From information provided by the Pacific Northwest National Laboratory in a news release, I learned that “Floating in the air and invisible to the eye, airborne particles known as secondary organic aerosols live and die. Born from carbon-based molecules given off by trees, vegetation, and fossil fuel burning, these airborne SOA particles travel the currents and contribute to cloud formation. Along for the ride are pollutants, the [Polycyclic Aromatic Hydrocarbons], that have long been thought to coat the particles on their surface.”
To use an analogy, think of the SOAs as free-roaming airborne particles and the PAHs, particles that also become airborne and likewise roam freely, also act as hitchhikers that can be and are picked up and carried by the SOAs.
What this tells me is that these particles are transient in nature and when floating about in air, effectively go wherever the winds they are riding on carry them. And such particles can travel thousands of miles.
So, since polluted air knows no boundaries, it follows then that there would be intercontinental dispersing or distribution of air pollution.
As it relates, in a Sept. 12, 2012 San Joaquin Valley Air Pollution Control District (SJVAPCD) of California news release, announced was that “The Valley Air District is currently funding a research project through [University of California at] Davis to measure ozone that enters the Valley’s airspace from sources outside the U.S., primarily Asia. The project uses aircraft-mounted monitors and surface monitors installed in the mountains east of Big Sur [California].”
The Valley Air District went on to announce that “There is growing evidence from previous research that transboundary ozone, defined as ozone entering California airspace that was not created in North America, is showing up at ground level monitors in California and elsewhere in the western U.S., where it contributes to public health impacts and exceedances of the Federal 8[hour] ozone standard.
It is explained in the SJVAPCD release that the study will continue for a period in excess of a year-and-a-half.
“The U.S. [Environmental Protection Agency] has directed air districts to determine the amount of ozone coming from beyond sources in the US, so that districts have a clear sense of how much ozone is under their control and how much is due to sources beyond EPA’s jurisdiction,” according to the SJVAPCD in the release.
Image above: NASA