Read The Stickies

Submitted by Anonymous on Wed, 2011-04-06 15:42

Thanks for the stickies and the data. Couple of questions.
1. How does your data compare with EPA or other published data for your area?
2. What is your estimate for average time it takes for Fukishima air (and radioactivity) to arrive in CA?
3. I realize the incredible dilution that occurs between Japan and US, but do you think your Iodine measurements support short term ongoing criticalities in Fukishima.
4. I realize that sample volume (and hence duration) affect the MDA, but shorter times are required to detect any spikes in radioactivity. Are you doing any short volume samples for spike estimation or are the MDA's just not useful on shorter volumes?

Thank You and learn, study and apply with this Nuclear Engineering Experiment in action:)

‹ WISCONSIN DHS air monitoring results Radioactive Nuclide ›

Hi, let me try to answer

Submitted by bandstra on Thu, 2011-04-07 12:54.

Hi, let me try to answer your questions:

1. Our data are similar to other measurements in the area. We have linked the to EPA and others, from our FAQ page: Are other groups making measurements like this?.

2. It takes about 5 days for the particles from Fukushima to reach California. You can see this in the results from University of Washington -- they saw no radioactive isotopes on 3/16, but then they saw them on 3/17. The first releases from Fukushima may have happened sometime around 3/12.

3. There is a great deal of uncertainty in the air transport of these isotopes from Japan, so we can't say anything with certainty. However, the spikes in our data are very likely weather-related, since they may correlate with weather patterns (rain, pressure fronts, etc.). The weather is changing, so we are looking forward to seeing the results of our next measurements.

4. We're not taking any shorter air samples since that would reduce our sensitivity too much. The Minimum Detectable Activity should scale roughly like 1/(collection time * sqrt(detector time)). So if we were to take our air samples for 12 hours instead of a full 24 hours, and if we measured them on our detectors for only 12 hours as well, the MDA would go up by a factor of about 2.8. Since we are already below or very close to our MDA, we probably would not be able to detect anything useful.

So we are essentially measuring the average over an entire day, which would include any spikes. If one is concerned about accumulated dose from the radiation, this daily average is still useful.

And your other two questions in your comment:

1. We are compiling a list of other sites on our FAQ page: Are other groups making measurements like this?

2. All of our spectra can be viewed by clicking on the "data" link in the last column of any of our tables (e.g., here).

Mark [BRAWM Team Member]

Thanks

Submitted by Anonymous (not verified) on Fri, 2011-04-08 05:13.

Appreciate the answers and am browsing the other linked sites and data. Thanks for the good work!

other sites

Submitted by Anonymous (not verified) on Wed, 2011-04-06 15:59.

Responding to my own post is bad form, but do you have a list of other sites, particularly engineering schools in CA or Hawaii doing sampling and analysis? I'm not a conspiracy theorist, but I do prefer non-governmental data.

Have you posted or made available the spectra from your sampling results, especially rainwater, and if so where?

Thanks