particulate matter

Take the gold, ditch the frankincense and myrrh

Image: Schwetzingen Heilige drei Könige by 3268zauber licensed under a Creative Commons Attribution-ShareAlike 3.0 License at

I’ve been reading through a Christmas advent book with my 3-year-old son.   From last night’s reading…

“On coming to the house, [the Magi] saw the child [Jesus] with his mother Mary, and they bowed down and worshiped him. Then they opened their treasures and presented him with gifts of gold, frankincense and myrrh.”1

What were the magi thinking?  Didn’t they know the IAQ implications of using frankincense and myrrh-based incense?2

2,000 years later, we have a better idea about the problems caused by incense.  There was a recent article published in the Indoor Air Journal titled, “Characterization of particles emitted by incense burning in an experimental house.3 The authors were interested in studying particle dispersion in homes, and incense was an ideal particle emitter of moderate intensity.  They burned incense for 15 minutes in the living room and monitored particles throughout an expirimental house.

Here are some of the findings:

  1. Matthew 2:11, NIV []
  2. Yes, frankincense and myrrh had other uses besides incense []
  3. Ji X, Le Bihan O, Ramalho O, Mandin C, D’Anna B, Martinon L, Nicolas M, Bard D, Pairon JC. Characterization of particles emitted by incense burning in an experimental house, Indoor Air. 2010 Apr;20(2):147-58. []
particulate matter

The Practicals of Particles

Have you ever looked at a sunbeam shining through a window? You will find airborne particles otherwise unseen by the naked eye. These particles are likely to be greater than 50 microns in diameter. A micron is a unit used to measure distance equal to a millionth of a meter. Imagine dividing a tiny, little millimeter into 1,000 smaller units… that’s a micron.

People can see these floating particles and can observe the build up of dust on surfaces. But are these particles really a concern? Most of these airborne particles settle out of the air and are never inhaled. Those visible particles that are breathed in are typically removed by the nose or upper respiratory tract. As for concentrations of these visible particles in a typical indoor environment, you may have a few hundred per cubic meter of air.

Now let’s make it interesting and discuss the particles that you cannot resolve with your naked eye.