Yes, it is November in Portland! So I thought I would write about sources of natural background radiation to which we are all exposed just by living here on Earth and how we can limit a child’s exposure to, or the long-term effects of, that exposure.
Natural background radiation is all around us. Living on Earth comes with avoidable and unavoidable risks of exposure to these natural sources termed cosmic, terrestrial and internal radiation:
- Cosmic radiation comes from space. The sun and stars supply a constant source of charged particles (protons) that penetrate the Earth’s atmosphere and magnetic field to shower ultra-violet light, gamma and beta radiation upon us.
- Terrestrial radiation refers to radiation sources found all over the Earth — in water, soil and plants — such as uranium, thorium, radon and their decay products. We ingest or inhale them without even realizing we are doing so.
- Internal radiation is within each of our bodies since the time we are born and includes minerals such as potassium-40, carbon-14 and lead-210.
We cannot easily control our exposure to terrestrial or internal radiation; however, we can and should take steps to protect ourselves and our children from cosmic radiation all year long. And, yes, even in November!
- The lens and the retina (the inside lining) of the eye are sensitive to radiation. Radiation damage to the eye in childhood, even before the age of 10, can result in damage that is realized only as an adult, for example cataract formation.
- Parents and grandparents can be good role models and help children to remember to wear their sunglasses. Sunglasses are really important when the sun is brightest, between 10 a.m. and 2 p.m., and when on the beach, at altitude, and even when there is snow. Carry sunglasses with you and teach children to do the same.
Wear sunscreen and a hat!
- The skin is the largest organ of the human body and is the most exposed to our environment – and the skin is sensitive to natural background cosmic radiation. Ultra-violet radiation causes sunburns, resulting in skin damage and potentially skin cancers that can cause skin deformity and can be fatal.
- Wearing a hat with a broad rim helps protect your face from the effect of UV radiation and can be more effective than sunscreen alone for delicate facial skin.
- Wear SPF 15 or greater sunscreen on exposed skin – even on cloudy days – to block or lessen the effects of UV radiation. When swimming, hiking, skiing, or engaging in activities that make you perspire, remember to reapply sunscreen at regular intervals.
Dianna M. E. Bardo, M.D.
Divisions of Diagnostic Radiology, Pediatrics and Cardiovascular Medicine
OHSU Doernbecher Children’s Hospital