N: 1. “opaqueness of the atmosphere,” 1706, probably a back-formation of hazy (q.v.). Sense of “confusion, vagueness” is 1797. The differentiation of “haze”, “mist”, “fog” (and other dialectal words) is unmatched in other tongues, where the same word generally covers all three and often “cloud” as well; this may be an effect of the English climate on the English language.
2. Suspension in the atmosphere of extremely small, dry particles which are invisible to the naked eye but numerous enough to give the sky an opalescent appearance.
3. Haze, suspension in the atmosphere of dry particles of dust, salt, aerosols, or photochemical smog that are so small (with diameters of about 0.1 micron = 0.00001 cm) that they cannot be felt or seen individually with the naked eye, but the aggregate reduces horizontal visibility and gives the atmosphere an opalescent appearance. Haze appears as a bluish or yellowish veil depending on whether the background is dark or light, respectively. With respect to these colours, haze can be discriminated from mist, which gives a grayish cast to the sky.
4. What is the difference between “mist”, “fog” and “haze”?
Fog, mist and haze all affect visibility, which is an important part of forecasts affecting many aspects of life from driving conditions to shipping and aviation.
Fog and mist differ by how far you can see through it – fog is when you can see less than 1,000 meters away, and if you can see further than 1,000 metres we call it ‘mist’.
Compared to “fog” and “mist”, “haze” is a slightly different phenomenon which is a suspension of extremely small, dry particles in the air (not water droplets) which are invisible to the naked eye, but sufficient to give the air an opalescent appearance.
These particles can also contribute to creating a red sky at sunrise or sunset.
S: 1. OED – https://bit.ly/2Db86QI (last access: 8 April 2019). 2. METEOTERM – International Meteorological Vocabulary, WMO – No. 182 (last access: 8 April 2019). 3. EncBrit – https://bit.ly/2IdmeNo (last access: 11 April 2019). 4. Met Office – https://bit.ly/2WZx2SI (last access: 11 April 2019).