Sun Exposure

CDC Yellow Book 2024

Environmental Hazards & Risks

Karolyn Wanat, David Fivenson, Scott Norton

When international travelers engage in outdoor activities, they might be exposed to more ultraviolet (UV) radiation (UVR) than they are accustomed to, particularly if travel takes them to sunnier locations, lower latitudes, or higher elevations. Even winter activities (e.g., snow skiing) can result in significant UVR exposure. Short bursts of high-intensity UVR (e.g., infrequent beach vacations), as well as frequent, prolonged, cumulative UVR exposure can cause acute effects (e.g., sunburn and phototoxic medication reactions) and delayed effects from chronic exposure (e.g., sun damage, premature aging, skin cancers).

Risk Factors

Time of year, time of day, and location influence a traveler’s UVR exposure. Most UVR reaches the earth’s surface during summer months. Ultraviolet B (UVB), which is more carcinogenic than ultraviolet A (UVA), is most intense from 10 a.m.–4 p.m. at higher elevations and in locations closer to the equator. Snow and sand reflect UVR, thereby increasing UVB exposure. Although UVA is less carcinogenic than UVB, UVA occurs at high intensity throughout daylight hours. UVA causes more acute photosensitivity reactions than UVB, and it contributes more to premature aging.

Ultraviolet Index

The US National Weather Service prepares a daily Ultraviolet Index (UVI) for most zip codes. The UVI is calculated by a computer model that couples solar energy delivered at ground level with the ozone forecast and adjusts for elevation, atmospheric aerosol properties, and cloud conditions. The globally accepted UVI scale ranges from 0 (at night or under a smoke-filled sky) to 16 (at high elevation in the tropics with no cloud cover). Higher UVIs indicate greater risks for skin- and eye-damaging UVR.

See daily UVIs for US locations. Global data for many sites outside the United States are available at the WHO website.

Underlying Medical Conditions

People with certain medical conditions are at increased risk for adverse effects of UV exposure. Solid-organ transplant recipients, for example, are at much greater risk for UVB-induced skin cancers. People with autoimmune connective tissue diseases (e.g., systemic lupus erythematosus) exhibit heightened photosensitivity. Counsel these patients on how to protect themselves during hours of maximal exposure.

Photosensitizing Medications

Many medications, including several prescribed specifically for travelers, can lead to photosensitivity reactions. Examples include:

Antibiotics, including doxycycline (and other tetracyclines to a lesser degree), fluoroquinolones, sulfonamides.

Many types of cancer therapies (e.g., chemotherapeutic agents, radiation therapy, some immunomodulators) can be sun sensitizers during treatment, and effects can linger even after completion of therapy.

Nonsteroidal anti-inflammatory drugs (NSAIDs), especially ibuprofen, ketoprofen, naproxen, piroxicam.

Other common medications (e.g., furosemide, methotrexate, sulfonylureas, thiazide diuretics, retinoids).



Sunburn is a common and self-limited condition caused by UVA or UVB. Clinical features vary from mild pink to painful red skin with swelling and blistering on exposed surfaces. Systemic symptoms can include headache, fever, chills, nausea, vomiting, and muscle aches. Sunburn is preventable and travelers should not regard it as an inevitable part of vacation.

Sunburn management consists of symptomatic pain relief. People rarely notice they are developing a sunburn while the burn is occurring. When discomfort begins, people can take cool baths or apply wet compresses and bland topical emollients (e.g., petrolatum, zinc oxide). Refrigerating topical emollients before application can provide added relief. Aloe vera commonly is used as a sunburn remedy, but studies regarding its benefit are equivocal.

Intact blisters should not be ruptured intentionally. Topical corticosteroids (e.g., hydrocortisone 1% cream or ointment) or diclofenac gel can decrease pain and inflammation. Sunburn patients typically benefit from rest in a cool setting, extra fluids, and oral pain relievers (e.g., acetaminophen, ibuprofen, naproxen). Systemic steroids do not improve symptoms or hasten recovery.

