What is Air?
Air is a mixture of gases that circle Earth, kept in place by
gravity. Air makes up Earth's atmosphere. The air we breathe is
78 percent nitrogen gas, 21 percent oxygen, 0.9 percent argon,
and 0.03 percent carbon dioxide, along with water vapor-floating
molecules of water. Also present are traces of other gases and
tiny bits of dust, pollen grains from plants, and other solid
particles. As our atmosphere extends higher and higher above
Earth, toward outer space, air becomes thinner and the
combination of gases in the air changes.
Why Air is Important?
Air is important for many different organisms for different
reasons. One of the main reasons it is important for humans is
that it contains oxygen - which we breathe. Furthermore, it
enables the removal of our waste CO2 - which is taken up by
photosynthesizing plant life. It provides us with a medium
through which we interact with our ecological environment ...
other Life forms on the planet. It is a major part of the
When people think about air pollution, they usually think about
smog, acid rain, CFC's, and other forms of outdoor air
pollution. But did you know that air pollution also can exist
inside homes and other buildings? It can, and every year, the
health of many people is affected by chemical substances present
in the air within buildings.
There are many different chemical substances that contribute to
air pollution. These chemicals come from a variety of sources.
Among the many types of air pollutants are nitrogen oxides,
carbon monoxides, and organic compounds that can evaporate and
enter the atmosphere.
Air pollutants have sources that are both natural and human.
Now, humans contribute substantially more to the air pollution
Indoor Air Quality (IAQ)
It is a term to the air quality within a building or Structure
and it relates to the health and comfort of building
occupants. IAQ can be affected by microbial contaminants (mould
bacteria and virus) gases include carbon monoxide, volatile
Organic Compounds. Indoor air is becoming an increasing more
concerning health hazard than door air. This is Additional LOAD
on the Air Condition System.
Indoor Air Contaminates
• Volatile organic compounds
• Airborne pathogens
• Repairable particulates
A) Volatile organic compounds (VOCs)
i. What is Volatile Organic Compounds?
• The term Volatile Organic Compounds refers collectively to a large number of organic vapors which contaminate indoor air. Over 300 VOCs have been identified in indoor air at concentrations exceeding 1 part per billion (ppb).
• The most commonly reported VOCs are formaldehyde, ethyl benzene, benzene, ortho, para, meta-sylenes, styrene, chlorinated solvents, including 1-1-1-trichloroehtane, tetrachloroethylelene & trichloroethylene, carbon tetrachloride, dichlorobenzene, methylene chloride and chloroform.
• VOCs are consistently found in higher concentrations indoors than outdoors.
ii. Sources of Volatile organic compounds
• The sources of VOCs are numerous and include building materials, cleaning solvents, paints, adhesives, carpets, hot water, and indoor combustion sources.
iii. What health effects can VOCs cause in human body?
• Symptoms associated with exposure to VOCs include conjunctive irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, emesis,
epitasis, fatigue, dizziness.
B) Air borne Pathogens:
Pathogens, or in this case better to stay, infectious agents are ubiquitous. Some of them are obligatory pathogens. Causes of severe diseases and therefore are well known. Some of them are obligatory pathogens. Cause of serve diseases and therefore well-known. Some of them are well-known but they are considered to be either less risky or it is believed that they are under control. Some of them are facultative pathogens, causing fewer infections and therefore mostly are unknown. All of them should cause health problems indoor as the indoor environment is very special.
Sources of air infection in indoor environment:
Transmission – passing of diseases from an infected individual or group to previously uninfected individual or group. The microorganisms (bacteria & viruses) that cause disease may be transmitted from one person to another by one or more of the following means:
• Droplet contact: - Coughing or sneezing on another person.
• Direct physical contact: - Touching an infected person.
• Indirect contact: – Air exchange is mostly inadequate, especially where ill people are
• Poor Ventilation: - Poor maintenance of ventilation/air exchange systems is rather
common, so the infectious dosage could be reached easily, if the source of infectious
agent is indoors.
Direct & indirect transmission infectious agents are easy in overcrowded interior. Microorganisms vary widely in the length of time that they can survive outside the human body, and so vary in how they are transmitted.
The air treatment solution is proposed on following basis:
Ozone has been successfully used in bars, smoking rooms,
cocktail lounges, taverns, airport smoking areas, lounges etc., smell, bacteria, mould, mildew and other micro organisms from the HVAC system. Smart sensors’ used ensure that the ozone in the treated room does not exceed 0.03 - 0.05 ppm. The ASHRAE standard for ozone is 0.05 ppm Ozone is increasingly being used in HVAC system to improve the indoor air quality and also to improve the energy efficiency of the HVAC cooling coils.
i. HVAC: Ozone reduces VOCs odors, and saves power by reducing fresh air required
and eliminate sick building syndrome.
ii. Air Disinfection: For sterilization of air in hospitals of air in hospitals, operation theaters &
iii. Air Deodorization: For hotel rooms, lobbies, STP rooms, garbage rooms, fish shops.
iv. Medical Healing: Ozone is used for accelerated healing of wounds etc.