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IAQ - Persistent Problems

Particles from HVAC registers, with unhealthy effects -

To remain broadly aware of indoor air quality (IAQ) issues, I check various sources[i]. The listserv of the National Center for Healthy Housing (NCHH, U.S.) is concerned with asthma and lead poisoning. Both have large costs in terms of child development and the time and resources of families, healthcare, and education. Lower income households and public agencies or institutions are disproportionately affected. Indoor air quality (IAQ) in residences can be especially problematic for asthma or other health conditions affecting breathing. NCHH is active in program, research, and advocacy areas. On occasion, elusive IAQ circumstances come to their attention. The attributes here appeared in a recent post:

two multifamily residential buildings… concerning “a substance that settles on all interior surfaces” … generally whitish and gritty (like sand)… sometimes tiny black specks… breathing problems …using inhaler regularly… but only sporadically before moving in… Increased itching and scratching of skin and scalp… photos of scabbed sores… General malaise, flulike symptoms… No discernible odor.

Facility managers are widely acquainted with IAQ for occupant comfort, safety, wellness, and productivity, and with closely associated O&M costs, especially occupant requests, energy consumption, and maintenance. Problems such as the above would be quickly diagnosed and resolved in our properties. What background would enable a property manager and HVAC contractor to analyze and correct problems with IAQ?

The larger picture -

The air handling side of HVAC systems and equipment of any size and configuration is subject to degradation of air quantity and quality, affecting comfort, wellness, and energy consumption. Contaminants - vapors, dusts, debris, microorganisms - originate from outside and within conditioned spaces. Accumulations of materials within equipment and ducts, some harboring microbes, are a principal consideration in configuring, operating, and maintaining HVAC. A variety of air cleaning methods and equipment are now available. The role of aerosols in spread of Coronavirus causing COVID-19 has accelerated their production and promotion. Nonetheless, cleanly maintained equipment and ducts and judiciously located, selected and applied filters remain powerful, reliable basic measures. Another basic consideration is ventilation, configured and operated in view of the space and occupants. For multi-tenant residential, commercial, and institutional buildings and facilities experiencing ongoing problems with air quantity, quality, and constituents, a deliberate, systematic search for the source will positively identify root causes and options for correction. There are effective countermeasures for every case. In an HVAC consultation, keep asking why until the details of proposed solutions are entirely clear.

A word on economic strategy -

In the event of multiple, coincident problems that in sum call for principal equipment replacement, an option consistent with circular economy is a thoroughgoing overhaul and update in place. This approach, competently planned and executed, is consistent with ESG principles and gaining recognition. “There is no silver bullet” for air quality notes a colleague with long experience with problem systems. There are, however, options. Overhaul in place versus new equipment is one such.

A rich information source -

ASHRAE, a global non-profit, is widely recognized and strongly influential in establishing and supporting consensus standards for HVAC. All HVAC contractors should be readily familiar with ASHRAE findings and recommendations. Many ASHRAE publications are available free and are accessible in style and content.

Resolution -

I will watch the listserv for postings about the problems reported. It is disappointing that any indoor environment ever gets to this point, given that air side investigation and analysis are straightforward and established.

[i] ASHRAE ( as notes in the blog, offers a wealth of information, reports, recommendations, and discussion. Despite the scope of content, navigation of the site is convenient. Worth singling out for IAQ understanding, investigation, remediation, and participation in the FM community, Pure Air Control Services ( offers a range of resources and knowledge online, as well as a regional (North America) presence. Over several decades, Pure Air has developed an investigative and restorative approach to HVAC consistent with reliability, economy, and ESG. They are attuned to IAQ, due in part to work with health care customers experiencing persistent problems.

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