For severe blistering cases, clinicians might need to hospitalize patients for fluid replacement (oral or intravenous) and pain control and treat them as they would burn patients, maintaining clean skin by gentle cleansing and treatment with emollients. Tense or painful blisters can be sterilely drained, but the blister roof should remain intact to serve as a sterile dressing.

Sun Damage & Skin Cancer

High-intensity or chronic exposure to UVR (particularly UVA) causes permanent loss of skin elasticity, wrinkling, and solar lentigines (brown macules with irregular borders), especially in people with fair skin. Avoiding sun overexposure and preventing sunburn are the best ways to avoid these skin changes.

The World Health Organization (WHO) characterizes UVR as a carcinogen with the potential to induce skin cancers via DNA damage. In addition, skin cancers are the most common malignancies in the United States, and basal and squamous cell carcinomas (BCCs and SCCs) are linked closely to UV exposure. BCCs typically appear as pearly, red papules that might bleed, ulcerate, or grow into nodules; they appear often on sun-exposed areas. BCCs rarely metastasize and are generally cured with excision or other local treatments.

SCCs present as scaling or bleeding papules or plaques on sun-exposed areas. Advanced or long-standing SCCs are 10× more likely to metastasize than BCCs. Solid-organ transplant patients who are on immunosuppressive therapy and patients with chronic lymphocytic leukemia are at increased risk for SCCs.

Melanoma is the most serious of the UV-associated skin cancers; it is also the least common, but its incidence is increasing among most populations. Risk factors for melanoma include fair skin, genetic susceptibility, and a history of blistering sunburns before the age of 18. Melanomas have a variety of clinical presentations, the most common of which is an irregularly bordered, darkly pigmented flat or raised spot on the skin that changes in size, shape, or both over time. For clinical suspicion for melanoma, clinicians should refer the patient for prompt evaluation and possible biopsy. Of the skin cancers, melanomas have the greatest morbidity and mortality; in 2018, the latest year for which incidence data are available, ≈84,000 new cases of melanoma of the skin were reported in the United States, and ≈8,200 people died from this cancer. Early detection and treatment (simple excision with margins) lead to complete recovery in most cases. Depending on the tumor stage, patients might need additional surgeries, evaluations, treatment with chemotherapeutic or biological agents, and regular monitoring.

While some reports describe an association between chronic and cumulative sun exposure and SCC, and intermittent intense sun exposure and blistering sunburns with BCC and melanoma, the evidence for this in the literature is mixed.

Other Photosensitivity Disorders

Increased exposure to sunlight, particularly UVA, can exacerbate existing skin conditions and can unmask photosensitivity disorders, such as autoimmune connective tissue diseases (e.g., dermatomyositis or systemic lupus erythematosus), phototoxic medication reactions, polymorphous light eruption, porphyrias, and solar urticaria. A person experiencing prolonged or severe symptoms after sun exposure (e.g., arthralgias, fever, pruritus, swelling) should seek medical evaluation.


Photo-onycholysis is a separation or lifting of the nail plate from the nail bed in people taking an oral photosensitizing agent, usually a medication, in association with intense sun exposure. The most common setting is someone taking doxycycline for malaria prophylaxis during a trip to a tropical location.


Phytophotodermatitis is a noninfectious condition that results from action of UVA radiation on naturally occurring photosensitizing compounds, furocoumarins, that occur in several plant families. In the tropics, the most common source is the photosensitizing juice of certain types of limes, often called Persian, wild, or key limes; in northern temperate regions, the most common source is giant hogweed (Heracleum mentagazzium). The interaction of UV light and the furocoumarins causes an exaggerated sunburn that creates a painful line of blisters where the juice was on the skin, followed by linear, brown, hyperpigmented patches that take weeks or months to resolve.


Travelers should prepare and plan to prevent sun overexposure. To encourage safe sun behaviors, clinicians can remind travelers that UVB radiation is highest during midday, that UV exposure still occurs in cooler weather and on overcast days, and that UVR increases with travel to lower latitudes (closer to the equator) and higher elevations.

