Indoor Environmental Quality (IEQ)
Employees responding to a Work Complaints survey reported difficulty doing their work because of poor indoor environmental quality. Those employees specified a number of factors as “stressors.” Being too hot or too cold were among the top complaints. All of the top five stressors related to indoor environmental quality (IEQ):
1. Lack of air movement
2. Being too hot in summer
3. Stagnant air
4. Cigarette smoke
5. Being too cold in winter
IEQ is a broader term than IAQ (indoor air quality). IAQ deals specifically with the condition of the air within the building’s occupied spaces. IEQ addresses the overall condition of the indoor space. Elements of IEQ include indoor temperature, ergonomics, aesthetics, noise and lighting, as well as the quality of the indoor air.
Sick Building Syndrome
IAQ is easy to overlook until a problem arises. Often, it is an accumulation of factors that cause the problem: smoke, odours, dust and high occupancy in an area with too little ventilation all can decrease comfort and affect employee productivity.
According to the World Health Organization, 30 percent of commercial buildings show signs of Sick Building Syndrome, including headaches, nausea, irritated nasal passages, itchy eyes and skin irritations.
In large buildings, IAQ problems are commonly associated with cooling towers, placement of air-intake vents, poor maintenance of mechanical systems, air ducts, and so on. The Legionella bacterium, the cause of legionnaire’s disease, is identified in cooling towers and other stagnant water reservoirs. Poorly maintained air-conditioning systems lead to respiratory infections for building occupants.
Ventilation and Interior Humidity
Ventilation dilutes stale indoor air with fresh outside air (presuming the outside air is clean). Ventilation is very beneficial for expelling carbon dioxide and also removes moisture, heat and odours. Air exchange requires a balance for comfort without necessitating excessive energy consumption. In the home, air filters, when replaced regularly, help clean the air as it enters the building.
Humidity plays an important role in indoor environmental quality. If it gets too low, it causes respiratory problems, particularly for people with allergies, sinus problems or asthma. If it gets too high, microbial growth increases exponentially.
So, sometimes moisture needs to be added to the air, and at other times, it must be removed.
Winter Months Worse for Indoor Air Quality
Low relative-humidity levels are associated with poor IAQ. ASHRAE standards suggest that a healthy humidity range is between 35-65 percent. In the winter, humidity levels typically drop below this ideal range and heating systems further dry out the air.
Dry conditions irritate the sensitive membranes in the nose, leaving you susceptible to airborne chemicals, viruses and allergens. Thus, frequent colds, allergic attacks and asthma during winter months are often the result of low indoor relative humidity.
High relative humidity can have an impact on absenteeism and increases the potential for respiratory illnesses among workers. Humidity levels exceeding 70 percent also encourage mold and mildew formation, which cause damage to furniture, carpet, mechanical and electronic equipment. In these circumstances, central-heating and air-conditioning systems combat high humidity by stripping moisture from the air.
In order to have adequate ventilation, ventilate your home or office at a rate of 0.35 air changes in one hour (15 cubic feet for each person per minute).