The Know Daily - Wednesday 2 July 2025

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A bold new chapter in tackling ocean plastic has begun. The Ocean Cleanup’s “30 Cities” initiative will work with urban partners around the globe to intercept plastic from rivers, aiming to cut ocean pollution by a third before 2030. With innovative tech and local collaboration, this mission is a powerful step toward cleaner waterways and a healthier planet.

🧴 The science behind sunscreen

We all know we should wear sunscreen but we don’t always know what’s going on behind the bottle. Here's the science of SPF, decoded.

What does the SPF number mean?
SPF stands for Sun Protection Factor, and it’s a measure of how well a sunscreen protects your skin from UVB rays – the kind that cause sunburn. An SPF 30, for example, theoretically lets you stay in the sun 30 times longer than you could without burning. But that doesn’t mean it blocks all the rays. SPF 30 blocks about 97% of UVB rays, while SPF 50 blocks around 98%. No sunscreen blocks 100%.

How is SPF tested?
In the lab, SPF is tested using controlled amounts of UV light on human volunteers. Scientists measure how long it takes for their protected skin to redden compared to unprotected skin. It’s precise but not perfect – people don’t apply sunscreen in thick enough layers, and sweat, swimming, or just a cheeky scratch can mess with the results. Because of this, dermatologists suggest to apply sunscreen generously and reapply every two hours.

Mineral vs chemical
There are two main types of sunscreen. Chemical sunscreens absorb UV rays and convert them into heat, which is then released from the skin. Some chemical sunscreen ingredients have faced pushback in recent years. Concerns include potential irritation and environmental effects (like coral reef damage) and studies showing that ingredients like oxybenzone and octinoxate could be absorbed into the bloodstream. While these findings don’t necessarily mean they’re unsafe, they’ve sparked more interest in mineral alternatives.

Mineral sunscreens use ingredients like zinc oxide or titanium dioxide to sit on top of the skin and physically reflect UV rays. They're often gentler on sensitive skin and start working right away – but can leave a white cast and can wash away with sweat or water.

Sunscreen ratings across the world
The UK and EU rate sunscreen with both SPF (for UVB) and a UVA star rating (out of 5). But head outside the UK, and the labels change. In the US, SPF is the focus, and UVA protection isn’t always clearly shown. Look for the term “broad spectrum” – that’s your cue that it protects against both UVA and UVB. In Korea and Japan, sunscreens use PA ratings, ranging from PA+ to PA++++. The more pluses, the higher the UVA protection. 

And in Australia – a country that takes sun protection very seriously – sunscreen is regulated like a medicine. You’ll find SPF ratings plus clear labels for broad-spectrum protection. Australia also sets a high bar for water resistance: products are tested for how long they protect in water (like 40 or 80 minutes), and “waterproof” claims are not allowed. If it’s on an Aussie label, you can trust it’s been rigorously tested.

👨‍👧 Parenthood policy: Ministers have launched a landmark review of paternity and maternity leave and pay as the government considers ways to make parental leave a right from your first day of employment with a company.

• The bigger story: The decision comes after hundreds of dads took to the streets of London and Edinburgh last month as they called for better paternity leave. Now ministers are considering the option of 50 weeks shared parental leave, with 37 weeks being paid. Officials say millions of families could benefit and give a better start to their children, given that one in three fathers do not take paternity leave because they cannot afford to.

🎶 Ticket touting: Telecoms company O2  is urging the government to introduce a 10% price cap on resale tickets after new analysis revealed fans sometimes spend five times face value.

🇪🇺 Prioritising protection: Denmark has taken over the six-month rotating presidency of the EU Council, with security being its overarching priority.

🚂 End of the line: The royal train is to be decommissioned following the annual financial report of the Royal Family, with the aim of “modernising and adapting to reflect the world of today”.

💼 Labour’s welfare bill: Sir Keir Starmer’s welfare bill has passed its second reading after a key reform was dropped in a last-minute concession.

👩‍🚀 Space spectators: NASA has teamed up with Netflix to bring the NASA+ streaming service to your living room, airing live rocket launches and spacewalks.

✈️ Affordable aviation: After a holiday without feeling the pinch? The World Airline Awards have revealed the best low-cost airlines.

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Trivia answer: A) The star appeared as a character on the streets of Los Angeles recruiting American players.

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