UV index in Bournemouth

An open-ended scale starting at 0 that measures the strength of ultraviolet radiation able to redden skin. From 3 to 5 protection is already advised, 8 to 10 is very high and above 11 is extreme. It depends on how high the Sun is, on the ozone layer, on altitude and on cloud.

Standard definition by WHO / WMO — Global Solar UV Index · UV index

Ozone formed near the ground when sunlight reacts with exhaust gases and solvents. It is not the ozone layer, which sits kilometres up and protects us: this one irritates the airways and rises on clear, hot, windless days.

Standard definition by U.S. EPA — AQI Technical Assistance Document · Ground-level ozone

The invisible part of sunlight with wavelengths below violet. UVB burns skin and is largely filtered by the ozone layer; UVA goes deeper, passes through glass and ages skin. The UV index sums both up by their reddening effect.

Standard definition by WHO / WMO — Global Solar UV Index · Ultraviolet radiation

The United States Air Quality Index, 0 to 500, which converts each pollutant concentration into a single score and reports the worst one. Up to 50 is good, above 100 it starts to affect sensitive groups, above 150 it affects everyone. The score is not linear in concentration: it follows breakpoints set by the EPA.

Standard definition by U.S. EPA — AQI Technical Assistance Document · AQI

A measurement published as soon as it is collected, before the agency’s final review. It can be corrected or withdrawn: earthquake magnitudes shift in the first hours, air-quality readings are revised weeks later. Use it to plan your day, not for regulatory or legal purposes.

Preliminary data