Airborne microscopic dust and smoke aerosol particles observed by the Earth Probe TOMS satellite. Desert dust storms, forest fires, biomass burning and volcanic eruptions can be observed.

1996	1997
1998	1999
2000	2001
2002	2003

Can you identify
- dust storms from western Africa, the Gobi Desert in China, and Australia?
- smoke from forest fires in Brazil, Canada, Indonesia, and eastern Russia?
- volcanic ash/aerosals?

The latter can be relatively brief events. See for example
2002, Nov 4, El Reventador, Ecuador. Reventador erupted early Sunday morning local time, and sent up smoke and hot ash about 15,000 m asl. This forced the International Airport in Quito to close immediately and the closure of schools in the area on Monday. http://www.vulkaner.no/v/volcan/latinam/reventador_e.html
2000, Aug 19, Aug 29, Miyakejima, Japan. A relatively large eruption during the afternoon of 18 August produced ~8x10⁹ kg of volcanic ash and lapilli, which covered the whole area of the island. The eruption column rose higher than 10 km and drifted southward. http://staff.aist.go.jp/geshi-nob/files/s00445-001-0184-z.pdf

References