Arctic haze is the phenomenon of a visible reddish-brown springtime haze in the atmosphere at high latitudes in the Arctic due to anthropogenic air pollution. A major distinguishing factor of Arctic haze is the ability of its chemical ingredients to persist in the atmosphere for an extended period of time compared to other pollutants. Due to limited amounts of snow, rain, or turbulent air to displace pollutants from the polar air mass in spring, Arctic haze can linger for more than a month in the northern atmosphere.

Arctic haze was first noticed in 1750 when the Industrial Revolution began. Explorers and whalers could not figure out where the foggy layer was coming from. "Poo-jok" was the term the Inuit used for it. Another hint towards clarifying this issue was relayed in notes by Norwegian explorer Fridtjof Nansen. After trekking through the Arctic he found dark stains on the ice. This was about a century ago. The term "Arctic haze" was coined in 1956 by J. Murray Mitchell, a US Air Force officer stationed in Alaska, to describe an unusual reduction in visibility observed by North American weather reconnaissance planes. From his investigations, Mitchell thought the haze had come from industrial areas in Europe and China. He went on to become an eminent climatologist. The haze is seasonal, reaching a peak in late winter and spring. When an aircraft is within a layer of Arctic haze, pilots report that horizontal visibility can drop to one tenth that of normally clear sky. At this time it was unknown whether the haze was natural or was formed by pollutants.