General Discussion
In reply to the discussion: Plutonium from Fukushima is a global catastrophe. [View all]Octafish
(55,745 posts)EXCERPT...
This is an important point
A .5 micron size dust particle is also equal to a .5 micrometer dust particle of plutonium. The EPA said that this size of particle is dangerous, because it is small enough to get into the lungs, and then go directly into the bloodstream from there, bypassing the filters in the nose and sinuses and avoiding the mucus that normally protects us from larger dust particles.
As you have just found out in the section above, some tiny pieces of particulate matter, PM 2.5, are small enough to pass from our lungs to our bloodstream, such as the .5 micron size particle of plutonium. http://www.hcdoes.org/airquality/monitoring/pm.htm
A small particle (we are not even talking about plutonium or other radioactive substance) inhaled into the lungs with normal breathing either inside or outside the house, can alter the body's defense systems against foreign materials, damage lung tissues, aggravate existing respiratory and cardiovascular disease, and can lead to cancer.
In some cases, PM exposure can even lead to premature death. Adverse health effects have been associated with exposures to PM over both short periods (such as a day) and longer periods (a year or more). The people who are most at risk are people with asthma, influenza, lung, heart, or cardiovascular disease, the elderly, and children.http://www.hcdoes.org/airquality/monitoring/pm.htm
WHY ARE NANO PARTICLES SO DANGEROUS?
The human immune system developed in a time and environment where dust was made of large particles. Humans have developed a means of protecting themselves against these large particles. Particles larger than 10 microns generally get caught in the nose and throat, never making it as far as the lungs. Unfortunately, more recent human activity has created many particles that are much smaller, which can make it past our natural defenses, and can enter our systems. Normal particles produced by Nature are larger than 10 microns, and the human lungs in the body are built with defensive mechanisms to filter out these larger particles.
This is why particles smaller than 10 microns are often called "inhaleable particulates" and are regulated by the USEPA. Particles that are smaller than 5 microns can get into the bronchial tubes and the top of the lungs. Particles smaller than 2.5 microns in diameter can get into the deepest portion of the lungs where the gas exchange occurs between the air and blood stream. These are the dangerous particles because the body has no efficient mechanisms for removing them. (You can also imagine what happens if even .5 of one micron sized nano particle of toxic and radioactive plutonium gets down into this region, cant you?)
CONTINUED...
http://agreenroad.blogspot.com/2013/08/how-dangerous-is-400-6000-pounds-of.html?m=1
Crazy.