There are many issues that most of us are unaware of regarding the street lights retrofit we are installing in Davis that goes beyond simply personal preference for a certain quality of light outside our homes.
To begin, we need to understand that while we may choose to light up the night the same as we choose to use fossil fuels, there are environmental consequences to that use. Just as we strive to limit the pollution from fossil fuels, we need to understand that light at night is a form of pollution and understand the consequences of that pollution which include:
-an increase in air pollution
-an increased risk for cancer in humans
-the (often unnecessary) use of energy and money
-an increase in glare that decreases safety
-an increase in current lighting levels that hampers our night vision
-a negative impact on animals
-a loss of the wonders of the night sky for everyone
Humans have an innate fear of the dark. We equate the dark with ignorance and the unknown. Culturally, light is a symbol of enlightenment, knowledge and security. We use light metaphors to describe understanding and the good; we think of lighting as a good thing but all good things taken to extremes have their dark side.
Street lighting became widespread in this country in the 1930’s when utility companies had excess energy at night and they needed a night time base load for their thermal power plants. Street lighting was the perfect solution. Street lights were made inefficient, so they used more energy. The light bulbs were designed to burn out to maintain an income stream for the manufacturers, suppliers and salesmen. Cities were charged a flat fee so they had no incentive to conserve. We stopped having excess energy to sell at night in the 70’s but by then municipalities were spending a large portion of their energy budgets on street lighting and it had become the norm and was considered (still is considered) a necessity when in fact it is the forgotten remnant of an obsolete energy practice.
In 2012 in the United States, 19% of our electric use is for lighting and 16% is used for outdoor lighting for a total cost of 11.6 billion dollars. Experts estimate 30% of that is wasted light; lighting where it is not needed, when it is not needed or direct uplight that illuminates the heavens. This wasted light costs us about 3.5 billion dollars every year. As Everett Dirksen said, “A billion here a billion there, and pretty soon you’re talking real money.”
The wasted energy amounts to 30 million barrels of oil and 8.2 million tons of coal and releases 14.1 million tons of CO2 into the air. In an effort to reduce the money spent and the CO2 produced, cities across the world are using these two criteria to retrofit their streetlights with LED lights. Unfortunately, this is a two dimensional solution to a multi-dimensional problem.
In Davis, these were two of the three goals of our retrofit. The third was to replace burned out fixtures. An energy audit was done by Siemens, the contractor who is also doing a complete energy audit of city owned buildings. To the best of my knowledge, that audit of streetlights was an inventory of the number of fixtures we have, the type and the absence or presence of numbering on each fixture and who owns the fixture, the city or PGE. What was not done was an assessment of where we have light, where we need light, when we need light, what kind of light is needed and HOW MUCH LIGHT IS NEEDED.
How does light at night increase air pollution other than by burning fossil fuels to power them? During night time hours, a form of nitrogen oxide, the nitrate radical NO3, is formed which breaks down chemicals that would otherwise form smog and ozone. This process is destroyed by sunlight and is inhibited by light at night. Night time cleansing is slowed 7% by the sky glow above cities and can increase the chemicals for ozone pollution the next day by up to 5%. You can read more about it here: http://cires.colorado.edu/science/spheres/air/lights.html
Since when does artificial light cause cancer? Well, it may not cause cancer but it increases the risk of breast cancer, ovarian cancer, prostate cancer and colon cancer. There is an extensive body of research on breast cancer based on the theory that nocturnal disruption of circadian rhythms reduces the production of melatonin. Night shift work increases the risk, blind women are at lower risk while partly sighted are at the same risk as other women, and according to the National Institute for Health, “nighttime light level co-distributes with breast cancer incidence worldwide.” These studies have resulted in the International Agency for Research on Cancer a part of the World Health Organization classifying shift work as a probable human carcinogen. The American Cancer Society includes “night work” as a cancer risk factor. The American Medical Association unanimously passed resolution 516 supporting light pollution control efforts and glare reduction efforts in 2009. While no one is saying blue rich white light (LEDs in their current incarnation) causes cancer, there is credible research that shows exposure to 6,500 CCT (ours are 4000) streetlight for one hour is expected to show measurable effects on human melatonin production. Here is a link to further information on medical research into light at night: http://physics.fau.edu/observatory/lightpol-health.html
There are other health problems associated with exposure to light at night including depression, obesity, diabetes and heart disease. We voluntarily expose ourselves to light at night in many forms–TV screens, computers and cell phones as well as our indoor lighting. If it concerns us, we can make lifestyle choices to minimize our exposure inside our homes UNLESS WE ARE CONSTANTLY BATHED IN LIGHT TRESPASS FROM CITY STREET LIGHTS. As a city, I believe we should make every effort to keep our lights shining where we want them (on the streets and sidewalks) and not in our homes. In case you think low levels of light are unlikely to cause problems, think again. Recent studies on mice show that chronic exposure to a dim blue/white light at night disrupts the circadian rhythms, suppresses melatonin production and increases inflammation. Turn those night lights off!
