Blue Light Blues

One by one, all of our warm white lights are being replaced by cold, harsh, bluish-white LEDs.  And it is happening fast.

Everywhere.  In our streetlights, our workplaces, even our homes.  How do you like looking into those blue-white vehicle headlights as compared with the yellow-white ones we have been using since the automobile was invented?

LED lighting is the way of the future, don’t get me wrong, but we should be specifying and installing LED lights with a correlated color temperature (CCT) of 2700K or 3000K—with few exceptions—not the 4000K or higher that is the current standard.

Why is 4000K the current standard?  Because blue-white LEDs have a slightly greater luminous efficacy than yellow-white LEDs.  Luminous efficacy is the amount of light you get out for the power you put in, often measured in lumens per watt.  But should luminous efficiency be the only consideration?  What about aesthetics?  In addition to luminous efficacy, there are other, more significant ways to reduce power consumption and greenhouse gas emissions:

  • Use the minimum amount of light needed for the application; no need to overlight
  • Use efficient light fixtures that direct light only to where it is needed; near-horizontal light creates annoying and visibility-impairing glare and light trespass, and direct uplight into the night sky is a complete waste
  • Produce the light only when it is needed through simple switches, time controls, and occupancy sensors; or, use lower light levels during times of little or no activity

Even the super-inefficient incandescent light bulb (with a CCT of 2400K, by the way), operating three hours each night uses less energy than the light source with the highest luminous efficacy operating dusk to dawn.  Think about it.

In my town, as in most now, the soothing orange 1900K high pressure sodium (HPS) streetlights are being replaced with 4000K LEDs.  That’s a big change.  It will completely transform our outdoor nighttime environment.  Warm-white compact fluorescents are 2700K, and even tungsten halogen bulbs are 3000K.  Do we really want or need 4000K+ LEDs?

We are currently witnessing a complete transformation of our illuminated built environment.  Not enough questions are being asked nor direction being given by citizens, employees, and municipalities.  The lighting industry generally wants to sell as many lights as possible at the highest profit margin.  We as lighting consumers need to make sure we have the right kind of light, the right amount of light, and lighting only when and where it is needed.

Bike Path to Nowhere

The Dodgeville area is badly in need of an off-road paved (asphalt) bike path.  Every time I go to Madison, I am envious of all the bike trails they have.  Why can’t small towns like Dodgeville and rural areas have some paved bike paths, too?  Brigham County Park in rural Dane County has a beautiful new trail.  Why not Iowa County?

I’d really like to see the Military Ridge Trail between Dodgeville and Ridgeway paved.  Anyone interested in serving on an ad hoc committee with me to make that happen?

There is a 5.1-mile paved trail called the Shake Rag Trail which runs along US Highway 151 between Dodgeville and Mineral Point, but it is far from ideal.  First of all, there is no safe way to bike to it from Dodgeville!  You can ride through the hospital parking lot to Heritage Lane, head south until you get to Brennan Rd., turn right, but when you get to WI Highway 23, you have to ride along the east shoulder of that busy road with fast-moving vehicles for 0.4 miles to get to the bike path, as shown in the map below.

What a relief!  You’ve now reached the paved bike path, and it is off-road!

But, after traveling only 0.5 mile, the bike path suddenly ends at Chris-Na-Mar Road.

You now ride 0.7 miles on Chris-Na-Mar Road, and then the off-road bike path starts up again.

Now, you get to ride 1.3 miles on an off-road paved bike path.  Yay!  But the bike path again abruptly ends at County Road YD.  It is not clear what you should do next except maybe turn around?

Persistence pays off, and if you soldier on you’ll find that you can ride 2.1 miles on County Road YD until you reach the off-road bike path again.  You’re almost to Mineral Point!

The bike path goes another 0.5 mile until it ends at Shakerag St. in Mineral Point.  You’ve traveled a total of 5.1 miles on the Shake Rag Trail, but less than half of it was on a bona fide bike path.