Sun Avoidance

If possible, travelers can decrease UV exposure by avoiding direct sun during peak hours, 10 a.m. to 4 p.m. Travelers can seek shade under trees, umbrellas, or other structures to reduce UV exposure; UV rays can still reflect off surfaces, however, including snow and sand. Studies show that concomitantly using shade and sunscreen is more effective than reliance on a single method to protect people from excessive UVR.


Sunscreens are topical preparations containing substances that reflect or absorb light in the UV wavelengths and reduce the amount of UVR that reaches the skin. There are two classes of active ingredients, known as UV filters, in sunscreen products: chemical (sometimes referred to as organic) and physical (sometimes referred to as mineral or inorganic). Sunscreen products can contain chemical or physical filters, or both, and might include >1 of each type. FDA regulates sunscreens and their filtering agents in the United States, but some other countries permit the use of chemical filtering agents not approved by the FDA. See Box 4-01 for filtering agents in sunscreen products from different countries.

Box 4-01 Choosing a Sunscreen

The most effective sunscreens are broad-spectrum, combining agents capable of filtering (either by absorbing or reflecting) both ultraviolet A and B (UVA and UVB) radiation.

The American Academy of Dermatology Practice Safe Sun guidelines (Box 4-05) recommend using products with a sun protection factor (SPF) ≥30.

Current labeling guidelines adopted by the US Food and Drug Administration (FDA) in 2010 indicate that broad-spectrum sunscreen products with an SPF ≥15 may state: If used as directed with other sun-protection measures, [this product] decreases the risk of skin cancer and early skin aging caused by the sun.

The same labeling guidelines do not permit manufacturers to claim that products are waterproof or sweatproof; sunscreens may be labeled “water resistant” for up to either 40 or 80 minutes.


Sunscreens sold outside the United States contain a much wider variety of UV filters.

The UV filters listed below have lower reported environmental toxicity, but none have yet come up for review before the FDA.

The FDA process for UV filter approval is under review and will most likely begin with systematic human toxicity testing of the currently allowed UV filters before agents in use elsewhere in the world are included.

In Europe, Japan, and Australia, commonly available UV filters in sunscreens include the following:

  • Mexoryl XL (drometrizole trisiloxane)
  • Neo Heliopan AP (bisdisulizole disodium)
  • Neo Heliopan E1000 (amiloxate)
  • Parsol 5000 (enzacamene, 4-MBC)
  • Tinsorb A2B (tris-biphenyl triazine)
  • Tinsorb M (bisoctrizole)
  • Tinsorb S (bemotrizinol)
  • Tinsorb S Aqua (polysilicone-15)
  • Uvasorb HEB (iscotrizinol)
  • Uvinul A Plus (diethylamino, hydroxybenzoyl hexyl benzoate)
  • Uvinul T 150 (octyl triazone)
  • In South America, commonly available UV filters in sunscreens include the following:
  • Mexoryl SL (benzylidene camphor sulfonic acid)
  • Mexoryl SO (camphor benzalkonium)
  • Mexoryl SW (polyacryamidomethylbenzylidene camphor)
  • PEG-25 PABA (ethoxylated ethyl-4-aminobenzoate)

Choosing a Sunscreen

Travelers can use many criteria when selecting a sunscreen, but in practical terms, the best sunscreens are those that people choose to use consistently. See Box 4-01 for additional details on choosing sunscreens.

Sun Protection Factor

The US Food and Drug Administration (FDA) uses a strict protocol to determine a product’s sun protection factor (SPF): how much UVB radiation is required to cause a sunburn on skin protected by topical sunscreen products versus the amount of UVB required to cause a sunburn on unprotected skin (see Box 4-02). SPF measures protection from UVB only, not UVA. Most people know that the higher the SPF, the greater degree of protection from UVB and from sunburn.

