There is well established evidence that exposure to ultraviolet radiation (UVR) from the sun can lead to skin cancer. Seeking shade is a practical form of sun protection when used with a combination of other protective measures.
Health effects from solar UVR
ARPANSA and other national and international health authorities, including the World Health Organization, have assessed that continuous exposure to ultraviolet radiation (UVR) from the sun causes harmful effects on the skin, eye and immune system.
Well-designed and positioned shade can significantly reduce UVR from the sun and is an important preventative measure to help reduce these risks
What shade is best for you?
The best shade is found inside buildings where reflected and diffuse UVR are completely blocked. However, if you are outdoors, shade can be provided by trees, shrubs or shadows cast from nearby buildings or objects, by awnings, tents and shade sails. It can be permanent, temporary or portable.
During times where sun protection is advised (when the UV index is 3 and above) use a combination of the five sun protection measures: Slip on sun protective clothing, Slop on sunscreen, Slap on a hat, Seek shade and Slide on sunglasses.
For most of the day there is as much scattered solar UVR from the sky as there is from the direct sun. For best protection, both direct and scattered solar UVR need to be considered.
The shade coverage depends on the positioning of the structure and the person under the structure with respect to the sun. Generally, shade structures of larger area offer more protection than smaller ones. There are also other considerations for a shade structure include variations in design, height of the shade canopy above the person, deterioration of the materials, the direction of the sunlight and the physical location of the person (e.g. at the centre is more shaded than the under the edge of the shade). As a rule of thumb, the less sky that is visible the greater the protection from scattered solar UVR.
Although shade is helpful, a combination of the five sun protective measures will be required if a person is outside during times where sun protection is advised.
UVR can also be reflected from surfaces such as snow, water and buildings. Hard surfaces such as steel, glass and concrete reflect more UVR than soft surfaces such as soil or grass. Lighter colours are more reflective than darker colours.
The best shade provides protection from the direct sunlight, excellent coverage of the sky and side protection from the reflective surfaces. It is also designed to factor in how shade moves with the position of the sun in the morning, midday and afternoon.
Different types of trees provide different levels of shade and UVR reduction. A heavy dense canopy can provide up to 90% UVR protection. A medium canopy can provide up to 60% UVR protection and is suitable for short stays. A light canopy provides poor UVR protection.
Manufactured shade options
There are a number of types of manufactured structures, ranging from permanent structures, adjustable or temporary and even portable types:
- Permanent shade includes shelter sheds, gazebos, verandas and fixed shade sails. They can use metals, polycarbonates, knitted and woven shade fabric.
- Adjustable shade includes items like shade sails, awnings and café umbrellas. As they are adjustable, they are usually made of knitted and woven shade fabric.
- Temporary shade structures are easy to set up and take down, and include large tents, marquees and beach shelters. They are usually made from knitted and woven shade fabric.
- Portable shade includes personal sun and beach umbrellas, and small sun shelters, and are typically made of woven shade fabric.
Sun protective materials
The effectiveness of a shade structure depends on the coverage and how effective the materials are at reducing UVR. The effectiveness of the material can be determined by testing it to determine its Ultraviolet Effectiveness (UVE) rating or for metals, glass or polycarbonates the Protection Factor (PF).
Metal sheets are usually used only on permanent shade structures and provide excellent UVR protection from the sun.
Polycarbonate is manufactured in either clear or tinted sheeting. The main purpose of the sheeting is to weatherproof an outdoor area while allowing visible light through. Transparent polycarbonates usually have PF ratings of 50+.
Glass is also used in car windows and in retractable doors, windows or skylights to enclose or weatherproof outdoor areas while allowing light through. Depending on the type of glass, the ultraviolet radiation protection provided is quite low for most tempered and plain glass types. Whilst double-glazed, laminated (e.g. windscreens) or tinted windows may block greater than 98% of UVR (e.g. PF 50+).
Shade fabrics are rated for either horticultural use to control visible light for plants or for human protection and given an ultraviolet effectiveness percentage (% UVE) rating using the Australian Standard AS 4174:2018 Knitted and woven shade fabric. The term shade fabric covers any fabric intended for, or used to provide shade, including materials used in the manufacture of umbrellas, tents, sun shelters, portable gazeebos and marquees, awnings, shade sails and shade cloth. The protection from shade fabrics varies depending on the material, colour, density, weave and coatings applied. Canvas and silver backed materials typically are greater than 98% UVE. Any fabric providing protection from the sun, sky and reflections, that has a rating of 97% UVE or above can provide all day protection from solar UVR.
Knitted or woven shade fabric
Initially shade fabric (also referred to as shade cloth) was used in the horticultural industry to limit the transmission of visible light and heat whilst still providing ventilation for the plants. Shade fabrics are typically made of UV stabilised high-density polyethylene (HDPE) or polypropylene. The transmission of solar UVR through shade fabric is dependent on the weave and its gauge with closer weaves offering greater protection against UVR. Shade fabrics also come in a range of outdoor shade products for personal use and are considered effective from 80.0 to 90.9% UVE; very effective form 91.0-94.9% and 95% UVE or greater is considered to provide the most effective protection. However, a high UVE rating should not be relied upon as the only form of UVR protection.
|Ultraviolet effectiveness (% UVE)||Protection Category|
|80.0 to 90.9||Effective|
|91.0 to 94.9||Very Effective|
|95.0 +||Most Effective|
The Cancer Council Australia provides further protective advice through national, state and territory Sunsmart programs and activities.