Dietrich Weyel, Sc.D. – Advanced Indoor Environmental Quality & Particles Physics in IEQ – Part 2

Air Date: 7-19-2013| Episode: 292


This week we discuss in further detail Advanced Indoor Environmental Quality (IEQ) with our Technical Director; Dr. Dietrich Weyel…

Full Description:

This week we discuss in further detail Advanced Indoor Environmental Quality (IEQ) with our Technical Director; Dr. Dietrich Weyel. Last week we laid the foundation with a discussion of toxicology, particle size, aerodynamic equivalent diameter, and where particles deposit in the respiratory track. This week we will get into more detail on the importance of aerodynamic equivalent diameter, how gasses behave in air and how this all ties into investigation and remediation of indoor environments.
Dr. Weyel “Dieter” is the IAQ Radio Technical Director; his Sc.D. is in Environmental and Occupational Health from the University of Pittsburgh. He taught at the University of Pittsburgh and Duquesne University, and he also has worked in the private sector at Bayer Corporation prior to starting his private consulting practice.
Z-Man’s Blog:
                                                                   Discussion with Dieter

IAQradio’s technical director Dieter Weyel, PhD., an academic and a practitioner; is an entertaining and knowledgeable guy who always brings a unique perspective to the topic at hand. On today’s broadcast of IAQradio, Dieter discussed particles.

Nuggets mined from today’s episode:
• A micron is 1/millionth of a meter. A human hair is 80-100 micrometers in size. The human eye can detect two 40 micron size particles side-by-side.
• The settling rate of particles is influenced by the particles: size, shape and density.
• The AED [Aerodynamic Equivalent Diameter] is based upon particle size, shape and behavior determines particle behavior.
• Particles deposit in human lungs according to size.
• Animal studies are necessary sometimes. Sacrificing animals for scientific study should only be done in return for good data. Animals used for scientific study often have a pedigree.
• 30 micron fibers have been found in human alveoli, fibers behave according to diameter as opposed to length.
• The alveoli, the lowest part of the human lung where oxygen transfer occurs is where health damage occurs. ≤25 micron particles deposit in the lung. ≤10 micron particles are respirable, depositable particles get to the alveoli.
• Smaller particles have a greater chance of entering the blood stream than larger particles.
• Chemical vapors and particles temporarily paralyze the human bodies self cleaning mechanism.
• Cigarette smoke particles quickly coagulate into particles of larger size.
• Indoors it is unlikely that ≤ 1 particles will settle out of the air indoor as dust, but rather attach to ceilings, walls or cold surfaces.
• Dust can adsorb vapors and carry them deep into human lung.
• The relative weight of gases is not relevant in real world situations as gases will inevitably mix together.
• Particle size is the most important factor in capture by air filtration devices.
• Electronic precipitators remove small particles effectively. Electronic precipitators don’t remove vapors. Electronic precipitators require routine maintenance.
• Air pollution studies in Pittsburgh originally focused on PM 10 (Particulate Matter 10 microns), then PM 5 and now PM 2.5.

Today’s Music: Particle Man by They Might Be Giants

Z-Man signing off
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