On Earth, pollution mixed with heat and sunlight creates a concentration of Ozone (O3 gaz) in the atmosphere (stratosphere + troposphere). This gaseous element, when released in the stratosphere, acts like sunscreen for all living organisms, shielding the Earth’s surface from most of the sun’s UV light (unless it creates depletion in the atmospheric layer).
However, when this concentration remains at ground level in the troposphere, it affects the air that we breathe as humans and therefore starts becoming a health hazard. When inhaled, ozone reacts chemically with many biological molecules in the respiratory tract, leading to a number of adverse health effects.
We call this secondary air pollution Photochemical Oxidation, also known as Summer Smog. Chemically speaking, photo-oxidant formation is a photochemical creation of reactive substances: it is formed in the atmosphere by nitrogen oxides and volatile organic compounds in the presence of sunlight, often the consequence of emissions from fossil fuel combustion. POP calculates the destructive effects of ozone in the troposphere over a time horizon of 100 years.