Don’t get me wrong, I’m really glad that the Shake Rag Trail got built.  But for any of you who have ridden the crushed rock Military Ridge Trail between Dodgeville and Ridgeway (all off-road), you’ll understand how much nicer Military Ridge Trail would be than the Shake Rag Trail if only it were paved.

Earth’s Changing Climate

The Intergovernmental Panel on Climate Change (IPCC) issued an important special report yesterday on climate change.  In the accompanying press release, they state the following:

    • Limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities.  Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This  means that any remaining emissions would need to be balanced by removing CO2 from the air.
    • This report will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.
    • We are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice.
    • Warming of 1.5ºC or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems.

In the Summary for Policymakers, the IPCC states that “warming from anthropogenic emissions from the pre-industrial period to the present will persist for centuries to millennia and will continue to cause further long-term changes in the climate system, such as sea level rise, with associated impacts.”

This last point is very important.  Even if humanity disappeared from the face of the Earth tomorrow, it will take centuries to millennia for greenhouse gases in our atmosphere to return to pre-industrial levels.

Richard Wolfson, Professor of Physics at Middlebury College in Middlebury, Vermont, states in his excellent 2007 video course, “Earth’s Changing Climate” (The Great Courses, Course No. 1219),

The atmosphere, living things, soils, and surface ocean waters all represent short-term carbon reservoirs.  Cycling among these reservoirs occurs mostly on relatively short time scales.  In particular, a typical carbon dioxide molecule remains in the atmosphere only about five years.  But the rapid cycling of carbon through the atmosphere-biosphere-surface ocean system means that any carbon added to that system remains there much longer—for hundreds to thousands of years. Because the added carbon cycles through the atmosphere, the level of atmospheric carbon dioxide goes up and stays up for a long time.

We’ve known about this aspect of climate change for a long time.  It is based on solid science.  Any action we take now, either positive or negative, will affect Earth’s environment many generations into the future.

I know of no better introduction to climate science than Richard Wolfson’s video course.  Even though it was produced 11 years ago, it is still completely relevant.

Earth’s Changing Climate, The Great Courses, Course No. 1219

Bad Lighting at Dodgeville High School

At a school board meeting in November 2017, concerns were raised about inadequate lighting for evening school events, so the Dodgeville School District directed Alliant Energy to install some additional lights.  The lighting was installed during a warm spell in January 2018, and the photographs you see below were taken during the afternoon and evening of June 17, 2018.

Rather than being used only when school events are taking place in the evening, these terrible lights are on dusk-to-dawn 365 nights a year.  They are too bright, poorly directed, poorly shielded, and the glare they cause on W. Chapel St. and N. Johnson St. could pose a safety concern for pedestrians not being seen by drivers experiencing disability glare.  I can imagine that adjacent neighbors are not too happy with the light trespass into their yards and residences, either.

This is a perfect example of poor lighting design and unintended consequences.  How could it be done better?  Look for the solution below the following series of photos documenting the problem.

Bleacher path floodlight produces a great deal of uplight, and illuminates the disc golf course far more than the bleacher path
Bleacher path floodlight is mounted in a nearly-horizontal orientation
Bleacher path floodlight
Bleacher path floodlight
Bleacher path looking towards the bleachers

 

Bleacher path looking towards W. Chapel St.

 

Bleacher path at night
Bleacher path floodlight lighting up the disc golf course. Also note how much brighter the illumination is from the newly-installed blue-white LED streetlight as compared with the orangish light from the older high pressure sodium (HPS) luminaire.
Bleacher path floodlight lighting up the disc golf course and basket
Large tree being brightly illuminated all night long with bleacher path in foreground
Sub-optimal parking lot lighting at Dodgeville High School
Overflow parking floodlight

 

Two additional overflow parking lot floodlights
Overflow parking floodlight

 

Overflow parking floodlights

 

Overflow parking floodlight glare and spill light

 