In theory, an SPF of 30 means that only 1/30th of the UVB reaches the skin—or that a person can remain in the sun 30× as long—when the sunscreen is applied. To achieve the desired SPF, however, a person must apply an adequate amount of sunscreen, avoid rinsing or rubbing or sweating it off, and reapply it every 2 hours. From a mathematical perspective, sunscreens rated as SPF 30 block 97% of UVB, SPF 50 block 98%, and SPF 100 block 99%. The FDA discourages claims of SPF >50 on a product’s label because it is meaningless.

Box 4-02 US Food and Drug Administration (FDA) sunscreen definitions


A measure of how much solar energy (UVB radiation) is required to produce sunburn on protected skin (i.e., in the presence of sunscreen) relative to the amount of solar energy required to produce sunburn on unprotected skin. As the SPF value increases, sunburn protection increases.


The FDA permits a sunscreen to be labeled as “broad spectrum” if it provides adequate protection from both UVA and UVB radiation.


Claims of water resistance on a sunscreen’s label must indicate whether the sunscreen remains effective for 40 minutes or 80 minutes while swimming or sweating, based on standard testing. Sunscreens that do not meet this standard must include a direction instructing consumers to use a water-resistant sunscreen when swimming or sweating.

The FDA does not define, nor does it use, the following terms: baby-safe, reef-safe, anti-aging, sport, kid-friendly, dermatologist-tested, all natural, sweat-proof, or waterproof.

Chemical (Organic) UV Filters

Sunscreens with chemical UV filters are absorbed into the skin and work like a sponge to absorb the sun’s rays. Chemical UV filters currently approved for use in the United States include avobenzone, cinoxate, ecamsule, homosalate, octinoxate, octisalate, octocrylene, and oxybenzone. Less commonly used filters include dioxybenzone, ensulizole, meradimate, padimate O, and sulisobenzone. Products containing chemical UV filters can be easier to apply and are less likely to leave a white residue than physical UV filters. People with naturally dark skin might be averse to using certain sunscreens because they leave a whitish appearance or ashy look; however, people with dark skin also need protection against the short- and long-term effects of UVR described above. Box 4-03 provides information on some possible health risks associated with use of chemical UV filters.

Physical (Inorganic) UV Filters

Physical, or inorganic, UV filters reflect both UVA and UVB from the skin’s surface. Worldwide, only 2 products are used as physical filters: zinc oxide and titanium dioxide. These metallic oxides are pulverized into microparticle or nanoparticle size, then mixed with a vehicle or emollient that permits them to be applied smoothly to the skin. Sunscreens might contain none, one, or both agents.

Physical sunscreens pose very little risk of causing allergic or irritant contact dermatitis (see Box 4-03). They can, however, leave a thin, white film or cast on the skin. Nevertheless, current products are cosmetically more acceptable than the older thick, opaque pastes.

Travelers also might opt for or be required to use sunscreens with physical UV filters due to reported adverse environmental effects of chemical UV filter–containing sunscreens (see Box 4-04). Some locations that require physical UV filters include Aruba, Bonaire, parts of Mexico, Palau, and the US Virgin Islands. In 2018, Hawaii passed a law banning sunscreens containing octinoxate and oxybenzone in response to evidence of their toxicity to coral marine life.

Box 4-03 Risks associated with sunscreen use: human


Contact dermatitis, both allergic and irritant.

Sun sensitivity (associated with avobenzone, cinoxate, octocrylene).

Several studies show that chemical UV filtering agents can be absorbed across the skin and reach detectable levels in human blood and tissues. Chemical UV filters have been widely detected in urine, blood, and breast milk. Many of these compounds are being studied as possible endocrine disruptors, which means they might interfere with hormones doing their normal bodily functions. The effects, if any, that chemical UV filters have on hormones like thyroid, estrogen, and testosterone in humans, marine or aquatic organisms, or ecosystems are unclear. In experimental animal studies, where much higher amounts of UV filter have been used, reports of significant changes in thyroid and sex hormones and potential effects on fertility and fetal development have been reported.

