Jeff May – Common and Under Recognized Sources of Indoor Bio-aerosols

Air Date: 2-5-2016| Episode: 400

Join us this week on IAQradio when we welcome Jeff May to discuss two presentations he gave at the Indoor Air Quality Associations 19th Annual Meeting; Mold in the Mechanical Leading Cause of Sick-building Symptoms and Under Recognized Sources of Indoor Bio-Aerosols…

Full Description:

Join us this week on IAQradio when we welcome Jeff May to discuss two presentations he gave at the Indoor Air Quality Associations 19th Annual Meeting; Mold in the Mechanical Leading Cause of Sick-building Symptoms and Under Recognized Sources of Indoor Bio-Aerosols. Some of the bio-aerosols he will discuss are obscure and others are surprising. We will also do a short preview of the EPA sponsored Institute of Medicine of the National Academy of Science, Engineering and Medicine conference on The Health Risks of Indoor Exposure to Particulate Matter. The conference is next week in DC and Radio Joe will be covering it for IAQ Radio. Jeff May is Principal Scientist of May Indoor Air Investigations, LLC in Tyngsborough, MA. Author of four books on IAQ (published by The Johns Hopkins University Press), including My House is Killing Me and The Mold Survival Guide, Jeff has been investigating building problems in homes, schools and office for over 25 years, and has examined by microscopy over 35,000 air and dust samples. A nationally recognized speaker on IAQ topics, Jeff is a member of IAQA, the Pan American Aerobiology Association, American Chemical Society, and the New England Chapter of the American Industrial Hygiene Association, among others. He is a Certified Indoor Air Quality Professional (CIAQP, Association of Energy Engineers), and is a licensed Mold Assessor in the state of Florida. He holds a B.A. from Columbia College (chemistry) and an M.A. from Harvard University (organic chemistry), and has served as an Adjunct Professor in the Department of Work Environment at the University of Massachusetts Lowell. LEARN MORE with Jeff May this week on IAQradio!

Cliffs Blog


Jeff May was the guest on our 400th episode of IAQradio. He is a chemist, building investigator, microscopist, author and speaker. Jeff is capable, curious and captivating.

Nuggets mined from today’s broadcast:

Many different allergens are found in mold spores. The allergen from an outdoor mold, Alt 1 allergen from Alternaria alternata commonly used for allergy testing may be inappropriate for allergy testing people with allergy to indoor mold species such as Aspergillus and Penicillium species.

Unlike large macrofungi which cause wood decay, few microfungi found indoors have the ability to breakdown wood.

The leading cause of sick buildings is microbial contamination in air conditioning.

Warning Labels should be affixed to air handlers, pointing out the risks and consequences of deferred maintenance.

According to NADCA, only 40% of association member air duct cleaners clean AC coils.

Refrigerator coils and condensate pans can harbor microbial contamination.

Fibrous lining material within HVAC system components, flex ducts and duct board are the parts of HVAC systems which are most difficult to clean.

Recommends, deep, pleated MERV 11 filters for keeping dust and particulate out of HVAC systems.

UVC light is very energetic, destroying most organic materials and known to breakdown adhesive in pleated-media. Commercial UVC light systems are effective, small residential systems generally aren’t.

Aerosol mist of spray-paint spheres in the 3-10 micron range are often misidentified as fungal spores by labs. Many labs misidentify basidiospores as Pen/Asp.

Has noticed a connection between HRVs and mold problems. Filters in HRVs are inefficient and/or not properly attached allowing moist dust particles to become a reservoir for fungal growth.

Burning jar candles, improperly vented combustion appliances, AC condensate pans, rust particles, drywall dust are all under recognized sources of surrogate allergens.

All fans, blowers and air moving devices attract dust by impaction.

Dust mites: masticate, defecate and fornicate.

Animal bedding is an underestimated reservoir for dust mites.

Surrogate allergen is a non-allergic substance that carries water soluble allergen on its surface. Examples include: keratin, drywall dust, rust particles, starch granules, etc.

Soot particles can act as surrogate allergens. Pollen and cat allergen are known to attach to soot particles.

“Bird bloom” particles are a hydrophobic substance (1-3 micron) shed by birds when they flap their wings. Bird breeders are at risk for allergic alveolitis.

Feather pillows and down quilts can cause “duvet lung”.

Actinomycetes has been found growing in toilet bowls, in humidifiers, on basement foundation walls, etc. Actinomycete spores are the size of bacteria. Actinomycetes are known to cause hypersensitivity pneumonitis.

Theorizes that the “wet animal smell” from wet wool is caused by animal oils that gets trapped between overlapping cuticle plates.

Rainstorms cause starch granules to swell, leak and explode releasing allergen attached to the starch granules; in Australia, this phenomenon is associated with an uptick of asthma admissions in emergency rooms.

Final comment: Amazed and disappointed by how little progress has been made in correcting known causes of environment related illness.

Today’s Music: Inspector Gadget Cartoon Theme YouTube

Z-Man signing off      webcast       portable microscope for field use.

Trivia Question : Who is usually given credit for making the first microscope?

 Answer: Zacharias Janssen