Overflow parking floodlight glare onto W. Chapel St. in Dodgeville
Overflow parking glare and spill light onto W. Chapel St. in Dodgeville

Solutions

Pedestrian-scale 2700K LED “soft” lighting could be installed along the bleacher path
https://www.rabweb.com/images/features/ledbollards/bollard-hero.png
Or vandal-resistant bollards could be used—even low voltage lighting
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If floodlights must be used, shield them, point them more downwards, and turn them off after 11:00 p.m. each night (or have them on only while evening school events are in progress)

In fact, regardless of the lighting solution, the lights should be either turned off or dimmed down to a lower level later at night.  (Security cameras will see just fine at lower light levels if that is a concern.)

Good neighbor outdoor lighting means minimizing GLUT:

Glare—never helps visibility
Light Trespass—no point in putting light where it is not needed
Uplight—sending light directly up into the night sky is a total waste
Too Much Light—use the right amount of light for the task, don’t overlight

Bike Ride to Ridgeway (and back)

Ridgeway, Wisconsin is a special place.  A point right on the central meridian of the Central Time zone and the 43rd parallel (90° W longitude and 43° N latitude) is within the city limits of Ridgeway, and you can almost get there from here.

The point 43° N, 90° W

You can easily bicycle to this location by taking the Military Ridge State Trail into the west side of Ridgeway and turning north onto Ternes Ct.  I wonder if there’s a marker along Ternes Ct. at its closest point to 43° N, 90° W. If not, we need to put one there.

Getting to the point 43° N, 90° W

But wait!  Right where Ternes Ct. intersects Bier St. and becomes a gravel road, there’s a sign that says “Game Farm, No Trespassing”.  Foiled!

You know, we should have regular bike rides from Dodgeville to Ridgeway and back along the Military Ridge State Trail.  Anyone interested?  The distance from the Wisconsin DNR parking lot in Dodgeville to Badger Mart right next to the trail in Ridgeway is 9.2 miles, so it would be an 18.4 mile round trip along pretty flat terrain.  Badger Mart in Ridgeway is a convenient place to stop for a snack and a beverage before heading back to Dodgeville, and they are open from 5:00 a.m. until 9:00 p.m. every day of the week.

Would love to see this trail receive an asphalt surface someday, but the existing screened limestone surface isn’t bad.

Please post a comment here or email me if you’re interested in making this ride with me from Dodgeville to Ridgeway and back!

Turn Down the Lights, Turn Up the Stars

We are presently witnessing a rapid transformation of our outdoor nighttime environment as many older lighting sources such as high pressure sodium, metal halide, and fluorescent are being replaced with solid state lighting, specifically light emitting diodes (LEDs).  Many of the lighting decisions being made today with little or no citizen input will have consequences that impact our nighttime environment for decades.

Rather than continuing to subscribe to the “more is better, dusk-to-dawn” approach to outdoor lighting, we need to utilize this new technology in creative and innovative ways (many already available) to improve our nighttime built environment while minimizing lighting’s deleterious effects on the natural world.  Three paradigm shifts are needed.

Paradigm Shift #1
Less light will usually work just fine (a little light goes a long way)

Paradigm Shift #2
Dusk-to-dawn lighting → Lighting on Demand

Paradigm Shift #3
Full intensity lighting → Multi-Intensity Lighting (dimmable)

When choosing the amount of light you need, one should always consider the task or tasks needing to be performed.  For example, the amount of light needed to identify a rural intersection is much less than is needed to play a baseball game at night.  In both cases, though, the light needs to be restricted to only the area needing to be illuminated: the intersection or the playing field.

Another example.  When my wife and I bought a house in Dodgeville, Wisconsin back in 2005, our front porch had a 100-watt frosted incandescent light bulb to light the porch that we could turn on whenever we had company in the evening.  Thinking it too bright, we replaced the 100-watt bulb with a 60-watt bulb, then tried a 40-watt bulb, and finally a 25-watt bulb.  The 25-watt bulb adequately illuminated the porch and the stairs leading up to the porch, so in it stayed.

