I checked airnow.gov and noticed that parts of CA and NV had astounding levels of air pollution — PM10 of 1447, beyond Beijing levels. A little checking showed that this reading was at Mono Shores on Mono Lake, CA. There did not seem to be fires in the area.
My best guess is that this is a dust storm caused by climate change combined with Los Angeles’s need for water. Dust from exposed lake bed causes very high levels of particulate pollution in spring and fall.
Scientists say climatic shifts, however, are bringing less snow to the Sierra Nevada and less snowmelt to Mono Lake. That means if Los Angeles keeps taking its allocated share, it will lead to a decline in lake levels and increased health risks for those exposed to windblown dust from the receding shoreline, according to the Great Basin Unified Air Pollution Control District.
To protect Mono Basin’s ecosystem and airshed, regulatory officials say, will require drafting new predictive models of precipitation, temperature and evaporation rates to control diversions into an aqueduct system that has transformed the ancient brine lake into the largest source of powder-fine air pollution in the United States.
A changing climate at Mono Lake could mean more dust storms in the Eastern Sierra — or less water for L.A.
If I have reached the wrong conclusion and there is some other local phenomenon that explains, this please comment.