Humans have evolved with the ability to see at night in low light. The light of the full moon shines on the earth at about 1/100 foot-candles. The standard for the lowest level of light (residential) in Davis is .6 foot-candles for each of our neighborhood light fixtures. This is about 60 times brighter than a full moon emanating from every light fixture! I think a reduction in this standard is in order.
The human eye is adapted to the dark. When the levels of light are lower, our eyes dilate, we lose the ability to see color but we can see graduations of light and dark. A higher intensity of light creates a sharp contrast with shadows, making the shadows appear impenetrable, whereas with a lower level of light the shadow of a building, a tree or a bush has more definition–our ability to distinguish objects actually improves. We have a tendency to increase the levels of light to “see better” even though visual functions at night are impaired by that increase. The shadows become a black foreboding unknown shape so we add more light and make the contrast even deeper and more difficult to distinguish shapes. One of the goals of most outdoor lighting is uniformity but research shows that we see better with overlapping ovals of light which help us to judge distance and see movement.
Over 30 percent of vertebrates and 60 percent of invertebrates are nocturnal and many of the rest are crepuscular, that is, active at dawn and dusk. All are potentially impacted by our use of artificial light. Up until the advent of LED lighting, outdoor lighting has been in the warmer color ranges and we know that even those lights have negative effects on animals such as sea turtles, but the blue rich white lights are much more harmful. Every light contributes to altering ancient patterns of mating, migration, feeding, and pollination. We cannot modify light half the time without consequences.
There are special concerns related to the color temperature of our LED lights. LED lights are promoted because they are closer to the color range of sunlight than most (but not all) of the lights they are replacing, making it possible to see some color at night, however there are specific problems with this kind of light at night that aren’t found with lights that are shifted toward the yellow and red end of the spectrum.
LED lights can be made in any color but they are most energy efficient in the Blue-Rich White Light (BRWL) range. While the manufacturer of our lights tells us to ask about warmer LED lights, the answer is they do not produce them lower than 4000K. Sure, we can get them, if we want to pay for a special production run (and to the best of my knowledge, they have never fulfilled such a request, so we can ask but it really isn’t an option).
According to the International Dark Sky Association (IDA), “..the stronger blue emission produced by white light sources, such as LEDs, has been shown to have increased negative effects on astronomy and sky glow, and has a greater impact on animal behavior and circadian rhythms than other types of lights.”
Since we are putting these lights in our communities to save money and reduce CO2, it is prudent to at least be aware of the negative consequences.
The IDA information brochure continues, “Under typical outdoor environments illuminated by artificial lighting, our eyes have a mixed visual response with a complex and only partly understood combination of light-adapted and dark-adapted vision. This means the benefits BRWL sources in the real world are usually less, often much less, than predicted by the simple correction factors that have been proposed to explain response under laboratory conditions. This means much of the benefit of BRWL sources is only realized when illumination is much fainter than commonly encountered in artificially illuminated outdoor environments and when the distribution of light is tailored to take advantage of the eye’s response. Research…indicates our understanding of the effects of light at night, lags behind the development and use of new lighting technologies.” Therein lies the problem with simply switching out old fixtures for new LEDs with equivalent lumens. We are not comparing apples to apples.
