What are you breathing at work? Time to fix your air conditioning system

By Sanath Kithsiri

Air conditioning is the process of controlling four basic parameters in a space; namely, temperature – both dry bulb and radiant, moisture content, air quality, air circulation as required by occupants, process or products. Air conditioners circulate and filter air, removing pollutants and mould from the air. This only holds true, however, if your system is kept clean and filters are regularly changed. Otherwise, the AC can actually contribute to indoor air pollution. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the area. High temperature and humidity levels can also increase concentrations of some pollutants.

Long-term exposure to poor indoor air quality can lead to respiratory diseases, heart disease, and even cancer. It can also exacerbate existing health conditions such as asthma. As such, maintaining good indoor air quality is not only crucial for our comfort but also for our health.

Generally, we spend 8-12 hours daily indoors at work, hence it is imperative for us to understand the impact of indoor air on our health and wellness as occupants. Indoor Air Quality (IAQ) is a large part of the overall indoor environment that has a direct impact on occupants. Better air quality means fewer pollutants in the air and more oxygen to breathe. And with the improved flow of oxygen to the brain, our cognitive performance gets better, hence resulting in an increase in productivity at work.

The most common and deadliest pollutants present in our working places are PM2.5, CO2, TVOCs.

PM2.5: They are these tiny and fine particles which tend to stay longer in the air than the heavy particles. This, therefore, increases the chances of humans or animals inhaling them into their bodies. They are able to penetrate deep into our lungs after bypassing the throat and nose, which may eventually result in them entering our circulatory system. They are known to worsen chronic diseases such as asthma, heart attack, bronchitis etc., in fact exposure to these fine particles could result in premature deaths from heart and lung diseases.

CO2: At room temperature, carbon dioxide is an odourless, colourless, non-flammable gas. When CO2 hits 1,000ppm in a room, workers feel slightly fatigued with common complaints of headaches and that result in low productivity. CO2 in the range of 2,000-5,000 ppm can result in poor concentration, loss of attention, increased heart rate and slight nausea.

TVOCs: They include a variety of chemical substances, which can lead to fatal health illnesses. Typically, VOC concentrations are up to 10 times higher inside as compared to the outdoors. These are typically even higher after new constructions and a “flush out” phase is required before the occupants can move in. 

A recent study by the Sustainable Energy Authority together with the Asian Development Bank (ADB) on indoor air quality in air conditioned offices found that the indoor air qualities (IAQs) are not at the satisfactory level in most places and IAQs are worse especially in air conditioned spaces having stand-alone air conditioners. Further, a recent study by teams from Harvard and Syracuse Universities on indoor air quality suggests that employees in green environmental conditions performed 61% better on cognitive tasks than in standard office conditions. And if one doubles the ventilation, cognitive performance can be increased by more than 100%.

Poor indoor air quality can lead to various detrimental health issues, and however we can minimise this risk and achieve the highest level of indoor air quality by taking care of the most common and deadliest pollutants presence in our working places such as PM2.5, CO2, TVOCs, etc. by employing the following:

1. Provide recommended ventilation by ASHRAE

Ventilation is the process of “changing” or replacing air in any space to provide high indoor air quality. The process of changing and replacing the air in a space helps in diluting the pollutant load in the air as the pollutant get diluted with new air coming in and replacing the old air. 

2. Improve air filtration

In order to minimise the risk of entering the pollutants to the space, air filters are used. The filter may get choked by the particles in the air with time and this will result reduction in air flow and ultimately poor indoor air quality and energy wastage. Hence, air filters should be cleaned thoroughly and periodically. In order to supplement the ventilation to further minimise the risk of virus transmission, indoor recirculation filtration should be used. This filtration should have certified H12/H13 grade HEPA filters that will ensure that any COVID particles that may be in the air in aerosolised form are also captured by the filters.

3. Maintain positive pressure

A space is in “positive air pressure” when the pressure inside the space is higher than the pressure outside. The resulting “positive air pressure” means the space prioritises trying to pushing out air rather than sucking in air from the outside.