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Link Between Cancer and Light Pollution February 26, 2009

Posted by linta in Effects.

city1Breast cancer is one among the most severe health effects of light pollution. In order to understand the link between the occurrence of breast cancer and light pollution, we should have an understanding of human body. It is a common knowledge that our body produces many hormones which are in fact chemical messengers. Melatonin is such a hormone produced by the pineal gland, the organ which regulates our wake-sleep-wake cycle. Which means this hormone helps the body to keep up a rhythm. The most important fact is that this hormone is suppressed by light and is active in darkness. Researchers have found out that when we are exposed to light at night, melatonin production retards within seconds. Thus this hormone is called “the hormone of darkness.” The function of melatonin that worth noting is that it makes the cancer cells to sleep at night. Which means it regulates the amount of oestrogen(female hormone) secreted. But, when the secretion of melatonin is retarded due to the exposure to light, oestrogen is secreted in large amounts leading to a higher risk of light pollution. This is illustrated by the fact that blind women are 36% less likely than those who are sigheted to be breast cancer patients. It has been observed that light pollution causes not only breast cancer, but also endometrial and prostrate cancers as well.

Sources: http://www.health24.com/medical/Condition_centres/777-792-1461-1671,31149.asp


(image) http://ngm.nationalgeographic.com/2008/11/light-pollution/img/17-toronto-aerial-night-665.jpg


Breast Cancer and Light Pollution February 25, 2009

Posted by linta in Effects.

Why are we so anxious about tackling pollution? Is it because we are awfully concerned about the welfare of our mother nature? Certainly not. We conserve our environment because we are concerned about our own welfare. We protect other animals from extinction because we are aware that the absence of one species harms survival of all other species, including humans, in the ecosystem. We hurry to find ways to deal with global warming and climate change because they are great threats to our very existence. Briefly, our aspiration to lead a healthy and peaceful life is the thing that forces us to conserve the nature. Likewise, light pollution is also a matter of concern because it has been proved that light pollution has serious implications on human health.

The most recent finding regarding the effects of light pollution in human health is that women who are exposed to artificial light are likely to be afflicted by breast cancer. Many studies, examining the relationship between breast cancer and light pollution, have been conducted so far. Let’s consider the study carried out by some epidemiologists in 147 Israeli communities. The study suggests that “when the brightest communities were compared to the darkest communities, the cities with the brightest lights had a 73% higher rate of breast cancer!” which is really appalling. Various studies suggest that those, especially females, who work at night or are exposed to artificial light, are very likely to develop breast cancer. I am not going into the complex scientific explanation behind this occurrence. However, it is really a sad that the reckless activities of human beings make the world a difficult place to live in.

Click the link that follows to have look on a  study examining the relationship between light pollution and breast cancer.    cancer-incidence

Source: http://www.homerglen.org/Environment/Lighting/BreatCancerAndLightPollution.pdf

Light Pollution and Energy Wastage February 23, 2009

Posted by linta in Effects.
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Now that we have seen the causes of light pollution, it is worthwhile to look at the effects. In fact, the effects are not limited to humans, animals are also affected by this phenomenon. However, before knowing how it affects other species, we should know how it affects us, humans. My grandmother is very sensitive to light and it can be said that she is ‘repelled by light’. She prefers sitting in dimness, so when we turn on the electric lights at night, she will go to another room where there is not much light. According to her, our house is more lit at night than it is during daytime. This has often led to small conflicts between my little sister and her. So, here comes the question. Are the effects of light pollution on human lives limited to such conflicts between those who hate light and those who cannot live without light? (Here, light stands specifically for artificial light.) Or are there more consequences that we do not notice?

Well, let’s see. As you have already assumed, light pollution does have some more consequences other than such little conflicts. Today, we will look at one of such effects, which is the wastage of energy. Scientists have been warning us about the future energy crisis due to the overconsumption and the reckless use of energy. The severity of this energy wastage is reflected in the fact that only in the U.S., the energy waste due to light pollution costs more than one billion dollars! Now, think about the globe as a whole. However, this doesn’t mean that we should stop using light at night, but we can still reduce its use. Do we need all these decoration lamps and flash lights that focus light up into the sky? One thing we should keep in mind that while one part of the world is still in darkness without electricity or other means of lighting the night, we are sinking in light! 

