Wajeeha Bashir

-004

BOT-406

AIR POLLUTION PREVENTION & CONTROL

Air Pollution can be defined as anything that contaminates the air to an extent that makes

the air dangerous to breathe, causing disease, death to humans, damage to other living

organisms such as food crops, or the natural or built environment..

• Air pollution happens when pollutants are carelessly discharged into the air. In other words, air pollution indicates the existence of impure, unsafe, and hazardous substances in the air.

Some Facts & Figures

• In the 1930s and 1940s, a factory smokestack issuing a thick plume of smoke was considered a sign of prosperity.

• Between 1945 and 1969, as awareness of air pollution problems gradually increased.

• 1963 and 1967 the federal government began to oversee and coordinate local and state air pollution control efforts.

• EPA & Clean Air Act• In the late 1980s, 3 problems arose in result of increasing

air pollution• Global air pollution • Ozone depletion• Acid Rain

Some Facts & Figures

Distribution of Pollution-Related Survey in 2014

Preventions

Control of air pollution

• Standard for Air

• Laboratory equipment

– – ambient air monitoring station

– - portable gas analyser

• Smoke Control Action Plan

“Criteria" air pollutants

Pollutant[links to historical tables of

NAAQS reviews]

Level

Carbon Monoxide (CO) 9-35 ppm

Lead (Pb) 0.15 μg/m3

Nitrogen Dioxide (NO2) 100-52 ppb

Ozone (O3) 0.070 ppm

Particle Pollution (PM) 35-50 μg/m3

Sulfur Dioxide (SO2) 75 ppb

Smoke Control Action Plan (SCAP)

AIM

To curb down the number of diesel driven vehicles emitting

black smoke

• Launched: August 2013

• 2 Main Components:

- Enforcement (road side checks and contraventions of smoky

vehicles by Police de L’Environnement)

- Sensitization campaign (TV and radio)

Laboratory equipmentS :

Different techniques are used for controlling air pollution caused by

• 'gaseous pollutants'

• 'particulate pollutants'.

Methods of controlling gaseous pollutants:

The air pollution caused by gaseous pollutants like hydrocarbons, sulphur dioxide, ammonia, carbon monoxide etc. can be controlled by using three different methods-

1. Combustion,

2. Absorption and

3. Adsorption.

1. Combustion:

This technique is applied when the pollutants are organic gases or vapours. The organic air pollutants are subjected to 'flame combustion or catalytic combustion' when they are converted to less harmful product carbon dioxide and a harmless product water.

2. Absorption:

In this method, the polluted air containing gaseous pollutants is passed through a “scrubber”containing a suitable liquid absorbent. The liquid absorbs the harmful gaseous pollutants present in air.

3. Adsorption:

In this method, the polluted air is passed through “porous solid adsorbents” kept in suitable containers. The gaseous pollutants are adsorbed at the surface of the porous solid and clean air passes through.

Methods of controlling particulate emissions:

The air pollution caused by particulate matter like dust, soot, ash etc. can be controlled by either destroying contaminants or removingthem from an exhaust stream before it is emitted into the atmosphere.

1. Fabric filters,

2. Wet scrubbers,

3. Electrostatic precipitators

4. Mechanical devices.

Mechanical Devices:

It works on the basis of following:

• Gravity: In this process, the particulate settle down by the action of gravitational force and get removed.

• Sudden change in the direction of air flow: It brings about separation of particles due to greater momentum.

Bag houses:

Designed to handle heavy dust loads, a dust collector consists of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust removal system (distinguished from air cleaners which utilize disposable filters to remove the dust).

• Fabric Filters: The particulate matter is passed through a porous medium made of woven or filled fabrics. The particulate present in the polluted air are filtered and gets collected in the fabric filters, while the gases are discharged. The process of controlling air pollution by using fabric filters is called 'bag filtration'.

Particulate scrubbers:

Scrubber is a form of pollution control technology. The term describes a variety of devices that use pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by some other contact method, so as to remove the pollutants.

• Wet Scrubbers: They are used to trap SO2, NH3 and metal fumes by passing the fumes through water.

Electrostatic Precipitators:

An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air), using the force of an induced electrostatic charge. Electrostatic precipitators are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulates such as dust and smoke from the air stream. As aerosol particles get precipitated on the electrodes

REDUCTION EFFORTS:

• More trees should be planted along roadsides and houses.• Use public mode of transportation• Conserve energy• Understand the concept of Reduce, Reuse and Recycle:• Emphasis on clean energy resources• Use energy efficient devices• Efforts to reduce pollution from mobile sources includes primary

regulation • Expanding regulation to new sources (such as cruise and transport

ships, farm equipment, and small gas-powered equipment such as string trimmers, chainsaws, and snowmobiles),

• Increased fuel efficiency (such as through the use of hybrid vehicles),

• Conversion to cleaner fuels or conversion to electric vehicles.

Titanium dioxide• It has been researched for its ability to lessen air

pollution. Ultraviolet light will release free electrons from material, thereby creating free radicals, which break up VOCs and NOx gases. One form is superhydrophilic.

• In 2014, Prof. Tony Ryan and Prof. Simon Armitage of University of Sheffield prepared a 10 meter by 20 meter-sized poster coated with microscopic, pollution-eating nanoparticles of titanium dioxide. Placed on a building, this giant poster can absorb the toxic emission from around 20 cars each day.

Titanium dioxide Sheets

CONCLUSION:

• Several attempts are being made world wide on a personal, industrial and governmental levels to curb the intensity at which Air Pollution is rising and regain a balance as far as the proportions of the foundation gases are concerned. This is a direct attempt at slacking Global warming. We are seeing a series of innovations and experiments aimed at alternate and unconventional options to reduce pollutants. Air Pollution is one of the larger mirrors of man’s follies, and a challenge we need to overcome to see a tomorrow.

REFERENCES:

• http://www.conserve-energy-future.com/causes-effects-solutions-of-air-pollution.php

• http://www.yourarticlelibrary.com/air-pollution/5-effective-methods-to-control-air-pollution-explained-with-diagram/28360/

• https://en.wikipedia.org/wiki/Air_pollution#Control_devices• https://soapboxie.com/social-

issues/AirPollutionSourcesEffectsPreventionandControl• http://www.importantindia.com/11729/10-ways-to-reduce-and-

control-air-pollution/• http://www.pollutionpollution.com/2012/05/how-to-control-air-

pollution.html• https://www.britannica.com/technology/air-pollution-control• http://www.conserve-energy-future.com/causes-effects-solutions-

of-air-pollution.php