Haze is the accumulation of dust, soot, ash and other particulates trapped in the atmosphere. Depending on the types of particles, haze can have both warming and cooling effects.
Previous studies have suggested haze levels are decreasing across the United States. But the study identified a few anomalies, small pockets of the alpine West where peak summertime haze levels continue to rise.
Atmospheric scientist Gannet Hallar confirmed the findings using instruments designed to measure aerosol optical depth, a metric for the amount of aerosols between the sensor and the sun.