Haze vs. Smog — What's the Difference?

Haze occurs when dust, smoke, and other dry particles obscure the clarity of the sky, often resulting from both natural events, like wildfires or volcanic eruptions, and human activities, such as burning fossil fuels. Smog, a type of severe air pollution, is a mix of smoke, chemicals, and fog, originally describing the combination of smoke and fog in urban areas during the Industrial Revolution. Modern smog, or "photochemical smog," is mainly formed by the reaction of sunlight with pollutants emitted by vehicles, industrial processes, and gasoline vapors.

While haze can reduce visibility, affecting respiratory health, and contribute to environmental degradation, it does not always stem from pollutants harmful to health. Smog, on the other hand, specifically refers to polluted air that poses significant health risks, including respiratory problems, heart disease, and worsening of asthma conditions. It also has detrimental effects on the environment, damaging crops, forests, and aquatic systems.

The occurrence of haze can be seasonal, linked to agricultural practices, or weather conditions, whereas smog is more closely associated with urban and industrial activities, becoming more prevalent with increased pollution levels. Haze might appear in both rural and urban areas, but smog is predominantly an urban phenomenon, exacerbated by weather patterns and geography that trap pollutants over cities.

Management and mitigation of haze involve controlling sources of particulates, like reducing deforestation and managing agricultural fires. Combatting smog requires comprehensive air quality management, including emissions reductions from vehicles and industries, and the use of cleaner energy sources. Both phenomena highlight the need for environmental policies and individual actions aimed at reducing air pollution and protecting public health.