In the Shadow of Smog: Insights into Photochemical Pollution and Preventive Measures

Traffic generator vehicles in urban areas of large population are responsible for the photochemical smog pollutants when react with the sunlight building up a unique type of air pollution. The pollution is a kind of mixture of several deadly gases which include, for instance, ozone, nitrogen dioxide, and volatile compounds. Photochemical smog may cause damage to places, plants, populations and animals, affecting people's health.

Photochemical smog is the outcome of oxidation reactions between sunlight, atmosphere, and combustion products. Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the pollutants that originate from the automobile exhaust pipes, factories, chimneys, and power plants, etc. This is a source of activation energy needed to initiate photochemical processes, from among the longest wavelengths of the sun present in the trans-violet rays spectrum. Molecules able to encounter another during the moment that the light makes (or, breaking) the chemical bonds may initiate new processes.

The reactive nitrogen can be also produced by photo-dissociation of nitric oxide (NO) and oxygen atom (O) as the reaction between an NO2 molecule in the air and the absorption of UV light. The other impurity may then react with the NOx molecules thereby enhancing the oxidising effect of the atmospheric O and NO. The same as O2, O2 will be absorbed by trans-violet radiation and form two separate oxygen molecules. (O). these birthing of the reactive oxygen molecules attached with oxygen molecules (O2) form the ozone (O3).

The cycle of ozone formation: The process entails that O3 and NO make NO2 and O2 as products.

 

NO+O3 => NO2 + O2

 

The nitrogen dioxide (NO2) absorbs the sucrose and crushes into nitric oxide (NO) and oxygen atoms (O) to release energy and proceed in the ozone cycle.

 

NO 2+ UV radiation → NO + O.

 

V. O. Cs. Reactions: molecules referred to as VOCs, which are released from different sources, and comprise of different number of carbon molecules, undergo photo reactions of ozone formation by taking part in the various chemical processes, in the presence of sunlight. Furthermore, they are able to synthesize peroxyacetyl nitrate (PAN) or the nitrogen-containing organic pollutants which belongs to this class.

Higher levels of tropospheric ozone (O3) and the soiling substances of nitrogen dioxide (NO2) undergoing photochemical processes and mixing with other secondary air pollutants such as secondary organic aerosol and particulate matter, the background brownish photochemical haze is created. A weather condition heightens their intensities and persistence ever so much. A thick layer of warm air staying right above a layer of cold air on the ground deters the pollutants from spreading while temperature changing and fog formation happen.

Visual identification of photochemical smog may be performed with means of the visible characteristics, such as the measuring instruments. Smog with a brownish color photochemical takes away the clarity and covering, has a strong odor due to the presence of volatile organic chemicals, and negatively affects health including eye and respiratory exaggeration, a strong coughing with your asthma attack.

The environmental agencies perform monitoring on the Air Quality Index (AQI) and disclose air quality from time to time. High values of AQI index mean that it’s photochemical smog inside the city which shows us that there is really ozone. High technology monitoring stations using electrochemical sensor based technology that measure the concentration of air pollutants identify areas with photochemical smog by using Air Quality Index that gives numerical rating to air quality from 0 to 500. Moreover, the categories and advancement of fog are identified through satellite observations enabling its positioning on the affected areas. Air samples are collected, subject to laboratory analysis, as we trying to find out whether pollutants such as ozone, nitrogen dioxide, and VOCs are presents.

First half of the 1900s saw the industrialization and urbanization trend in Europe. NO2 attaches to aerosols and pollutants which freezes in colder temperatures and precipitated on the ground leading to the production of photochemical fog events. The growing trend of coal being used for generating heat and supplying energy due to high demand for these services and the emergence of mass transportation systems is a major reason behind a rise in the amount of pollutants that are released in the urban areas.

London smog: In the early 1900s, London suffered from several periods of really thick fog that was created by the mixture of sulfur dioxide (SO2) and smoke particles. The result was a blanket of air so dense, it was a struggle to breathe in and gasping in the air itself brought discomfort to the lungs. This was harmful to their health. This health problem increased as more chemicals were introduced in the food. Fog-bound London is another familiar image that evokes claustrophobic frustration for the narrator.

Los Angeles Fog: In the 1940s another kind of fog occurred that wasn't only from the sulphur emissions, but also from high level ozone and visible particles persistence. The science has shown that, NOx as well as VOC which have been emitted from vehicles and industries combined with the sunlight undergo a reaction and produce a photochemical smog.

