Berman, D Wayne; Crump, Kenny S (2003). Final draft:technical support document for a protocol to assess asbestos-related risk. Washington DC: U.S. Environmental Protection Agency. p.474. When the Sun's light reaches the Earth's atmosphere it is scattered, or deflected, by the tiny molecules of gas (mostly nitrogen and oxygen) in the air. Because these molecules are much smaller than the wavelength of visible light, the amount of scattering depends on the wavelength. This effect is called Rayleigh scattering, named after Lord Rayleigh who first discovered it.

Charlemagne, the first Holy Roman Emperor (800–814), is said to have had a tablecloth made of asbestos. [31] All diesel cars that use AdBlue will give you plenty of warning if you're running low. You’ll usually be alerted with a dashboard warning at around 1,500 miles from running out, along with an amber warning light. This warning will remain on every time you restart your car until the AdBlue levels have been topped up to the desired level. What happens if you run out of AdBlue?

The author of Viagra and vision attributes cyanopsia after taking sildenafil to diminished enzyme activity, thereby sensitizing the retinal rod cells. [1] Rod cells are most sensitive to light of wavelengths near 498 nm; such light appears blue-green. When light levels are low enough for both rods and cone cells to be active ( mesopic vision) the enhanced rod activity induces the bluish visual tint. The modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao (meaning 'shimmering, lustrous'). [8] In heraldry, the word azure is used for blue. [9] Lamm, SH; Levine, MS; Starr, JA; Tirey, SL (1988). "Analysis of excess lung cancer risk in short-term employees". American Journal of Epidemiology. 127 (6): 1202–9. doi: 10.1093/oxfordjournals.aje.a114913. PMID 3369419.

Six mineral types are defined by the EPA as "asbestos" including those belonging to the serpentine class and those belonging to the amphibole class. All six asbestos mineral types are known to be human carcinogens. [95] [96] The visible fibers are themselves each composed of millions of microscopic "fibrils" that can be released by abrasion and other processes. [52] The Straight Dope: Is talcum powder asbestos?". www.straightdope.com. 16 February 1990 . Retrieved 3 April 2017. Leonelli, C.; Veronesi, P.; Boccaccini, D.; Rivasi, M.; Barbieri, L.; Andreola, F.; Lancellotti, I.; Rabitti, D.; Pellacani, G. (2006). "Microwave thermal inertisation of asbestos containing waste and its recycling in traditional ceramics". Journal of Hazardous Materials. 135 (1–3): 149–55. doi: 10.1016/j.jhazmat.2005.11.035. PMID 16406335. Libby Asbestos – US EPA Region 8". Epa.gov. Archived from the original on 5 February 2010 . Retrieved 12 January 2010. In painting and traditional colour theory, blue is one of the three primary colours of pigments (red, yellow, blue), which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green. Mixing all three primary colours together produces a dark brown. From the Renaissance onward, painters used this system to create their colours. (See RYB colour model.)

In 1999, the EPA began cleanup efforts in Libby and now the area is a Superfund cleanup area. [82] The EPA has determined that harmful asbestos is released from the mine as well as through other activities that disturb soil in the area. [83] Talc [ edit ] A laboratory heat spreader made of asbestos, on a tripod over a Teclu burner