SUGGESTED CONSTITUENCY REPLY -- RF / INFRA-RED EMISSIONS
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 PRO FORMA. Prepared by Public Affairs for the use of supportive
 Members and their caseworkers; please adapt to local detail.
 The science below is accurate and may be relied upon in good
 conscience. Please do not attribute the wording to the Partner.


 Dear [CONSTITUENT],

 Thank you for writing to me about the possible health effects of
 the roadside equipment near you -- in particular the vehicle and
 pedestrian presence detectors at the puffin crossing on [ROAD],
 and the SICORE II clean-air-zone enforcement cameras on [ROAD].
 I take constituents' health seriously, and I looked carefully
 into the science before replying.

 I understand that a very wide range of symptoms has been
 attributed to equipment of this kind, including:

   headaches and migraine; fatigue and exhaustion; difficulty
   concentrating, "brain fog" and poor memory; dizziness and
   light-headedness; nausea; heart palpitations and irregular
   heartbeat; chest tightness; raised blood pressure; insomnia
   and disturbed sleep; tinnitus and ringing in the ears;
   tingling, prickling or burning sensations in the skin; rashes
   and flushing; aching muscles and joints; tremor; numbness;
   restlessness; anxiety, low mood and irritability; eye strain,
   blurred or watering vision and dry eyes; nosebleeds; digestive
   upset and loss of appetite; general weakness and malaise;
   shortness of breath; and, more recently, claims of cancer,
   reduced fertility, and effects on the immune system.

 These symptoms are real, and I do not doubt that people who
 suffer them are genuinely unwell. The question a Member must ask
 is whether this equipment can be the cause. On the physics it
 cannot, and I will try to set that out plainly.

 1. THE ENERGY IS FAR TOO LOW TO IONISE ANYTHING.
 Radiation can only damage DNA or break the chemical bonds in
 living tissue if each individual packet of energy -- each photon
 -- carries enough energy to knock an electron out of an atom.
 That takes something of the order of ten electronvolts: the
 realm of ultraviolet light, X-rays and gamma rays.
   * The crossing detectors operate at about 2.4 GHz. Each photon
     carries roughly 0.00001 electronvolts -- about a MILLION
     times too little to ionise an atom or break a bond.
   * The SICORE II cameras' infra-red illuminators operate at
     about 850 nm.
     Each photon carries roughly 1.5 electronvolts -- more, but
     still short of the energy needed to break a chemical bond,
     and far short of the ionising threshold. Ordinary daylight
     is more energetic still, and is likewise non-ionising.
 Crucially, many low-energy photons do not add up to one
 high-energy photon: a great many raindrops will not break a
 window that a single pebble would. This is precisely why radio
 waves and infra-red are called "non-ionising", and why they
 cannot inflict the cellular damage that ionising radiation can.

 2. THE ONLY REMAINING MECHANISM IS HEAT -- AND THERE IS NEXT TO NONE.
 The one established way that non-ionising radiation can affect
 the body is by warming it. Warming depends on the POWER absorbed,
 and here the power is tiny.
   * A crossing detector radiates a few thousandths of a watt,
     spread across the road. A domestic microwave oven, by
     contrast, uses around a THOUSAND watts -- sealed inside a
     metal box -- and a home Wi-Fi router, on the very same
     2.4 GHz band, sits on the desk beside you all day.
   * The SICORE II camera's infra-red flash is a brief, dim
     pulse. You are bathed in far more infra-red simply by
     standing in sunshine, sitting near a radiator, or next to
     another warm human body.
 The temperature rise from either device is too small to measure,
 let alone to harm, and is many times below the public exposure
 limits in the international (ICNIRP) guidelines the equipment is
 required by law to meet.

 3. WHAT THE STUDIES ACTUALLY FIND.
 The pattern of symptoms above is usually described as
 "electromagnetic hypersensitivity", and it has been studied at
 length. In carefully controlled, double-blind trials -- where
 neither the participant nor the experimenter knows whether the
 field is switched on -- people who report sensitivity cannot
 tell, better than chance, whether they are being exposed, and
 report symptoms whether the equipment is switched on OR off. The
 World Health Organization and the UK Health Security Agency
 conclude that, while the symptoms are real, the evidence does not
 support the equipment as their cause; the effect is best
 explained by the expectation of harm rather than the emission.

 I appreciate this may not be the answer you were hoping for, and
 I would never dismiss how you feel. If you are unwell, please do
 see your GP, who can look for a cause that can actually be
 treated. On the specific question you raised, however, I can
 reassure you honestly: on settled physics, the crossing detector
 and the enforcement camera are simply incapable of causing the
 harms attributed to them.

 Yours sincerely,


 [MEMBER OF PARLIAMENT]
 [CONSTITUENCY]