Radiation Monitor
Live readings from our own Geiger counter in Brevard County, explained.
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LiveBrevard County / Space Coast0.039µSv/h
Updated 8:55 PM ET (2 min ago)
What this means: This reading is within the typical range of natural background radiation. Background radiation comes from natural sources such as the ground, cosmic rays from space and radon in the air.
Around the world, natural background radiation measured outdoors is typically about 0.01 to 0.2 µSv/h (10 to 200 nanograys per hour, United Nations scientific committee UNSCEAR). The green arc on the dial shows that range.
If this rate held for a full year, it would add up to about 0.34 mSv (34 millirem). For comparison, the U.S. Nuclear Regulatory Commission says Americans receive about 6.2 mSv (620 millirem) a year on average from all sources, about half of it from natural background.
CPM (counts per minute) is how many radiation events the Geiger tube detected in one minute. µSv/h (microsieverts per hour) is a dose rate; the counter converts CPM to µSv/h with its maker’s factor, so it’s an estimate.
Informational, not official. From The Space Coast Wire’s own Geiger counter in Brevard County. Not for safety decisions; in an emergency follow official guidance from Brevard County Emergency Management and the National Weather Service. Sources: UNSCEAR 2000 Report, Annex B; U.S. NRC, “Doses in Our Daily Lives”; U.S. EPA RadNet.
Understanding the Numbers
- CPM (counts per minute) is how many radiation events the Geiger tube detected in one minute. It goes up and down a little from minute to minute; that’s normal for any counter.
- µSv/h (microsieverts per hour) is a dose rate. The counter converts CPM to µSv/h with its maker’s factor, so treat it as an estimate.
- Typical background: Around the world, natural background radiation measured outdoors is typically about 0.01 to 0.2 µSv/h (10 to 200 nanograys per hour, United Nations scientific committee UNSCEAR). The green arc on the dial shows that range.
- Your yearly dose: For comparison, the U.S. Nuclear Regulatory Commission says Americans receive about 6.2 mSv (620 millirem) a year on average from all sources, about half of it from natural background. Most natural background exposure comes from radon in the air, with smaller amounts from cosmic rays and the Earth itself.
Why Readings Change
The EPA notes that normal background radiation differs from place to place, depending on altitude and the natural radioactive material in the soil and air, and that weather such as rain, snow and changes in air pressure can raise or lower readings for a while. That is why a short bump on the dial is usually not news. Our dial has no warning levels of its own: the green arc is the typical outdoor range UNSCEAR reports, and nothing more.
How We Measure
A Geiger counter owned by The Space Coast Wire reports to our server every couple of minutes. We publish the count rate, the dose-rate estimate and the time only. The card shows Offline if no new reading arrives for 10 minutes. This is not an official monitor; for official radiation monitoring see the EPA’s RadNet.
Sources: UNSCEAR 2000 Report, Annex B (outdoor gamma dose rates); U.S. Nuclear Regulatory Commission, “Doses in Our Daily Lives”; U.S. EPA, RadNet frequent questions.