Introduction
We started the CleanAirApartment.com project while we were in Beijing, China for the 2008 Olympic Games. Beijing is a city known around the world for its air pollution problem, and we were there to work with the U.S. Olympic Committee on "Operation Clean Air" - a first-of-a-kind project to outfit US athlete residential and training facilities with ultra-high efficiency air cleaning.

We knew we would be living in Beijing ourselves during this project, and we thought it would be really interesting to see just what levels of air cleaning we could get in our own apartment.

We installed advanced air purification and wired the apartment indoors and outdoors with sophisticated air quality monitoring so that people worldwide could observe our progress. We were surprised ourselves when our measurements showed up to 99% improvement when compared to the outdoor air.

Going Global
Now we are taking Clean Air Apartment global and will be adding different homes around the world to prove the concept that advanced air purification can help create healthy living environments no matter where you live. The air cleaning systems used will vary from home to home depending on different aspects of the homes' designs. They will be a mix of existing and new technologies, depending on what is needed to create the healthiest possible indoor environment.

What the Measurements Mean
For our air quality tests we currently use laser-based particle counters. Our data is based on three times daily collections, between 8 AM and 8 PM.

All three measurements (PM10, PM2.5 and PC0.3) refer to airborne particles. PM 10 refers to particle mass (total weight) of suspended particles less than 10 microns in size. It is heavily biased toward large dust. PM 2.5 refers to the particle mass (total weight) of suspended particles less than 2.5 microns in size. It is a better indicator for particles that are actually harmful to human health. PC 0.3 refers to the total number of airborne particles (particle count) 0.3 microns in size. It is one of the best indicators for harmful fine and ultra-fine particles generated by automobiles and industry.

The World Health Organisation (WHO) guideline for PM 10 is 50 µg/m3, 24 hours mean and 20 µg/m3, annual mean. The WHO guideline for PM 2.5 is 25 µg/m3, 24 hours mean and 10 µg/m3, annual mean. There are currently no official health standards for PC 0.3. However, many air quality experts agree that particle count is a better indicator of air quality than PM 10 or PM 2.5, because small particles that contribute little to particle mass are the most dangerous in terms human health.