Irregular cleaning and maintenance of a facility’s HVAC system can harm the health, wellbeing and efficiency of employees, visitors and patients.
The moment one enters a large office space or a corporate hospital, one breathes a sigh of a relief. The floor is spotless, the furnishings are clean, and the air is cool – this seemingly immaculate environment is something we take for granted, without realising that what we are inhaling as breaths of fresh air may be loaded with lethal germs that can destroy our health.
What maintains comfort inside a building? The centralised HVAC system, which is like a network of blood vessels that give off branches to every room, maintaining a certain temperature and relative humidity. These mostly unseen ducts create an artificial environment inside a facility, which we feel is superior to the hot, grimy outdoors. But if the duct system and the cooling machinery isn’t regularly cleaned and maintained, the system degenerates into something that transfers germs from one interconnected room to another.
For example, the same HVAC system supplies air to both an operation theatre in which an infected wound is being operated upon, and an ICU which must remain sterile. The OT and the ICU are connected to each other by ducts; imagine the consequences of air from the former being pumped into the latter. Centralised cooling is a great concept on paper, but also has the potential of becoming a centralised dispenser of germs; think of an office environment in which employees spend 8-10 hours a day, six days a week, in which an ill-maintained HVAC system itself causes illness.
In recent years, India is paying a lot of attention to outdoor air quality. Most of us have forgotten about the other half of air quality: indoor air quality. The US Environmental Protection Agency (EPA) estimates that we spend 80-90% of our time indoors; hence, indoor air quality affects our quality of life to a far greater degree. It was ranked by the EPA as among the top five environmental health risks to public health.
What is indoor air quality (IQA)? It is loosely defined as the quality of air inside the building, as represented by concentrations of pollutants and thermal (temperature and relative humidity) conditions that affect the health, comfort, and performance of the occupants. Facilities such as commercial offices and manufacturing facilities should be concerned about their IQA if they are concerned about the comfort and efficiency of their employees, while hospitals – where people come to recover their health – need to pay attention to the air inside hospitals which can adversely impact health.
Sick building syndrome (SBS) is a condition in which building occupants experience acute health and comfort effects which are linked to the time spent in the building by them, but with no specific illness or cause identified. It is not a clinically diagnosable disease. Inadequate ventilation is the main cause. Its symptoms are diverse, and include eye or throat irritation, headache, dizziness, fatigue, difficulty in concentration, dry or itchy skin, and nausea.
Carbon dioxide is generated inside a building primarily by human metabolism. Build-up of this gas indoors indicates inefficient functioning of the ventilation system, and is a good indicator of ventilation rates. According to the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), an indoor carbon dioxide level of more than 1000 parts per million can cause SBS symptoms, and requires adjustment of the ventilation system.
Sources of indoor air pollution
• Volatile organic compounds from cleaning products, insecticides, pesticides, aerosols, paints, solvents.
• Suspended particulate matter from carpets, paints and polishers.
• Gases like carbon monoxide, nitrogen oxides and sulphur dioxide. Effects of these pollutants on the occupants of a building:
• Respirable Suspended Particulate Matter: Diseases of the upper and lower respiratory tract, asthma, chronic obstructive lung disease, lung cancer.
• Volatile organic compounds: Liver and kidney disorders, irritation to the eyes, nose and throat, skin rashes and respiratory problems.
• Pesticides: Skin diseases
• Nitrogen oxides: irritation to the skin, eyes and throat, cough.
• Carbon monoxide: Headache, shortness of breath.
• Sulphur dioxide: Lung disorders and shortness of breath