What are UV levels and how can you protect yourself?

# What Are UV Levels and How Can You Protect Yourself?

Ultraviolet radiation from the sun reaches Earth constantly, but its intensity varies by location, season, time of day, and cloud cover. The UV Index, a scale from 0 to 11-plus, measures this intensity and guides safe sun exposure decisions.

Our bodies need some UV exposure. Sunlight triggers vitamin D production in the skin, a nutrient essential for bone health, immune function, and calcium absorption. Most people require 10 to 30 minutes of midday sun exposure several times weekly to maintain adequate vitamin D levels.

However, excessive UV exposure damages skin cells' DNA. Over time, this accumulation of damage leads to melanoma and non-melanoma skin cancers. The World Health Organization estimates that one in three cancers diagnosed worldwide is skin cancer.

UV intensity peaks between 10 a.m. and 4 p.m., particularly during spring and summer months. The UV Index rises significantly at higher altitudes and near the equator, where UV rays penetrate the atmosphere more directly. Reflective surfaces like water, sand, and snow intensify exposure by bouncing rays back onto skin.

Protection strategies shift based on the UV Index. On low-risk days (Index 0-2), sunscreen isn't necessary for brief outdoor time. At moderate levels (3-5), apply broad-spectrum sunscreen with SPF 30 or higher. When the index reaches high (6-7) or very high (8-10) levels, seek shade during peak hours, wear protective clothing, hats, and sunglasses alongside sunscreen.

Broad-spectrum sunscreen blocks both UVA and UVB rays. UVB rays cause burning; UVA rays penetrate deeper and accelerate aging and damage. Apply sunscreen generously 15 minutes before