[CINC] FW: Facts about Trans-Pacific transport of pollution, radioactive materials

[judy w]

The California Air Resources Board sent out the attached information to local air districts.  I thought it might come in handy to pass on to park visitors.





























Please note that ARB has now posted a user-friendly splash
page for Calif.
city-specific background radiation monitoring levels. 

 http://www.arb.ca.gov/newsrel/2011/ca_radiation.htm

The goal here is to make it clear there is no danger, and
then allow viewers to access the actual raw monitoring information on the EPA
radnet site. 

We have included an explanation at the bottom of the
splash page in case the average user is not familiar with gross beta and gamma
cpm units.

Feel free to link at will.

Cheers

Stanley

Stanley Young 

Director of Communications

California Air Resources Board 

916-322-1309 office 

916-956-9409 cell 

syoung at arb.ca.gov

 

  

 









From: Young,
Stanley at ARB [mailto:syoung at arb.ca.gov] 

Sent: Thursday, March 17, 2011
3:16 PM

Subject: Facts about Trans-Pacific
transport of pollution, radioactive materials



 





FYI: You may find this useful. Stanley





 









FACTS ON TRANSPORT OF POLLUTION AND POSSIBLE
RADIOACTIVE MATERIAL ACROSS THE PACIFIC TO CALIFORNIA 

From:    California Air Resources Board 

Contact: Stanley
Young 916-322-1309, 916-956-9409 cell, syoung at arb.ca.gov

March 17, 2011

-          ARB
researchers have studied the movement of pollution from Asia to California since 2001.

 

-          Dilute
amounts of Asian pollution (dust, soot, etc.) are present in the air high over California (3,000 to
more than 15,000 ft.) on most days, especially in the period from April through
October.

 

-          Pollution is greatly diluted as it crosses the Pacific.  In China’s larger cities particle
concentrations  of 200 micrograms per cubic meter (µg/m3) are
common, and polluted air often covers tens of thousands of square miles, yet
typical concentrations of Asian pollution measured in California are very low, on the order of 5
µg/m3.

 

-          Pollutants leaving Asia at low altitude
have a tendency to deposit a significant fraction of their mass into the ocean.
 (Releases to date from Fukushima
do not appear to reach high altitudes.)

 

-          Only material that is lofted a mile or more above sea level has a strong
potential to reach North America

 

-          Material that does make it across the Pacific is diluted as larger
particles settle into the ocean and thinned as it is dispersed over millions of
square miles.

 

-          Material in
transit is also prone to be scavenged by clouds and rained into the ocean.

 

-          Pollution coming from Asia usually takes
about a week to cross the Pacific (we have observed a
range of about 5-15 or more days), thus it is likely that there would be ample
warning and time to develop fairly precise predictions of the exact path of any
large radiation cloud, should one develop.

 

-          In California, we commonly see dilute
Asian material at elevated sites, such as the crest of the coastal
mountains or in the Sierra Nevada.

 

Additional Background: 

-          The Asian
material we measure comes from many thousands of industrial sites and power plants
and many millions of vehicles.  Material from a single source (such as the
stricken power plant at Fukushima) would be
extremely dilute when it reaches California.

 

-          The typical
air flow from Asia arrives in coastal areas (such as California
or Hawaii)
riding over the top of the air near the ocean.  In Hawaii, we see Asian
material about twice as often at the measuring station at the top of Mauna Loa
(11,150 ft.) than at the station at Haleakala (3,800 ft.), and maximum
concentrations are about twice as high at the higher altitude site.

 

-          In California, we commonly see dilute
Asian material at elevated sites, such as the crest of the coastal
mountains or in the Sierra Nevada.  Asian
material is observed about 10 times more often at Mt.
Lassen or at Pinnacles
National Monument than at Pt. Reyes
National Seashore or Redwood
 National Park, and the
concentrations at the coastal sites tend to be about ½ of the already dilute
upland measurements.

 

-          Data from
our very limited set of low altitude measurements elsewhere in California suggest that
concentrations of Asian pollution are generally lower at low altitude away from
the coast as well.

 

-          Finally,
looking at the Chernobyl reactor disaster (the only other large reactor fire
and release on which we have data), although the radioactive cloud spread
across much of Europe, and a dilute plume was tracked circling the Northern
Hemisphere, the areas of high radiation exposure and significant health risk
were confined to a zone about 100 x 400 miles in extent.  By analogy, it
seems unlikely that very high radiation exposure could reach across 5000 miles
of ocean from the source.   












 		 	   		  
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