Breathing Better: The Indoor Air Quality?(IAQ)
Did You Know?
Indoor Air could be several times more polluted than Outdoor air? We tend to think that our home and office are safe and clean, But in reality, the case is different.
Why is IAQ important?
We spend 90% of our time indoors?—?Whether it is home or the office, we live in a building. Yet we do not think about the air we breathe in. There are several contaminants inside the buildings we live in. We breathe the contaminated air continuously leading to a decrease in productivity, fatigue, and headaches, dizziness, and sometimes it causes life-threatening diseases as well. Prioritizing IAQ is essential for health, well-being, and overall quality of life.
What is IAQ?
ASHRAE standard 62.1 defines IAQ as:?
"Indoor air quality (IAQ) is the quality of air within and around buildings and structures, especially as it relates to the health and comfort of building occupants. Acceptable indoor air quality is defined as air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction."
Common Indoor Air Pollutants:
1. Radon:
A harmful gas that we cannot see, smell, or taste is found in the soil and rocks we use to build, it can also be in the concrete we use and can enter the buildings through the cracks in the walls. Radon(Rn-222, Rn-220, Rn-219) disintegrates in the air to release radioactive “radon daughters”. when we inhale the radon daughters, it enters our lungs and disintegrates to release radiation there. This radiation reacts with lung cells and damages the DNA and eventually causes lung cancer. It is the second leading common cause of lung cancer after smoking.
2. VOC (Volatile Organic compounds):
~Phthalates?—? found in cosmetics, hair sprays, plastic toys, and food packaging. Long-term exposure can cause issues in reproductive health.
~Tetrachloroethylene?—?found in laundry products. It can cause headaches, dizziness, and confusion. Long-term exposure can affect the liver and kidney and it has also been associated with cancers.
~Formaldehyde?—? in furniture, pesticides, adhesives, etc. It causes irritation to the eyes, nose, skin, and throat. It is also associated with certain types of cancers.
3. Ozone(O?):
A strong oxidizing agent that is released from printers, and photocopiers. Since it is a strong oxidizing agent it could react with the organic materials that make up our body and can damage our lungs once it is inhaled. It also has negative effects on metals, plants, and plastic materials as well.
4. Carbon Monoxide(CO) & Nitrogen Dioxide(NO?):
~CO?—? is produced during incomplete combustion of carbon-containing fuels such as petrol, natural gas, oil, coal, and wood. At home, the source could be gas stoves, lanterns, burning wood, and charcoal. It causes headaches, dizziness, and nausea and if exposed to higher amounts can lead to death.
~NO??—? is produced during high-temperature combustion process. It can aggravate respiratory issues, particularly asthma. Long-term exposure can lead to decreased function of the lungs.
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5. Aerosols (Particulate Matters)
A common type of Indoor Aerosol is Particulate Matter(PM). It is a suspension of particles in the air. PM can be grouped depending on its size.
~PM 10?—?There are particles that are 10 micrometers and are less in diameter. For reference, human hair is about 50 to 70 micrometers. Sources can be construction sites, incinerating the waste, combustion from vehicle exhaust. These can enter through our noses to the lungs.
~PM 2.5?—?These are particles that are 2.5 micrometers are less. When this is inhaled, this can go deeper and damage lung tissues.
~PM 0.1?—?These can go further deeper into blood stream and circulate our body like oxygen molecules.
The health effects of PM depend on how long you have been exposed to it. It can range from irritation of the nose, throat, inflammation of the lungs, aggravates asthma, pre-term birth, lowering birth weight, and premature death in people with heart and lung disease.
6. Bioaerosols (Bacteria, Fungi & Viruses)
These are airborne particles containing biological materials such as bacteria, fungi, and viruses. Their composition and size may vary based on their environment. These enter the buildings through airstream, HVAC passages, etc.
~Bacteria?—?There are good and bad bacteria. Some harmful bacteria such as Mycobacterium Tuberculosis causes Tuberculosis, which is highly contagious. It causes respiratory issues. Another one named Legionella?—?a type of bacteria which causes Legionellosis, it is a kind of respiratory infection. Its severity ranges from the less serious Pontiac fever to the fatal Legionnaires disease. Legionella survive and reproduce in water between 25 and 45 degrees Celsius with an optimum temperature between 32 and 42 degrees Celsius. It lives under the temperature of 70 degrees Celsius and dies above that temperature. It can be found in stagnant water systems of a building such as cooling towers, water tanks, water distribution systems, etc.
~Fungi?—? These reproduce sexually and asexually with spores. which can contaminate the indoor air. These could enter into the indoor environment through air stream from HVAC and it is everywhere in nature. There are various groups of fungi?—?yeasts, rusts, mold, mildews, and smuts. Alternaria?—?a fungi which does not cause any disease but can cause issues to allergic patients. Cladosporium- another fungi, which does not cause any disease, but can be found on dead plants and wet building materials.
~Virus?—?These rely on a host to live on. Some viruses are transmitted from person to person like “Orthomyxoviridae”?—?it is an influenza virus, highly contagious and spread mainly through droplets from coughing, and sneezing. sometimes it spreads through air as well.
In the building, if the Relative Humidity is 70% or above, the carbon containing materials may adsorb the moisture, facilitating the growth of the bioaerosols. Thus contaminating the IAQ. It's essential to maintain proper humidity level 40% - 60% to prevent the growth of bioaerosol contamination.
7. Sick Building Syndrome(SBI) & Building Related Illness(BRI)?:?
These are two common building-related health issues due to poor IAQ. These are caused by previously discussed Bioaerosols.
~SBS?—? is a situation where the occupants experience acute health and comfort effects when they are inside the building but once they exit the building they immediately feel better. Some symptoms may be headache, dizziness, irritation to the eyes, nose, throat, poor concentration, and fatigue.
~BRI?—? It is a clinically diagnosed illness that is directly related to poor IAQ. Unlike SBS, BRI takes much more time to recover after exiting the building. Some symptoms are fever, cough, and muscle aches.
From what you've read so far, You might think "Cant we do anything about indoor pollutants? Are we doomed? "
Well, we are fighting back with technology. Let me put forward some of those.
Final Thoughts
IAQ is the need of the hour. It is just not about the comfort, it is about survival. It is as vital as improving energy efficiency in the building or reducing carbon footprints, IAQ must be prioritized. An Energy efficient building with poor IAQ could end up harming its occupants. We must prioritize sustainability in building design and operation.