SUN EXPOSURE

• A large proportion of recent scientific studies on the environment's impact on the skin cover sun radiation impact. 
• According to research, the sun is responsible for 90% of damage to the skin.
• The skin aging process can be either extrinsic or intrinsic. It is well known that the sun leads to extrinsic skin aging.
• Excessive sun exposure can also cause skin cancer and it has been found that 90% of nonmelanoma skin cancers are caused by exposure to ultraviolet radiation.
• This type of skin aging is called "photoaging" and is now considered a special field of research in the larger extrinsic skin theme.
• Research in this field has been profound in the last few years and there was proof that skin aging has different effects on distinct populations and ethnicity. 
• It is known that sun exposure increases the risk of skin cancer, but the risk depends on the type of skin. People with lighter skin have lower levels of melanin in their skin, which provides them with less natural protection against UV radiation.
• Dermatologists classify skin types into six categories, from I being the lightest. People with category IV skin type or more are more protected from sun UV radiation, thanks to higher levels of melanin in their skin. 

AIR POLLUTION

•  92% of the world's population live in cities that do not comply with the World's Health Organization's air quality standards.
• A recent ongoing study could potentially also discover a link between air pollution and skin aging.
• Contaminants materials resulting from pollution affect the skin and can cause premature aging, pigmentation spots, or even acne.
• In some cases, it can lead to more serious diseases such as cancer, psoriaris, and dermatitis. 
• The skin operates as a protection against pollution but this function can be weakened by pollutants, and lead to toxicity in human organs. 
• Some components of air pollution are called ambient particulate matter (PM), which can be created by volcanic activity or combustion of fossil fuels, or even the production of chemicals. There has been increasing evidence showing that human skin exposure to PM has negative effects attached to it, such as an increase in the risk of developing eczema, and even a modification of the physiological properties of skin. The mechanisms of how this happens are not well know. 
• Other negative impacts of air pollution include dryness, dullness, roughness and discoloration of the skin.
• Some studies have found that NO2 air pollution has caused the formation of pigments in women over 50 in Germany. An increase of 10mg/m3 NO2 resulted in a 25% growth in pigment spots.

WATER QUALITY

• In the US, around 63 million people are affected by the risk of polluted tap water that might be unsafe for drinking.
• Polluted water can cause skin infections. 
• The chlorine present in tap water can cause damage to the skin and accelerate its aging.
• It is a toxic chemical that can affect the skin negatively.

HUMIDITY

• The skin is very sensitive to humidity levels to which it is exposed. A high level of humidity makes it more prone to host harmful bacteria, increase the risk for rashes and general irritation. A low level of humidity can make the skin dry up.

TEMPERATURES

• Research has shown that exposure to heat can generate the production of elastotic material in skin, and cause severe skin aging.
• A study has shown that Caucasians leaving in Australia, where temperatures and sun exposure is higher, have experienced accelerated skin aging compared to Caucasians living in the UK, the US and Canada.