Let There Be (Less) Light?

In the August 20 edition of The New Yorker, David Owen has a fascinating article about outdoor lighting and light pollution. Because it relates to several environmental and health issues from wildlife habitat to human cancer rates, I thought it would be worthwhile mentioning here.

Since beginning to write about green building and sustainable design several years ago, I've also long been interested in the properties of natural light, especially daylighting - how natural light is introduced into architectural spaces. I work from home in front of a window and keep all the lights in the house off until dark. I couldn't ever go back to working under fluorescent lights.

But this article is about something related yet different: how important the absence of light can be, or at least a more judicious application of it. And not just for the sake of astronomers, who can see less with their high-powered telescopes than Galileo could see in the 1600s with the equivalent of a coke bottle - all because of light pollution.

The desire for security has prompted throughout public spaces the increased use of exterior lighting. But many of these fixtures actually inhibit the ability to see or prevent crime. Bright unshielded floodlights are one of the most common types of outdoor security lighting. Yet these "glare bombs", as one lighting expert in the story calls them, "cast much of their light sideways, into the eyes of passersby, or upward, into the sky," Owen explains. "Diminishing the level of nighttime lighting can actually increase visibility."

It reminds me of how home kitchen lighting has changed. It used to be the whole room was flooded with light from overhead. But in a modern kitchen, there's more likely to be task lighting that shines onto countertop workspaces.

Besides visibility issues, outdoor lighting has been found to have a huge effect on both humans and animals. Our 24-hour body clock, or circadian rhythm, is such that we've evolved to experience darkness at night. If we experience too much light at nighttime, it can lead to a reduction in natural melatonin production, which Owen explains is "a cancer-protective agent whose production is severely diminished in people exposed to light at night". One study, for example, showed a strong correlation between breast cancer sufferers and working the night shift. My girlfriend's aunt passed away from breast cancer many years ago, and she routinely worked late hours at a grocery store.

Large levels of artificial outdoor light have also shown to harm a variety of wildlife, particularly in bird and insect populations. In Florida, sea-turtle populations have been devastated by artificial lighting--they come out from the ocean to hatch their eggs and get drawn into town, where they're often run over by cars or attacked by other predators.

Here in Portland, my residence is right outside a big streetlight, and after reading this article (if not before), I'd like to inquire with the city about turning it off, or failing that, replacing it with a less pervasive lamp that focuses more squarely on the street and sidewalk. I'm already pulling enough late nights writing as it is; I don't need my street lamp giving me or the girlfriend cancer.

And as it happens, a review of Portland's outdoor lighting might be able to prompt some large savings through greater energy efficiency. In Owen's article, Calgary is reported to have saved about two million dollars annually by switching to full-cutoff (shielded) and reduced-wattage streetlights. That's a nice potential chunk of change for our city's budget. And maybe I wouldn't wake up in the middle of the night with a blanket wrapped around my head in a subconscious search for darkness.

Comments

[brett]

I haven't read Owen's article yet (I'm about 6 months beind in my New Yorkers) but I do recall that a former Eugene mayor a few years ago tried to change the streetlighting to a kind of lamp that didn't blot out the stars and consume so much energy.

[gerry]

Portland's street lights are only bright when they're outside your house. Walking or driving at night, when visibility is the concern, these things are pretty dim. Any dimmer would be pretty alarming in some neighborhoods.

[john]

Some blinds on your windows might help too. I once did the research necessary to win an argument with a county commission who wanted me to replace old street lights with more energy efficient ones. These are great to buy when installing new lights but the energy expended by the manufacturing and shipping of these new lights can never be recouped, nor can the expense.

[Lynne Eldridge M.D.]

Thanks for this great post. And, thank you for bringing up the cancer risk associated with night lighting. Since we are frightened by the "C" word with one half of men and one in three women expected to develop cancer (skin cancer not included) in their lifetime, perhaps this will help people listen to other issues as well.

I agree that melatonin plays a role in cancer prevention. While studies are going back and forth on whether night workers have a higher incidence of breast cancer, we know that airline personal have an elevated risk. On the other side of the equation, completely blind women have a very low risk of developing breast cancer.

Shades are a great idea while we look into more acceptable lighting ideas, but this is very important. We are sitting back trying to understand why Marin County (not from from Portland) is considered the breast cancer capitol of the world with one in four women expected to develop breast cancer. Issues such as lighting at night that many make a difference need to be addressed! Thanks!

[ssschaffer]

I am torn on this issue.

On one hand, I taught observational astronomy in the Bay Area for several years and know first hand the problems light pollution has on our night skies. I even wrote a law review article about this issue and consulted with the folks in Tuscon, AZ who instituted strict light control ordinances to protect their local telescopes (Kitt Peak).

My understanding of the issue is two-fold: (1) one should use certain types of lighting technology, and (2) one should hood the light in a way to direct it in an appropriate path. Tuscon is awash in the yellowish (and some would say, sickly) low pressure sodium lights. And these lights have hoods that direct the light downward, and not upward or outward. Also, these low-pressure sodium lights emit very particular wavelengths of light, and these particular wavelengths are more easily filtered out by the astronomers so that they can make their observations. But, as anyone who has experienced these yellow lights can attest, their light is just not "friendly."

On the other hand, I see great value in the warm glow of incadescent lighting. Lighting can completely change the way you feel inside a room, and outside in the park. I am in complete support of the projects to light up Portland's bridges. And this comes just when we've seen the greatest advance since the light bulb -- the development of full-spectrum LEDs which are much more efficient and longer lasting than just about anything out there.

Personally, I think we are about to see a revolution in lighting where just about every light will be replaced with color-tunable LEDs. The trick then comes with deciding just where you want the light directed -- up, down, sideways. This is where we need the most work.

[Sean Casey]

Great post and comments regarding this issue. I agree it's as much a quality of life issue as anything else.

Not to engage in too much "subject drift", but indoor lighting can be problematic as well.

A few years ago when there were power grid issues on the west coast, many stores reduced their lighting as a conservation measure. I remember walking into the Safeway on NE Broadway, pleasantly surprised to see half the lighting ballasts turned off. That store was always so bright in there, so it was great not having to squint, or wear sunglasses, while shopping. Just enough to see the products, without having to look at every pore on peoples faces.

I understand the need for displaying products and security et al... but sometimes it goes a little overboard.

Thanks for allowing me to comment.

[craig]

Sadly, I see a lot of statements here that aren't really true. I'm not going to delve into them, because I am so glad to see people who care enough to be interested. Most people aren't.

Lighting is indeed complicated. That's why there are professionals who devote their careers to the topic. I know there are some great resources in Portland who would be happy to share their knowledge and experience. Look them up. Call them. And listen to their views on LEDs, daylight, fluorescent lighting, and dark-sky.

[zilfondel]

Thick drapes/curtains also help, especially during winter. Obviously, during summer they aren't so helpful when its hot inside...

[Dave_YYC]

I didn't know Calgary is making strides to change - and I live here! BTW the link to the New Yorker article is: http://www.newyorker.com/reporting/2007/08/20/070820fa_fact_owen
- it is a very good article.

[Duncan Munday]

I've been really interested by all of your comments. What I believe to be the most prominant issue is that of energy loss due to un-necessary lighting. It is interesting that lighting can be more focused but very few people use this method.
I think it boils down to the point that everyone should make their own small changes to help save energy in their homes, and then try and persuade councils to do the same. Tip to you- Led light bulbs and PIR Sensors. To find out more, visit www.deslamps.co.uk