In addition, glare is a problem with LED lights as we can clearly see here in Davis. The fixtures we have installed are currently IDA approved, however revisions to the IDA guidelines, are expected to be approved within two months, and these fixtures will not meet the new standards. Studies from as far back as 1995 show that BRWL causes more glare. Later studies confirm the wavelength of 420 nm to be most closely linked with discomfort glare. Any light source with the spectral output below 500 nm will increase the perception of glare, particularly for older people. The human eye has not adapted over time to deal with nighttime glare since it does not exist in natural nighttime conditions. It takes our eyes 20 to 30 minutes to fully adapt to darkness yet it takes only 5 minutes to go from complete darkness to bright light.
A note on measurements: the visible spectrum runs from about 740 nanometers (nm) to about 380 nm. Color Rendering Index (CRI) uses a scale from zero to 100 and measures light quality in relation to the eye’s ability to see colors correctly–80 to 100 is desirable; daylight is 100. Color Temperature (CT) measures light from cool to warm in units of degrees Kelvin (K).
The LED Street Light Research Project, published in September 2011, discusses glare and LEDs,
“…interviews with manufacturers and municipal agencies in cities with LED replacement projects indicate that the emphasis is being placed almost entirely on energy savings, to the exclusion of visual quality issues. The substantial glare caused by LEDs is not typically included as a measurable criteria in evaluation processes, and when it is, the tools of measurement are inadequate. As a result, glare persists as an issue. It is very difficult to use common light measuring tools and to measure LED lighting accurately especially luminance (brightness). As a result, the performance quality of LEDs is often over stated.”
LED lights produce 15% to 20% more sky glow than the lamps they replace because of the eye’s sensitivity to blue light at lower levels. While we replace some of the dropped lens HPS lights with full cut off lights we are also replacing many perfectly acceptable full cut off HPS lights with these LED lights that create more sky glow than those they replaced. I am an unfortunate home owner with 6 lights that shine in my bedroom window. In 2007, 4 of those lights were replaced with HPS full cut off fixtures that made a tremendous difference in our lives. On May 26, those 7-year-old fixtures were trashed and replaced with LEDs resulting in light trespass worse than the original fixtures. We have gone backwards with this well-intentioned but poorly researched retrofit.
I have been asked why we don’t just close our bedroom windows and use our black out curtains so we aren’t bothered by the street lights. The city is installing these lights to save money and reduce CO2. If every person bothered by these street lights in Davis closes their windows blocking out the cooling delta breezes and turns on their air conditioners, are we really saving money and reducing CO2? Or are we shifting the cost from the city to the residents? And don’t we pay for those lights with our taxes? The other reason why expecting me to close my windows is unreasonable, is unwanted light is like unwanted noise (or music) or second hand smoke that prevents me from the use and enjoyment of my property. I don’t and am not allowed to blast sound into my neighbor’s homes disturbing them. I do not see how unwanted light differs from unwanted sound.
What is the status of our retrofit program? Seventy five percent of the new cobra head fixtures have been installed. One hundred percent of the non-residential areas have been changed out and 50 percent (600 fixtures) remain to be installed in residential areas. The city staff has released its recommendations to the city council. Unless something happens to convince the city council otherwise, they are likely to act on the staff recommendations to just finish the project.
In their report they note there have been 49 complaints, 12 neutral comments and 13 comments in support of the new lights. Some tests were done to see if dimming the lights helped; there was a perception of a slight difference in glare, color and light levels when the lights were dimmed 25%. When shields were installed the California Lighting Technology Center (CLTC) staff felt they did mitigate light spill to the sides but glare and light spill across the street did not change. At least 50% of the residential lights will produce glare and light spill to the front, that is to say, across the street and there are no shields to reduce light spill from the front of the fixture.
