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Instalatii electrice I16 martie, 2020

Lumina si sanatatea

Dorin BEU, Ph.D., P.Eng., CAPI

Lighting Engineering Laboratory, UTCN

Historical changesThe city that never sleeps

◼ 24 hour rhythm

◼ use of only the built environment

◼ Low lighting level

◼ Blue light!

150 years ago

◼ Human rhythm based on the natural light

◼ Working outside

◼ Siesta

◼ Renewable energy

Balance restored

How important is light for plants?Photosynthesis

The general equation for photosynthesis is therefore:

2n CO2 + 2n DH2 + photons → 2(CH2O)n + 2n DO

Carbon dioxide + electron donor + light energy → carbohydrate

+ oxidized electron donor.

Photosynthesis changes sunlight into chemical energy, splits water

to liberate O2, and fixes CO2 into sugar.

Lighting quality• Patterns of light and dark affect both our perceptions of the world and our

emotional and physiological responses, and thus they are essential in

gathering information about the physical world.

• Good- quality lighting

• Poor- quality lighting

Lighting quality• Patterns of light and dark affect both our perceptions of the world and our

emotional and physiological responses, and thus they are essential in

gathering information about the physical world.

• Good- quality lighting

• Poor- quality lighting

Lighting quality

Human needs affected by light

Are we facing a new way of thinking

lighting?

A revolution – Marc Fontoynont

Visual confort, task performance and social

communication

Green solutions!

Aesthetic judgement

Health, safety and well- being

Facts:

• Recent studies about the growth of the risk developing breast cancer at women and

prostate at men for those who work in the night shift

• Light therapy for old people

• Jet-lag problems

• The situation of the miners from Chile in 2010 -Survival for

69 days without natural light

• The study of NASA in the problems about circadian rhythm (changing the notion of time)

Simple questions?

• Why we sleep at night?

• Why we wake-up in the morning?

• What are chrono-types?

Health, safety and well- being

New retinal photoreceiversS Day/night detectors, which send bright tickles to the neural photobiological path, in order

to control the circadian rhythm:

l peak sensitivity in the blue color.(almost 480 nm), which fits with the spectral

distribution of the sky during the day

l Slow response (about 10 seconds compared

to milliseconds for cones and rods) makes them insensitive to changes

in ambient lighting fast.

l Rarely distributed in the retina (103 compared with 106 108 cones and rods), can

not identify details like cones

T Melanopsin is essential for pineal gland in order to produce or not melatonin.

Circadian photobiology

S Light signals are received by the

photosensors from the retina (others than

those from the cones and rods) which

send signals to the suprachiasmatic

nucleus SCN) via retino-hypothalmic tract

(RHT) and towards pineal glands via

sympathetic nervous system.

S The main hormone responsable for the

circadian rythm is melatonin.

Circadian photobiology

MelatoninMelatonin level

S Stays high during the night when

we sleep

S Comes down in the morning

when we wake up

S Opposite to body’s temperature

Schematic representation of the level of melatonin secretion, body’s temperature

during the night and the afternoon sleep.

New retinal photoreceivers

• ipRGC - (intrinsically photosensitive retinal ganglion cells) discovered in 1990:

Located in the retina , near ganglionic and collecting cells

LAN Light At Night

When people routinely burn the midnight oil, they risk suffering depression and

learning issues, and not only because of lack of sleep. The culprit could also

be exposure to bright light at night from lamps, computers and even iPads.

LAN Light At Night

• Melatonin - oncostatic neurohormone

• Breast cancer risk is several times higher in developed countries

LAN Light At Night

• Artificial light with a strong blue component could affect human circadian

cycles and the hormonal system, and could result in diseases ranging from

sleep disorders, immune system disorders, macula degeneration,

cardiovascular diseases, diabetes and osteoporosis to breast cancer.

• Some comparisons of the light of different artificial light sources claim further

health disadvantages related to fluorescent lamps as compared to incandescent

lamps.

LAN Light At Night

French lighting regulations – July 2013

• Indoor lighting of commercial buildings shall have to be turned off one hour

after the end of the occupation period and facade illumination before 1 am.

• Facade illumination shall be forbidden one hour before sunset and after

1am.

• Lighting of shop windows shall have to be off between 1 am and 7 am.

Principles of good lighting *

1. Daily dose of natural light received by the people of West seems too small.

2. Healthy light is dependent on a healthy dark.

3. Light for biological action must be in the field in which the nonvisual system is

more sensitive(blue)

4. Determining light dose received in the eye (directly from the light

source or reflected fromsurrounding surfaces).

5. The time exposed at the light influences the effect of dose.

* CIE committee report on “Ocular Lighting Effects on Human Physiology, Mood, and Behaviour" (TC 6-11)

New TC committees

• Lighting specifications during the day for populations deprived from sufficient daylight exposure.

• Lighting scenarios to reduce effects of jet-lag

• Daylight exposure optimization

• Clinical treatment through light exposure

• Sleep disorder

• Seasonal Affective Disorder

• Visually impaired persons

• Alzheimer patients

• Vitamin D synthesis

Conclusion

• We only have 130 years of experience in electric

lighting

• Many questions about the effect over 10-30 years

• The need for more investment in research

• Interdisciplinary

Johannes Peter Muller 1801-1858

• Visual perception is related

to specific neural pathway

(start from eye and end in

the brain (area V1).

• Information flux have

attached visual properties.

What we see in fact?

• A reverse image on 4 degree solid angle!

Jonathan

Haidt

Haidt argued that the human mind is like a

rider on an elephant. Rider is reason, and

the elephant shows the emotions in these

proportions 1: 9

We, lighting engineers, consider that the man is a rational being and

for such a man we provide lighting,

but in reality, the human is not rational, but automatic and emotional

being.

Nature is disorderly, powerful and chaotic

• ... we see what we want to see, according to what we know about the world.

We are afraid of chaos and will reduce the uncertainty. We put on the nature

our own system (structure), to simplify everything what can be simplified.

What do we provide?

• The appropriate amount of light

• The size of the observed object

• Contrast

• The time of observation

• Luminance distribution in the visual field

St. Joseph does his work precisely, despite the bad light.

WHAT WE PROVIDE

is not enough!!!

because SEEING IS A COMPLEX PROCESS

with all the consequences of complexity.

Thank you for your attention!