This newsletter summarizes the latest research related to indoor air quality.
Research Summaries
Simulation results indicate that, without wearing a face mask, the aerosol particles released from a coughing-infected person can be spread throughout nearly one-quarter of a grocery store in less than 6 min. Building and Environment
This study found that low relative humidity was common in office buildings, which was associated with increased reports of some symptoms. Indoor Air
Common household detergents were generally able to achieve a 99% (2 log) removal rate of a SARS-CoV-2 surrogate from non-porous surfaces. In some cases, water and a wipe were just as effective. Journal of Occupational and Environmental Hygiene
This study found that outdoor air seemed to be the main contributor to the total load of fungi found indoors, while airborne bacteria appeared to be mainly linked to indoor sources. Environmental Research
An enclosed, ceiling-mounted UV system not only reduced airborne bacteria but also reduced viable bacteria on non-high-touch surfaces when tested in various commercial spaces. Journal of Occupational and Environmental Hygiene
The underlying biological mechanism for chemical intolerance may be the activation of mast cells triggered by common chemical inhalants, foods, and drugs. Environmental Sciences Europe
In a study evaluating airborne mold pre- and post-renovation, an Instascope (a fluorescent aerosol cytometer) was found to have a significant positive linear correlation to measurements using a Mycometer (a biochemical assay). Indoor Air
Monitoring HVAC return air with an AerosolSense Sampler may be an effective surveillance solution for COVID-19. American Journal of Infection Control
Viruses can remain viable in carpet and dust for several hours to days, and cleaning with heat and disinfectants may be more effective than standard vacuuming. Indoor Air
Indoor environments have a complex mixture of bacterial and fungal species that can vary greatly from space to space. Respiratory health outcomes could be more influenced by the composition of these various mixtures rather than the absence or presence of individual species. Environmental Research
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Additional Resources
- ASHRAE’s Position Document on Limiting Indoor Mold and Dampness in Buildings (newly updated)
- National Air Duct Cleaners Association (NADCA) has updated its free standard “Assessment, Cleaning, and Restoration of HVAC Systems”
- ISIAQ webinar: COVID-19 and the Role of Buildings
- Office temperatures are less comfortable for women largely due to overcooling
- Simulation of coronavirus in an aerosol
- Good review article on COVID transmission by Bill Nazaroff
- A group is studying how the prevalence of COVID-19 might be correlated with the CO2 concentration in classrooms
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| How often have you asked, “what is an acceptable concentration of ________?” I have been working hard with an ISIAQ committee to develop a database of international IEQ guidelines to help answer that very question. After years of development, the website is now live! Check it out at https://ieqguidelines.org. Your feedback is appreciated. Happy New Year everyone! Ian Cull, PE, CIH [email protected] (312) 920-9393 |