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Healio Interview

Disclosures: The authors report no relevant financial disclosures.
January 21, 2022
4 min read

Q&A: Passive air sampler clip detects personal exposure to SARS-CoV-2


Healio Interview

Disclosures: The authors report no relevant financial disclosures.
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Initial findings indicate that a passive air sampler clip can detect airborne SARS-CoV-2 indoors and may provide a way for individuals in high-risk settings to assess their personal exposure to the virus.

The Fresh Air Clip, which is currently under development by Yale University researchers, allows virus-laden aerosols to continuously deposit onto a polydimethylsiloxane filter without the need for power sources, according to findings published in Environmental Science & Technology Letters.

Source quote: We hope that the Fresh Air Clip is going to be useful not just during the COVID-19 pandemic but also well beyond.

Using a PCR or rapid test kit, the filter can be analyzed for SARS-CoV-2 RNA to determine an individual’s personal exposure, according to Krystal J. Godri Pollitt, PhD, PEng, an assistant professor of epidemiology and chemical and environmental engineering in the schools of public health and engineering and applied science at Yale University, and Jodi D. Sherman, MD, an associate professor of anesthesiology and epidemiology in environmental health sciences in the schools of medicine and public health at Yale University. At about an inch in diameter, the clip is magnetic, lightweight and reusable and can be worn for multiple hours or days at a time. The device has to be cleaned before a new filter can be inserted and the clip reused.

In a preliminary study, Pollitt, Sherman and colleagues distributed clips to 62 volunteers who wore the instrument for 5 days. PCR analyses detected SARS-CoV-2 RNA in five of the clips, four of which were worn by restaurant staff and one by a staff member at a homeless shelter, according to a press release.

Healio spoke with Pollitt and Sherman about the Fresh Air Clip and how it can be used in health care settings.

Healio: Can you provide more detail about how the air sampler works?

Pollitt: The device consists of a chamber that is mounted in a magnetic clip. Inside that chamber, we have a polymer film that is used to collect airborne virus, either in a droplet or aerosol form. We can then use a PCR to test the polymer film for exposure. The clip is small so it can be easily worn over PPE while working.

In terms of the duration that can pass in between sample collection and testing, we have tested samples and left them out for 2-week periods, and we haven't seen any degradation of the viral material. We obviously wouldn't want to leave it out for that length of time just to have responsiveness for feedback to the wearer, but in theory, a duration of time can pass before testing.

Healio: What are the implications of this kind of device if it was commercialized for health care workers?

Pollitt: The Fresh Air Clip can be worn to assess personal exposure to airborne virus or be placed in a room as an area sampler. Monitoring airborne virus means we don't have to wait until someone is infected before alerting people of possible exposure. We have high sensitivity of identifying exposure events with the clip, requiring a minimum of four SARS-CoV-2 RNA copies to be present per cubic meter of air.

The clip can also inform risk assessment. Do we need additional infectious disease control measures to be implemented in the space if we don't have sufficient ventilation or if we have too many people that are present, especially if they are potentially affected?

Jodi D. Sherman

Sherman: And it is not just a matter of ventilation. It can also impact the consumption of PPE by detecting when additional measures are indicated, so it is a matter of supply chain resilience.

The air sampler can be an easier way, or certainly a potential way, for preventing spread in future pandemics or detecting other viruses. Using this technology in a space like the emergency rooms is a good way to detect something early.

Healio: What current research are you doing with the air sampler?

Pollitt: Since our initial test, we have continued use of the device in health care facilities across the New Haven [Connecticut] area.

Healio: What has the response been like on the air samplers from individuals who have tested the device?

Sherman: It’s extremely easy to use and people are very excited to be able to have such a device. Right now, it doesn’t have immediate feedback, so that’s an area of future development. It’s in an exploratory phase, but I can tell you the opportunity for development definitely provides an extra layer of comfort for health care workers.

Healio: Do you plan on expanding the application of the air sampler to other viruses?

Pollitt: That's exactly where we've been shifting our focus to: How can we expand the panel of respiratory viruses that we're testing for? We have currently expanded it to influenza and rhinovirus, but that could be expanded further.

The device can be useful in a number of settings, including school and travel environments. We hope that this is going to be useful not just during the COVID-19 pandemic but also well beyond.

Sherman: Right now, we're challenged by limited resources for doing COVID-19 PCR testing, but this device is particularly good to use for early detection and possibly a way of conserving resources. We talked about conserving PPE or being more strategic in our use of PPE and similarly more strategic in our use of individual testing for patients, staff and in the community.

Healio: Can you speak about the sustainability of a device like this?

Pollitt: The clips are reusable. Only the polymer film is replaced between uses.


Angel DM, et al. Environ Sci Technol Lett. 2022;doi:10.1021/acs.estlett.1c00877.

Wearable air sampler assesses personal exposure to SARS-CoV-2. Published Jan. 12, 2022. Accessed Jan. 14, 2022.