The mist in the air over Ecuador’s southern sierra, including Cuenca, is the result of dust being blown northward from Peru, not from volcanic ash.
A Wednesday morning report from the University of Azuay air quality index service that the haze over Cuenca was due to an eruption of the Sangay volcano in Morona-Santiago Province was corrected later in the day by Ecuador’s Geophysical Institute. “The eruptive activity at Sangay is currently very low and prevailing winds are carrying any emissions to the west and northwest, away from Cuenca and Loja,” the institute said.
Throughout the day on Wednesday, the University of Azuay’s air quality index showed Cuenca’s air to be in the “unhealthy” range for fine particulate matter. The service advised those with respiratory diseases and the elderly to stay indoors.
Late Wednesday, Ecuador’s Meteorological Institute issued a statement saying that, in addition to the wind-borne Peruvian dust, “a number of factors” were creating the hazy conditions. “The dust and humidity from the Amazon jungle are being trapped by a large dome of high pressure over Ecuador’s southern sierra region. The high pressure is keeping the dust and moisture close to the ground and not letting it escape into the upper atmosphere.”
The institute said that high pressure will remain in place through Thursday but begin to break down Thursday night and Friday. It said the northerly winds from Peru will also dissipate.
Early Thursday, the Cuenca Risk Management Office repeated the Universtiy of Azuay advisory that those with respiratory illnesses and older adults should limit their time outdoors due to poor air quality. The office said that despite high levels of particulate matter, the dust does not pose the same health risk as similar levels of volcanic ash.