So, you’re saying that San Francisco-Oakland-San Jose, CA has also been redesignation from nonattainment to attainment? That’s confusing, but the EPA source that cites Raleigh-Durham, NC & Charlotte, NC (Moderate <= 12.7ppm - Maintenance)
Are rated the same as
San Francisco-Oakland-San Jose, CA (Moderate <= 12.7ppm - Maintenance)
Says… Data is current as of July 31, 2022
It clearly says… Status Nonattainment and Maintenance Areas
Maintenance areas are areas that were once in nonattainment and are now currently meeting the NAAQS for the pollutant in question. Under Section 175(a) of the CAA, the state needs to show the area will be meeting the NAAQS for a 10 year period. After 8 years, under Section 175(b) of the CAA, the state needs to model to show that the area will continue for another 10 years after the first 10 years ends. There are four types of designations - attainment, nonattainment, maintenance and unclassifiable/attainment.
Further, your EPA map seems to lack some credibility. for example, Gary In doesn’t show up in any of the map for air quality esp. sulfur dioxide. Have you been to Gary In? The EPA map shows that the air quality in Lake Tahoe is worse than Gary In.
And further, it’s interesting how all the air bad air quality immediately disappears right at the border of Nevada. Lake Tahoe somehow has a Level 3 Nonattainment, and Carson City-Genoa (20min away) is zero. Or, Imperial Valley is a serious all 6 pollutants (I assume a lot of this is Agriculture) and then right at the border of Nevada and Arizona it goes to zero when the prevailing air direction is West to East all most 100% of the time.
Attainment/nonattainment designations are done by metro statistical areas. All it takes is one monitor showing air levels above the NAAQS for the whole area to be designated nonattainment. Bad air quality doesn’t just disappear. Between the area that has a monitor showing levels above the NAAQS and the next nearby city or state, there has been enough dispersion so that the levels are not above the NAAQS. There are good models today that show how pollutants are transported by the winds.
So, please understand, I think NC is a wonderful place; I’ve been to your Blue Ridge Mountains. I have a friend who just bought a place in Asheville, and wants me to come visit. I hear there are some great places for mountain biking. As for the EPA air quality information metrics today, I’d much rather be here at my place in Lake Tahoe than Gary, Indiana even though the EPA is telling me that Gary, Indiana is cleaner.
The EPA is not telling you anything. They are just collecting the data reported by the 50 states. It is the states that run the monitoring networks. If you have a problem with the air quality information in Indiana, your beef is with Indiana, not EPA.