Photochemical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight, creating a brown haze above cities. It tends to occur more often in summer, because that is when we have the most sunlight.

What is photochemical smog Class 11?

Photochemical smog refers to a type of smog which is formed when the ultraviolet light from the sun reacts with nitrogen oxides present in the atmosphere. This smog can cause a lot of adverse effects on humans and other living organisms.

Why Photochemical smog is so called?

Ground-level ozone constitutes one of the major components of photochemical smog, so called because of the photochemical reaction of air pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) with ultraviolet light (sunlight); thus, the O₃ levels vary strongly with season and the highest levels ...

What is photochemical smog and what are its effects?

Photochemical smog is formed when pollutants like hydrocarbons and nitric oxide interact with sunlight to form chemicals like NO2, Peroxyacyl nitrate (PAN), ozone, acrolein and formaldehyde. ... Photochemical smog leads to cracking of rubber and extensive damage to plant life.

What is the difference between photochemical smog and industrial smog?

It is produced when nitrogen oxides and volatile organic compounds in automobile and fossil-fueled power-plant emissions combine with oxygen in the air in direct sunlight. Whereas industrial smog casts a gray pallor over the areas it affects, the nitrogen dioxide in photochemical smog creates a dingy, brownish haze.

Photochemical Smog (Animation)

What is photochemical smog give examples?

Photochemical smog is a type of smog produced when ultraviolet light from the sun reacts with nitrogen oxides in the atmosphere. ... Cities that experience this smog daily include Los Angeles, Sydney, Mexico City, Beijing, and many more.

What is the other name for photochemical smog?

Photochemical smog, which is also known as “Los Angeles smog,” occurs most prominently in urban areas that have large numbers of automobiles. It requires neither smoke nor fog. This type of smog has its origin in the nitrogen oxides and hydrocarbon vapours emitted by automobiles…

Why is photochemical smog called LA smog?

Photochemical smog: This type of smog was observed in Los Angeles(1940s) and hence named as Los Angeles smog. It is formed when the air contains NO ₂ and hydrocarbons and the mixture is exposed to sunlight. As the reaction take place in the presence of light to form the smog, it is called photochemical smog.

What does the term photochemical mean?

1 : of, relating to, or resulting from the chemical action of radiant energy and especially light photochemical smog. 2 : of or relating to photochemistry photochemical studies.

What is photochemical smog Slideshare?

Photochemical Smog is an air pollution ,formed when photons of sunlight hit molecules of different kinds of pollutants in the atmosphere. AIR POLLUTANT Primary Air Pollutant NOx , VOCs Secondary Air Pollutant Ozone(O3) , PAN. Process Involving Formation Of Photochemical Smog.

What is photochemical smog Wikipedia?

Photochemical smog, often referred to as "summer smog", is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone. Photochemical smog depends on primary pollutants as well as the formation of secondary pollutants.

What is photochemical smog in environmental chemistry?

Photochemical smog is a type of air pollution due to the reaction of solar radiation with airborne pollutant mixtures of nitrogen oxides (NOx) and volatile organic compounds (hydrocarbons). Smog is a byproduct of modern industrialization. ... Oxidation: Photochemical smog is also referred to as oxidizing smog.

What is photochemical process?

photochemical reaction, a chemical reaction initiated by the absorption of energy in the form of light. The consequence of molecules' absorbing light is the creation of transient excited states whose chemical and physical properties differ greatly from the original molecules.

What is the photochemical phase?

The photochemical phase of photosynthesis is also known as light reaction. It is responsible for the formation of high-energy chemical intermediates, ATP and NADPH, and it includes light absorption, water splitting and release of oxygen.

What is a photochemical reaction give one example?

Definition: Refers to any chemical reaction which occurs as a result of light energy from the sun. For example, ozone is formed through a photochemical reaction involving nitrogen dioxide and reactive organic compounds.

Is photochemical smog called London smog?

Sulfurous smog and photochemical smog are two distinct types of smog recognised so far. Sulfurous smog, also known as London smog, develops due to high concentration of sulfur oxides in the air.

Is classical smog London smog?

Option A: Classical smog has smoke, fog and sulphur dioxide components and is found in humid conditions. They are present where there is a high concentration of particulate matter and sulphur dioxide is produced because of combustion of fuels. ... It is also known as London smog or sulphurous smog.

Is photochemical smog a secondary pollutant?

Secondary pollutants are pollutants which form in the atmosphere. These pollutants are not emitted directly from a source (like vehicles or power plants). ... Photochemical smog is made up of various secondary pollutants like ozone, peroxyacyl nitrates (PANs), and nitric acid (seen in Figure 2).

Which of the following is responsible for photochemical smog?

Hydrocarbons, oxides of nitrogen and carbon monoxide are responsible for photochemical smog.

Is photochemical smog a primary pollutant?

Photochemical smog is composed of primary and secondary pollutants. Primary pollutants, which include nitrogen oxides and volatile organic compounds, are introduced into the atmosphere via vehicular emissions and industrial processes. ... Photochemical smog is most common in sunny and dry cities, like Los Angeles.

What is photochemical smog discuss different types of smog?

At least two distinct types of smog are recognized: 1) Sulfurous smog (or 'London-type' smog); 2) Photochemical smog ('Los Angeles-type' smog). Sulfurous smog results from a high concentration of sulfur oxides in the air and is caused by the use of sulfur-bearing fossil fuels, particularly coal.

Which is major pollutant present in photochemical smog?

Detailed Solution. Photochemical smog forms when NOx and VOCs react in the presence of solar radiation to form ozone. The solar radiation also promotes formation of secondary aerosol particles from oxidation of NOx , VOCs, and SO₂.

Which pollutant is the major contributor to photochemical smog?

Option 2 is the correct answer: Ozone is the major contributor to photochemical smog.

What is an example of a photochemical?

Examples of photochemical reactions

Photosynthesis: plants use solar energy to convert carbon dioxide and water into glucose and oxygen. Human formation of vitamin D by exposure to sunlight. Bioluminescence: e.g. In fireflies, an enzyme in the abdomen catalyzes a reaction that produced light.

Where do photochemical reactions occur?

Photochemical reactions of organic matter can take place in surface waters and any irradiated surfaces of organic or inorganic substrata. The prerequisite for photochemical reactions is the absorption of radiation.