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Light Pollution


This piece on Hong Kong’s out of control light pollution is a good reminder of one of the least controlled means of pollution. While maybe it isn’t as damaging as water or air pollution, humans have made evolutionary adjustments for night and constant light could potentially have long-term damage on human health. In the short-term, the absence of night can be devastating for many animals, as we may well be seeing in the Hong Kong area with fireflies and other insects.

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  • Just the other day, I heard the song “City of Light” on some radio station, which reminded me of John Rechy’s novel of the same title, and I suddenly thought, “I bet most people today think of ‘night’ not as being ‘when it’s dark’ but ‘when there’s artificial light'” and, then, “It hasn’t been that way very long at all, really.”

  • Vance Maverick

    I remember a discussion 20 years ago or so on rec.arts.books, where someone wondered what was wrong with the opening “It was a dark and stormy night.” One answer was that “dark” was redundant — calling one night darker than another was meaningless. Evidently this person had never noticed the presence or absence of the moon.

    (Just goes to show you what a moon can do.)

  • Birdman Berto

    What a stinking shithole. Szechuan food is good though.

    • Warren Terra

      Your opinion about Szechuan food is doubtless a great comfort to the Cantonese people of Hong Kong.

    • Chester Allman

      I know this is trolling, but Hong Kong is fantastic. A great, messy, brawny, urban wonderland.

  • Yosemite Semite

    At Christmastime, we were in Puerto Rico, and we visited one of the nature reserves on the island. This reserve, Las Cabezas de San Juan near Fajardo on the north-eastern tip of the island, has within its boundaries a bio-luminescent lagoon. There are a couple of others on the island as well. These lagoons are home to dinoflagellates, minute water organisms that glow at night if the water is agitated. These organisms are sensitive to ambient light, and don’t glow if the light level is high. (We happened to visit the reserve on a night with a full moon, so — guess what — no bioluminesce.) In preparation for our visit to the lagoon, our guides took us through a slide show about the phenomenon and the organism. A part of that presentation included a light pollution map of the world. Our guide said that Puerto Rico had the highest light pollution index in the world. The reserve was taking steps to reduce the light pollution at the lagoon, but it’s difficult. The type of light pollution the guide was referring to was probably what is called in this report PAHI (Protected Area Human Impact). In Puerto Rico, it’s 100%. From the report: “Countries such as Puerto Rico and Martinique feature PAHI values of 100%, thus not even having a single region within their designated protected areas which is more than 5km away from settlements, i.e. the threshold for areas to be considered as potentially not influenced.” Those islands are too small to have natural areas more than 5km away from human habitation. Las Cabezas is just over a low rise from the town of Fajardo, a town of 40,000. Go soon before they disappear altogether. Pick the dark of the moon for your visit.

    • “Go soon before they disappear altogether.”

      Appropriate for at least 50% of the world’s species.

  • Karen

    I can’t find the link now, but I recall reading that melatonin – the sleep regulating chemical that responds to light — may play a part in diabetes. From what I remember, too much light interferes with melatonin production, which in turn interferes with sleep. Sleep deprivation can cause insulin resistance. Diabetes is a horrible disease, which both my husband and my mother suffer, and I want to make sure my kids avoid it. That apparently means avoiding places with light pollution.

  • ChrisTS

    I believe that sleep studies of individuals (i.e., diagnostic studies) begin with black out conditions as the default for ‘normal’ sleep. I believe (AFAICR) that studies in the ‘midnight sun’ countries also begin with black out conditions and work from there to determining best practices for those who live in those countries.

    Humans are highly adaptable, but living in an area in which night is severely adumbrated for any significant portion of the year is a strain on us. It seems that those who live year-round in the midnight sun areas have adapted to take advantage of the ‘no night’ periods to struggle through the ‘almost no day’ periods.

    • mpowell

      Doesn’t this just mean you have to have the right curtains? Or is it not sufficient for your apartment to be really dark?

  • I once asked a friend whose stepfather was Swedish about the suicide rate statistics, and she replied that when she was visiting her mother for the Christmas holiday, they went for a walk on Christmas Day and found a Swede who had killed himself, I believe by hanging.

    Also, SAD:


    There are many different treatments for classic (winter-based) seasonal affective disorder, including light therapy, medication, ionized-air administration, cognitive-behavioral therapy and carefully timed supplementation[24] of the hormone melatonin.

    Photoperiod-related alterations of the duration of melatonin secretion may affect the seasonal mood cycles of SAD. This suggests that light therapy may be an effective treatment for SAD.[25] Light therapy uses a lightbox which emits far more lumens than a customary incandescent lamp. Bright white “full spectrum” light at 10,000 lux, blue light at a wavelength of 480 nm at 2,500 lux or green (actually cyan or blue-green [26]) light at a wavelength of 500 nm at 350 lux are used, with the first-mentioned historically preferred.[27][28]

    Bright light therapy is effective[18] with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source[13] for 30–60 minutes. A 1995 study showed that 500 nm cyan light therapy at doses of 350 lux produces melatonin suppression and phase shifts equivalent to 10,000 lux bright light therapy in winter depressives.[27] However, in this study, the improvement in depression ratings did not reach statistical significance. A study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination.[29] Discovering the best schedule is essential. One study has shown that up to 69% of patients find lightbox treatment inconvenient and as many as 19% stop use because of this.[13]

  • Rarely Posts

    Light pollution can also be deadly for sea turtles and certain migratory birds. Also, human beings might benefit mentally from actually seeing the stars. As someone who grew up in an East Coast industrial city, visiting the rural, wild Southwest really blew my mind. The night sky was at least as impressive as the geological formations and wildlife. I know that’s “merely” an aesthetic concern, but it would be nice to at least preserve those opportunities.

    • Karen

      Aesthetics is important and underappreciated as a factor in our mental health. Looking at ugly all day and with no contact with the natural world can make us seriously depressed. Besides, why should we have to endure ugly? It’s not that difficult or expensive to make the physical environment pleasant. Planting flowers and picking up trash isn’t difficult, and light pollution can be addressed without too much effort as well. We do have to acknowledge that esthetics matters.

    • Dan Miller

      Of course, Hong Kong is aesthetically gorgeous. De gustibus and all that, but it’s hard to deny.

  • Carbon Man

    Won’t SOMEBODY think of the insects and fireflies!?? Oh noes!

    It’s a curious morality Loomis has–an unborn baby can eat shit and die, but we must protect insects at all costs.

    • Yes, Jennie dear, we realize that like the fictitious Kalonians of the Lensman series, you see no value in women if they aren’t bearing babies.

    • Cody

      I think if we manage to kill all the other remaining species on earth, the unborn “babies” won’t be the only ones dying early.

  • Malaclypse

    And yet you seem compelled to comment, on this issue you don’t care at all about.

  • MatthewN

    From a perfectly me-centric standpoint, as a telescope owner, I applaud efforts like these.

    I live in a city almost proud of its light pollution, Las Vegas.
    I have to drive my telescope two hours out into the desert to completely escape the insanely large light bubble surrounding the city.

    At least in the desert southwest this option is still available to me. It would be harder if I lived in Trenton.

    • Dano

      I live in Colo and the drilling rigs wrecked our dark-sky site. So I hear ya.



  • Brandon

    Oh yeah smarty-pants? Never heard of Arctic summers? :smug:

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