It is about airpollution and ventilation

1. AIR POLLUTION
BY:
Dr. Nayana
MPH 2nd year

2. • The term "AIR POLLUTION"
signifies the presence in the
ambient (surrounding) atmosphere
of substances (e.g., gases, mixtures
of gases and particulate matter)
generated by the activities of man
in concentrations that interfere
with human health, safety or
comfort, or injurious to vegetation
and animals and other
environmental media resulting in
chemicals entering the food chain
or being present in drinking-water
and thereby constituting additional
source of human exposure.

3. AIR POLLUTANTS
• More than 100 substances which pollute air have been identified. The important ones are
carbon monoxide, carbon dioxide, hydrogen sulphide, sulphur dioxide, sulphur trioxide,
nitrogen oxides, fluorine compounds, organic compounds (e.g., hydrocarbons, aldehydes,
ketones, organic acids), metallic contaminants (e.g., arsenic, zinc, iron resulting from smelting
operation), radio-active compounds, photochemical oxidants (e.g. , ozone).
• Others include asbestos, beryllium, mercury, benzene, fluorides, vinyl chloride, lead and
radiation. Contaminants differ greatly from place to place depending upon the specific
complex of contaminant source.
• Pollutants may be in the form of solids, liquids (vapour) or gases.
• The combination of smoke and fog is called "smog".

4. Outdoor Air Pollution
• Outdoor air pollution is also known
as Ambient air pollution.
• This pollution is caused by
emissions from cars, trucks,
industries, construction sites, and
many more activities.
• Majority of the fine particulate
matter comes from the burning of
coal, diesel and petrol by vehicles,
power plants, industries and
biomass burning.

5. Common Outdoor Air Pollutants:
Particulate matter
•PM10: Particles with 10 micron diameter. Majorly contains dust particles which can pass
through nose, throat & enter lungs.
•PM2.5: Particles with 2.5 micron or less diameter. These particles enter deep into our lungs
& bloodstream.
Gaseous
•Sulphur Dioxide (SO2): This gas is colourless and has strong odour. It is formed from the
burning of coal, petrol, diesel, etc.
•Nitrogen Oxide (NO2): It is formed by burning of coal, petrol, diesel and natural gas.
NOx combines with SO2 to form acid rain.
•Carbon Monoxide (CO): It is produced during incomplete burning of coal, petrol, diesel,
wood & natural gas.
•Ozone (O3): Ground level ozone is harmful to our health. It is emitted by cars, chemical
plants & power plants, etc.
•Volatile Organic Compounds (VOCs): VOCs are produced from burning of petrol, diesel and
coal. VOCs are also released from glues, dry cleaning products, etc.

7. Indoor Air Pollution
• Indoor air pollution is also known as
Household air pollution.
• It means contamination of air inside
houses, buildings and work areas.
Chulhas, dust & smoke contribute to
household air pollution.
• Indoor air pollution is equally, if not
more harmful than outdoor air
pollution.

8. Common Indoor Air Pollutants:
• Particulate matter: Biggest contributor is
outside air. Other indoor sources may include
heaters, chulhas, burning of wood, etc.
• Tobacco: Smoking and second-hand tobacco
contributes to indoor air pollution and it also
raises risk for cancer and heart attacks.
• Chulhas: Smoke from burning wood, cow-
dung and crop waste for cooking is very
harmful as it leads to respiratory diseases and
lung infections.
• Dust: Fine particles of dust can enter our
nose, throat and lungs which can be harmful
for our health. Dust also acts as a carrier for
bacteria and viruses.

10. Health implications of Air Pollution:

16. Air pollution dispersion refers to the way pollutants disperse or spread in the
atmosphere.
AIR POLLUTION DISPERSION

17. Several factors influence this dispersion:
• Meteorological conditions: Wind speed, direction, temperature, and atmospheric
stability play a crucial role in dispersing pollutants. For instance, strong winds
can help disperse pollutants over larger areas, while stable atmospheric
conditions might trap pollutants close to the ground.
• Topography: Mountains, valleys, and urban structures can affect the dispersion
of pollutants. They can create barriers that block the movement of air, leading to
the concentration of pollutants in specific areas.

