Efeitos dos Telefones Celulares sobre a Sa ú de Humana Dr. Renato Sabbatini Faculdade de Medicina UNICAMP

O 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 After  Top: You can see M artin Cooper making a phone call on the fi rst mobile cell phone ever invented.  Bellow: You can se e today’s type of mo bile cell phone. Martin Cooper

Cell Phone Usage Explodes  In 1994, 16 million A mericans subscribed to cellular phone ser vices. Today, more t han 110 million Ame ricans are subscribe rs.

How 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 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 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 tissue E.g. Radio-frequency energy, visible light and microwave radiation

Radiation 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 Reaction

Health 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 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 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 Spectrum

Drive Now Talk Later  A new evaluation by the Harvard Center for Risk Analysis (HCRA) estima tes that the use of cell p hones by drivers may re sult in approximately 2,6 00 deaths, 330,000 mod erate to critical injuries, and 1.5 million instance s of property damage in America per year.