Smog

Oxidation អុកស៊ីដកម្ម                           exhaust ផ្សែងបញ្ចេញចោល,ចំហាយបញ្ចេញចោល

Haze អ័ព្ទ                                              photochemical smog ផ្សែងគីមី

Cylinder ស៊ីឡាំង                                  tailpipe បំពង់ស៊ីមាំង

Hue ព៌ណលាំ                                       decompose ញែកធាតុ

Irritation ក្រហាយ

The oxidation of exhaust gasses is one of the primary sources of the world’s pollution. The brown haze that is poised over some of the world’s largest cities is properly called photochemical smog; it results from chemical reactions that take place in the air, using the energy of sunlight. The production of smog begins when gasses are created in the cylinders of vehicle engines. It is there that oxygen and nitrogen gas combine as the fuel burns to form nitric oxide (NO), a colorless gas. The nitric oxide is forced out into the air through the vehicle tailpipe along with other gasses.

When the gas reaches the air, it comes into contact with available oxygen from the atmosphere and combines with the oxygen to produce nitrogen dioxide (NO₂), which is a gas with a brownish hue. This nitrogen dioxide plays a role in the formation of acid rain in wetter or more humid climates and tends to decompose back into nitric oxide as it releases an oxygen atom from each molecule; the released oxygen atoms quickly combine with oxygen (O₂) molecules to form ozone (O₃). The brownish colored nitrogen dioxide is partially responsible for the brown color in smoggy air; the ozone is the toxic substance that causes irritation to eyes.

Extracted from the book of LONGMAN Preparation Course for the TOEFL Test and translated by Ty Theavy