"You have to work hard to offend Christians. By nature, Christians are the most forgiving, understanding, and thoughtful group of people I've ever dealt with. They never assume the worst. They appreciate the importance of having different perspectives. They're slow to anger, quick to forgive, and almost never make rash judgments or act in anything less than a spirit of total love . . . No, wait--I'm thinking of Labrador retrievers!" David Learn, 1998

Monday, March 21, 2011

How to interpret info on radiation levels - 2

     NOTE: This is a continuation of my March 19 post, "How to interpret information on radiation levels from AQMD.gov - Part 1"

The Air Quality Management District (AQMD) is posting "daily radiation monitoring updates" in our area and probably in yours as well. For instance, their report today for Los Angeles County is, "No increased risk detected above background levels."

AQMD daily radiation monitoring update
for Monday, March 21, 2011:
No increased risk detected above background levels
For the complete AQMD update, click here.
This page will be updated by noon each day with the latest information.
To view the latest EPA radiation data, click here, or here.

     This is a scientific interpretation of the data, but it is still an interpretation, that is, an opinion. This one-size-fits-all reassurance must be compared against the actual numbers and your individual history of exposure (See Part 1). To their credit, AQMD.GOV provides these numbers and a graph.
     Here is today's graph. It shows that radiation levels in Los Angeles County did rise above pre-event levels on March 14 and March 21 (today), although today's spike may be due to electrical interference. These increases in radiation are apparently infinitesimal and that is why they claim there is no additional risk. But my father would have pointed out that any additional radiation can increase the risk of cancer, especially in a person whose personal levels are already high. Today's graph:

These levels are thousands of times below any conservative level of concern.

Los Angeles - Gross Beta

The beta gross count rate measures the radiation from all radionuclides that emit beta particles, which is indicated by the term gross or total. The term count rate tells us how quickly beta particles are being detected, which indicates how much radioactivity the monitor is seeing.

Notes on the Data

  • Brief gaps in RadNet data represent instrument error.
  • Larger gaps (>1 day) occasionally appear when RadNet monitors are taken offline for servicing.
  • Electrical interference can cause spikes, shown on the graph as one point significantly higher than the rest of the data.
  • As you view the data, be aware that there are often large differences in normal background radiation among the monitoring locations because background radiation levels depend on altitude and the amount of naturally occurring radioactive elements in the local soil. What is natural in one location is different from what is natural in another.

These levels are thousands of times below any conservative level of concern.

Los Angeles - Gross Gamma

The gamma data measures radiation from all radionuclides that emit gamma rays and splits them into ranges of energy. The word gross, or total, indicates that the measurement is from all gamma emitting radionuclides. Not all gamma rays have the same amount of energy. Breaking the data into discrete energy ranges helps scientists to determine which radionuclides may be present.


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