Recent reports of potential carcinogenicity of sunscreens were the result of poor manufacturing practices that allowed contaminants (e.g., benzene) to taint the products and were not due to intrinsic carcinogenicity of the sunscreen agents.


Rarely, cause skin irritation.

People should avoid using as sprays, because inhaling metallic nanoparticles can be harmful to the lungs.

Box 4-04 Risks associated with sunscreen use: environmental

Among the most concerning reports about sunscreens is that ultraviolet (UV) filters might harm marine ecosystems. This is a complex and unresolved point, because coral is damaged by a variety of environmental changes, especially cycles of increased ocean water temperatures. Laboratory evidence suggests that high concentrations of certain UV filters damage the symbiotic algae, known as zooxanthellae, that live within the live tips of coral, causing a loss of color known as “coral bleaching.” Repeated cycles of bleaching can kill living coral. Many other marine and aquatic organisms are also being studied for possible effects caused by chemical sunscreens. Overall, less evidence shows that physical UV filters (zinc oxide and titanium dioxide) pose toxicity to humans, animals, or the environment.

Clinicians should suggest that travelers choose sunscreens that are the least harmful for marine ecosystems. Several states and nations have legislation prohibiting the use of chemical (organic) sunscreens in favor of products containing physical (inorganic) UV filters, zinc oxide or titanium oxide. Many ocean resort destinations have banned some of the chemical UV filters; these include Hawaii, the US Virgin Islands, Palau, Bonaire, Aruba, Mexico, Brazil, and numerous locations in the European Union. Travelers should check regulations in effect at their destination prior to departure.

When selecting sunscreens that contain chemical UV filters, travelers should choose products that contain less than 3% avobenzone, 3% cinoxate, 3% ecamsule, 10% homosalate, 5% octinoxate, 5% octisalate, 5% octocrylene, or 5% oxybenzone.

Good sources of independent information for consumers and travelers on ever-changing sunscreen information include Consumer Reports and the Environmental Working Group, both of which regularly review and rate sunscreen products and their components.

The National Oceanographic and Atmospheric Administration (NOAA) provides a useful infographic on this topic.

Sunscreens for Children

Parents or guardians should protect children <6 months old from direct sun exposure, opt for shade, and dress children in lightweight long-sleeved shirts, long pants, wide-brimmed hats, and sunglasses. They can protect infants by using covered strollers or perambulators, umbrellas or parasols, and hats, rather than by applying sunscreen.
For children >6 months of age, parents or guardians should use sunscreens with physical UV filters (titanium dioxide or zinc oxide) rather than chemical UV filters; physical UV filters are less likely to irritate young children’s sensitive skin. Teens might want an oil-free sunscreen for the face to help avoid exacerbations of acne due to thicker, oily preparations. Adults can safely use sunscreen marketed for children.

Applying Sunscreen

Guidelines for sunscreen use recommend regular application of lotions or cream-based broad-spectrum UVA and UVB blocking (SPF ≥30) products (see Box 4-05). People should reapply sunscreen to all exposed areas every 2–4 hours. The average adult needs 1 fluid ounce (1 shot glass full) for each application. People should gently and evenly spread sunscreen, not rub in, on all exposed skin ≥15 minutes prior to going outside to allow UVR blocking effects to penetrate the outer skin layers. Stick or roll-on sunscreens are easy to apply, but people often apply these unevenly, leading to sunburned areas missed during application. If travelers choose to use these products, they should gently spread the product after application.

