When you’re in a car, train or bus, do you choose a seat to avoid being in the sun or do you like the sunny side?

You can definitely feel the sun’s heat through a window. But can you get sunburn or skin damage when in your car or inside with the windows closed?

Let’s look at how much UV (ultraviolet) radiation passes through different types of glass, how tinting can help block UV, and whether we need sunscreen when driving or indoors.

What’s the difference between UVA and UVB?

Of the total UV radiation that reaches Earth, about 95% is UVA and 5% is UVB.

UVB only reaches the upper layers of our skin but is the major cause of sunburn, cataracts and skin cancer.

UVA penetrates deeper into our skin and causes cell damage that leads to skin cancer.

Glass blocks UVA and UVB radiation differently

All glass used in house, office and car windows completely blocks UVB from passing through.

But only laminated glass can completely block UVA. UVA can pass through other glass used in car, house and office windows and cause skin damage, increasing the risk of cancer.

Car windscreens block UVA, but the side and rear windows don’t

A car’s front windscreen lets in lots of sunshine and light. Luckily it blocks 98% of UVA radiation because it is made of two layers of laminated glass.

But the side and rear car windows are made of tempered glass, which doesn’t completely block UVA. A study of 29 cars found a range from 4% to almost 56% of UVA passed through the side and rear windows.

The UVA protection was not related to the car’s age or cost, but to the type of glass, its colour and whether it has been tinted or coated in a protective film. Grey or bronze coloured glass, and window tinting, all increase UVA protection. Window tinting blocks around 95% of UVA radiation.

In a separate study from Saudi Arabia, researchers fitted drivers with a wearable radiation monitor. They found drivers were exposed to UV index ratings up to 3.5. (In Australia, sun protection is generally recommended when the UV index is 3 or above – at this level it takes pale skin about 20 minutes to burn.)

So if you have your windows tinted, you should not have to wear sunscreen in the car. But without tinted windows, you can accumulate skin damage.

UV exposure while driving increases skin cancer risk

Many people spend a lot of time in the car – for work, commuting, holiday travel and general transport. Repeated UVA radiation exposure through car side windows might go unnoticed, but it can affect our skin.

Indeed, skin cancer is more common on the driver’s side of the body. A study in the United States (where drivers sit on the left side) found more skin cancers on the left than the right side for the face, scalp, arm and leg, including 20 times more for the arm.

Another US study found this effect was higher in men. For melanoma in situ, an early form of melanoma, 74% of these cancers were on the on the left versus 26% on the right.

Earlier Australian studies reported more skin damage and more skin cancer on the right side.

Cataracts and other eye damage are also more common on the driver’s side of the body.

What about UV exposure through home or office windows?

We see UV damage from sunlight through our home windows in faded materials, furniture or plastics.

Most glass used in residential windows lets a lot of UVA pass through, between 45 and 75%.

Single-pane glass lets through the most UVA, while thicker, tinted or coated glass blocks more UVA.

The best options are laminated glass, or double-glazed, tinted windows that allow less than 1% of UVA through.

Skylights are made from laminated glass, which completely stops UVA from passing through.

Most office and commercial window glass has better UVA protection than residential windows, allowing less than 25% of UVA transmission. These windows are usually double-glazed and tinted, with reflective properties or UV-absorbent chemicals.

Some smart windows that reduce heat using chemical treatments to darken the glass can also block UVA.

So when should you wear sunscreen and sunglasses?

The biggest risk with skin damage while driving is having the windows down or your arm out the window in direct sun. Even untinted windows will reduce UVA exposure to some extent, so it’s better to have the car window up.

For home windows, window films or tint can increase UVA protection of single pane glass. UVA blocking by glass is similar to protection by sunscreen.

When you need to use sunscreen depends on your skin type, latitude and time of the year. In a car without tinted windows, you could burn after one hour in the middle of the day in summer, and two hours in the middle of a winter’s day.

But in the middle of the day next to a home window that allows more UVA to pass through, it could take only 30 minutes to burn in summer and one hour in winter.

When the UV index is above three, it is recommended you wear protective sunglasses while driving or next to a sunny window to avoid eye damage.

Theresa Larkin, Associate Professor of Medical Sciences, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

One in three of us will develop cancer at some point in our lives. But survival rates have improved to the point that two-thirds of those diagnosed live more than five years.

This extraordinary shift over the past few decades introduces new challenges. A large and growing proportion of people diagnosed with cancer are living with it, rather than dying of it.

