Most Air Purifiers Are Tested Behind Closed Doors. Ours Was Not.

TL;DR

• IIT Kanpur tested the Atovio Pebble in a 10 m3 room with the door kept fully open throughout all three trials, not in a sealed chamber.

• A sealed chamber test would not reflect how a wearable personal purifier is actually used, because the Pebble is worn in spaces where doors open and air moves freely.

• The door-open setup created continuous outdoor air inflow, the exact condition where conventional indoor room purifiers show negligible measurable effects.

• Three independent trials measured breathing zone PM mass at mannequin height using a gravimetric dust sampler at 5 L/min and 0.1 mg resolution filters.

• Trial results: 38.33%, 52.66%, and 40.44% reduction in breathing zone PM. Average: 43.8% (IIT Kanpur Field Efficacy Testing Report).

• The IIT Kanpur report confirms the reduction was not dependent on room enclosure. It occurred directly in the breathing microenvironment.

The Test Setup Was Not an Accident. It Was a Choice.

When most people think of an air purifier being tested, they imagine a sealed room with no air coming in or going out. Particle levels start high, the purifier runs, and particle levels drop. That is a valid test for a device whose job is to clean a fixed, enclosed volume of air.

The Atovio Pebble is not that kind of device. It is a wearable personal air purifier worn around the neck. It does not clean a room. Its job is to reduce what the person wearing it inhales, right at their breathing zone, in whatever environment they happen to be in. Testing it in a sealed chamber would not reflect the conditions in which it is actually used.

This is why the National Aerosol Facility at IIT Kanpur made a deliberate choice: they tested the Atovio Pebble in a 10 m3 room with the door kept fully open for the entire duration of every trial. Not partially open. Fully open. Outdoor air flowed in continuously throughout. That is a test setup that reflects how a wearable personal device is actually used.

What the Door Being Fully Open Actually Simulates

A room with its door fully open is not a controlled sealed environment. Outdoor air enters and mixes with indoor air continuously. Pollutants flow in from outside. The air in the room is not a fixed, contained volume. It is constantly being replenished from outside.

Think about where the Atovio Pebble is actually used. Someone wearing it at an office desk with the room door open. Someone sitting in a cab with the window slightly down. Someone at a workstation in a space with cross-ventilation. Someone at a clinic waiting room with people coming in and out. In every one of these situations, the air around the user is not contained. Doors open and close. Air moves. New pollutants enter.

The IIT Kanpur report explicitly states that the door-fully-open setup ensured continuous inflow of outdoor air throughout, and that these are conditions where conventional indoor room purifiers typically show negligible measurable effects. These are the kinds of conditions a wearable personal purifier faces in everyday use.

Why a Door-Open Test Reflects How the Atovio Pebble Is Actually Used

The Atovio Pebble is worn by a person who is sitting at a desk, riding in a cab, or working in a space where doors open and close and air moves in from outside. That is the environment it needs to perform in. Testing it in those exact conditions, with the door fully open and outdoor air continuously flowing in, gives a direct and honest answer to how much it actually reduces what the person wearing it inhales.

A door-open test with real outdoor air coming in is also a harder standard to demonstrate performance against. Pollutants are not contained. They are actively entering the space throughout the test. Showing a consistent reduction in breathing zone PM under those conditions is meaningful precisely because the conditions are dynamic and realistic, not because they are controlled and contained.

The Atovio Pebble's value to the person wearing it is how much it reduces the pollutants entering their lungs in the conditions they actually face. The door-open setup is the right test because it is the honest one.

What Each Trial Found in the Door-Open Conditions

The test used a calibrated personal dust sampler at 5 litres per minute, equivalent to the human tidal breathing rate at rest. The sampler inlet was positioned at the breathing zone height of a life-sized mannequin. Filters had a 0.8 micrometre pore size and were weighed using a microbalance with 0.1 mg resolution, capturing actual particulate mass. Three separate trials were run, each with and without the Pebble operating.

In Trial 1, PM concentration at the breathing zone was 207 micrograms per cubic metre without the Pebble and 127 micrograms per cubic metre with it, a reduction of 38.33%.

In Trial 2, the reading without the Pebble was 269 micrograms per cubic metre and 127 micrograms per cubic metre with it, a reduction of 52.66%. This was the highest reduction across all three trials, occurring in a room where outdoor pollution was flowing in continuously throughout.

In Trial 3, which ran for two hours rather than one, the reading without the Pebble was 173 micrograms per cubic metre and 103 micrograms per cubic metre with it, a reduction of 40.44%. The two-hour trial demonstrated that the reduction was not a short-term effect but held consistently over extended operation.

Average across all three door-open trials: 43.8% reduction in breathing zone PM concentration.

What These Numbers Mean for How You Actually Use the Pebble

A 38% to 53% reduction in breathing zone PM in a room with the door fully open is a meaningful result. It means that in the kind of conditions where the Pebble is actually used, including offices, cabs, and spaces with natural air movement, the device creates a measurably cleaner zone around the face of the person wearing it.

The IIT Kanpur report specifically notes that the reduction is not dependent on room enclosure or recirculated air. It occurs directly within the user's breathing microenvironment. For a wearable personal purifier, what happens at the breathing zone is the more relevant outcome than what happens to the room overall.

A full overview of the field efficacy test including methodology and all trial findings. And why the breathing zone is measured the way it is, and what that means for your real personal exposure.

The Bottom Line

IIT Kanpur did not test the Atovio Pebble in a sealed chamber. They tested it in a room with the door fully open, with continuous outdoor air inflow, because that is what reflects how a wearable personal purifier is actually used. And across three independent trials in those conditions, the Pebble reduced breathing zone PM by an average of 43.8%. The test was designed to reflect real conditions. The results were consistent across all three trials.