Student Works


John Brechbill & Justin Trainor

MDes 2023

Design for preferable consumption.


As the impact of climate change becomes more and more apparent in our daily lives, the need for clean air in the home has become a pressing concern for many people. On average, Americans spend 90% of their time indoors, so access to clean, breathable air has a direct impact on our long-term health. Traditional HEPA-based air purifiers are e€ective at removing particulate matter from the air, but they have a variety of serious downsides: they are expensive to replace, stationary, unable to capture dangerous volatile organic compounds (VOCs), and most notably, once they’ve reached their end-of-life, HEPA filters require disposal in a landfill where they will essentially never biodegrade. Clearly, an alternative is required, and our project, Microcosm, aims to take on the traditional weaknesses of air purifiers by making use of a natural air purifying powerhouse: moss. Our autonomous moss-based air purification system moves freely around a space, filtering both VOCs and particulate matter. Once the moss reaches the end of its life span, it can be composted, as the frame of the moss is made entirely of biodegradable materials.


For this project, we selected a sheet moss, Hypnum Imponens, that is a widely-available species with demonstrated e€ectiveness in large-scale moss air filtration applications. Moss can also grow easily on complex geometric surfaces, which allows us to use organic materials and shapes for the main body of the device. Furthermore, as it grows on these uneven surfaces, it creates more surface area, enabling more air purifying power. By combining the surface area of the moss with the suction of a small electric fan, Microcosm achieves robust air purification performance. On top of it all, moss is relatively easy to maintain and grow. Even when not properly maintained, it can stay alive for up to 6 months and continue to purify your air. However, properly maintaining the moss simply requires that it gets a few hours of sunlight and stays moist throughout the day.

Testing the performance of the Microcosm purifier system using incense
Testing the performance of the Microcosm purifier system using incense

To house and support the moss, our initial goal was to fabricate a porcelain ceramic “chassis”. Ceramic was a natural choice for this project, as its environmental impact is miniscule, its cost is low, and its porous structure allows moss to grow. However, after several rounds of iteration it became clear that the tedious manufacturing processes as well as ceramic’s fragility would make it difficult for such a piece to ever reach consumer level scalability. Therefore, an analog chassis was created out of wood. To pull air through the moss filter layer, two large fans were positioned at the top of the unit. The suction created by the fans draws outside air through the moss, removing VOCs and most particulates, after which it is pushed through an activated carbon sheet to remove any remaining particles that were not trapped.

To target areas with the worst air quality in real time, Microcosm utilizes a set of waypoint air quality sensors. These small waypoints can be freely moved around by a user, and as soon as they measure an unsafe level of VOCs or particulate matter, a signal is sent to Microcosm via Bluetooth. Users can track air quality readings from these pucks, as well as the onboard sensor within Microcosm, at any time through the Microcosm app. The app also allows users to see where Microcosm has traveled, and they can build out custom routines to fit their own needs.

Final Design

Microcosm is more than a replacement for traditional air purifiers – it outperforms them in every regard. It’s better for the environment, as it relies on nature to purify the air rather than large quantities of plastics like traditional HEPA filters; it’s better for humans, as it can clean the air in multiple areas of the home while introducing a wonderful source of green life; and it’s better for the plants involved, as they are taken care of autonomously without relying on human input. This device represents an important example of how designers can create environmentally friendly solutions without sacrificing performance in form or function.

Microcosm prototype


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