EEfeitos dos Telefones Celulares sobre a feitos dos Telefones Celulares sobre a Saúde HumanaSaúde Humana

Dr. Renato Sabbatini

Faculdade de Medicina

UNICAMP

O Que São Telefones CelularesO Que São Telefones Celulares

São pequenos rádios que operam com baixos níveis de potência de transmissão

Utilizam ondas eletromagnéticas invisíveis, na mesma faixa usada pelos fornos de microondas, rádio e TV

Todos se conectam a antenas centrais chamadas de estação rádio base

Before and AfterBefore and After

Top: You can see Martin Cooper making a phone call on the first mobile cell phone ever invented.

Bellow: You can see today’s type of mobile cell phone.

Martin Cooper

Cell Phone Usage ExplodesCell Phone Usage Explodes

In 1994, 16 million Americans subscribed to cellular phone services. Today, more than 110 million Americans are subscribers.

How Cell Phones WorkHow Cell Phones Work

1. Transmitter takes sound of voice and encodes it onto a continuous sine wave

2. Transmitter sends signal to the antenna

3. Antenna propagates the signal (electromagnetic radiation)

Electromagnetic RadiationElectromagnetic Radiation

Made up of waves of electric and magnetic energy moving at the speed of light

All electromagnetic energy falls on the electromagnetic spectrum, which ranges from extremely low frequency (ELF) radiation to X-rays and gamma rays

Types of Electromagnetic RadiationTypes of Electromagnetic Radiation

Ionizing radiation:• enough electromagnetic energy to strip atoms and

molecules from the tissue and alter chemical reactions in the body. E.g. Gamma rays and X-rays

Non-ionizing radiation: • typically safe• causes some heating effect, but usually not enough to cause

any type of long-term damage to tissueE.g. Radio-frequency energy, visible light and microwave radiation

Radiation Health ScaresRadiation Health Scares

Magnetic fields from power lines and leukemia in children (late 1970s)

• Subsequent studies found no connection between cancer and power lines

Cancer from computer monitors (around same time)• While some radiation emitted from computer monitors,

studies have shown that they don't raise cancer rates Potential for radiation damage caused by cell phones (mid

1990s)• Studies on the issue continue to contradict one another

Public ReactionPublic Reaction

Health Scare ReasoningHealth Scare Reasoning

All cell phones emit some amount of electromagnetic radiation

Most users place phone against head Good chance that some of the radiation will

be absorbed by human tissue

Radiation AbsorptionRadiation Absorption

Computer model of human head in cross section shows distribution of the energy absorbed from a cellular telephone handset

Most of the energy is absorbed within the first 1-2 cm beneath the surface of the skull

Are We SafeAre We Safe

FDA: “The available scientific evidence does not demonstrate any adverse health effects associated with the use of mobile phones."

• Doesn't mean that the potential for harm doesn't exist. FCC: HIGH levels of RF radiation can damage human

tissue • RF radiation has the ability to heat human tissue, like the

way microwave ovens heat food• Body is not equipped to dissipate excessive amounts of heat.

Eyes particularly vulnerable due to the lack of blood flow in that area

Electromagnetic SpectrumElectromagnetic Spectrum

Drive Now Talk LaterDrive Now Talk Later

A new evaluation by the Harvard Center for Risk Analysis (HCRA) estimates that the use of cell phones by drivers may result in approximately 2,600 deaths, 330,000 moderate to critical injuries, and 1.5 million instances of property damage in America per year.