Air Pollution


What is air pollution?

Air pollution is the presence of unwanted substances or pollutants which have an adverse effect on humans, animals and plants, and for sure on the air quality. The frequently present categories contributing to the air pollution are sulphur oxides, nitrogen oxides, Volatile Organic Compounds (VOC) and small dust particles.

What causes air pollution?

The main causes of air pollution are the traffic, industries and agriculture. During all these processes, air pollutants are emitted. Large concentrations of substances like Volatile Organic Compounds negatively affects public health and ecosystem.

Traffic is held responsible for air pollution most of the times. Emissions caused by traffic are mainly includes carbon dioxide, carbon monoxide, nitrogen oxides, VOC and small dust particles.

Industrial processes are responsible for the emission of chemical wastes in large quantities. Industrial processes leads to the emission of carbon dioxide, carbon monoxide, nitrogen oxides, sulphur dioxide, VOC and methane.

Nitrous oxide is mainly caused from agriculture processes as denitrification process includes emission of mitrous oxide. Also, the application of fertilizers causes emission of ammonia, nitrogen oxide and methane. The extensive use of pesticides also causes the emission of many toxic chemicals.

Lastly, the indoor air pollution caused by the people or consumers. This leads to dual pollution as the products have caused air pollution in its manufacturing cycle, and later they cause air pollution in its distribution and application.

What are the main environmental effects of air pollution?

The main environmental effects of air pollution are briefed below:

Acid Deposition

Acid deposition can be primarily characterized as acid rain, snow and fog or gas and dust is one of the main effects of air pollution. During fuel combustion, acid deposition is mainly formed as emission of nitrogen oxide and sulphur dioxide becomes sulphuric acid and nitric acid when are in contact with water.


Eutrophication is caused in water by an increase in plant nutrients. The higher availability of nutrients in water plants like duckweed and algae to grow extensively. The extensive growth blocks the sunlight supplies to water. Also, the plants use all available oxygen, which cannot be renewed as heterotrophic plants need light to perform photosynthesis.


A combination of words smoke and fog. Smog is of two types summer smog and winter smog. Summer smog also called as photochemical smog is a brown oxidising fog mainly consisting ozone. The primary causes of photochemical smog are VOCs and nitrogen oxides which are emitted through vehicles and industries. Humans cannot adapt to smog as it causes eye and respiratory irritations. Ozone causes serious damage to plant as well.

Winter smog also referred as acid smog mainly consists of foggy elements. Winter smog is found in areas where vertical dispersion of air pollutants is nearly not possible. Temperatures decreases during the day. Winter smog is formed when temperature is low and the sulphur dioxide concentration increases.

How does air pollutants spread and how to handle this?

How far air pollutants are transported primarily depends on the size of compounds and the height at which the pollution was emitted into the air. Fumes emitted into air through high smoke mixes with air maintaining the local concentrations. However, wind transports compounds making the pollution disperse. Rain removes pollutants from the air causing precipitation and consequentially soil and water pollution.

We can predict the dispersion of air pollutants very easily with the computer models as air is not a very complex medium. A computer model calculates by different parameters such as wind direction, wind speed, humidity, cloudiness and temperature. These predictions are of great value when toxic clouds are taken into consideration as they are a danger to human health.

What causes indoor air pollution?

The primary cause of indoor air pollution are the gases or particles into the air because of inadequate ventilation. Inadequate ventilation increases the indoor pollutant levels by not bringing in enough outdoor air to dilute indoor emissions which leads to the failure of carrying indoor air pollutants out of the household. Dust, moisture, fungus, molds, pet dander, Volatile Organic Compounds (VOC), odour causing contaminants, bacteria in washrooms, high humidity and temperature also increases the levels of indoor air pollution.

What is PM2.5?

Particles less than 2.5 µm (micrometres) are called Particulate Matter 2.5 or PM2.5. They are 1/30th of the average width of a human hair which makes it almost negligible that cannot be seen with naked eyes. Particulate matter 2.5 can be seen only with an electron microscope. PM2.5 or fine particulate matter is 2.5 micrometers or less in diameter. These fine particles are produced from combustion, motor vehicles, power plants, residential wood burning, forest fires, industrial processes and agricultural burning.

