How Do You Like the Deciview?
Hotline, Spring 2002
by Walter Goldburg, GASP President
That question may make no sense to you now, but in time it will. That’s because Congress required the U.S. Environmental Protection Agency to do something about the haze problem that afflicts both the eastern and western United States. The problem is, you can’t see as far as you used to, a matter of serious congressional concern, especially in states where tourism is important. There is also the issue of haze vs. good health, but consider tourism first. Do you really want to put the family in the car and spend a lot of money to drive them to a distant scenic spot that is enveloped in haze? In recent decades we have watched human-made pollution reduce visibility from 90 miles to 20 miles in eastern parks and from 140 to 50 miles or so in the west.
Haze regulations, which came into effect in 1999, stipulate that all states must devise plans that will increase the clarity of the air by something like one “deciview/year,” starting roughly six years from now. So what is a deciview? It’s an improvement in air clarity that is just discernable to the typical eye. A deciview is the analog of a decibel of sound, if that helps.
Now let’s take up the impact of haze on health. Haze is produced by fine particles suspended in the air - particles so small they take a very long time to fall to the ground. The suspended particles lodge in our lungs, thereby generating a variety of devastating effects on our health. These particles are typically smaller than 2.5 microns in diameter, small enough to require a good microscope to see them. The regulators call them PM 2.5, where the “PM” simply means particulate matter.
PM 2.5 will be separately regulated by the Clean Air Act. I use the words “will be” because the implementation of the PM 2.5 regulation has been delayed for years through court actions taken by the trucking industry and others. Very recently these opponents lost their final battle to delay and weaken this important regulation.
So, in the matter of haze and PM 2.5, we see a coming together of aesthetic and health issues that are too important to be brushed under the rug (where more fine particles can surely be found.)
Next time: what are these fine particles that comprise PM 2.5 and how do they affect our health?