File:Haze Over China (MODIS).jpg

English: A widespread gray haze hung over eastern China on October 17, 2023, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this true-color image of the region. The haze is thickest just north of the Shandong Peninsula, where both the land and the waters of the Bohai Sea are barely visible.

Outbreaks of haze frequently occur over the lowlands of eastern China, especially in cooler weather when aerosol pollution from coal and wood burning for heat add to the year-round emissions from industrial activity and vehicles. Smoke from fires and dust storms can also contribute aerosols that degrade air quality.

Temperature inversions are also more common as temperatures drop. Air normally cools with altitude, but during an inversion warm air settles above a layer of cool air near the land or water surface. The overlying warm air acts like a lid and traps pollutants near the surface, especially in basins and valleys, creating a gray haze easily visible from space.