Why opacity cannot be the singular clean-air determinant

If a picture is worth a thousand words, then a view is worth a thousand pictures, handily!

And, what does this all have to do with, exactly?!

Quality is what we’re talking about and what the implications of view and view quality are on quality of air.

And, that’s it? That’s it.

So, what are we talking about? In a word: opacity.

Wait. What?

opacity 1. the state or quality of being opaque. 2. something opaque. 3. the degree to which a substance is or may be opaque. …”1

Relating opacity to air, the less opaque, the less clouded, the clearer the air, does this not reflect air purity level? What about the inverse, or, in other words, that which is more opaque, more clouded, duller, by the same token, is this not an indication that air has been made more impure, a condition in which the air-quality rating is: Poor?

All of which brings up a good – and the next – point: Which is that opacity should not and cannot be the singular clean-air determinant.

Illustrative examples

It was but a few months ago that many were remarking on how much cleaner the air in many municipalities and localities around the world had gotten.

Various assessments were conducted to try to quantify that. One of those barometers was, of course, visibility, which is really a measure of how far the eye can see. Visibility is usually categorized thusly: good visibility; poor visibility.

So, let’s look at situations where visibility is obscured and still air quality is anything but poor.

Such is the case with fog, high altitude, ground-level or otherwise. Fog can occur at any time of the year, even in summer. That’s right, summer. Think coastal California.

Or, it could be nothing more than a blanketed-with-birds sky. (Reference the photo above).

Though the second may be a bit of a reach, the point is made. That said, it goes without saying that good and bad air quality can occur in the company of fog-, bird-blanketed- and clear sky alike.

This is just as an item of interest but does not necessarily deal with the subject at hand – an aside, in other words.

What this has to do with is a situation which is conducive to the formation of ozone and, by association, smog in the atmosphere and, coupled with sunlight, such is able to form sullying the skies.

But, then notice what can happen when in addition to the ambient light, heat is added to the mix, so much so that the discoloration in the air just disappears. Don’t believe? This kind of stuff just couldn’t be made up. It really does happen.

All reasons supporting the position that air quality should not and cannot be determined simply by opacity alone.


  1. Random House Webster’s College Dictionary, 1991, p. 947

Image above: Jerry Segraves

– Alan Kandel

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