Purifying indoor air with 3 20-in box fans and 3 x Honeywell CF200A1024 (FPR 10/MERV 12 Air Filters)
Post date: May 12, 2015 10:17:35 PM
PART 1 - Initial Introduction
My room has a bit of dust in it and I sneeze every so often. While thinking about how to address this I started researching Air Purifiers. I eventually stumbled across the following YouTube videos which I found very interesting:
In order to quantify these findings, I used a Dylos DC1100 Pro Air Quality Monitor which has been used by students at MIT in their own research papers 
During my research I started by looking at some low-end ~$200 Honeywell Air Purifiers, particularly the HPA300B. However, as I began to read more, ultimately I found what is considered one of the best air purifiers in the industry--the IQ Air Health Pro Plus which retails for $800-$1200 depending on your options.
It was fascinating one could achieve a ~90% reduction in air particulates with only a fraction of the cost by using a box fan. Further, with box fans I could distribute the load across multiple fans in different areas in the room. So out I went, I bought 3 box fans ($16.98/ea) and 3 air filters (Model: Honeywell CF200A1024) ($31.98/ea), on the side of the air filter box it says they can last up to 1 year!
Link to the Dylos DC1100 Pro Air Quality Monitor is shown below:
Here is one of the three air filters being used, attached to one of the box fans:
I started out with 1 box fan and 1 air filter and within about 30 minutes the air "seemed" fresher and cleaner. It is difficult to describe as I have never worked in a clean room. I needed to quantify whether this was true or just wishful thinking. After seeing the YouTube videos above, particularly the first one I bought 2 more fans and filters. Then I ordered the Dylos air quality monitor to check the particulates in the air. What 3 box fans can do is really amazing as you will soon see below.
This article is split up into 3 parts:
1. This initial introduction.
2. The before/after of when I got home and after 1 hour of having all 3 fans run on low.
3. Once #2 reached its lowest point, I turned off the filters for ~1hr and see where the particulates went, initially it was slow for them to increase; however, once I turned on the HVAC and AC as it is summer where I live, the particulates sky rocketed. However, once I turned the filters back on even with the HVAC running, the particulates dropped down to much better levels.
PART 2- Before and after
When I took my first sample of the ambient air in the room (left) and after 1 hour on (right)
Per the manual  above on page 6:
The number on the left represents small particles and the number on the right large particles.
PART 3 - Air quality over time
For part 3 I performed an experiment:
1. At 5:07PM I turned off the air filters (speed was low setting)
2. At 5:13PM I turned on the HVAC system w/Air Conditioning.
3. At 5:32PM I turned on the air filters (speed was low setting)
4. At 5:40PM I turned on the ceiling fan (to improve overall air circulation)
The data speaks for itself, the box fans and air filters with good air circulation can really work wonders for your air quality!
In the next graph we see the particle high as when I am at work I turn off the air filters. The small particle count increases to 100,000+ particles and small particles to upwards of around 400-800 per cubic foot. Once I get home, I turn on the filters and it drops dramatically. The spike occurred when I was tearing apart some cardboard boxes. It stayed very low throughout the night which is clearly seen below: