Light and Sound
as serious pollutants
Jan Hollan
CzechGlobe –
Global Change Research Institute
(of Acad. Sci. Czech Rep.)
and
Department of Public Health,
Masaryk University, Brno
Pollution: what's that?
• centuries ago: religious notion only
• 60's: toxic additives to the environment
• now:
• alteration of the natural state by adding
anything
• – if harmful to us or other beings,
• that might be difficult to find
Pollutants affecting physics of
environment
• radiation
• - electromagnetic waves
• - acoustic waves
• heat
• (like that from thermal power plants)
• particulate matter in the air
• greenhouse gases
• (= gases absorbing and emitting longwave
    infrared radiation)
• (see more on IS for 3. grade on PM and Climate Change)
Radiation
• at which wavelength ranges
• is the energy flux density around us
• really large?
Radiation
• - at those we feel as heat:
• Solar (tenths of a micrometre to several
micrometres):
• up to 1 kW/m2
- but not all the time
• longwave infrared (3 μm to over 100 μm):
• 0.4 kW/m2
- from our environment at
 18 ºC, all the time
• 0.5 kW/m2
- from our face if very warm
• 1/3 kW/m2
- from the atmosphere to the
surface: the average greenhouse effect
Radiation in public view
• something surely dangerous, harmful
• - that from decay of radioactive elements:
ionizing radiation
• It is measured in energy terms (J/kg), but
its influence is chemical in fact
• even UV radiation affects molecular bonds
and is harmful (even if we need it a bit: D)
Radiation which matters more
• ionizing radiation: strict rules, good
measurement, no real problem for most
people
• UV: everybody knows
• Visible radiation (light), audible radiation
(noise) have far more serious impact to all
of us
Noise then and now
• how to get back to harmless levels?
Noise?
•
Noise - various meanings
• strong sound
• sound with no recognizable tones, no
melody
• any sound we don't want to hear
• antipode of silence
• Noise – the same root as Nausea
Noise / Sound
• Sound pollution?
• (sound: OK, good, healtny, reasonable...)
• Therefore: Noise pollution
• or, better, Acoustic pollution
More noise targeting us
• Natural phenomena
• Anthropogenic sources, preindustrial
• Its new sources in the 20-th century
• … and in the 21-st one...
Lack of silence
and people being addict to it
Physics of Sound
• pressure fluctuation
• energy flux: a square of pressure amplitude
Weber-Fechner law
• what we perceive, is the ratio of inputs
• - i. e., the increment of the
• logarithm
Quantification
• L
p
= 10 dB · log(p
2
/p
0
2
)
• p
0
= 2 · 10
−5
Pa
• L
I
= 10 dB · log( I / I
0
)
• I0
= 10
−12
W/m
2
•
• That's for 1000 Hz...
What's 1000 Hz?
• and what spectral composition the real
sounds have,
• like speech
• ...from Voice type on Wikipedia:
Damage of “hairs”
• that is, of amplification 105
times (50 dB),
esp. for high frequencies:
• http://www.cochlea.org/en/noise
• http://www.cochlea.eu/en/pathology/presbycusis
• (on hair cells:
http://www.cochlea.eu/en/hair-cells )
Some loudness levels
• pneumatic chipper at 1 metre 115
• hand-held circular saw at 1 metre 115
• power lawn mower at 1 metre 92
• diesel truck 50 km/h at 20 metres 85
• passenger car 60 km/h at 20 metres 65
• conversation at 1 metre 55
• quiet room 40
• … and what about less?
• - we don't really measure silence
Ten times, two times, three
times..
•
• How many decibels it amounts to?
5 dB, that is some ratio of energy
fluxes
• and further 5 dB the same ratio
• together, it is 10 dB, that is 10x more
• so, 5 dB is a square root of that, or roughly
• 3:1 ratio:
• 5 dB more means (just a bit more than) 3x
more
•
• and 3 dB, 6 dB, 9 dB?
5 dB, that is some ratio of energy
fluxes
• and further 5 dB the same ratio
• together, it is 10 dB, that is 10x more
• so, 5 dB is a square root of that, or roughly
• 3:1 ratio:
• 5 dB more means (just a bit more than) 3x
more
•
• and 3 dB, 6 dB, 9 dB?
• 2x, 4x, 8x
• (now you'll be able to read logarithmic scale...)
Health effects
• en.wikipedia.org/wiki/Noise_health_effects
•
• hearing impairment – over the aging-dependent one
• (high frequencies most affected, loss of speech
recognition)
• tinnitus
• hypertension
• cardiovascular
• discomfort, anger
• sleep disturbance
•
Sleep well?
• Darkness
• and silence
• are a must
Technical measures
against noise
•
• barriers to its propagation
•
• emission reduction
•
• protect yourself
Light as a pollutant
• Light pollution – no heavy issue?
•
• Outdoors: any light added artificially
• (at night) alters its natural state
•
• Indoors? It has no natural state, being
artificial itself. As long as we light it on
purpose:
• light which could harm our health...
Darkness: a basic attribute of
night
• Darkness, what's that?
•
• Less light than short ago
• or in adjacent area.
• Common in daytime too...
•
• There is light outdoors in nature at night,
• but less of it below a roof or in a forest.
•
• No light: just totally enclosed spaces.
Darkness unwanted
- a symbol of ugliness
- source of anxiety and fear
- …but no real danger
- just a necessity to move with more caution
•
• we see at night: night is not black, just gray
•
Darkness unwanted
- a symbol of ugliness
- source of anxiety and fear
- …but no real danger
- just a necessity to move with more caution
•
• we see at night: night is not black, just gray
•
Darkness wanted
- for rest
- contemplation or prayer
- storytelling
- privacy
- and for the nature, of course
•
•
•
Light themes
• discussion: do you have enough darkness
for sleep? How do you protect yourselves
from light if it disturbs you?
• How long do you sleep in various situations
(response on leaflets)
• Why the sleep is so important, even for
studying...
• light measurement below the table, by the
wall, by the window, outside, to the eyes
• yellow glasses influence
Day and night alteration:
the basic rhytm of our world
- sunny day 30 thousand to 100 thousand lux
- 1/1000 lx at night
- overcast: 3x to 30x less
- day/night ratio: 3 millions to 1000 millions
- full moon night – 1/10 lx
(the ratio day/night diminishes 100x)
•
•
log (horizontal illuminance / 1 lx)
clear sky, with/out Moon
Artificial lighting
- originally, just flames (wood, fat), not easy
and not everywhere
- then enhanced flames
- then electricity, everywhere, whole night
- 24 / 7 ...
Its advantages
- people out of nature don't like darkness,
even adults
- darkness is full of ghosts
- today, no ghosts, but: murderers, robbers...
- seeing your way makes walking or riding
easier
- but no crime reduction, on the contrary...
and disadvantages
- loss of natural habitat  (species disappear,
ecosystems, culture, quality of life)
- people don't know night environment any
more
- visibility and orientation impairment due to
glare
- loss of touch of the Universe
- tremendous expenditures
- and greenhouse gas emissions
- health impairment due to lacking darkness
The first awareness that a
problem exists – the 60's
some astronomers
- before the discharge lamps began to
replace old bulbs and before the superstition
that
“everything is to be lit” became common
but:
Squires WA, Hanson HE. 1918. The
destruction of birds at the lighthouses on the
coast of California. Condor 20: 6–10.
Outdoor lighting impacts,
Czechia, 2003, one thoudand
persons >15 years
sleep disturbance by 5 %, due to light at night
pentrating to bedrooms as one of the two
most serious reasons
unwanted, not enough reduced light into
bedroomse, affecting another 10 %
using night shades with success, further
20 %
glare perceived as a problem by tens of per
cent
replacement of true nighttime landscape by
lamps themselves – almost half of the
population complains,
diminished visibility of stars due to glare, says
almost half of the population
too bright sky even where there is no glare,
says quarter of the population.
... loss of heavens may be more serious than
we might guess...
Brno, Kuhberg
• Clear sky: 1 to 2 centilux instead of 1
millilux
• Overcast: decilux levels
Life in nature
• most animals active at night
• darkness is the basic protection
• alteration of light environment is fatal for
them
•
• The points or areas of superhigh luminance
are the worst,
• but
• even the mere absence of natural darkness
is a problem
Some impacts
- turtles going away from sea instead towards
- confused, injured, dead birds
- eutrophicated freshwaters
- decimated insect populations, influencing
whole ecosystems (mayflies 100 years ago,
now...)
- stress for coral reefs (added to temperature,
acidity, chemical pollution)
- where are the fireflies?
Light is a serious pollutant
• Photopollution:
• degradation of photic habitat
• by artificial light
• (Verheijen, 1985)
•
• Darkness is a biological imperativ
•
• Scotobiology
Circadian rhythm, melatonin
• natural night and melatonin production is
11 h in average (more in winter, less in
summer)
•
our electric culture shortened it to the
sleeptime
•
• breast and prostate cancer, obesity,
diabetes
Stevens, R.G. Electric power use and breast cancer: a hypothesis. Am.
J. Epidemiol. 125, 556 (1987).
Stevens, R.G. Light-at-night, circadian disruption and breast cancer:
assessment of existing evidence. International Journal of Epidemiology
38, 963 -970 (2009):
Background Breast cancer incidence is increasing globally for largely
unknown reasons. The possibility that a portion of the breast cancer
burden might be explained by the introduction and increasing use of
electricity to light the night was suggested >20 years ago.
Methods The theory is based on nocturnal light-induced disruption of
circadian rhythms, notably reduction of melatonin synthesis. It has
formed the basis for a series of predictions including that non-day shift
work would increase risk, blind women would be at lower risk, long sleep
duration would lower risk and community nighttime light level would codistribute
with breast cancer incidence on the population level.
Results Accumulation of epidemiological evidence has accelerated in
recent years, reflected in an International Agency for Research on
Cancer (IARC) classification of shift work as a probable human
carcinogen (2A). There is also a strong rodent model in support of the
light-at-night (LAN) idea.
Conclusion
If a consensus eventually emerges that LAN does increase risk,
then the mechanisms for the effect are important to elucidate for
intervention and mitigation. The basic understanding of
phototransduction for the circadian system, and of the molecular
genetics of circadian rhythm generation are both advancing
rapidly, and will provide for the development of lighting
technologies at home and at work that minimize circadian
disruption, while maintaining visual efficiency and aesthetics. In
the interim, there are strategies now available to reduce the
potential for circadian disruption, which include
• extending the daily dark period,
• appreciate nocturnal awakening in the dark,
• using dim red light for nighttime necessities,
• and unless recommended by a physician, not taking melatonin
tablets.
Kloog, I., Haim, A., Stevens, R.G., Barchana, M. & Portnov, B.A.
Light at Night Co-distributes with Incident Breast but not
Lung Cancer in the Female Population of Israel.
Chronobiology International 25, 65-81 (2008).
Kloog, I., Haim, A., Stevens, R.G. & Portnov, B.A.
Global Co-Distribution of Light at Night (LAN) and Cancers of
Prostate, Colon, and Lung in Men.
Chronobiology International 26, 108-125 (2009).
Kloog, I., Portnov, B.A., Rennert, H.S. & Haim, A.
Does the Modern Urbanized Sleeping Habitat Pose a Breast
Cancer Risk?
Chronobiol Int 28, 76-80 (2011)
Due to its disruptive effects on circadian rhythms and sleep
deprivation at night, shiftworking is currently recognized as a
risk factor for breast cancer (BC). As revealed by the present
analysis based on a comparative case-control study of 1679
women, exposure to light-at-night (LAN) in the “sleeping
habitat” is significantly associated with BC risk (odds ratio
[OR]=1.220, 95% confidence interval [CI]=1.118–1.311;
p<.001), controlling for education, ethnicity, fertility, and
alcohol consumption. The novelty of the present research is
that, to the best of the authors' knowledge, it is the first study
to have identified an unequivocal positive association
between bedroom-light intensity and BC risk. Thus,
according to the results of the present study, not only should
artificial light exposure in the working environment be
considered as a potential risk factor for BC, but also LAN in
the “sleeping habitat.”
Gooley, J.J. et al. Exposure to Room Light before Bedtime
Suppresses Melatonin Onset and Shortens Melatonin
Duration in Humans. J Clin Endocrinol Metab
(2010).doi:10.1210/jc.2010-2098
Millions of individuals habitually expose themselves to room light in the hours
before bedtime, yet the effects of this behavior on melatonin signaling are not
well recognized. Objective: We tested the hypothesis that exposure to room light
in the late evening suppresses the onset of melatonin synthesis and shortens the
duration of melatonin production. Design: In a retrospective analysis, we
compared daily melatonin profiles in individuals living in room light (<200 lux) vs.
dim light (<3 lux). Patients: Healthy volunteers (n = 116, 18-30 yr) were recruited
from the general population to participate in one of two studies. Setting:
Participants lived in a General Clinical Research Center for at least five
consecutive days. Intervention: Individuals were exposed to room light or dim
light in the 8 h preceding bedtime. Outcome Measures: Melatonin duration, onset
and offset, suppression, and phase angle of entrainment were determined.
Results: Compared with dim light, exposure to room light before bedtime
suppressed melatonin, resulting in a later melatonin onset in 99.0% of individuals
and shortening melatonin duration by about 90 min. Also, exposure to room light
during the usual hours of sleep suppressed melatonin by greater than 50% in
most (85%) trials. Conclusions: These findings indicate that room light
exerts a profound suppressive effect on melatonin levels and shortens the body's
internal representation of night duration. Hence, chronically exposing oneself to
electrical lighting in the late evening disrupts melatonin signaling and could
therefore potentially impact sleep, thermoregulation, blood pressure, and glucose
homeostasis.
Pollution of the enviroment by
man-made light
still increases, quickly
The rise should be stopped and
reversed, so that we get to a
sustainable course
Similar to fossil carbon
emissions
Both pollutants considred harmless 40 years
ago,
both are very harmful.
Solution:
don't waste so much, be careful
Basic rules for outdoor lighting
(like in Slovenia and most of
Italy)
No emissions horizontally and upwards
Using just that much light, what's necessary
for the task, no more than 1 cd/m2
or 10 lx
Ads max. 10 x more luminance than
surroudings (3 x is enough)
Yellow, faint light (lux to dekalux)
for night work
and just centilux/millilux levels
for moving during sleeptime
should become a norm
Can you spoil your eyes by faint light?
• Did you ever hear „light up! don't damage your
vision“?
• What physiology mechanism could do that?
• All creatures, do they have their vision
spoiled? Do just the happy people supplied
with electricity see really well when old?
• Faint light does not contract eye pupils, so the
vision is to be properly in focus. People over
50 have to use various glasses, cheap ones
are OK, but more than 1 or 2 are needed
• Very faint light implies more effort for the brain
only, so we are tired and go to sleep sooner –
OK!
Light is a good servant,
but a bad lord!
http://amper.ped.muni.cz/light/declaration/