Indoor Air Pollutants

Introduction

We generally think air pollution as the outdoor air pollution because of the circumstances we are living in. The dusty roads, old vehicles, unmanaged construction, and industrialization have led us to think so. But what if I say that the air pollution is more inside your room than the outside environment? What if I show you that the effect of indoor air pollutants is more severe than the outdoor air pollutants? Well, it is true and it is true by a huge margin. Since space is so confined the concentration of indoor air pollutants is much higher than those on the outside. Some of the most common air pollutants (as recognized by EPA) have 2.5 times more concentration inside the room than outside. So, when next time you take out the mask inside the room, think twice. Generally, we have become so habituated with the sources of indoor air pollutants that we neglect them. Why has the topic of indoor air pollution been a topic of discussion? It is because people spend 70-98% of their total time in the indoor environment. In March 2010, WHO estimated that 4.3million people die annually from household air pollution. This is surprisingly more than 2 times the death caused by HIV-AIDS. However, we have always prioritized AIDS over indoor air pollution. Environment Protection Agency (EPA) has shown that among these 4.3 million people 2.8 million people die in developing countries. Since space is so confined the concentration of indoor air pollutants is much higher than those on the outside. So, these problems had led us to the concept of Indoor Air Quality and Indoor Air Pollutants.

Indoor Air Quality

Indoor Air Quality (IAQ) refers to the quality of air inside a closed room or structures like cars, buses, buildings, halls etc. It relates to the human health and human comfort. It is the measure of cleanliness or purity of the air inside the structure. Degradation of indoor air quality is called indoor air pollution. IAQ is affected by smoke, harmful gases, organic substances, chemicals, dust, bacteria and other pollutants. Hence, they are indoor air pollutants. The measures to improve IAQ include source control of pollutants, filtration, proper ventilation and residential sanity.

Indoor Air Pollutants

Indoor air pollutants are the matters or organisms that degrade the indoor air quality, decrease the human comfort and ultimately degrade the health of people. These are the active constituents that degrade the IAQ. These include everything from the general chemicals we use like cosmetics, paints, tiny fabrics particles, dust, smoke, and bacteria. So, we will see of each of the indoor air pollutants in detail.

1. Indoor/Second-hand smoke:

Second-hand smoke is the smoke from the secondary source which affects the people other than the main smoker. It is also called passive smoking. Indoor smoke generally means smoke inside the room like smoke in the kitchen. Indoor smoke causes the death of 2.8 million people in developing countries annually. Second-hand smoke causes pneumonia in 40% of the children born from the infected mother. They include the gaseous and particulate matter of size less than 2.5 ppm. They can break the lung’s natural defense. The major sources are cooking stove in rural areas, smoke from the cigarette, smoke from outdoor etc. They cause a respiratory problem and lung cancer.

2. Radon:

Radon is invisible radioactive atomic gas. They are obtained from radioactive decay of radium. They are released from soils and rocks because they may contain or of radon. These soils and rocks when used in buildings for construction act as the source of radon. Generally, this is a more common pollutant for the developed countries as they use lots of nuclear energy. In the US most lung cancer is caused by radon exposure. It causes skin burning, irritation, genetic disorder and cancer.

3. Molds and other allergens:

Molds are biological pollutants. They arise due to moisture growth of mold colonies or from natural substances like animal dander. Some molds contain harmful chemicals like mycotoxin. A headache, asthma, conjunctival irritation, allergy are common effects caused by molds.

4. Carbon Monoxide:

They are colorless, odorless but must acutely toxic gas. They are produced due to the incomplete combustion of hydrocarbons or insufficient oxygen. So, burning of firewood and hydrocarbon inside the room can produce carbon monoxide because of lack of oxygen. This carbon monoxide is very fatal. It is also known as a slow poison. Even automobiles’ exhaust serves as the source. CO mixes with haemoglobin and forms Carboxyhaemoglobin which fails to pick up oxygen from the environment. So, there will be lack of oxygen inside the body. Hence, it causes sleepiness, confusion, disorientation, unconsciousness, coma and finally death. Even 1% concentration of CO in the atmosphere is fatal for life.

5. Volatile Organic Compounds:

They are emitted as gases from liquids or solids. Paints, lacquers, perfumes, cleaning supplies, pesticides, adhesives like dendrites, super glue etc serves as a prime source of volatile organic compounds. So, we should be very careful while using these products. The most common product among these perfumes. We never are cautious while we spray perfume. But it is very harmful. Hence, it should be used safely. Office equipment like printers, glues, permanent markers is also common sources. Acrolein and formaldehyde are emitted from overheated oil which again are the indoor pollutants and can cause irritation and burnings. They cause irritation, drowsiness, headache, and allergy. Fatal diseases like kidney damage, liver infection, central nervous system disorder, cancer are also more common effects.

6. Bacteria:

Bacteria are all around us. Some bacteria are useful and some are harmful. Bacteria like Legionella, Mycobacterium tuberculosis, Staphylococcus aureus result from outbreaking of medical facilities and are the prime source of indoor pollutants. They cause airborne and waterborne diseases and moreover they enhance other diseases.

7. Asbestos fibers:

They are the building materials. They are the material of tiles, shingles, heating systems etc. worn-out tiles, tiles while drilling or breaking by any other means causes small dust or its particulates to release in the air. Inhaling of this particulate is very harmful. They act as a slow poison. Its inhalation causes lung cancer.

8. Carbon Dioxide:

Carbon dioxide is one of the major and most common indoor air pollutants.

Human is the major carbon dioxide producer. They are found in smoke and oxygen deficit room. They decrease the amount of oxygen and cause suffocation. They cause dizziness, sleepiness, headache and irritation.

9. Ozone:

Ozone is the allotrope of oxygen. They are produced by UV- ray hitting ozone layer, lighting, high voltage devices and also as by-products of other pollution. They are also emitted from office equipment like printers, Xerox machines etc. They are found in significant amount in old smaller jets. They are very reactive and can react with the cosmetic products used. They cause irritation to lung tissue and chest pain.

10. Other Particulates:

They include poisonous gases like NOx and Sox. They include the gases released from gas stoves, smoke from mosquito coils etc. They cause respiratory problem like asthma, breathing problem and irritation

Conclusion

Basically, what we are thinking of clean room is not actually the clean one. It may also contain one of the most harmful substances that can cause several diseases and can even cause death. Our ignorance and carelessness are responsible for the pollution. In fact, if we become ill due to these pollutants then we blame the outside sources but never try to seek the sources inside our room. By the way, who else would think that something so close to us can betray us?

So, these are the common indoor air pollutants. Remember that outdoor air pollutant like dust from outside, emissions from vehicles can also act as indoor air pollutants. The most common measures to control indoor air pollution are to have a proper ventilation system, frequent cleaning, applying the concept of green construction and more importantly, we have to control the source of indoor air pollutants.

References:
1. Mackenzie L. Davis & David A. Cornwell, “Introduction to Environmental Engineering”, McGraw Hill.
2. Gilbert M. Masters, Standford University, “Introduction to Environmental Engineering and Science”, Printice Hall.
3. Stephan Konz, Kansas State University, “Work design”, Grid Publishing Inc., Colombus, Ohio
4. C. S. Rao, “Environmental Pollution Control Engineering”, New age International (P) Limited, Publishers, India.