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Get the Chicago, IL local weather forecast by the hour and the next 10 days. ... Chicago News & Weather. ... --UV Index. 6:31PM Sunset. 2 mph F 3 km ...
Get the Chicago, IL local weather forecast by the hour and the next 10 days. ... Chicago News & Weather. ... --UV Index. 4:20PM Sunset. 5 mph F 8 km ...
Get the Chicago, IL local weather forecast by the hour and the next 10 days. ... Chicago News & Weather. ... 1 UV Index. 4:30PM Sunset. 9 mph F 14 ...
The directive on 'ozone in ambient air' came into force in 2002. The long-term objective is to limit the number of days with average ozone concentrations above 120 μg/m 3 to less than 25 days a year (see table below). The objectives of the directive are in line with the World Health Organization's guidelines for ozone.
Environment Canada launched it as part of the weather forecast on May 27, 1992, making Canada the first country in the world to issue official predictions of UV levels for the next day. [15] [16] Many other countries followed suit with their own UV indices. Initially, the methods of calculating and reporting a UV index varied significantly from ...
Decreases in ozone amounts lead to increases in UV radiation. Calculations of UV irradiance based on relationships with total ozone and total irradiance suggest that UV irradiance has increased since the early 1980s by 6-14% at more than 10 sites distributed over mid- and high latitudes of both hemispheres.
Ozone in the ozone layer filters out sunlight wavelengths from about 200 nm UV rays to 315 nm, with ozone peak absorption at about 250 nm. [55] This ozone UV absorption is important to life, since it extends the absorption of UV by ordinary oxygen and nitrogen in air (which absorb all wavelengths < 200 nm) through the lower UV-C (200–280 nm ...
However, because of the presence of Reaction 2 and 3, NO x and ozone are not in a perfectly steady state. By replacing Reaction 6 with Reaction 2 and Reaction 3, the O 3 molecule is no longer destroyed. Therefore, the concentration of ozone keeps increasing throughout the day. This mechanism can escalate the formation of ozone in smog.