Improving Ventilation Helps Reduce Transmission of SARS-CoV-2
It may be a considerable amount of time before herd immunity is attained via vaccination. Yet pressure continues to coerce us back into offices, factories, schools, etc.
On 1st March 2021, the WHO released a guideline in which they state “Understanding and controlling building ventilation can improve the quality of the air we breathe and reduce the risk of indoor health concerns including preventing the virus that causes COVID-19 from spreading indoors.”
One should not assume their building has good IAQ (indoor air quality). But how do we know if our office buildings are adequately ventilated? Some modern buildings have gone high tech and incorporate sensors that prominently display data or can be accessed from an app. It would be a good idea to chat with the building management to see if they monitor IAQ in any way. But if they do not then a variety of services exist in which experts can come and relatively quickly measure several test parameters using certified and calibrated equipment. Four parameters have emerged as being important to reduce transmission:
Humans exhale carbon dioxide at 40,000 ppm while natural clean air contains an average of 413ppm. IAQ experts measure the difference in CO2 between outdoor air and indoor air and enter this data into a calculation that helps determine how frequently fresh air is used to dilute stagnant indoor air. Generally speaking, it is advised to keep CO2 levels below 1,000ppm indoors.
Relative Humidity (RH)
RH levels below 40 percent cause bioaerosols (potentially laden with the virus) to shrink in size and stay aloft longer in an indoor setting. In addition, low humidity dries our mucous membranes and inhibits our body's natural defence against airborne viruses. However, RH levels above 80 percent encourage mould growth within a building. A balance must be struck and the “sweet spot” has been determined at 40 to 60 percent.
Airborne Particulate (PM2.5)
This fraction of particulate is known to evade our natural “dust removal” defences and reach deep into our lungs, even crossing into our bloodstreams. A building with a good filtration system should be able to bring this particulate fraction down to acceptable levels. If your building has high particulate levels it means bioaerosols are also not being cleared out of the air.
Volatile Organic Compounds ( VOCs)
Building managers have dramatically increased the use of disinfectants in their premises. But did you know some disinfectants contain VOCs, some of which are classified as hazardous to health? Some tenants report various respiratory ailments and/or headaches since their offices have become inundated with these “pandemic products.” It has been found that manufacturers of these products do not always disclose these ingredients.
Even older buildings have begun to employ various technologies to reduce particulates/bioaerosols. Three common technologies are UVGI (ultraviolet germicidal irradiation), NPBI (needlepoint bipolar ionization) and upgrading to MERV 15 filters.
Intertek can measure a wide variety of IAQ parameters. Maybe it’s time to chat with the building management?