In the 1950s the scientists were doing researches to uncover chemical compounds and chemical process that were making the air around Ozone layer which is made up of oxygen and nitrogen, among others by hydrogen and ionizing radiation. This process is equally a main part of fact findings of what kind of relationship exists between the sunlight and particular pollutants. The nitrogen oxides (NOx) included in combustion of fuel by cars that weons to have. Also volatility organic compounds (VOCs) produced by industrial operations, gasoline, or solvents were defined, too. Political powers came as concern of people about the health implications of photochemical pollution rose when researchers went on with study of resultant impact on health. Through The Clean Air Act, that was enacted in 1963 to control air quality by limiting the emissions of pollutants that most often lead to smog, the United States intends to reduce the level of pollution.

 

When people start to realize that ozone hole has been caused by chemicals (eg. CFCs) in 1970s they get in a rather difficult situation to ban the chemicals altogether in stratosphere. In spite of regulations and improvement of air quality index from the 1980s which are recent, photochemical smog is still a problem for many urban areas. Fast urbanization, growing vehicle ownership, and rise of the industrial activity in the city area, respectively. Conduct to the emission of NOx and VOCs.

 

To date, a lot of extremely bright scientists have made real inventions on smog created by the sunlight.

 

Researcher: Ari Jan Hagen-Schmidt Nationality: Dutch-American Contribution: NOx and VOCs (VOCs) photochemical smog were identified as the pollutants that contributed to the problem.

Researcher: Harold S. Johnston Nationality: American Contribution: showed how elements in smog form when the ozone and specific pollutants interact (characteristics of photochemical smog), and determined how they are influenced by other pollutants.

Researcher: Paul Crutzen Nationality: Dutch Contribution:  studies on atmospheric chemistry involved which are nitrogen and some other gases emissions and their effects on ozone depletion and photochemical smog.

Researcher: Frank Sherwood Rowland Nationality: American Contribution: Found the CFC's (chlorofluorocarbons) effects in the ozone depression, the pollution they bring to ground level, and the photochemical smog. Proved my ability to work with others by doing this research along with the collaboration of Mario Molina.

Researcher: Mario J. Molina Nationality: Mexican-American Contribution: first became aware of the CFCs ozone layer destroying characteristics, in collaboration with Rowland, and just like and contributed to the understanding on how the compounds are able to form photochemical smog.

Researcher: James G. Anderson Nationality: American  Contribution: Concentrates on the chemical audit of the atmosphere and its importance in   the climate and air quality. Carries out studies on the elemental chemical process of photochemical haze productions and the compound pollutions in the air.

 

Different acts have been enforced in order to control the production:

 Key approaches include:

 1. In an effort to reduce emissions, we will curtail the use of polluting agents.

2. Tougher emission standards should be issued as a means to fulfil this objective.

3. In order to enforce the use of cleaner technologies and fuel is the way in which the organizations should control this problem.

4. VIRM needs to be invoked to have such vehicle inspection programs working.

5. For example, taking a walk, biking or public transport is efficient and economical methods in lowering fuel consumption.

6. One of the significant measures to curb energy consumption starts from urbanization itself.

7. To apply the use of clean energy sources.

 

International agreements, for instance, the Montreal Protocol deal, are a prime example that the focus is on substances contributing to a hole in the ozone layer or photochemical smog, like chlorofluorocarbons. The emission control policies developed by the EPA intend to regulate emissions from the different emission sources thus there are also requirements of maintenance of fuel quality standards.

Some key years and milestones related to these policies: Some key years and milestones related to these policies:

 

Year	Milestone
1940-1950	Exploration of ozone layer that has been triggered by light induces research into its origin.
1963	USA adopts the Clean Air Act which empowers EPA as the new institution with a mandate to monitor air quality.
1970	The modification of the U. S. Clean Air Act through such provisions extends the scope of the issue under exploration; pollution is the key focus point
1980-1990s	Such an awareness of the global nature of smog is what pushes the international dimension of efforts to cooperate.
1987	Enacting the Montreal Protocol to stand alongside the ozone layer destruction and toxigens formation problems.
1990	Various countries put into place emissions standards since they focus on a number of compounds like NOx and VOCs.
2000s	Strategies to reduce the air pollution as well as air quality standards need to be put in motion.
2010	A never-ending process of researching creates the perfect strategies that exact less of harm to the atmosphere and purify it as well.