Your headlight is foggy primarily due to the degradation of the plastic lens caused by environmental factors.
Here's a breakdown of the reasons:
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UV Radiation: Prolonged exposure to the sun's ultraviolet (UV) rays breaks down the polymers in the plastic headlight lens. This causes oxidation, which results in a hazy or yellowed appearance.
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Heat: The heat generated by the headlight bulb itself contributes to the breakdown of the plastic over time.
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Road Debris and Chemicals: Constant bombardment from road debris (rocks, sand, salt) and exposure to chemicals (car wash detergents, road salts) scratch and erode the lens surface.
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Oxidation: The outer layer of the plastic lens oxidizes when exposed to the air. This oxidation leads to the formation of a hazy or yellowish film.
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Manufacturing Process: Some fogging can occur due to imperfections or impurities in the original plastic used to manufacture the headlight.
In short, headlights are constantly exposed to harsh conditions that degrade the plastic over time, leading to that foggy or yellowed appearance.