Box 4-05 Recommendations for safe sun exposure for travelers

  • Avoid direct sun exposure between 10 a.m. and 4 p.m. when ultraviolet (UV) rays are strongest.
  • When going outside, opt for shady areas, such as the full shade provided by natural or man-made fixed objects. Trees provide varying degrees of sun protection depending on the density of the foliage.
  • Consider using portable shade shelters (e.g., awnings, canopies, umbrellas and parasols, beach tents, similar shade structures). Look for items made with fabrics having a UV protection factor (UPF) >30.
  • Wear lightweight long-sleeved garments made of fabric with a UPF >30.
  • Wear a hat with circumferential brim ≥3 inches wide that shades the face, neck, and ears. Do not rely on standard baseball caps; opt for sun-specific caps that include ear and neck flaps, many of which are made of UPF fabrics.
  • Wear sunglasses to protect eyes from UV radiation.
  • Remember that UV light reflected off water, snow, or sand can amplify UV radiation received.
  • Apply a broad-spectrum sunscreen daily, ≥15 minutes before going outside to allow absorption in the skin’s outermost layer.
  • Choose a sunscreen that protects against UVA and UVB rays. Use products with a sun protection factor (SPF) ≥30; to adequately cover the body, apply ≥1 fluid ounce (equivalent to 2 tablespoons or a shot glass) of sunscreen.
  • Reapply sunscreen every 2–4 hours, more frequently when sweating or after being in water. Be sure to apply sunscreen to commonly missed areas (e.g., ears, tops of the feet).
  • Apply a lip balm with SPF ≥30. Remember that many lip balms are simply petrolatum-based moisturizers for chapped lips; look specifically for products labeled as SPF 30 or more.

Source: Adapted from the American Academy of Dermatology Association’s Practice Safe Sun guidelines.

Spray Sunscreens

People often apply spray sunscreens unevenly, especially under breezy conditions. Consumer Reports (July 2020) recommends holding the spray nozzle 1 inch from the skin and spraying until the skin glistens uniformly, then gently spreading the product to evenly coat the skin, even if the product claims to be “no rub.” Some environmental health organizations discourage use of spray sunscreens because the contents are as likely to get into the environment as they are to get onto a person’s skin.

People should avoid spraying the sunscreen on or near the face, because the particulate components can injure the eyes or damage lung tissue if inhaled. People should spray their palms and then apply the sunscreen to their faces. Similarly, parents or guardians should avoid spray products for small children due to risks for inhalation and getting product in children’s eyes; adults should spray product on their own hands and then apply onto the child’s skin.

Protective Clothing

Sun-protective garments (e.g., pants, long-sleeved shirts, hats) protect against UVR, but efficacy depends on the fabric. Thicker fabrics with tighter or denser weaves (e.g., denim), offer higher UV Protection Factor (UPF). Like SPF, the UPF of a fabric or material represents the fraction of UVR that penetrates the material. UPF 50, for example, means only 1/50th of the UVR gets through the fabric; 98% of UVR is blocked. A UPF rating of 15–24 is considered good, 25–39 is very good, and ≥40 is excellent. Many outdoor clothing and active wear manufacturers now use densely woven, lightweight, quick drying, synthetic UPF fabrics to make extremely comfortable shirts, pants, and hats.

Many companies also use UPF fabric to make swim-shirts, also called rash guards. Swim-shirts are available with short or long sleeves or with built-in hoods. Because UPF 50 fabric blocks 98% of UVR, a person does not need to apply sunscreen to surfaces covered by the shirts, and parents might choose these for young children who dislike having sunscreen applied. Surfers, lap swimmers, and open-water swimmers might prefer smaller, tighter sizes for a streamlined (hydrodynamic) feel in the water.


The ideal hat has a circumferential brim ≥3 inches wide that shades the face, neck, and ears. People should not rely on standard baseball caps for sun protection, because these do not protect the ears or neck. Instead, people should opt for sun-specific caps that include ear and neck flaps, many of which are made of UPF fabrics. These can be quite effective, especially for children.


UVR exposure can have short- and long-term damaging effects on the eyes. UVA can harm central vision by damaging the macula. UVB can damage the anterior eye (cornea and lens); acute exposure can lead to corneal burns, and extended exposure can lead to cataracts. UVR can penetrate clouds and haze, so people should protect their eyes regardless of atmospheric conditions.