 Image URL: http://earthfirst.com/wp-content/uploads/2008/10/light-pollution.jpg 

Where is light pollution? February 19, 2009

Posted by linta in My words.


earth at night 

    I have met many people who do not agree that light pollution exists in their places. For example, I have friends in Chittagong who believe that there is no extra light in the sky above this economic capital of Bangladesh. However, the city appears to be filled with artificial lights- street lamps, decorating lamps, light from shops, shopping malls and hotels….light is everywhere. ‘But, still there is not enough light to cause pollution. Look at the night sky, how many stars are there? Even the moon is shining with full bright.’ But I have a question- have those who are satisfied with the night sky in Chittagong or any similar cities, ever compared the sky above their head with the sky visible in a rural region? The answer must be no, because otherwise they will not believe that light pollution is only a conceptual phenomenon which does not exist for real.

    My district Pathanamthitta is the youngest district in Kerala. However, the city is approaching the so called ‘modernization’ and thereby light pollution. The most obvious proof is that there are not many stars in the sky above Pathanamthitta city. With Jewellery shops, shopping malls and other business shops,companies and offices, Pathanamthitta is growing. Along with this development, light pollution is also growing. There is a large stadium in the heart of my city which serves as the venue for  many important programs. Whenever a circus or shopping festival comes to our city the stadium will be the venue. During such festive days, at night, a flash light can be seen above the city which is visible even in far away places. Still now, I don’t any idea about the use of that light. Even my village which lies 3 km far away from the city has also started to show some signs of light pollution like the orange or yellow haze in the sky, absence of stars… but again we are confused-where is light pollution? The answer is that light pollution is (almost)everywhere. This makes it difficult to recognize. See the image of earth at night taken by NASA. How many countries are there which are free from light pollution?

Why does the night sky glow? February 19, 2009

Posted by linta in Causes.

glowLight pollution can be simply described as the presence of light where it is not wanted. This gives our sky a pinkish orange haze which is visible especially at night. And guess what, there are no more stars visible in the sky. Why or how does it happen?

 It is obvious that light causes light pollution. However, for convenience of study, the light that escapes to the night sky and causes light pollution can be classified into different categories. Here, I would like to adopt the classification method employed by Muskoka Watershed Council in their so called Technical Bulletin about light pollution  as it seems easy to understand and covers most of the main points. According to them,there are five major categories of light pollution- Light trespass, over-illumination, glare, cutter and sky glow. Now let us see what these are. Light trespass refers to the spilling out of light where it is not supposed to be present. Obviously, this trespassing light is from the earth and we humans allow it to happen. Over-illumination also results from human activities such as the “excessive use of light”. Glare is an other type of light pollution. If there is a large contrast between bright and dark areas, it can be called glare. Clutter is another type of light pollution which usually results from badly designed street lights which makes an “excessive grouping of lights.” This often lead to accidents. The last one,  sky glow, is the most obvious sign of light pollution especially in cities. As the name indicates, the sky appears to be glowing due to the reflection and scattering of light by atmospheric particles. All the above categories of light pollution are present around us, but we do not notice them. It is shocking to realize that we are living in world sunk in light. 

source: http://www.muskokaheritage.org/watershed/PDFs/DarkSkyLighting.pdf   

Image URL: http://media.photobucket.com/image/sky%20glow/curstkate/glow.jpg?o=3

“Our Vanishing Night” February 14, 2009

Posted by linta in My words.

Lonely star

This is the title of an article published in the National Geographic magazine a few months ago. Until reading this article in our homeroom as a part of our weekly article analysis, I had no idea about the issue discussed in the it-light pollution. It is funny that most of us do not know much about this phenomenon. Pollution is such an inevitable part of our education curriculum even in primary classes. However, our knowledge about different types of pollution is very limited as there are more kinds that we do not notice or know about. Light pollution is such an occurrence.

If you are in a city, haven’t you ever wondered why there are not many stars in the sky? Whenever I asked the same question, my mother had a convincing answer that just like sunlight hiding the stars during daytime, clouds hide them at night.  However, there were times when I was not satisfied with this answer because if it was so, why those clouds were invisible? Sky was like an empty blanket above my head. As it is night, we cannot see those clouds. It is really convincing, isn’t it? For me, it was enough. However, there was still one doubt remaining – why don’t those clouds cover the moon? Are they above the moon(which is utterly impossible) to hide the stars only?

Now, I have the answer to those questions and I got the answer from that article which I mentioned before. Though there are not clouds in the sky, (artificial)light hides the stars just as natural light does during day time. As it says in the article “Our vanishing night”, we are the ones who allow artificial light to spill out into the sky, without focusing it into land where it is needed and thereby invite light pollution. As long as light continues to spill out into the atmosphere, there will be  hardly any stars visible in the night sky.