How Air Pollutants Affect Human Health ?

Air borne constituents reduce the quality of air and thus make it unacceptable for use. Air pollutants contain millions of pollutants and contaminants that degrade the quality of air making it unhealthy and also leading to cumulative effect on human beings. These contaminants can come to the conditioned space from outside or can be the product of some bacteria germinal activities inside the conditioned space itself. Let us list some of the most common contaminants that are present in the air and their sources and how they affect the occupant’s health and comfort.

Some of the most common contaminants are enumerated here. It is to note that the presence of a particular contaminant in the conditioned space depends on the surrounding area and the sources present therein. Lets see as to which are the most prominent ones.

Allergens (or the substances that cause allergy) have their sources in dust, cooking exhaust, smoking fumes, tobacco smoke, moulds, pets and many other sources. They cause skin and eye irritation.

Bacteria and viruses which are the root cause for many diseases have their sources in pets, moisture or accumulated water and also in unhygienic people.

Carbon dioxide, carbon monoxide, oxides of nitrogen and sulphur dioxide are few of the most poisonous gases having sources in incomplete combustion of fuels, burning of rubber and evaporation of stored chemicals.

Odoriferous chemicals are the product of inefficient cooking, decaying organic matter and burning or evaporation of chemicals.

Formaldehyde and volatile organic compounds have their sources in construction materials,furniture polishes and cleaning products.

All these contaminants affect the health of the occupants in short or long run. The intensity of the effect on all the types of contaminants will not be same but will vary, for example some of the contaminants will render the occupants allergic while some will cause detrimental effect on their health and some might be just annoying. We will distinguish the contaminants on the intensity of effect it causes on the occupants. We will segregate the contaminants into four categories as – Contaminants causing short term effects,Carcinogens,Contaminants causing detrimental effects on health,Annoying contaminants.

A high concentration of a particular gas in the conditioned areas can be fatal or even cause death. These types of fatal contaminants are carbon monoxide, bacteria and biological contaminants. Carbon monoxide is a colorless and odorless gas which is product of incomplete combustion of fuel oils or due to malfunctioning of combustion appliances. Combustion appliances in the conditioned area could be stove, water heater or furnace. It is also the main constituent of the exhaust of motor vehicles. It is the reason of thousands of deaths each year.

Certain disease causing bacteria get transmitted by air. One of such disease is tuberculosis. The bacteria causing tuberculosis is tubercle bacillus, which tends to stay afloat in air when exhaled by a diseased person. This can be prevented only by proper isolation and ventilation methods.

One more type of bacteria that can be extremely harmful for the people with weak immune system is legionella, bacteria that causes legionnaire’s disease. The bacteria multiply very easily in warm water and when the water is sprayed or splashed, the bacteria becomes airborne and gets into the lungs. The germinal sites of these kinds of bacteria are water coolers, cooling towers and domestic hot water systems.

The symptoms of the short term bacteria diseases are often unnoticeable and thus can be extremely fatal.

Carcinogens are the pollutants that are supposed to be known as the most dangerous as they cause cancer which is still considered untreatable. Cancer is a matter of grave concern as there are no short term symptoms and by the time they surface, it’s often too late. The main source of carcinogens that affects human is tobacco smoke, which has always be a major concern in maintaining good indoor air quality. The tobacco smoke leads to lung and heart cancer, not only to the smoker but also to the non smoker. Tobacco smoke is fatal both in long and short run.

Another carcinogen is the gas radon. It is found naturally, resulting from the decay of radium in the soil.

Air contaminants such as volatile organic compounds, bacteria, viruses, ozone, allergens etc can cause detrimental effects on health if not fatal. Such contaminants cause irritation of eyes, skin and mucous membrane. They produce rashes or result in cold like symptoms.

Many contaminants though not health hazardous may cause distraction or irritation to occupants. Contaminants like odoriferous chemicals, body odors, rotten food and molds are examples of narking contaminants

Fundamentals of HVAC system by Robert McDowall