Then there is the issue of dusk-to-dawn lighting.  Many years ago, we switched outdoor lighting on or off as needed, but technological advancements later allowed us to have a light come on at dusk and stay on all night until dawn.  Now, think of all those lights burning when no one is there to use them.  If security is a concern, there is even newer technology that will do a far more effective job of detecting intruders than simply leaving a light on all night long.  In fact, a dusk-to-dawn light is not needed at all as part of an effective security system.  So, why not use 21st-century technology to have outdoor lights automatically turn on when needed and turn off when not needed?  Some LED light bulbs even come now with integrated occupancy sensors.  Lighting on demand could and should be replacing most dusk-to-dawn lighting within the next few years.

What about some roadway and parking lot lighting that must remain on all night long?  Those lights could be at full brightness during times of high traffic such as during the evening hours, but dimmed to 50% when traffic is lower, such as after midnight.  Once again, 21st-century technology makes this easy to do.

LED lighting lends itself very well to frequent on-off switching and dimming, but much of what is currently being installed is too blue.  As you can see in the table below, typical LED light sources have a substantial “spike” at the blue end of the visible light spectrum as compared with other white light sources.

Not only does blue light scatter more in the atmosphere and within our eyes, but many people perceive bluish-white light as colder, more clinical, than the warmer white light where this blue spike is absent, as shown below.  The blue spike in LED lighting can be removed either by using filtering, or by using a different phosphor that gives a warmer white spectrum.  Strongly preferred for both indoor and outdoor lighting are LED light sources with a correlated color temperature (CCT) of 2700K or 3000K.  2700K is the standard for indoor lighting, and yet 4000K is most often used for outdoor lighting.  Why?  Let’s move the standard for outdoor lighting to 2700K or 3000K.

By properly shielding lights so they only shine downwards, by using lights that are no brighter (or bluer) than they need to be, and by turning lights off when they are not needed—or dimming them during times of lower activity—we all will be helping to improve both our natural and celestial environment.

Turn Down the Lights, Turn Up the Stars *

* Suzy Munday, May 11, 2018

Additional Thoughts

In thinking about 21st-century lighting, one’s thoughts naturally towards 21st-century power generation.  We do not think often enough about the many advantages of a more decentralized power grid, where nearly everyone is generating some power with solar panels and small-scale wind turbines, as well as other local sources of energy such as geothermal.   As we once again consider building nuclear power plants (which will still be quite vulnerable to terrorism) and continue to build expensive fossil fuelish power plants and ugly high-voltage transmission lines, why not a paradigm shift towards decentralized energy production instead?

Illumination Levels: Then and Now

The following excerpts are from the 1911 and 1925 editions of A Text-Book of Physics by Louis Bevier Spinney, Professor of Physics and Illuminating Engineering at Iowa State College (now Iowa State University) in Ames, Iowa.

From the 1911 edition…

ILLUMINATION

516. The intensity of illumination of any surface is defined as the ratio of the light received by the surface to the area of the surface upon which the light falls.  A unit of intensity which is oftentimes employed is known as the foot candle, and is defined as the intensity of illumination which would be present upon a screen placed at a distance of one foot from a standard candle.  The meter candle is a unit of intensity which is employed to some extent.

The table below gives a number of values of illumination such as are commonly observed, the intensity of illumination being expressed in foot candles.

Suitable for drafting table    .    .    .    .    .    5 to 10

Suitable for library table   .    .    .    .    .   .    3 to 4

Suitable for reading table   .    .    .    .    .   .  1 to 2

Required for street lighting   .    .    .    .    .  0.05 to 0.60

Moonlight (full moon)    .    .    .    .    .    .   .  0.025 to 0.03

 

And from the 1925 edition…

ILLUMINATION

532.  The eye has a remarkable power of adaptation.  In strong light the pupil contracts and in weak light expands, so that we are able to use our eyes throughout a range of illumination which is really quite astonishing.  However, the continued use of the eyes under conditions of unfavorable illumination causes discomfort, fatigue, and even permanent injury.  Experiment and experience show that eye comfort, efficiency, and health considerations demand for each kind of eye work a certain minimum illumination.  Some of these illumination values taken from tables recently compiled are given below.

