Most people associate skin cancer risk with beach days or backyard barbecues, but the science tells a different story. Two of the most overlooked sources of  UV  ultraviolet radiation  exposure in everyday life are car windows and office windows​;​ Here’s what office workers  need to know about skin cancer, and what you can do about it. 

Your Commute Is a UV Exposure Event 

Whether you drive, take the bus, or ride the train, your commute exposes you to UV often without you realizing it. For workers who are commuting, this daily exposure adds up quickly. 

There are two types of UV radiation to understand: UVB rays (think B for Burn) , which cause sunburn, and UVA rays (think A for Aging), which penetrate more deeply into the skin and are primarily responsible for both premature aging and the DNA damage that can lead to melanoma. UVA rays account for approximately 95% of all UV radiation that reaches the Earth’s surface. They are present year-round on cloudy days, in winter, and through glass.¹ 

This difference between UVA and UVB rays matters for commuters. A car’s front windshield is made of laminated glass, which blocks up to 98% of UVA radiation, but the side and rear windows of most vehicles are made of tempered glass​;​ which offers much less protection.  

A study of 29 vehicles found that between 4% and 56% of UVA radiation passed through side and rear windows, and the level of protection had nothing to do with the car’s age or price​,​ only the type of glass, its colour, and whether window film had been applied.² 

A more recent study evaluated UVA and UVB transmission across a range of gas, hybrid, and electric vehicles. It found that most cars offer strong protection from the front windshield. However, non-luxury vehicles provided much less protection from UVA 

The study also found that mileage, rather than the age of the vehicle, was linked to how much UVA protection the driver’s side window provided. ³ 

The health consequences of this uneven exposure are well documented. Research in the United States where drivers sit on the left side has found that skin cancers appear significantly more often on the left side of the face, scalp, arm, and leg. For melanoma in situ, an early form of melanoma, 74% of cases occurred on the left side compared with 26% on the right.²  

In countries where drivers sit on the right, the pattern reverses. The message is clear: repeated daily exposure to UVA rays through unprotected car windows can cause uneven, cumulative skin damage and may increase the risk of melanoma over time.  

For those who take public transit, the concern is somewhat different but equally important. Sitting beside a bus or train window during a sunny commute can also expose the skin to UVA rays. Walking to and from transit stops adds direct exposure to the full spectrum of UV radiation, including UVB rays, which can cause sunburn and contribute to skin cancer risk. This is especially important during the spring and summer months, when the UV Index in many Canadian cities regularly reaches moderate to high levels.  

Office Windows Don’t Protect Your Skin 

Arriving at the office doesn’t end your UV exposure​,​ it simply changes its character. For office workers, the window seat or desk near a glass exterior wall may feel pleasant and bright. Physiologically, however, it carries a daily skin cancer risk that most workers have never considered. 

Standard glass used in most home, office, and car windows blocks the majority of UVB rays, the ones that cause sunburns. But it does not effectively block UVA rays, which are longer wavelengths capable of passing through glass year-round. UVA exposure causes genetic damage to cells in the innermost part of the top layer of skin, where most skin cancers originate. Because this damage doesn’t produce the immediate feedback of a sunburn, it accumulates silently over months and years.⁴ 

A peer-reviewed paper published in a photomedicine journal and indexed on PubMed described the problem clearly: people are exposed to ambient solar UV radiation throughout their daily routines, intentionally and unintentionally. Because UV radiation is diffusely scattered by the atmosphere and environment, a person sitting under a roof including inside a building is not completely protected from the sun’s rays. The authors called for broader adoption of photoprotective window films in residential, commercial, and institutional buildings.⁵ 

The real-world risk of sitting near a window is measurable. Research shows that skin can sustain UV damage in as little as 30 minutes at midday in summer, or within one hour in winter, even while indoors, when a home or office window allows more UVA rays to pass through.² For an employee sitting at a desk beside a window for six to eight hours a day, five days a week, this repeated exposure can add up over months and years.  

This type of exposure is known as incidental sun exposure.⁹ It can be harmful because the exposure adds up over time, and most people are unaware it is happening.⁴ Think about what happens to furniture or flooring near a sunny window: the same UV energy that fades your carpet can also damage the cells in your skin.  

The Bigger Picture: Cumulative Exposure and Melanoma Risk 

Individually, a morning commute or an afternoon near a window may seem like a trivial source of UV exposure. Cumulatively, across a working career, the burden is anything but trivial. 

In Canada, approximately 10,800 people were diagnosed with melanoma in 2025, and three to four Canadians die from the disease every day. Much of the risk is linked to UV exposure. Unlike a day at the beach, however, UV exposure through glass can happen without sunscreen or even being aware of it. For people who spend time near windows every day, this exposure can add up over many years.  

The Canadian Cancer Society notes that outdoor workers face a skin cancer risk three times greater than indoor workers largely because of cumulative UV exposure,⁶ but as the science on window transmission makes clear, returning office workers are not fully protected indoors either. The combination of a daily commute in an untinted vehicle and a desk near a south- or east-facing window recreates a meaningful, consistent UV exposure profile​ -​ one that warrants deliberate protection. 

