Air Purifier

Project For
Carleton University

Third Year (2019)

Key Focus
  • CNC
  • Design Process
  • Incremental Innovation
  • Systems
  • Group Collaboration
Project Length
11 weeks
“An air purifier to improve the lives and health of elderly without compromising portability within the home, ease of use or aesthetics”.

This project was assigned to us for the full duration of a semester in third year. The focus of the project was to practice incremental innovation of an existing product as well as how to make these products more portable. We picked from a handful of product options and worked in groups to research what was already on the market and existing technologies before breaking off to focus on an individual area of improvement. My groups product was air purifiers and I decided to focus on how that could be optimized for an item for older adults.

01 Research

Disassembling an Air Purifier

My group and I felt the best way to start off this assignment was to disassemble an existing air purifier to see some of the key components, investigate how it works and explore different strengths and weaknesses.



HEPA Air Filter

HEPA stands for High Efficiency Particulate Air which is a filter that traps particles though layers of extremely thin fiber glass strands that are sealed in a plastic or metal frame. This filter comes in both a replaceable or washable version.

Centrifugal Fan

A centrifugal fan increases a pressure that enters by pushing it against the casting. It consists of blades on a circular hub and is said to “turn air 90 degrees” as it blows out perpendicular to where it enters. I decided this would work best in my design as it has the ability to create a large amount of air pressure from static air allowing it to overcome the static friction of the HEPA filter.

Social Impacts

Based on a study conducted in 2018 it has been shown that the use of personal air purifiers can reduce the blood pressure of older adults living in urban areas. However there is a gap in the air purifying market, existing air purifiers are too complex, bulky or not visually on par with the elderly demographic.


Source: Morishita M, Adar SD, D’Souza J, et al. Effect of Portable Air Filtration Systems on Personal Exposure to Fine Particulate Matter and Blood Pressure Among Residents in a Low-Income Senior FacilityA Randomized Clinical TrialJAMA Intern Med. 2018;178(10):1350–1357. doi:10.1001/jamainternmed.2018.3308

02 Ideation

Design Brief 

My goal is to create an air purifier for the elderly population, around the age of 60 or above.  My intent is to design an air purifier that elderly people can reposition around their home and aesthetically want to display in different rooms. It will also focus on an easier filtration replacement process and better understanding of how the purifier is working and when it is time to switch the filter.



Best handle and body orientation to fit key components while being easy for elderly to grab and carry

Power Supply

Eliminating the need to use a plug in chord by incorporating conductive charging with charging pads

Visual Appeal

Making the purifier both aesthetically pleasing and distinctive to the elderly population with use of form, colour and contrast

03 User Testing

Sandblasted Goggles to impair vision
Sandbags on wrists and ankles to add resistance to limbs
Gloves to impair finger fidelity similar to arthritis
Bungee chords connected to limbs to limit range of motion and tension on limbs

Old Age Simulation

User testing was a very important component of my design process, mainly to determine the type of handle that made the product easiest to move around. Since I couldn’t test on elderly people I had to create a system to mimic the effects of aging.


I used bungee chords and bags of sand tied to the test subjects wrists and angles to restrict movement. I used gloves to limit accuracy of hands and mobility in fingers. Finally I used sandblasted goggles to impair eyesight. 


For the test prototypes I created three different boxes out of foam which had chambers cut out in the middle to hold a 2lb weight, the amount the battery and fans I would include in the air purifier would weigh. Each prototype featured different types of handles and box orientations. The test subjects were asked to pick up and place each prototype from 3 different heights as well as attempt to place the prototype on a mock charging port which fits onto pre-cut holes on the bottom of each protoype.



My Expectations:

I made this prototype as I thought the soft strap could be place over a shoulder which might be an easy way to carry it, especially if the user can use only use one hand if they use a cane or need to hold a railing. Additionally I had elastic straps the users could slide their hands into if they had stiff fingers from arthritis.

Users Thoughts:

Testers found this model had a lot of precision placing on the charging port with the two elastic slots on the sides but it was hard to get their hands into them. Additionally they found the long handle to flimsy and difficult to place and no one put it on their shoulder as I had anticipated.


My Expectations:

I made this prototype T-shaped as I thought users could place their hands in the cut out section and not have to bend their fingers. I also included a soft short strap at the top that users can pick up the air purifier with or just rest their hand underneath to lift, again if they have problems closing their fingers.

Users Thoughts:

Test subjects overall found this model confusing, most only used the top handle and didn’t think to place their hands under the cutouts which was my original intent for ease of carrying since the user wouldn’t have to wrap their hands around it.


My Expectations:

The stand out feature on this prototype is the 180 degrees handle. My thought with this handle was that users could easily slide their hands around the handle to switch from carrying it from the top to the sides without letting go. Again they could also just rest their hands underneath the handle to lift if they have difficulty closing their fingers.

Users Thoughts:

Overall this was test users favourite model. They liked the ability to carry it with one or two hands and slide around from the top to the sides without releasing the handle. Additionally people said the handle could be thicker and closer to the body.


My Expectations:

This prototype was made to see how easy it would be for users to place the air purifier on different charging ports so the air purifier battery could run for longer periods without the user having to constantly plug the purifier into a wall outlet.

Users Thoughts:

Most people found the base very difficult to use. They had a hard time lining up the cut out on the bottom of the model with the knob. They suggested making the knob wider or longer and more dome shaped. Additionally they suggested making it shallower.

04 Reiteration

After deciding which type of handle and dimensions worked best from the user testing I went back to the drawing board to fine tune my form. This was done through sketches and low fidelity models.

05 Construction of Model

The first thing I did to create this model was create a solidworks model of the body so I could CNC ren foam. The CNC routered out the main shape of the body so I only had to clean it up with some hand sanding a create a subtly rounded back face. Next I used the bandsaw to cut the handle out of a piece of  Basswood which I had to split the handle into two parts and glue them together. I then used a rasp and sandpaper to fillet the edges. Finally I sealed it with varnish. I put a layer of Gesso on my model, then I used a spray gun to build up layers of paint. I cut dowels and drilled holes in the handle and body. I then added epoxy to the handles and stuck dowels through the holes. Additionally I added vinyl decals.

06 Final Model and Documentation

How It Works

General Arangement