COVID-19 and indoor air quality

Under Level 5 of the COVID-19 lockdown, all non-essential services were halted, workplaces were closed and workers were sent home. With the gradual relaxation of the lockdown restrictions under Level 4 and, now, Level 3, more and more workplaces have reopened and many workers have returned to work. This phased return to work has required employers to ensure that they take all reasonably practicable measures to ensure that their employees are protected against infection with SARS-CoV-2 at the workplace. Risk assessments must be performed and appropriate control measures must be put in place to reduce the risk of infection/transmission as far as possible. Employee training and awareness, social distancing, hand hygiene/sanitation, compulsory use of face masks, physical barriers – all play important roles in addressing the COVID-19 risk within the workplace. With employers focusing their attention on these “primary” control measures however, the importance of the quality of the indoor work environment and, in particular, Indoor Air Quality (IAQ), is often overlooked.

Whilst there is currently little evidence to show that SARS-CoV-2 is likely to be transmitted from one workspace to another via ventilation systems, such systems are responsible for moving air around, diluting or extracting airborne contaminants and generally conditioning the air within buildings. Poor performance of building ventilation systems may therefore increase the risks of transmission/infection simply by exposing occupants to potentially higher concentrations of airborne pathogens including SARS-CoV-2.

There are several simple measures which can be taken to mitigate these exposure risks, including maximising the inflow of fresh replacement air into the workplace as far as possible. In a central HVAC (heating, ventilation, air conditioning) or MVAC (mechanical ventilation, air conditioning) system, this may require that outdoor dampers are fully opened which can impact on workplace temperature control/regulation. Opening of windows and doors as a supplementary measure can also be effective in improving ventilation of office spaces although, in winter, occupants may be reluctant to take this step. Central HVAC/MVAC systems can be activated an hour or two before the arrival of workers in order to flush the building of airborne contaminants prior to occupation. Similarly, the HVAC/MVAC can be run for several hours after the building is vacated in order to flush out contaminants which may have accumulated during the day. Toilets and ablutions could be under mild negative pressure (simple extraction fans) in order to prevent escape of air into adjacent work environments.

The question is, how do you know if your workplace ventilation is adequate?. Fortunately, the quality of indoor air as a measure of workplace ventilation, can be quickly and easily assessed. Measurement of ambient concentrations of carbon dioxide, carbon monoxide, ambient air temperatures, ambient relative humidity and linear air movement within office environments provides important information on the adequacy of ventilation and allows for informed comment on the need for remedial actions.

Geozone Environmental can assist you in assessing the Indoor Air Quality within your work environments and is able to recommend appropriate remedial actions should these be required.

Contact us for a free quotation.