The Tomorrow.io REST Weather API air insight category will trigger for any of the events below.
Air Stagnation (Advisory)
Issued for atmospheric conditions stable enough to cause air pollutants to accumulate in a given area, in cases where the following criteria are met and conditions to continue for at least 72 hours or are underway or are expected to start within 24 hours:
(1) morning and afternoon mixing height of 1,500 ft AGL or less
(2) morning and afternoon transport winds of 10 kts or less
Dense Smoke (Advisory)
Issued when visibilities at or below 1/4 of a mile.
Dust (Advisory)
Issued when there is a sudden drop in visibility to one mile or less, but greater than 1/4 mile, resulting in widespread or localized blowing dust.
Blowing Dust (Advisory/Warning)
Issued when there is a long duration event of widespread or localized blowing dust reducing visibilities to one mile or less.
1 mile for 3 hrs or more with sustained winds 25 mph
Dust Storm (Advisory/Warning)
Issued when there is a sudden drop in visibility to 1/4 mile or less resulting in widespread or localized blowing dust.