Excessive UVB exposure, even over several hours, can cause a corneal sunburn, also called photokeratitis or snow blindness. Photokeratitis causes extremely painful sensitivity to light, often causing a person to keep their eyes closed for several hours or more. Snow blindness can occur when UVR reflected off snow nearly doubles the UV exposure to the eye. Other symptoms include copious tearing (watery eyes), injected sclerae (noninfectious pink eye), or a gritty foreign-body sensation of the eye. These symptoms are usually temporary and rarely cause permanent damage to the eyes.

Long-term UVR exposure can lead to cataract formation, age-related macular degeneration, benign conjunctival growths (called pterygium and pinguecula), and cancers of the eyelids or even the conjunctivae.
Sunglasses provide UV protection for the eyes. Wrap-around sunglasses or those with sun-blocking sidepieces provide the best UV protection. People should choose close-fitting frames that contour to the shape of the face to prevent exposure to direct and reflected UVR from all sides and angles.

People also should choose sunglasses that are rated UV 400; these block nearly 100% of damaging UVR. Lenses should have a uniform tint throughout; although gray tints offer the best color fidelity, tint color (e.g., amber, gray, green) does not affect sun protection efficacy. Polarized or mirrored lenses are not more effective at protecting against UVR. Inexpensive, non-branded sunglasses rated UV 400 are just as effective as expensive, designer-label sunglasses. Parents or guardians should provide appropriate eye protection for children. Some contact lenses offer a modicum of UV protection, but people should also wear sunglasses with contact lenses.

The American Academy of Ophthalmology and the American Optometry Association provide recommendations and information on gradient, transitional, and prescription sunglasses at these websites: Tips for Choosing the Best Sunglasses; Recommended Types of Sunglasses; and Ultraviolet (UV) Protection.

Beach Umbrellas & Sunshade Shelters

Several types of shade shelters are available: umbrellas, canopies, and tents. Many shelters marketed for sunshade combine several features. People should choose a shelter made with a fire-resistant UPF 50 fabric, usually nylon or polyester, and a durable but lightweight frame. Additional features travelers should consider are the size needed to accommodate number of people who will use the shelter at once; the weight and ability to collapse and easily transport the shelter; water-resistant fabric for rain squalls; open or mesh sides that allow adequate air circulation; ability to securely anchor the shelter to the ground with stakes, fillable sandbags, or a combination; and easy assembly, ideally by 1 person. Standard camping tents generally are unsuitable for sun shelters.

Travelers should select beach umbrellas with ample diameter and directional tilt, so the protective field can be adjusted as the sun rises and crosses the sky. Tall umbrellas with a small surface area lose their protective benefits when the sun is at a low angle. Wind gusts can uproot and launch umbrellas, posing a safety hazard. Therefore, people should select an umbrella with parts that can be attached securely to each other and placed firmly in the ground. Screw-type bases can anchor an umbrella in the sand, but usually are sold separately. Travelers should be aware that some public beaches limit the size of shade shelters that can be used.

Sunless Tanning

Topical sunless tanning products are a safer way people can gain a tanned look. Although these products make the skin appear darker, they do not provide photoprotection, and travelers should still use sunscreen when exposed to UVR. Sunless tanning products can produce streaking when people sweat or go swimming and can generate an unnatural orange hue on areas of the skin where applied.

Many people believe that getting a pre-vacation tan by using tanning beds will help protect them from vacation sunburns. However, tanning bed lights rely on UVA, which is associated with premature aging. Tanning by this method is roughly equivalent to using an SPF 4 sunscreen, which will not prevent sunburns or other forms of solar damage.

Additional Sources of Information

Consumer Reports (CR) and the Environmental Working Group (EWG) review and rate sunscreen products and their components annually. In general, CR ratings emphasize human safety, ease of use, truth in advertising, cost, and performance, while the EWG emphasizes environmental safety. Both identify sunscreens by brand name.

The following authors contributed to the previous version of this chapter: Karolyn A. Wanat, Scott A. Norton

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