## Key findings

- The plasma device inactivates SARS-CoV-2 by altering its structural integrity.
- Exposure to the device did not cause acute toxicity in rats over 4 weeks.
- Some serum chemistry parameters changed in rats and require further evaluation.

## Abstract

Cold atmospheric plasma (CAP) displays antiviral properties, and its efficacy and safety in daily use are subject to full elucidation. In this work, we develop an air-fed CAP device, by inhaling and filtering, to directly inactivate SARS-CoV-2 in the air. The plasma shows a high intensity with reactive nitrogen and oxygen species in optical emission, with plasma electron temperature and density of 0.31 eV and 3.25 × 1017 m-3, respectively, confirming a strong discharge for SARS-CoV-2 disinfection. A qualitative analysis of the device’s discharge process is conducted using a two-dimensional fluid model. The disinfection results show that the typical SARS-CoV-2 morphological spikes disappear after plasma treatment, and the proteosomes of the SARS-CoV-2 virus change. In addition, we conduct experiments on rats to evaluate the safety of the air plasma device in daily use. Rats’ behavior, body weight, food consumption, organ histopathology, and blood biochemical indicators after exposure to this device are evaluated. These results demonstrate that under our experimental conditions, this prototype plasma–air circulation system altered the structural integrity of SARS-CoV-2 and did not produce overt acute toxicity in rats over 4 weeks, although some serum chemistry parameters changed and require further evaluation.

The online version contains supplementary material available at 10.1038/s41598-026-36088-y.