FOOT-CANDLES

Streets    .    .    .    .    .    .    .    .    .     .    .    .    .    .    1/20 to 1/4

Living rooms; Halls and passageways    .    .    1 to 2

Auditoriums; Stairways and exits;
Machine shops, rough work    .     .    .    .    .    .  2 to 5

Classrooms; Laboratories; Offices;
Libraries; Machine shops, close work    .    .    5 to 10

Engraving; Fine repairing work; Drafting;
Sewing and weaving, dark goods  .    .    .    .     10 to 20

 

By comparing the 1911 and 1925 data with the illumination levels recommended today by IESNA, we can see that recommended light levels for streetlighting have increased anywhere from 40% to 380% since 1925.  A cynic might say that we need more light than our ancestors did to see well at night.  As you may have noticed, light levels have been steadily creeping upward, everywhere, over the last few decades.

Recommended Illumination Levels for Streetlighting

Year        Minimum    Average    Maximum

1911             0.05                ???               0.60

1925           0.05               0.25               ???

1996          0.07                1.20               ???

Have you ever noticed how well you can see at night when the full moon is lighting the ground?  The full moon provides surprisingly adequate non-glaring and uniform illumination at just 0.03 footcandles!  For inspiration, take a look at the following text from an Ames, Iowa city ordinance, dated July 8, 1895:

“The said grantees shall keep said lamps in good condition and repair, and have the same lighted every night in the year from dark until midnight, and from 5:00 a.m. until daylight, except such moonlight nights or fractions of the same as are not obscured by clouds, and as afford sufficient natural light to light the streets of said city.”

This was originally published as IDA Information Sheet 114 in November 1996, and authored by David Oesper.

Dodgeville Street Project Proposals

As illustrated below, a lot of drivers in Dodgeville take a dubious “short cut” from King St. to Iowa/Bequette by way of W. Leffler instead of taking King St. all the way to Iowa/Bequette.  Most of the people taking this short cut are leaving Lands’ End and heading to their homes in the Madison metro area.  These folks are not Dodgeville / Iowa County taxpayers.  Here’s the problem.  W. Leffler has been beat all to hell and is badly in need of resurfacing.  All that Lands’ End traffic has contributed mightily to the degradation of W. Leffler.  Now, as a bicycle commuter trying to get from Lands’ End to most of the rest of Dodgeville (always a dangerous proposition), it makes sense to use W. Leffler to minimize the amount of time I have to ride my bike on busy King St. and very busy Iowa/Bequette.  But W. Leffler is so broken up that for safety reasons I need to ride near the middle of the road—but a steady stream of vehicles takes the short cut down W. Leffler instead of staying on King St. up to convenient entrance ramp to Iowa/Bequette.  It is a no-win situation for Dodgeville bicyclists.  One solution would be to have W. Leffler dead end at King St. with only a bike-path connector between King St. and W. Leffler, though I suspect that would be quite unpopular in our auto-centric community.  Another solution would be to resurface W. Leffler and never let it degrade this much again.  Is that too much to ask?  It is a short street, after all.

The Lands’ End Shortcut to the Madison Metro Area

I’m not a big fan of roundabouts, but if ever there was a case for one it would be at the intersections of Iowa/Bequette, N. Main, E. Spring, and W. Spring.  In my crude map overlay below, it looks like one building would probably have to be removed.  The roundabout would need to be designed to easily accommodate the comings and goings of fire trucks from the nearby fire station.  Presently, this “octopus” of an intersection is dangerous, and I completely avoid ever making a left turn there.  Why not prohibit all dangerous left turns at these intersections by installing a roundabout where every turn will be a right turn?

