Indoor air quality (IAQ) is an ongoing process: the natural tendency of interior spaces is to gather pollutants, not to get rid of them. Poor office air quality can lead to discomfort and a series of health issues, as well as a decrease in productivity, so you should not overlook the topic.
If you want to improve IAQ strategically, there are three complementary approaches:
- Filtering pollution out of the air.
- Extracting the air itself and replacing it with fresh air.
- Limiting the release of pollutants indoors.
Let’s look more closely at each of them.
Filtering Pollution Out of the Air
The basic principle of filtering is simple: indoor air is forced through a device that can capture pollutants, releasing cleaner air after the process. However, there are a few practical aspects to consider:
- Some pollutants are alive, while others are simply chemical substances. Methods that kill microorganisms are ineffective against non-living pollutants like particulate matter.
- Pollutant size varies drastically, and this influences the filtering method of choice. For example, a pollen grain is many orders of magnitude larger than a VOC molecule. Larger pollutant particles can be trapped mechanically, but molecular gases are unaffected.
- The chemical composition of pollutants varies. There are methods that induce chemical reactions to break down some pollutants into harmless substances.
The main drawback associated with filtering methods is that air must be forced through a device, requiring fan power. As a consequence, relying only on filtering to achieve air quality can represent a high electricity cost.
Another thing to pay attention to is, when filters are clogged with dust, they might do more harm than good. So they need to be replaced on a regular basis or better, indoor air can be monitored in a way so facility managers know precisely when filters need to be changed.
Finally, indoor plants** are great natural air filters. They absorb and metabolize various substances that are harmful for humans, including many types of VOCs, while producing oxygen during photosynthesis – which also improves indoor air quality. In addition, plants have positive effects on mood and concentration, which is why biophilic design is on the rise.
Additional Benefits of Having Plants in the Office
**Updated November 2019.
The decades-old claims about the power of plants to improve indoor air quality might be totally wrong, according to a recent study by the Drexel University. Researchers say that the experiments conducted in previous studies were done in lab-controlled environments.
According to their findings, in the real world, hundreds of plants would be required in a single room to come close to the air-cleaning capacity of just one air purifier.
Although we should be cautious about the findings of this study, it casts reasonable doubts on a generalized belief, and opens up a new and interesting perspective on this topic.
Controlling Pollutant Levels with Ventilation
Since outdoor air is typically cleaner than indoor air, a simple solution to control pollutants is keeping a constant fresh air supply. In fact, building codes throughout the world normally specify a minimum outdoor airflow for building interiors. This is generally based on two factors: floor area and occupancy.
There is a concept called demand-controlled ventilation (DCV), which is based on measuring the concentration of a substance indoors and adjusting airflow accordingly; if pollutant levels are high, the ventilation system supplies more cubic feet per minute of fresh air to dilute them.
Conventional DCV systems use carbon dioxide measurement because it correlates with human occupancy. However, pollutant levels do not always match occupancy, so a more innovative approach is to control ventilation by measuring key pollutants. For example, Foobot can measure particulate matter (PM) and volatile organic compound (VOC) concentrations, and these inputs can in turn be used to control ventilation.
With respect to fans, the conventional approach is to operate them intermittently when full airflow is not required. However, adjusting their speed is more efficient: fan motors above 1 horsepower can be controlled effectively by variable frequency drives (VFD), while fractional horsepower fans can use brushless DC motors, also known as electronically commutated motors (ECM).
Intermittent fan operation provides savings depending on the duty cycle. For example, operating the fan 80% of the time results in 80% energy use compared with full-time operation. On the other hand, reduced speed operation provides cubic power savings: a fan at 80% speed draws 51.2% of the power compared with an identical fan at full speed (80% x 80% x 80% = 51.2%), which translates into less energy use, and so smaller bills.
Therefore we could conclude that combining a DCV system that, in addition to CO2, tracks other pollutants such as VOC and PM2.5, with a variable-speed-driven fan, would provide both improved indoor air quality and energy savings for your office.
Limiting the Release of Pollutants
In many cases, it is possible to cut pollutant emissions at the source. For this, you first should know which the main air pollutants that can be found in an office are.
In general, you should avoid the use of cleaning products without adequate ventilation at the same time you make sure dust does not accumulate.
Aromatic candles should also be avoided since they are an important source of particulate matter, you may use aromatic plants instead.
New furniture and office supplies, like markers and white boards are also known to emit large amounts of VOCs – you can leave these items outdoors during their initial emissions or buy VOC-free supplies.
Watch out for thirdhand smoke. Noxious substances from cigarettes impregnate clothes, hair, and skin and slowly release into the air for hours, silently polluting your office even though smoking is prohibited indoors in most regions. A simple partial solution would be to ask smokers to wear clothes that they won’t take inside the office, while smoking as well as to wash their hands before getting back in the office. But this can be hard to get this accepted.
Keep in mind that some pollutants are living organisms, including mold and dust mites. These are very difficult to eliminate directly, but you can remove their main source of sustenance, which is moisture. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends that relative humidity be kept between 30% and 60%. This is one of the indoor air variables that can be measured by Foobot.
Mold and dust mites are very difficult to eliminate directly, but you can remove their main source of sustenance, which is moisture. ASHRAE recommends that relative humidity be kept between 30% and 60%.
How Can You Achieve the Best Results?
If pollutant levels in the air are lowered, indoor air quality (IAQ) is improved. This can be accomplished by filtering these pollutants out of the air, exhausting them outdoors using the ventilation system, or preventing their release or ingress in the first place. The best results can be achieved by deploying all three strategies simultaneously.
Monitoring and actuation are time consuming tasks, and even if you had a team working full time on keeping the air quality of your office within healthy levels, you most likely wouldn’t achieve the same results as those Artificial-Intelligence-driven technology would.
Foobot’s technology automatically monitors your office air quality 24/7/365. Thanks to the use of Machine Learning algorithms our technology is able to control your HVAC system to counteract spikes of some pollutants, humidity, temperature, or occupancy, and keeping comfort at the same time. This way your office occupants will breathe healthier air, see productivity levels increase and energy bills tank. Learn more here.