Measuring sun exposure in outdoor workers

Sun exposure is a key feature of summer for many people, especially in countries like Canada where pleasant weather can seem so fleeting. Unfortunately, sun exposure (in particular ultraviolet radiation) is the primary cause of skin cancer, the most common cancer in Canada. Skin cancer is also one of few cancers where diagnoses are increasing. Some people are willing to take the risk in their leisure time, but for those who work primarily outdoors, choice is not an option. Consequently, outdoor workers have a much greater chance of getting skin cancer later in life. Outdoor work is very likely one of the reasons that men are at higher risk of skin cancer than women in Canada, given that men are employed in approximately 80% of outdoor jobs. This includes work in construction and farming industries, as well as building services, recreation, and the public service.

While cancers caused by a person’s work are taken seriously in general, skin cancer isn’t often thought of as an occupational disease. This is even the case in countries where workers can access compensation for a skin cancer diagnosis. This dichotomy may have something to do with the complicated relationship that we have with the sun; for example, outdoor workers often select their jobs because they like being outdoors and in the sun. Therefore, they may be more likely to blame this preference for the exposure they received at work and in their leisure time. In addition, there aren’t any formal exposure limits for sun exposure in Canada (nor in most countries). Perhaps most importantly though, outdoor workers often work in jobs that pose a more immediate risk to safety than a potential skin cancer diagnosis years in the future. Construction workers and their supervisors, for example, are more concerned about losing a finger or falling from a height than they are about a skin lesion.

Because of these considerations, until recently, there had never been any measurement of outdoor workers’ exposure to ultraviolet radiation in Canada. This is important for two reasons. Firstly, if we want to do something to reduce exposure to a carcinogen at work, we need to know what the levels workers are being exposed to; otherwise we have no way of evaluating the effectiveness of efforts to reduce that exposure. Secondly, when we don’t have objective measurements of an exposure, it hinders our ability to actually quantify the risk of that exposure. In skin cancer epidemiology, the only “measurement” of exposure is typically a self-reported estimate of how much time a person has spent outdoors on a typical day over their lifetime. Our estimates of skin cancer need better, more objective measures of exposure (at work and otherwise).

Recently, we shared exposure monitoring results from the Outdoor Workers Project, a study involving construction and horticultural workers in and around Vancouver, Canada. The results indicated that even in a location not typically considered risky from a sun exposure perspective, workers are at risk of skin cancer in the summer months. A person’s job title, age, and the weather forecast all contributed to higher sun exposure measurements; younger construction workers on sunnier days had the highest exposure levels. The mean exposure level was around one SED (standard erythemal dose, a typical measure of sun exposure), which puts fair-skinned individuals at risk of sunburn and subsequent cancer. The highest measurement in the study was 19 SED, a dangerous level of exposure for even darker-skinned workers.

As our summers continue to heat up and become drier and drier, the risk of sun exposure at work will continue to increase. Sun safety for outdoor workers will need to be a top priority. Many people living at higher latitudes (including Canada, but also much of northern Europe) need to protect themselves if they work primarily outdoors, and employers should be aware of their responsibility to protect their workers. Tips for employers and workers need to be practical, since we can’t eliminate sun exposure (nor would we want to)! The Sun Safety at Work Canada project is helping to enhance the capacity of workplaces to address this challenge. Going forward, we need more research on how to reduce the risk of skin cancer in outdoor workers, and we need to better quantify exposure levels by job type and location to improve skin cancer epidemiology overall.

Featured image credit: Construction by Skeeze. CC0 Public Domain via Pixabay.