Where a roundabout is needed in Dodgeville

Falling Ice Chunks

There are a number of documented cases of large chunks of ice falling out of a clear blue sky.  After we eliminate ice falling from airplanes or nearby thunderstorms, there still appear to be some events that remain unexplained.

I first heard of this phenomenon over ten years ago, when a 50-pound chunk of ice fell through Jan Kenkel‘s roof in Dubuque, Iowa on Thursday morning, July 26, 2007.

These unexplained falling ice chunks are been given a rather inappropriate name: megacryometeor.  Why don’t we just call them “falling ice chunks”  or FICs for short, at least until they receive an explanation?

It almost certainly is some sort of unusual atmospheric phenomenon, as ice balls from space would vaporize before they reach the ground.

An unknown blogger (in Spain?) has been documenting news articles about all manner of falling ice chunks since the Dubuque event.  The blog is called HALS, which is the plural abbreviation for hydroaerolite—certainly a better name than “megacryometeor”—though this perhaps is also a geological term used to describe “silty sediments transported by the wind and deposited on a temporarily wet surface”.

Obviously, more peer-reviewed scientific research needs to be done on these falling ice chunks, megacryometeors, hydroaerolites, or what have you.

The LED Lighting Revolution

Solid state lighting, namely light-emitting diodes (LEDs), are completely revolutionizing indoor and outdoor lighting.  Here’s why:

  1. White LEDs on the market today have a system luminous efficacy ranging from 50 (least efficient) to 80 (average) to 140 (most efficient) lumens per watt.  This far exceeds the luminous efficacy of incandescent (5-35 lumens/watt), and generally exceeds compact fluorescents (45-60 lumens/watt).  Prototypes of the next generation of white LEDs have luminous efficacies up to 150 lumens/watt, and theoretically 200-250 lumens per watt may someday be achievable.  Since the traditional white light source of choice for outdoor lighting has been metal halide with a luminous efficacy of 65-115 lumens/watt, white LEDs are well on the way towards replacing metal halide.  Even the more efficient orange high pressure sodium (HPS) lights, with an efficacy of 150 lumens/watt, are nearly matched by the best white LEDs.  Only monochromatic low-pressure sodium (LPS) with an efficacy of 183-200 lumens/watt will give more lumens per watt than the best white LEDs.
  2. White LEDs last much longer than other light sources: 50,000 to 100,000 hours (between 12 and 24 years, operating dusk-to-dawn 365 days a year).  In comparison, high pressure sodium typically lasts about 5 years, and metal halide a little less at 4 years.
  3. Unlike high-intensity discharge (HID) sources such as metal halide, HPS, LPS, and mercury vapor, white LEDs are “instant on / instant off” with no warmup time to full brightness, so they can be switched on and off as often as you like with no shortening of bulb life; and they are easily dimmable. LEDs will render dusk-to-dawn lighting a questionable option rather than an operational necessity.

My only concern is that we finally “get it right” with LEDs instead of blindly following the “more is better” philosophy as we have with every lighting efficiency improvement in the past.  Low levels of white light (fully shielded to minimize direct source glare) is the most effective and efficient way to provide adequate illumination.  This shouldn’t come as a surprise, however.  Think of the light provided by a full moon as we have this week.

Unfortunately, most places that is not what is happening.  Light levels are increasing, as is the amount of lighting.  We seem well on the way towards eliminating anything resembling a natural nighttime environment for most people.  I don’t know about you, but that is not a world I want to live in.

References
DIAL (15 June 2016). Efficiency of LEDs: The highest luminous efficacy of a white LED.  Retrieved from https://www.dial.de/en/blog/article/efficiency-of-ledsthe-highest-luminous-efficacy-of-a-white-led/.

Kyba, C., Kuester, T., et al. 2017, Science Advances, 3, 11, e1701528