Post #1803: What’s normal for PM 2.5 in my area?

Posted on July 1, 2023

 

Currently our AQI is a mere 87, for fine particulates (PM 2.5).  That’s a relief.  Just a normal amount of air pollution.

Or is it?  I’ve kind of lost track of what was normal for my area.  It’s not like I paid attention to the AQI for most of the past decade.

So here, for Fairfax County, VA, I’m posting a table of AQI statistics, for PM 2.5. based on the period 2010-2022.  Just so that I can refer to it as needed.  Briefly, only 1% of days exceed the 99th percentile.  Half of days exceed the 50th percentile.  And so on.

Source:  Analysis of data from the U.S. EPA.

From this, I conclude that the current level of fine particulates in the air is still far from normal.  The current AQI of 87, for a July day, in my area, is just under the 99th percentile of all July days 2010-2022 (which, per the table, would be an AQI score of 92).

Eyeballing it, we might have had a July day like this once every two or three years, in the period leading up to 2023.

So, not unheard-of.  But still far from what we (used to) consider typical, in my locality.