This document discusses air pollution and smog. It defines smog as a type of air pollution that is a mixture of air pollutants like nitrogen oxides that combine with sunlight to form ground-level ozone. Smog forms due to emissions from vehicles, industry, and fossil fuel burning. It can cause health issues and is worsened by temperature inversions that trap pollutants. Groups most at risk include children, outdoor workers, and those with respiratory diseases. Detection methods include visible haze and air quality index measurements.
9. 4. Particulate Matter (PM)
Figure 1. The size of
various particles in
comparison to the
width of a human hair.
10. Alveolar sac
(sectioned)
Alveoli
Bronchioles
Alveolar duct
Goblet cell
(secreting
mucus)
Mucus
Epithelial cell
Cilia
Major components of respiratory system
Stage 1 (5-9)
Stage 3 (4-5)
Stage 2 (5-6)
(Diameter in mm)
Stage 4 (2-3)
Stage 5 (1-2)
Stage 6 (0.5-1)
PM and Their Targets
11. Type Size (aerodyanmic diameter mm )
TSP
(Total suspended
particles)
Between 20-50 micrometers
PM10 less than 10 micrometers
• may reach the upper part of the airways and lung.
PM2.5 2.5 micrometers and smaller
• regarded as more dangerous because they penetrate
more deeply into the lungs and may reach the
alveolar region
Ultrafines Particles with aerodynamic diameters 0.1 micrometers
and smaller
Particulate Matter (PM) Standards in Asia
Table 1. Categories of PM according to size
15. Introduction
Smog is a type of air pollution.
Combination of the words smoke and fog to refer to
smoky fog.[1]
Mixture of air pollutants-nitrogen oxides and other
chemical compounds- that combine with sunlight to
form ground-level ozone that hangs like a heavy haze
over many cities in industrialized countries
->portmanteau word is a combination of two (or more) words , and their definitions, into one new word.
->[1] - Schwartz Cowan, Ruth (1997). A Social History of AmericanTechnology. Oxford University Press. ISBN 978-0-19-
504605-2
16. a familiar and serious problem in London from the 19th century
to the mid 20th century during the industrial revolution
17. Sulphurous Smog
Industrial Smog (London)
Created when fossil fuels are burned in power plants
and home furnaces.
contains soot particulates from smoke, sulfur dioxide
and other components.
Gray colored
18. Photochemical Smog
Derived from
◦ Vehicular emission
◦ internal combustion engines
◦ industrial fumes
that react in the atmosphere with
sunlight to form photochemical
smog.
A common sight in Los
Angles , USA
19. Cause Of Smog
Nitrogen oxides and volatile organic
compounds—that combine with sunlight
to form ozone.
Major smog occurrences often are linked
to heavy motor vehicle traffic, high
temperatures, sunshine, and calm winds.
Weather and geography affect the
location and severity of smog, as
temperature regulates the length of time
it takes for smog to form
20. Cause Of Smog(continued)
Ozone levels :-
Photochemical
(summer smog)
forms when
pollutants such as
nitrogen oxides and
organic compounds
react together in the
presence of sunlight.
A gas called ozone is
formed.
21. Cause Of Smog(continued)
When temperature inversions occur (that is, when
warm air stays near the ground instead of rising) and
the wind is calm, smog may remain trapped over a city
for days.
Ironically, smog is often more severe farther away from
the sources of pollution, because the chemical reactions
that cause smog take place in the atmosphere.
22. Smog and Temperature Inversion
Smog is ,when the warm air
mass moving over an area is
capped , due to the warmer air
layer sitting over a city and
prevents the normal mixing of
cooler, denser air.The air
instead becomes still and over
time the lack of mixing causes
pollutants to become trapped
under the inversion, developing
significant amounts of smog.
23. Historic Tragedy due to Smog
In December 1952, for example,
such an inversion occurred in
London. Because of the cold
December weather at the time,
Londoners began to burn more coal,
which increased air pollution in the
city. Since the inversion was present
over the city at the same time, these
pollutants became trapped and
increased London’s air pollution.The
result was the Great Smog of
1952 that was blamed for thousands
of deaths.
24. Effects Of Smog
Compromise human health, harm the environment,
and even cause property damage.
Cause health problems such as asthma, emphysema,
chronic bronchitis etc.
Eye irritation
Reduced resistance to colds and lung infections.
The ozone in smog also inhibits plant growth and can
cause widespread damage to crops and forests.
25. Risk From Smog
Anyone who engages in strenuous outdoor activity—
from jogging to manual labor—may suffer smog-related
health effects. Physical activity causes people to breathe
faster and more deeply, exposing their lungs to more
ozone and other pollutants.
Four groups of people are particularly sensitive to
ozone and other air pollutants in smog:
1. Children
2. Adults who are active outdoors
3. People with respiratory diseases
4. People with unusual susceptibility to ozone
26. 1. Children :-
◦ Active children spend a lot of time playing
outside.
◦ children are also more prone to asthma—
the most common chronic disease for
children—and other respiratory ailments
than adults.
2. Adults who are active outdoors :-
◦ Healthy adults exercise or work outdoors as
they have a higher level of exposure
27. 3. People with respiratory diseases :-
◦ No medical evidence that the ozone in smog causes
asthma or other chronic respiratory diseases, but
◦ people who live with asthma or such diseases are
more sensitive and vulnerable to the effects of ozone.
◦ they will experience adverse effects sooner and at
lower levels of exposure than those who are less
sensitive.
4. Elderly people are often warned to stay indoors on
heavy smog days.According to the most recent medical
evidence, elderly people are not at increased risk of
adverse health effects from smog.
28. How Do We Recognize/Detect It?
Smog is a visible example of air pollution.
In addition, most cities measure the concentrations of
pollutants in the air and report the results to the public.
Standardized measures have been established, like Air
Quality Index, which compares pollution levels from city to
city.
Air Quality
Air Quality Index
(yardstick)
ProtectYour Health
Good 0-50 No health impacts are expected when air quality is in this range.
Moderate 51-100 Unusually sensitive people should consider limiting prolonged
outdoor exertion.
Unhealthy for
Sensitive Groups
101-150 Active children and adults, and people with respiratory disease,
asthma, limited prolonged outdoor exertion.
Unhealthy 151-200 Active children and adults, and people with respiratory disease,
such as asthma, should limit prolonged outdoor exertion,
everyone else, especially children should limit prolonged outdoor
excretion.
Very Unhealthy
(Alert)
201-300 Active children and adults, and people with respiratory disease,
such as asthma, should limit prolonged outdoor exertion
everyone else, especially children, should limit outdoor exertion.