In our recently published research we examined the cancer experiences of 81 New Zealanders (23 Māori and 58 non-Māori).

We found survivorship not only entailed managing the disease, but also “wrangling” a complex health system.

Surviving disease or surviving the system

Our research focused on those who had lived longer than expected (four to 32 years since first diagnosis) with a life-limiting or terminal diagnosis of cancer.

Common to many survivors’ stories was the effort it took to wrangle the system or find others to advocate on their behalf, even to get a formal diagnosis and treatment.

By wrangling we refer to the practices required to traverse complex and sometimes unwelcoming systems. This is an often unnoticed but very real struggle that comes on top of managing the disease itself.

The common focus of the healthcare system is on symptoms, side effects of treatment and other biological aspects of cancer. But formal and informal care often falls by the wayside, despite being key to people’s everyday experiences.

The inequities of cancer survivorship are well known. Analyses show postcodes and socioeconomic status play a strong role in the prevalence of cancer and survival.

Less well known, but illustrated in our research, is that survival is also linked to people’s capacity to manage the entire healthcare system. That includes accessing a diagnosis or treatment, or identifying and accessing alternative treatments.

Survivorship is strongly related to material resources, social connections, and understandings of how the health system works and what is available. For instance, one participant who was contemplating travelling overseas to get surgery not available in New Zealand said:

We don’t trust the public system. So thankfully we had private health insurance […] But if we went overseas, health insurance only paid out to $30,000 and I think the surgery was going to be a couple of hundred thousand. I remember Dad saying and crying and just being like, I’ll sell my business […] we’ll all put in money. It was really amazing.

Assets of survivorship

In New Zealand, the government agency Pharmac determines which medications are subsidised. Yet many participants were advised by oncologists or others to “find ways” of taking costly, unsubsidised medicines.

This often meant finding tens of thousands of dollars with no guarantees. Some had the means, but for others it meant drawing on family savings, retirement funds or extending mortgages. This disproportionately favours those with access to assets and influences who survives.

But access to economic capital is only one advantage. People also have cultural resources – often described as cultural capital.

In one case, a participant realised a drug company was likely to apply to have a medicine approved. They asked their private oncologist to lobby on their behalf to obtain the drug through a compassionate access scheme, without having to pay for it.

Others gained community support through fundraising from clubs they belonged to. But some worried about where they would find the money, or did not want to burden their community.

I had my doctor friend and some others that wanted to do some public fundraising. But at the time I said, “Look, most of the people that will be contributing are people from my community who are poor already, so I’m not going to do that option”.

Accessing alternative therapies, almost exclusively self-funded, was another layer of inequity. Some felt forced to negotiate the black market to access substances such as marijuana to treat their cancer or alleviate the side effects of orthodox cancer treatment.

Cultural capital is not a replacement for access to assets, however. Māori survivorship was greatly assisted by accessing cultural resources, but often limited by lack of material assets.

Persistence pays

The last thing we need when faced with the possibility of cancer is to have to push for formal diagnosis and care. Yet this was a common experience.

One participant was told nothing could be found to explain their abdominal pain – only to find later they had pancreatic cancer. Another was told their concerns about breathing problems were a result of anxiety related to a prior mental health history, only to learn later their earlier breast cancer had spread to their lungs.

Persistence is another layer of wrangling and it often causes distress.

Once a diagnosis was given, for many people the public health system kicked in and delivered appropriate treatment. However, experiences were patchy and variable across New Zealand.

Issues included proximity to hospitals, varying degrees of specialisation available, and the requirement of extensive periods away from home and whānau. This reflects an ongoing unevenness and lack of fairness in the current system.

When facing a terminal or life-limiting diagnosis, the capacity to wrangle the system makes a difference. We shouldn’t have to wrangle, but facing this reality is an important first step.

We must ensure it doesn’t become a continuing form of inequity, whereby people with access to material resources and social and cultural connections can survive longer.

Kevin Dew, Professor of Sociology, Te Herenga Waka — Victoria University of Wellington; Alex Broom, Professor of Sociology & Director, Sydney Centre for Healthy Societies, University of Sydney; Chris Cunningham, Professor of Maori & Public Health, Massey University; Elizabeth Dennett, Associate Professor in Surgery, University of Otago; Kerry Chamberlain, Professor of Social and Health Psychology, Massey University, and Richard Egan, Associate Professor in Health Promotion, University of Otago

This article is republished from The Conversation under a Creative Commons license. Read the original article.