Astronomical Society of Victoria Inc
Registered number
A0002118S
GPO Box 1059
Melbourne, Vic 3001
Australia
Sic itur ad astra
www.asv.org.au
24 November 2010
Mr John Brumby MLA
Level 1
1 Treasury Place
Melbourne Vic 3000
Our ref: lp241
Mr Ted Baillieu MLA
325 Camberwell Road
Camberwell Vic 3124
Mr Greg Barber MLC
Suite G-01
60 Leicester Street
Carlton Vic 3053
Dear Party Leaders,
PROPOSED ‘ENERGY-SAVING’ STREETLIGHTS ARE HEALTH AND
ENVIRONMENTAL HAZARDS
The replacement streetlights proposed in current electioneering have not hitherto been
properly examined for adverse effects on health, biodiversity and the environment.
Exposure of humans and other mammals to artificial light at night can disrupt their
circadian rhythms and suppress secretion of the neurohormone melatonin.
Established or possible consequences include increased risks of certain cancers,
obesity, Type 2 diabetes and dementia. Adverse consequences may become apparent
only after many years of ordinary exposures to light at night.
The American Medical Association has a policy condemning light pollution for
reasons including its potential carcinogenicity.
The blue component of light has the strongest adverse circadian effects. Blue-rich
light sources include mercury vapour lamps used for existing streetlighting in
Melbourne’s suburban streets, fluorescent lamps including the compact fluorescent
lamps (CFLs) promoted as energy-saving, metal halide lamps used for sports and
billboard floodlighting, blue and bluish-white light emitting diodes (LEDs), and
screens for TV, video and computers. Safer blue-poor sources include incandescent
light bulbs, red, yellow and green LEDs and the high pressure sodium (HPS) lamps
that give an orange tint to Melbourne’s main roads.
In November 2009, the UK Royal Commission on Environmental Pollution
concluded that light pollution, which includes light spill and glare, should be reduced
greatly and that unless and until supported by further biological studies, replacement
streetlights should not use lamps that emit more blue light than existing sodium
lamps. The fluorescent lamps used in the streetlights proposed for Melbourne do not
comply with this recommendation.
Itai Kloog and colleagues have published several studies of cancer rates in 147 towns
in Israel and 146 countries worldwide as a function of satellite measures of upward
waste light from those places. There are no significant correlations for light with
colon or lung cancer (included as negative controls), but strong positive correlations
with breast and prostate cancer; see the following graph. Correlation does not
necessarily mean causation, but the results are consistent with numerous laboratory
studies on adverse biological effects of exposure to light at night.
ANNUAL CANCER RATE V. LIGHT AT NIGHT
Kloog et al. (2009, 2010)
Cancer Rate
per 100 000
200
Prostate Cancer
100
Breast Cancer
0
0
50
100
150
Light at Night [Satellite, nW/(cm 2.sr)]
Using reliable published data, I have calculated the change in blue light emissions
when a lamp such as an ‘energy-saving’ fluorescent is substituted for the existing
mercury vapour type. Coupled with Kloog’s results, it is then easy to calculate the
expected change in cancer risks.
Compared with light from the existing mercury vapour lamps, light from the lamps in
the proposed streetlight changeover will have a 13% additional risk of breast cancer
and 37% additional risk of prostate cancer. If instead the change is made to bluishwhite LED streetlights, which are already in trial use in Portugal, the increases in risks
are still bad, 8% and 22% respectively. But if the UK Royal Commission line is
followed and the conversion is to high pressure sodium lamps, the respective results
would be -10% and -29%, ie useful reductions in cancer risks. Furthermore, about the
same amount of light on the road would be produced by using 50-W HPS lamps,
representing energy savings of about 37% compared with the existing 80-W mercury
lamps. Even with superior full cutoff fittings to eliminate unused upwards waste
light, the cost would still be lower. There would also be a welcome reduction of over
50% in artificial skyglow, but the current changeover proposal would increase the
skyglow effect by 140% or more, which greatly concerns this Society.
The case against the current proposal appears already to be strong enough to warrant
application of the Precautionary Principle, which is enshrined in Victorian health and
environmental laws: if a public health or environmental risk poses a serious threat,
lack of full scientific certainty should not be used as a reason for postponing measures
to prevent or control the threat. By all means let us has have reduced-energy
streetlighting, but not at the terrible costs attached to the present proposal.
Yours faithfully
Barry A. J. Clark PhD
Director, Outdoor Lighting Improvement Section
Astronomical Society of Victoria Inc
[Registered number A0002118S]
http://www.asv.org.au
Phone: (03) 9459 2760
Email: bajc@alphalink.com. Au
Addendum: Some of the references used in this work
Blask DE, Dauchy RT, Brainard GC, Hanifin JP. (2009) Circadian stage-dependent
inhibition of human breast cancer metabolism and growth by the nocturnal melatonin signal:
consequences of its disruption by light at night in rats and women. Integrative Cancer
Therapies, 8(4) 347 –353. DOI: 10.1177/1534735409352320. Online at
http://ict.sagepub.com
Kloog I, Haim A, Stevens RG et al. (2008) Light at night co-distributes with incident breast
but not lung cancer in the female population of Israel.
Chronobiology International, 25(1): 65-81. ISSN 0742-0528 print/ 1525-6073 DOI:
10.1080/07420520801921572. Online at
http://dx.DOI.org/10.1080/07420520801921572
Kloog I, Haim A, Stevens RG et al. (2009) Global co-distribution of light at night (LAN) and
cancers of prostate, colon, and lung in men.
Chronobiology International, 26(1): 108-125. DOI: 10.1080/07420520802694020.
Online at http://dx.DOI.org/10.1080/07420520802694020
Kloog I, Stevens RG, Haim A, Portnov BA. (2010) Nighttime light level co-distributes with
breast cancer incidence worldwide.
Cancer Causes Control. Published online, 3 August 2010 DOI: 10.1007/s10552-010-9624-4
Online at http://dx.DOI.org/10.1007/s10552-010-9624-4
Stevens RG. (2009) Light-at-night, circadian disruption and breast cancer: assessment of
existing evidence. International Journal of Epidemiology [Epub ahead of print, 23 April
2009] PMID: 19380369. Online at http://www.ncbi.nlm.nih.gov/pubmed/