Criterion D- Ozone Essay assignment
Hyo-Jin Kim
Tropospheric ozone is one of the main components of photochemical smog which has
unwholesome influence, especially on human’s respiratory system.
Ozone has a number of properties and contains both beneficial and disadvantageous
depending on its level of atmosphere. Ozone is an allotrope form of oxygen with consists of 3
oxygen atoms bond together by the UltraViolet light. Formation of ozone is created when the
oxygen encounters a chemical reaction powered by the sun’s radiation. This energy breaks down
the oxygen molecules into a single atom. (Britannica School, 2014) Because the free oxygen
atom is unstable, the oxygen atom collides with other oxygen molecules which leads to form
ozone. Additionally, ozone acts as a powerful oxidizing agent such as oxidizing sulphur dioxide
to sulphur trioxide. It also has the appearance of a pale blue gas that is explosive and toxic even
in low concentrations. Compared to oxygen, the mass is approximately 1.5 times heavier and
more soluble in water.
Over 90% of the ozone is found in the stratosphere which is 10-50 km above earth’s
surface. (Stattersfield) Stratospheric ozone can strongly absorb radiation in the UltraViolet light
to protect the earth’s surface and inhabitants from the harmful radiation of the sun. Stratospheric
ozone occurs naturally in the upper atmosphere where it forms a protective layer to shield the
UV rays. (US EPA,OAR) Without this ozone layer, all of the radiation from the sun would reach
the earth that there would be a damage towards the plants, animals and humans. Consequently,
10km above the earth is the lower level ozone in the layer of the troposphere. As ozone is
bonded in an unstable condition, this tropospheric ozone or ground level ozone becomes the
byproduct of fossil fuel combustion.
Tropospheric ozone is a major component of photochemical smog which forms a
reaction with primary pollutants such as Volatile Organic Compounds, nitrogen oxide and the
UV light unlike the ozone in the stratosphere. Contrary to the ozone having an essential function
in the stratosphere, tropospheric ozone acts as a highly reactive secondary pollutant.
Photochemical smog is a type of air pollution due to the reaction between primary pollutant
mixtures and the ozone, producing the brown haze which cause the tropospheric ozone to be
harmful. (The LibreText) Despite the fact that the ground level ozone is not emitted directly into
the air, since it reacts with the primary pollutants and chemicals such as nitrogen oxide, VOC
and hydrocarbons. In addition, the primary pollutants would produce secondary pollutants such
as ground level ozone. Thus the majority of these pollutants are forming the tropospheric ozone
which is caused by hydrocarbon combustion in vehicles, factories and power plants. (US
EPA,OAR) Apart from this, the pollutants could flow around the earth through the wind to create
a circulation. Then the ozone in the troposphere would have safer effects. However, the
pollutants would be captured in the air if there's an inversion layer where the temperature of the
atmosphere in a region stops decreasing with elevation. Instead, it turns out to be warmer which
indicates the reason why photochemical smog is remaining in the troposphere. Since the hot air
always rises while the cold air descends, the photochemical smog wouldn’t rise in the inversion
layer. (J.M.K.C. Donev et al.) Thus, it is a significant factor as the nitrogen oxide, VOC, heat and
UV light are maintaining over urban areas. The concentration of photochemical smog depends
on the temperature, amount of sunlight and the environment in the city. Hence, urban cities that
have modern industrialization includes warm, gentle winds, sunny and dry climate, which will
produce more photochemical smog.