18. • Type of pollutants: Different pollutants behave differently in the
atmosphere. Some may dissipate quickly, while others can linger for longer
periods or react with other compounds in the atmosphere, forming
secondary pollutants.
• Emissions sources: The location, height, and intensity of emissions
sources significantly impact how pollutants spread. Industrial areas,
vehicular traffic, and residential areas all contribute to pollution, and their
dispersion patterns vary.

19. • The ozone layer, a region of the Earth's stratosphere, plays a crucial role in
protecting life on the planet by absorbing the majority of the sun's harmful
ultraviolet (UV) radiation. Ozone depletion refers to a reduction in the
concentration of ozone molecules in this layer.
• The primary cause of ozone depletion is the release of certain human-made
chemicals containing chlorine and bromine atoms, such as
chlorofluorocarbons (CFCs), halons, and other ozone-depleting substances
(ODS). These compounds were commonly used in older refrigerators, air
conditioners, aerosol sprays, and some industrial processes.
• When these substances reach the stratosphere, they are broken down by UV
radiation, releasing chlorine and bromine atoms. These atoms then
catalytically destroy ozone molecules, leading to a reduction in the ozone
layer's thickness
OZONE LAYER DEPLETION

20. The consequences of ozone layer depletion are severe and include:
1.Increased UV radiation: With less ozone to absorb it, more UV radiation reaches
the Earth's surface. Higher UV levels can lead to skin cancers, cataracts, weakened
immune systems, and harm to marine ecosystems, crops, and other vegetation.
2.Climate effects: Changes in the ozone layer can also impact atmospheric
circulation and temperature patterns, potentially influencing the Earth's climate.

21. PREVENTION AND CONTROL OF AIR POLLUTION

22. The control of air pollution is ultimately an engineering problem. The WHO
has recommended the following procedures for the prevention and control of
air pollution :
(a) Containment : That is. prevention of escape of toxic substances into the
ambient air. Containment can be achieved by a variety of engineering
methods such as enclosure, ventilation and air cleaning. A major contribution
in this field is the development of "arresters" for the removal of contaminants.
(b) Replacement : That is, replacing a technological process causing air
pollution, by a new process that does not. Increased use of electricity, solar
power generation, natural gas, and central heating in place of coal have
greatly helped in smoke reduction. There is a move now to reduce lead in
petrol which is a cumulative poison. In India also deleaded petrol is being
used.

23. (c) Dilution : Dilution is valid so long as it is within the selfcleaning capacity of the
environment. For example , some air pollutants are readily removed by vegetation.
The establishment of "green belts" between industrial and residential areas is an
attempt at dilution. The capacity for dilution is, however, limited and trouble occurs
when the atmosphere is overburdened with pollutants.
(d) Legislation : Air pollution is controlled in many countries by suitable legislation,
e.g., Clean Air Acts. Legislation covers such matters as height of chimneys, powers to
local authorities to carry out investigations, research and education concerning air
pollution, creation of smokeless zones and enforcement of standard for ambient air
quality. To decrease the nuisance of air pollution, the Government of India have
enacted "The Air (Prevention and Control of Pollution) Act" in 1981.

24. (e) International action : To deal with air pollution on a world-wide scale, the
WHO has established an international network of laboratories for the
monitoring and study of air pollution. The network consists of two
international centres at London and Washington, three centres at Moscow,
Nagpur and Tokyo and 20 laboratories in various parts of the world. These
centres will issue warnings of air pollution where and when necessary.

25. Ventilation refers to the process of bringing fresh air into an enclosed space and
removing stale or polluted air from that space. It's essential for maintaining
good indoor air quality, whether in homes, workplaces, or other buildings.
VENTILATION

26. Types of ventilation
1. NATURAL VENTILATION - Natural ventilation is the simplest system of
ventilating small dwellings, schools and offices. In this method, reliance
is placed on certain forces which operate in nature . These are:
• THE WIND
• DIFFUSION
• INEQUALITY OF TEMPERATURE

27. 2.MECHANICAL VENTILATION -
Mechanical or artificial ventilation may be of the following types :
(1) Exhaust ventilation.
(2) Plenum ventilation.
(3) Balanced ventilation.
(4) Air conditioning.

28. THANK YOU