What is PM10?

All scientists classify particulate matter by size. PM10 or coarse are particulate matter having the diameter between 2.5 micrometers and 10 micrometers. Its slightly bigger in size than PM2.5 but if we take human hair as reference, it is too small in size as human hair is between 50-70 micrometers thick. They can be seen with naked eyes. Smoke and dust are examples of PM10.

What is Indoor Air pollution?

Air pollution is mostly associated with the presence of smog, emissions from the power plants and vehicles. However, these are examples of outdoor air pollution. The presence of pollutants such as gases, formaldehyde, mold, pollen, tobacco smoke, radon, carbon monoxide, asbestos and lead are the main causes of indoor air pollution. In fact, the indoor air is 5 times more polluted than the outdoor air.

How indoor air pollution is harmful?

Indoor air pollution can have both short and long-term impact on health. The short term effects consist of eye and throat irritation. The long-term effects, however, can lead to serious health issues such as cancer and respiratory disease. Exposure to high levels of indoor air pollutants such as carbon monoxide can also be fatal.

What is an Ionizer

An ionizer plays an important role in purifying the indoor air by electrically charging the air molecules. The ionizers creative negatively charged ions using electricity and discharges them into the room. The negative ions attach to the positively charged particles such as dust, bacteria, pollen, smoke and other allergens present in the room. When the positive and negatively charged ions merge together, they create dense dirt particles, which can’t float in the air. The ionizers remove microbes, odors and particulates from the indoor air.

How does an Ionizer help us?

Studies have shown that ionizers used in the air purifiers can efficiently remove bacteria, dust, cigarette smoke, mold, pollen and odors. Asthma patients, people suffering from seasonal allergies or hay fever may experience significant difference in the air quality on using an air purifier. In addition, ionizers also have some physiological benefits such as increased well-being, decreased skin temperature, and resistance to infection.

What is HEPA technology

High Efficiency Particulate Air or High Efficiency Particulate Assistance (HEPA) is an air filter that has been manufactured, tested, certified and labeled according to the recent HEPA standards. The filters have a very fine, glass-fiber medium that captures microscopic particles passing through it. They use a combination of diffusion, interception and inertial impaction to catch and trap the harmful contaminants present in the indoor air.

What is 4 stage purification process

The air purifiers from KENT use a 4 stage purification process. The HEPA air purifiers have 3 filters and an ionizer to effectively remove the contaminants present in the indoor air and improve the quality. Each of the filters play an important role in different stages to purify the indoor air and reduce pollution. The primary filter removes the large and visible pollutants such as human hair, debris, cob webs. The next stage consists of activated carbon filter the removes smell and odor. In the third stage, the anti-bacterial HEPA filter traps carcinogen particles such as bacteria, pollen, allergens, mold and dust. Lastly, the ionizer freshens and purifies the indoor air. The negative ions released by the ionizer freshen.

What is CADR?

Clean Air Delivery Rate (CADR) is a performance indicator scale, which is assigned by the Association of Home Appliance Manufacturers (AHAM). CADR rating measures the efficiency of an air purifier by taking into account the room size and volume of clean air produced per minute by the appliance. CADR rates the removal of pollen, dust and smoke present in the indoor air. The higher is the rate of CADR, the better is the air quality. There are three different CADR ratings provided on the AHAM seal. The ratings of CADR are as follows:

  • Tobacco Smoke 10 to 450 CADR
  • Dust 10 to 400 CADR
  • Pollen 25 to 450 CADR
What is the best air purifier for someone with asthma?

Presence of indoor air pollutants is the main reason of increasing amount of breathing problems and asthma. HEPA air purifiers are ideal for dealing with breathing problems and asthma. The HEPA filtration technology used in the air purifiers catch and trap the allergens that trigger asthma and other breathing problems. These filters catch and trap 99% SPM which are as small as 0.3 microns. HEPA air filters also traps the carcinogen particles such as PM 2.5, pollen, allergens, mold and cigarette smoke particles.