Haze is primarily caused by tiny pollution particles in the air interacting with sunlight. This interaction leads to the absorption and scattering of light, reducing visibility and affecting the color of what we see. The more pollutants present, the greater the scattering and absorption, resulting in more significant haze.
Sources of Haze-Causing Particles:
Numerous sources contribute to the particulate matter responsible for haze. These include:
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Human-made sources:
- Traffic emissions: Vehicles release pollutants that contribute significantly to air pollution and haze.
- Industrial emissions: Factories and industrial processes release various pollutants into the atmosphere.
- Stubble burning: Agricultural practices, such as burning crop residue, release large amounts of smoke and particulate matter.
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Natural sources:
- Wildfires: Wildfires generate substantial amounts of smoke and ash, causing widespread haze.
- Volcanic activity: Volcanic eruptions release gases and particles into the atmosphere, leading to volcanic smog (vog).
- Windblown dust: Wind can carry dust particles over long distances, contributing to haze formation.
Types of Haze:
While the underlying cause remains the same (light scattering by particles), the composition of these particles and resulting haze can vary:
- Air pollution haze: This is the most common type, caused by human activities.
- Volcanic haze (vog): A specific type of haze caused by volcanic eruptions.
- Wildfire haze: Smoke and ash from wildfires significantly impact air quality and visibility.
The severity of haze depends on the concentration of these particles and weather conditions. High humidity can sometimes worsen haze, but unlike fog, haze commonly occurs in dry conditions. The US EPA identifies particulate matter pollution as a major cause of reduced visibility (haze) across many regions.
