The distribution of UV levels across the world varies greatly depending on geographic location, altitude, time of year, and environmental factors. UV radiation is measured using the UV Index, a scale that indicates the risk of harm from unprotected sun exposure. The higher the UV Index, the greater the potential for skin and eye damage.
1. Africa
- Equatorial Regions: Africa experiences some of the highest UV levels globally due to its proximity to the equator and large areas of desert, like the Sahara. UV Index levels regularly exceed 11+ (considered extreme) in countries such as:
- Kenya, Uganda, Ethiopia, Nigeria: UV levels are consistently high, especially during summer.
- South Africa: Southern regions experience moderate to high UV levels, ranging from 7-9.
2. Australia and Oceania
- Australia: This continent has some of the world’s highest UV Index values, regularly reaching 11+ during summer, especially in northern regions (Queensland, Northern Territory).
- Sydney and Melbourne: In summer, UV Index often exceeds 10-12.
- New Zealand: UV levels reach 7-11 during the summer, especially in the north.
- - The depletion of the ozone layer has contributed to extreme UV radiation levels in the region. 3. Asia - Southeast Asia: Countries like Thailand, Indonesia, and Malaysia frequently have UV Index values between 9-11, especially in coastal and tropical areas. 4. Europe - Southern Europe: UV levels are higher in Mediterranean countries such as Spain, Italy, Greece, and Turkey, especially during summer, with UV Index values between 7-9. 5. North America
- United States:
- Southern States: High UV levels are found in states like Florida, Texas, California, and Arizona, where the UV Index often reaches 9-11 during summer.
- Northern States: UV Index values are generally moderate (5-7) in regions like New York, Washington, and Michigan.
- Canada: UV levels are lower overall, especially in northern regions, with summer UV Index values ranging from 4-7.
- Mexico: UV levels are very high, particularly in the coastal and desert regions, with UV Index values often reaching 9-11.
6. South America - Equatorial and Tropical Areas: Countries like Colombia, Ecuador, and Brazil near the equator have high UV levels, often reaching 9-11. - Andes Mountains: High-altitude regions in countries like Peru, Bolivia, and Chile experience extreme UV Index values, often 10+.
- Southern South America: UV levels decrease slightly in countries like Argentina and Chile, but still reach 6-9 during summer.
7. Antarctica
- Despite being cold, Antarctica experiences high UV radiation levels during its summer months (November to February), particularly due to the thinning of the ozone layer. The UV Index can range from 3-10, depending on the location and time of year.
- South Asia: UV levels in India, Pakistan, and Bangladesh can reach 8-11 during peak summer.
- East Asia: While China and Japan generally have lower UV levels, regions like southern China and Taiwan experience moderate to high UV Index values, especially in the summer months.
- Middle East: High UV levels in countries like Saudi Arabia, UAE, and Iran, with UV Index often reaching 9-11 in the desert regions.
- Northern Europe: UV levels are generally moderate, with countries like Norway, Sweden, and Finland experiencing UV Index values of 3-5 during summer.
- Western Europe: Countries like France, Germany, and the UK have lower UV levels, generally between 5-7 during summer.
UV Levels by Geographic and Environmental Factors
1. Equatorial Regions:
- Countries located along the equator have consistently high UV levels year-round. These regions receive the most direct sunlight.
- Examples: Ecuador, Indonesia, Uganda, Brazil.
2. Altitude:
- The higher the altitude, the stronger the UV radiation. For every 1,000 meters increase in altitude, UV radiation increases by about 10-12%.
- High-altitude cities and regions like La Paz (Bolivia), Quito (Ecuador), and the Himalayas experience extreme UV Index values.
3. Desert Regions:
-- Deserts reflect more UV radiation due to sand and lack of vegetation. Deserts in regions like the Middle East and Africa (Sahara) often have UV levels of 11+.
4. Polar Regions:
- During polar summers, when the sun doesn't set, UV radiation can still be high, despite the cold temperatures.
- However, during polar winters, UV exposure is minimal due to long periods of darkness.
Seasonal Variation
- Summer: UV levels are at their highest during summer months across all continents.
- Winter: UV radiation is lower during winter, especially in northern and southern latitudes. However, snow can reflect UV rays, increasing the risk of sunburn.
Summary of UV Levels Across Cities:
- Cairo, Egypt: UV Index 9-11 (Extreme)
- Rio de Janeiro, Brazil: UV Index 9-11 (Extreme)
- Cape Town, South Africa: UV Index 7-9 (High)
- Tokyo, Japan: UV Index 5-7 (Moderate-High)
- Los Angeles, USA: UV Index 7-9 (High)
- London, UK: UV Index 3-6 (Moderate)
- Sydney, Australia: UV Index 10-12 (Very High)
Understanding UV levels can help individuals take appropriate precautions depending on where they are located and the time of year, ensuring better sun care practices.