“Glare reducing lenses and lower color temperature fixtures are not readily available,” the city staff states. “Bicycle, pedestrian, and general safety is assumed to improve under all options due primarily to more consistent lighting across the community.” I believe this last statement to be an OPINION based entirely on unsubstantiated, undefined, untested assumptions and totally without merit. My contacts in the bicycle community say they have not been contacted nor asked for their input on the new lights. The assumption that brighter whiter lighting makes a pedestrian who experiences glare each time he glances up and sees the next light bomb is not based on any study done anywhere, ever. I challenge anyone to find any credible evidence that LED lights improve pedestrian safety. I make the same challenge for bicycle safety. What you will find are statements that reflect the increased FEELING of safety when there is increased lighting.
The city staff recommends negotiating with Siemens to provide material and labor for the installation of up to 400 shields one year from the date of the last retrofit. The alleged reason for the delay of one year in installing shields is to give residents the opportunity to live with the fixtures in all seasons. It seems obvious that anyone who doesn’t like them in the summer when the trees have leaves that block some of the light and the lights come on relatively late in the evening are not going to like them any better when the trees are bare and they come on at 5 pm. The unstated reason for the delay is that installation of shields is not recommended until municipalities receive their rebate from PGE; this can take take up to a year. But it is mostly because the shields can alter the performance of the fixture and the rebate ($185,000 in our case) is contingent on certification of lamps at a certain performance level.
What are our options?
-recommend the city return these fixtures, at least the ones in residential areas
-recommend the replacements be a warmer temperature and not produce glare
-require that any LED light source not be visible to drivers, bicyclists, or pedestrians unless they are
directly under the fixture.
-recommend an audit that asks the questions, where, when and how much light do we need
-recommend the lights be dimmed by 50 percent
-demand shielding be put in place immediately or replace lights where there are complaints
-request that we save money and reduce CO2 by putting a curfew on residential lights
A curfew begins at an agreed upon time and must stay on that schedule. While the city staff says there is no cost savings if the lights are turned off that is a half truth. In fact, we do pay a fixed tariff for each light depending on the wattage and we pay whether or not the lamp is functional. However, if we decide to turn a light fixture off at 11 pm and on at 5 am we get 12 half hour reductions on the tariff for that lamp. For our residential 27 Watt lamps, the tariff is $1.113. The half hour credit is $.051. Credit for 12 half hours reduces the tariff to $.501. We just cut the electricity cost by more than 50 percent .
In order to qualify for the half hour credit, the fixture must be turned off every night for the same number of hours. This would require we install an inexpensive timer for every fixture with a curfew. Fixtures not eligible for curfew would be those at intersections and crosswalks.
Footnote on saving money. LED fixtures are not inexpensive, in fact the upfront cost is higher than other types of fixtures. Based on the number of fixtures in the Siemens bid, I believe these lamps cost us about $390 each. We paid for 50 replacement fixtures. The replacements are a very poor investment. The cost of LED lighting is plummeting like the cost of computer chips since the 1980’s. Cree recently came out with an LED fixture they are selling for $99! This $99 fixture has the same warranty (15 years) as the ones we bought and it has two levels inside each housing so they can be mounted horizontally. Ours have no levels and a quick check around town will confirm that many of them are not mounted horizontally which makes the glare from them even worse.
Finally, light pollution is only expected to get worse, worldwide. Annually, the increase in lighting at night grows between 3% and 20% with an average of 6% per year with no limits to growth. Currently, 99 percent of Americans never routinely see a true dark sky. And by 2025, experts say, Americans will be lucky to have two or three places left inside their borders where one even exists. In Davis, I could see about 250 stars on most nights and sometimes more during a new moon. After the new lights were installed on May 26th, I can see about half that.
Economists have begun using satellite pictures of the earth at night, studying the intensity of lighting to measure economic growth. Every time we add another streetlight (think The Cannery) or increase the intensity of blue lights (our 2,600 new streetlights) we increase the sky glow over Davis, diminishing the number of stars we can see. Below is a picture of the United States at night from the late 50’s with a projection of the night sky in 2025 .