File:Eastern China (MODIS 2016-02-12).jpg

English: On February 8, 2016, the Moderate Resolution Spectroradiometer (MODIS) flew over eastern China and captured this true-color image of the region.

Although the landscape is painted with a wash of gray haze, the skies are relatively clear for this time of year. The cool air of winter often brings temperature inversions to eastern China, causing thick haze to build up and obscure the land from satellite view. Air normally cools with altitude, but during an inversion warm air settles above a layer of cool air near the surface. The warm air acts like a lid and traps pollutants near the surface, especially in basins and valleys. Even without an inversion, however, haze and smoke can be seen settling in the valleys between mountains and valleys.

Clicking on the 1 km link allows better viewing of the image, and the red hotspots scattered across the region can more easily be seen. The smoke from many of these fires can be seen blowing in the prevailing wind direction. Smoke undoubtedly plays a role in the haze, but is not the only issue. Coal-fired stoves have traditionally been a significant cause of haze in the cool winter, and industrial pollution also plays an important role.