Shielding life: Light pollution

There is no question that the US inventor, Thomas Alva Edison, should get the lion's share of credit for lighting up the world. The genius, who gave us the long-lasting electric bulb more than a century ago, would perhaps never have imagined that the blanket-cover of these bulbs over our cities would create "light pollution".

Quality lighting

With the major metropolitan cities in the developed and developing nations having no or limited place for sky-gazers, Arizona-based The International Dark-Sky Association (IDA) has taken up the task to preserve and protect the night-time environment and the heritage of dark skies through quality outdoor lighting.

"Light pollution is caused due to an adverse effect of artificial light, including sky glow, glare, light trespass and light clutter," says Johanna Duffek, Sections Coordinator at the IDA, in an e-mail to XPRESS.

Duffek says light pollution wastes energy, affects astronomers and scientists, disrupts global wildlife and ecological balance and has been linked to negative consequences on human health.

"Light pollution affects us in many ways," says Duffek, since specified periods of light and dark, known as circadian rhythms, are essential for good health for most life on Earth, including humans. Researchers have established that exposure to artificial light at night reduces the human body's production of melatonin, the hormone that monitors the body's clock that indicates that it is dark.

Circadian disruption

"Reduced levels of melatonin promote growth of breast tumours in women, while men are prone to prostate cancer," says Duffek. Even the WHO's International Agency for Research on Cancer has noted that "shift-work involves circadian disruption in humans".

Glare is also a big problem for humans, especially senior citizens. "The older we become, the longer it takes for our eyes to adjust to darkness," says Duffek. It is estimated that it takes our eyes a full 20 minutes to fully adjust to darkness after being in an illuminated area.

"If you have shielded [outdoor] lighting that does not allow light above the 90 degree angle, most of the glare is eliminated. This is important for night-time driving because as drivers pass unshielded lighting along the road, they may become temporarily blinded by the glare," says Duffek.

Duffek throws the spotlight on simple measures to protect our environment such as switching lights off in unoccupied buildings, outdoor lights not pointing up to the sky or shielding lights that create sky glow.