Oct. 2, 2006 Assignment #2 Due Today Assignment #3 online – Due Wed. Oct. 11 Lab #4 online Quiz #1, Mon. Oct. 16 or Wed. Oct. 18? Examples, Examples Electromagnetic Radiation and Health Examples, Examples

Electromagnetic Radiation and Health Growing number of sources of EM radiation –Natural sources –Man-made sources Health risks –High frequency radiation (UV light and higher) –High power radiation (microwave ovens) –Controversy over effects of lower frequency, lower power radiation

Ionizing Radiation Ionization: High energy EM radiation hits particle and splits it –Electron released creating free electron and free radical atom → chain reaction Effect on living tissue of ionization = bad Energy is proportional to frequency. EM radiation with UV light frequency and higher is ionizing

Ionizing Radiation Sources Natural Sources Man-made Sources Solar radiation Medical and industrial x- rays Cosmic radiation Medical and industrial tracers Radioactive Elements UraniumRadonPotassium-40Carbon-14Thorium Sterilizing medical hardware and food Radiation therapy Sterilizing insects Smoke detectors Nuclear power plants

Health Effects of Ionizing Radiation Acute Exposure –depends on dose Anything between sunburn and death Chronic Exposure –Cancers of all sorts

Non-ionizing Radiation Insufficient energy to cause ionization High energy non-ionizing radiation still won’t cause ionization –Ionizing energy: depends on frequency not amplitude –UV frequency: THz

Sources of Non-ionizing Radiation Mostly man-made sources Electronics and electrical devices –FCC/Industry Canada regulations High voltage power lines Mobile phones and base stations WLANs, bluetooth Microwave ovens Cordless phones Number is growing

Health Effects of Non-Ionizing Radiation Thermal – increase temperature of molecules –Microwave oven –Smaller scale effect in any RF field Non-thermal – uncertain as to any non-thermal effect –Potentially: damage to cells, DNA, chromosomes REFLEX study, Cemfec project, Interphone project, Perform-A project, and others

Measuring EM Exposure Specific Absorption Rate –Measures absorption of EM radiation by body –RF electronics have SAR ratings available to users –Less than 1.6watts/kg is max level allowed

Health Effects of Non-Ionizing Radiation Independent Expert Group on Mobile Phones “Weight of evidence does not suggest that there are adverse health effects from exposure to RF fields below guideline levels, but the published research…has limitations, and mobile phones [and WLANs] have only been in widespread use for a limited time. The possibilty therefore remains open that there could be health effects from exposure to RF fields below guideline levels; hence more research is needed.” “Weight of evidence does not suggest that there are adverse health effects from exposure to RF fields below guideline levels, but the published research…has limitations, and mobile phones [and WLANs] have only been in widespread use for a limited time. The possibilty therefore remains open that there could be health effects from exposure to RF fields below guideline levels; hence more research is needed.”

What then to do?

WHO suggests: –Take precautions to minimize exposure –Limit cellphone use –Limit WLAN use (how do we do that at OC) –Limit wireless use by children –Place high power antennas away from people –Microcell networks