Air quality at home

The main themes related to Indoor Air Quality (IAQ) in buildings are numerous and considered an essential part of building sustainability. In this article we shall limit our discussion to some, such as natural lighting, moderate ambient temperatures and humidity, ventilation, air filtration, source control, maintenance and cleaning, education, monitoring, human behaviour and occupant health. 

The sources of pollution inside our homes are many, such as human activity, combustion products, emission from building materials, dust, nanoparticles, microorganisms, pets and pesticides. The condition affecting buildings occupants, typically marked by headaches and respiratory problems, is called Sick Building Syndrome attributed to unhealthy or stressful factors in the environment such as poor ventilation or inadequate air quality. 

Natural lighting inside the residences, expressed as window to floor ratio for better distribution of natural lighting, and window to wall ratio, for avoiding glare and heat losses, which is limited to 0.15 in the LEED specifications for zone 3 in domestic structures for the purpose of energy effectiveness. There is no point in increasing the ratio to allow for further sunlight to purify the interior air by an Ultra Violet (UV) natural process, because UVC alone (neither UVA nor UVB) is the most effective on viruses and germs and can purify the air naturally. However, UVC doesn't reach the surface of our planet as it is substantially absorbed by the upper Ozone layers in the atmosphere. Thus, UVC systems can be installed for use in coils and ducts if high hygiene is required, such as in hospitals.

When the exterior air quality is good, proper ventilation is crucial for maintaining good IAQ, particularly for homes. It involves the exchange of indoor and outdoor air to dilute pollutants and provide fresh air. Effective ventilation systems, such as mechanical ventilation with efficient air filters and adequate outdoor air intake rates, can also help remove contaminants and improve IAQ. However, excessive ventilation can lead to heat losses in winter or heat gains in hot summers, so a balance between IAQ, thermal comfort and energy efficiency ought to be managed. It should be noted that natural forced ventilation such as air infiltration through cracks in window and door frames, due to low quality of glazing frames, can satisfy the ventilation required in many traditional homes in Jordan without opening windows or doors, therefore monitoring air quality is important before any action is to be pursued.

Regular monitoring of IAQ parameters can help identify potential issues and ensure compliance with established standards and guidelines. This can involve measuring levels of pollutants, assessing ventilation rates, and conducting air quality testing to ensure the effectiveness of IAQ management strategies. Basic gases and compounds that ought to be monitored are: 

Carbon Dioxide that can lead to drowsiness, poor concentration, and increased fatigue; Carbon Monoxide which is an odorless and colorless gas produced by the incomplete combustion of fossil fuels. It is highly toxic and can be life-threatening in high concentrations; Volatile Organic Compounds (VOCs) which are emitted as gases from various products such as paints, cleaning agents, adhesives, and furnishings that cause irritation of the eyes, nose, and throat, respiratory problems, allergic reactions, nausea and fatigue; Radon gas which is a naturally occurring radioactive gas that can seep into buildings through cracks in the foundation and pipes. Prolonged exposure to high levels of radon can increase the risk of lung cancer; Formaldehyde which is a colorless gas used in the production of building materials, furniture, and household products that causes respiratory irritation, allergic reactions, asthma exacerbation, eye and mucous membrane irritation, and long term health effects. 

Particulate Matter of tiny particles suspended in the air, including dust, pollen, mold spores, and other airborne pollutants can also cause respiratory problems, cardiovascular effects, allergies and asthma. Although simple filtration systems play a good role in removing airborne particles, allergens, and pollutants from the indoor air, however, high-efficiency air filters, such as HEPA (High-Efficiency Particulate Air) filters, are crucial in trapping a wide range of particles and enhancing better IAQ by reducing the presence of pollutants, thus managing and controlling potential sources of indoor air pollutants.

Eliminating or managing the source of pollution is also most important when it comes to IAQ. This includes identifying and minimising or eliminating sources such as VOCs from building materials, paints, cleaning agents, and furniture. For example, when purchasing paints make sure it is VOC free. Controlling heating sources, such as fire places, fuel heaters, as well as managing moisture to prevent mold and microbial growth, particularly in dwellings of poor thermal quality and inefficient ventilation and heating systems, where water vapor condenses on walls and within cupboards which incites fungus growth. To control condensation humidity can be controlled by installing fans in bathrooms and kitchens, avoiding burning gas fuel which produces great amounts of water vapor and using proper ventilation techniques. Also, regular maintenance and cleaning practices are essential for maintaining good IAQ inside our dwellings. This involves cleaning HVAC (Heating, Ventilation, and Air Conditioning) systems, air ducts, and filters.

Finally, promoting education and awareness about IAQ among building occupants, facility managers, and maintenance personnel is crucial. Providing information on the importance of IAQ, potential sources of pollutants, and best practices for maintaining good IAQ can empower individuals to take proactive steps in improving the indoor environment and change their behavior, such as using free VOCs paints and ventilating the bathroom after a shower. Other human behaviour can significantly influence IAQ, such as encouraging good practices of proper disposal of waste, avoiding smoking indoors, and using environmentally friendly cleaning products can help improve IAQ and create a healthier indoor environment. By focusing on these themes, building owners, facility managers, and occupants can work together to create healthier indoor environments and ensure better IAQ in buildings and consequently better health for the occupants and more productive and a happy way of life.

By Ayoub Abu Dayyeh is an energy and green building consultant