Research published in PubMed studying Canadian outdoor workers across British Columbia, Ontario, and Nova Scotia found that the mean personal UV dose among participants was nearly five times the recommended exposure limit, and that just 14% of workers experienced levels considered acceptable.⁷ While commuters and office workers face lower absolute doses, the principle is the same: UV exposure that feels incidental is often far higher than people assume. 

What You Can Do: A Practical Protection Plan for Returning Workers 

The good news is that practical, affordable protection is available for every part of the returning worker’s day. Here is what you can do to protect yourself:  

In the Car 

  • Apply a broad-spectrum sunscreen with SPF 50+ or higher to your face, neck, left arm, and hands before your morning commute and reapply if your commute home is in daylight. 
  • Consider UV window film for your driver’s side and rear passenger windows. Quality UV window film can block up to 95% of UVA radiation, and it is a one-time, durable investment. Look for a film that specifically states “UVA and UVB blocking performance​​”​​. Confirm local tinting regulations before installation.² ⁴ 
  • Keep your windows closed while driving. Even untinted windows reduce UVA exposure compared to an open window, where skin is in direct sunlight.² 
  • Wear UV-blocking wraparound sunglasses when the UV Index is above 3 which, in most Canadian cities, is the case on most sunny days from March through October.² 

On Transit or Walking to the Office 

  • Apply broad-spectrum sunscreen to all exposed skin before leaving home. Reapply at lunch if you go outside. 
  • Wear a wide-brimmed hat and UV-blocking sunglasses for walking portions of your commute. 
  • Choose lightweight, long-sleeved layers for your commute​,​ especially UPF-rated fabrics to protect your arms and shoulders without overheating. 

At Your Desk 

  • If you sit near a window, apply a daily moisturizer with broad-spectrum SPF 30+ to your face, neck, and the back of your hands. This simple habit takes seconds and offers meaningful cumulative protection. 
  • Talk to your building manager or facilities team about UV window film for south- and west-facing windows, particularly in areas with workstations. Look for UV window film that blocks 99% or more of solar UVA and UVB for residential and commercial use.⁴ 
  • If you have a choice, position your workstation at least 1.5 to 2 metres from large sun-facing windows, or in a spot where direct sunlight does not fall on your skin. 
  • Wear UV-blocking sunglasses when glare from windows is significant eye UV exposure that accumulates over years increases the risk of cataracts and ocular melanoma.² 

Conclusion: The Return-to-Office Is a New Sun Safety Moment 

The potential impact of UV exposure from commuting five days a week and working near windows is often overlooked when we talk about protecting workers. Yet the science is clear, and there are simple steps people can take to reduce this everyday exposure.  

Your car’s side windows do not reliably protect you from UVA radiation. Your office windows do not either. The cumulative UV exposure from commuting and desk work is invisible, painless, and relentless. It is a real and modifiable risk factor for melanoma. 

Melanoma Canada encourages Canadians who commute or work in an office to use this as an opportunity to build better daily sun protection habits. Apply sunscreen before leaving home, consider UV-protective window film for your car, and be aware of your UV exposure when sitting near office windows. Small, consistent steps that become part of your daily routine can help reduce your UV exposure and protect your skin over time.  

 

About the Author: Katya is a fourth-year medical student in McGill University’s MDCM program, pursuing dermatology through CaRMS. Her research focuses on dermatology, skin cancer, health economics, and bioethics, and she has authored more than 50 peer-reviewed publications. She collaborates with dermatologists and patient organizations across Canada and mentors medical students interested in research. Outside of medicine, she enjoys film photography, graphic design, and pastel drawing.

References 

  1. Essuntials. (2024, November 6). Can you get sunburned throughwindows? How UV rays affect you indoors. Retrieved from https://www.essuntials.com/blogs/journal/can-you-get-sunburned-through-windows 
  2. University of Wollongong /The Conversation. (2025, March 17). Can you get sunburnt or UV skin damage through car or home windows? Retrieved from https://theconversation.com/can-you-get-sunburnt-or-uv-skin-damage-through-car-or-home-windows-246599 
  3. Boxer Wachler BS, Boxer WM. (2025). Evaluation of UV-A and UV-B transmission through the windows of gas, hybrid, and electric vehicles. PubMed. PMID: 39825984.
  4. Skin Cancer Foundation. (2025). UV Window Film & Tint. Retrieved from https://www.skincancer.org/skin-cancer-prevention/sun-protection/uv-window-film/
  5. AlmutawaF, et al. (2004). Use of UV-protective windows and window films to aid in the prevention of skin cancer. PubMed. PMID: 15479155. 
  6. Canadian Cancer Society. (n.d.). Sun and UV. Retrieved from https://cancer.ca/en/cancer-information/reduce-your-risk/be-safe-at-work/sun-and-uv
  7. Saunders MJ, et al. (2019). Solar ultraviolet radiation exposure among outdoor workers in three Canadian provinces. PubMed. PMID: 31165866.
  8. Professional Institute of the Public Service of Canada (PIPSC). (n.d.). Return to workplaces. Retrieved fromhttps://pipsc.ca/news-issues/return-to-workplace 
  9. Skin Cancer Society https://www.skincancer.org/skin-cancer-prevention/sun-protection/uv-window-film/