When someone exposes their skin to sunlight, it has positive and negative health effects. A positive effect is that UV radiation stimulates the production of vitamin D, which is necessary for healthy bones and muscles. On the other hand, in the short term UV radiation also causes the skin to burn and age faster. In the long term, it is one of the main causes of skin cancer. In 2019 more than 800 people died from skin cancer in the Netherlands.
The amount of UV radiation that reaches the ground is often summarised in one number: the sun's power. Sun power is a measure of how quickly your skin burns. Sun power increases the higher the sun is in the sky. So in spring and summer, the sun's strength is greater than in fall and winter. And in the middle of the day, the strength of the sun is greater than early in the morning or late in the afternoon. RIVM continuously measures how much UV radiation passes through the atmosphere. Based on these measurements we publish the current sun strength.
UV radiation and climate
The amount of UV radiation in the Netherlands has increased in recent decades. This is partly because the protective effect of clouds (and air pollution) has decreased. A second cause is that the ozone layer has become thinner. Therefore the ozone layer protects less against UV radiation.
In addition, the number of warm days has increased. With an increase in the number of warm days, it is expected that UV radiation exposure will increase because people are engaging in more outdoor activities.