The effects of indoor air quality
Studies have shown that poor indoor air quality can have a detrimental effect on productivity, health and overall happiness, potentially leading to an increase in absenteeism and staff turnover in the workplace. Karl Walker of Beckhoff and Jacques De Bruyne of Upzio look at what can be done to improve environmental monitoring in buildings.
It’s estimated that the average person spends around 80-90% of their life indoors and while we often pay little regard to the quality of the air around us, studies have shown that indoor air in homes, schools, offices and other places of work can often be more polluted than the air outside, particularly in buildings with limited ventilation. This undoubtedly impacts on the health and wellbeing of building occupants and the situation is now worsening due to the recent drive to improve air tightness in modern structures.
Although in the past tangible measures to improve indoor air quality have been routinely overlooked or simply ignored, issues surrounding healthy working environments have come to the fore recently, with various studies identifying links between air quality and productivity within the workplace. The improved focus on delivering better working environments in offices and other commercial buildings is an important step in the fight against sick building syndrome – a poorly understood phenomenon that can negatively affect productivity and increase sick days, absenteeism and staff turnover. Though further research is needed, inadequate ventilation is often cited as a significant contributing factor.
Unsurprisingly, high occupancy spaces are associated with unnaturally high levels of CO2, but poor indoor air quality can also be attributed to a broad range of unexpected sources. Pollutants can be found in building materials, internal furnishings and cleaning products or produced through actions such as cooking or painting. Unwanted biological invaders such as dust mites, mould and suspended allergens can also impact upon air quality and even pollutants from external sources can ingress through windows, doors or other openings.
Pollutants emitted from common office equipment, carpets, paint, aerosols etc. are known as volatile organic compounds (VOCs) and concentration levels are commonly much higher in buildings where ventilation is limited. New buildings in particular register higher readings as the new materials all generate particles at the same time. A number of systematic human exposure studies have reported a decrease of cognitive abilities and various adverse health effects caused by exposure to elevated VOC levels. As a practical, cost-effective method of surveying indoor environments for contamination, the total VOC (tVOC) concept has been introduced. Global consensus on the issue has resulted in the emergence of guidelines for tVOC standards of indoor air quality. tVOC levels that are considered as acceptable range from ~0.6 to ~1mg/m3. Humidity levels can also have a direct bearing on the health and wellbeing of building occupants and optimum levels are generally between 30-70% relative humidity (rh).
Even with a modern ventilation system in place, there is still a risk that it won’t be doing the job expected of it and maintaining air quality levels - most ventilation systems don’t take room occupancy into account, operating in the same way whether there are two people in the room or 100. A more intelligent approach to ventilation control is needed.
The solution, therefore, is often to measure air quality and ventilate accordingly. This is sometimes done using a traditional CO2 sensor but results can vary and levels of accuracy can deteriorate over time, plus the information provided by these sensors doesn’t tell the whole story as CO2 levels will not provide any information on other pollutants in the room. In order to guarantee good indoor air quality a more complete environmental monitoring system is needed and this is where the building automation system comes in.
Designed to work with the existing building management system, environmental measurement panels can now be installed using standard cabling and require no external power supply. Connected to a control system, these unobtrusive devices don’t require programming or configuration and can be customised to blend seamlessly with any room décor, whether in an office building, hotel room, retail environment or even a cruise ship cabin. Once installed, the panels will automatically monitor air quality and other environmental parameters and users can access all of the relevant information at the touch of a button. These measurements include:
- Relative humidity
- Light level
- Dew point
As the control system continuously monitors all connected devices and makes decisions based on its programming, optimum conditions can be maintained at all times. Not only does this help to improve the overall wellbeing of building occupants, it can also help to save energy by managing temperature, light levels, etc. when rooms are not in use.
Despite efforts to improve employee/occupant wellbeing, there are still plenty of situations where CO2 levels are not considered or routinely ignored. For example, it’s not unheard of for air handling units to be turned off in the winter months in order to save money on energy consumption without the building operator realising that the same units provide the all-important ventilation to the building.
The technology is now available to accurately monitor and control indoor air quality in our buildings. By using intelligent control solutions as a platform for air quality measurement panels it’s possible to achieve unrivalled reliability, scalability and industrial performance, ultimately helping to foster a happier, healthier indoor environment for all building occupants.