When the photochemical smog is breathed in by humans who particularly are asthmatics,
ozone can trigger serious breathing problems and aggravate asthma attacks. Generally, ozone
causes throat irritation, chest pain, coughing and could possibly lead to permanent lung tissue
damage. It also worsens chronic bronchitis and emphysema. However, people who have
respiratory diseases such as asthma would create their lungs to be more vulnerable to ozone
exposure and sensitive to allergens, even at lower ozone levels. (“Ozone: Health and
Environmental Effects”) Consequently, long term exposure of ozone in photochemical smog
would increase the risk of premature death. Increase of respiratory symptoms, frequency of
asthma attacks, and depletion of lung function would be noticeable for asthmatics when the
ozone levels are high, especially in the spring and summer. According to the Environmental
Protection Agency, “Ozone is highly reactive in the respiratory tract… Epithelial cells lining the
respiratory tract are the main target of ozone and its products. ” It is the reaction that ozone have
with the proteins and lipids on the surface of epithelial cells where inflammatory mediators are
released. This leads the ozone induce inflammatory response that would affect the bronchioles
and alveoli which has the fundamental role human’s lungs for gas exchange. Because people
with asthma would be more sensitive than non severe asthmatics, it would be dangerous when
Air Quality Index is 101 or higher. (“Air Pollution and Asthma | AAFA.Org”) AQI 51-101 is the
moderate state where usually people who are sensitive would receive uncomfortableness. With
the data collection by AirVisual, 50 countries have the moderate AQI or even higher. (“World
Air Quality Index (AQI) Ranking”) If there’s no solutions or improvements are made, the
number of asthmatics would continuously increase by the ozone level.
Nevertheless, the problem of tropospheric ozone pollution can be solved by reducing the
amount of nitrogen oxides, VOCs and direct emitted resources. Since these chemicals contribute
to photochemical smog and ozone, minimizing the sources could be beneficial. Thus, adding the
vapor recovery nozzles, redeveloping cleaner burning gasoline and confirming strict emission
limits for power plants could possibly improve the situation. (US EPA,OAR) As a specific
example, a company Auto Alliance is exchanging the vehicles to electric device. With this
process, the vehicles would only produce 3.3% of the ozone resources in 2030. (“Clean Car
Progress”) Perhaps it would require a number of years, but it contributes to reduce the ozone
within photochemical smog, and asthmatics.
Therefore, ozone in the troposphere provides negative impacts on society by affecting
asthmatics specifically. Primary pollutants such as nitrogen oxide, hydrocarbons and VOCs
cause photochemical smog to appear as one of the air pollution in urban areas, although the
concentration of tropospheric ozone could be decreased by reducing the sources of vehicles.
Works Cited
“Air Pollution and Asthma | AAFA.Org.” Aafa.Org, Oct. 2015,
www.aafa.org/air-pollution-smog-asthma/.
“Clean Car Progress.” Alliance of Automobile Manufacturers, Auto Alliance,
autoalliance.org/energy-environment/clean-car-progress/. Accessed 28 Nov. 2019.
Craig Freudenrich. “How Ozone Pollution Works.” HowStuffWorks,
science.howstuffworks.com/environmental/green-science/ozone-pollution1.htm.
Accessed 28 Nov. 2019.
Hanania, Jordan, et al. “Ground Level Ozone - Energy Education.” Energyeducation.Ca,
4 Jan. 2019, energyeducation.ca/encyclopedia/Ground_level_ozone. Accessed 10
Nov. 2019.
Levitan, Dave, and Ensia. “Ozone Pollution Grows, but It Can Be Fixed.” Scientific
American, 22 Feb. 2018,
www.scientificamerican.com/article/ozone-pollution-grows-but-it-can-be-fixed/.
“Ozone: Health and Environmental Effects.” MNN - Mother Nature Network, 6 Feb.
2009,
www.mnn.com/health/fitness-well-being/stories/ozone-health-and-environmentaleffects. Accessed 8 Nov. 2019.
Stattersfield, Eloise. “The Ozone Notepad.” Bris.Ac.Uk, University of Bristol,
www.chm.bris.ac.uk/motm/ozone/Low.htm. Accessed 9 Nov. 2019.
The LibreText. “Important Properties of Ozone.” Chemistry LibreTexts, 6 June 2019,
tinyurl.com/r589hvl. Accessed 9 Nov. 2019.
US EPA,OAR. “Health Effects of Ozone in Patients with Asthma and Other Chronic
Respiratory Disease | US EPA.” US Environmental Protection Agency,
www.epa.gov/ozone-pollution-and-your-patients-health/health-effects-ozone-patie
nts-asthma-and-other-chronic. Accessed 10 Nov. 2019.
“World Air Quality Index (AQI) Ranking.” Airvisual.Com, 28 Nov. 2019,
www.airvisual.com/world-air-quality-ranking. Accessed 20 Nov. 2019.
‌