Thread by @loganemitchell

Do you want Utah to improve #AirQuality?

EPA is reconsidering the PM2.5 standard & accepting public comments until Mar 28.

It's a once-in-a-generation opportunity & they need to hear from Utahns who are most affected.

Comment here👉 regulations.gov/docket/EPA-HQ-…
Context below 🧵

There are two PM2.5 standards:
1) annually averaged PM2.5 (set to 12 ug/m3)
2) 24-hr average PM2.5 (set to 35 ug/m3)

In UT we meet the annual avg since most of the yr we have low PM, but for a decade we exceeded the 24hr PM2.5 during winter inversion episodes.

The 24hr PM2.5 std was introduced in '97. Science in early 2000s showed standard was too high, so in 2006 it was lowered to 35ug/m3. It's calculated w/ 3yrs of data, so in 2009, 3 counties in UT exceeded the standard.

Exceeding the standard empowered @UtahDEQ to lower emissions & we've made progress. PM2.5 has gone down a little & in 2019 we met the 24-hr standard.

Now there's no more regulatory push for more emission reductions (except to meet ozone standards, which we're also exceeding).

I'd like to hope the UT legislature would prioritize #AirQuality to the same extent they're doing w/ the Great Salt Lake, but I don't see that happening.

With tighter EPA air quality standards, Utah would have to keep lowering emissions.

That's where you come in.

EPA's proposing to lower the annual PM2.5 std but keep the 24-hr std at 35 ug/m3 BUT they're accepting comments to revise the 24hr std down to 25 ug/m3!

Lowering the annual std wouldn't help Utah much

Please submit a comment asking EPA to lower the PM2.5 24-hr std to 25 ug/m3!

Anyone who just lived through the inversion the last few days knows that the current 24-hr PM2.5 standard is NOT protecting public health, which is the whole point of the National Ambient Air Quality Standards (NAAQS)!

https://twitter.com/loganemitchell/status/1622044741415366657

There are very few places in the US affected by 24hr PM2.5 (map below is a few yrs old, before we met the standard).

That's why it's CRITICAL that the EPA hears from Utahns - we live with bad 24-hr PM2.5 & have the most experience with it.

EPA needs to hear HOW it affects you.

Also: The EPA gets advice from the Clean Air Scientific Advisory Committee (CASAC), an independent group of science advisors.

A majority of the CASAC recommended 24-hr PM std set to 25-30 ug/m3.

The EPA is proposing to IGNORE the CASAC's recommendation & keep the 35 ug/m3 std!

EPA needs to hear from Utahns. Comments can be brief:

1) Ask EPA to set the 24-hr PM2.5 standard to 25 ug/m3 to protect public health

2) (optional) Tell EPA how the current standard isn't sufficient based on your experience living in Utah

Comment here: regulations.gov/docket/EPA-HQ-…

Got questions? Let me know & I'll respond as much as I can.

I'd like to see local coverage of the EPA's proposed PM2.5 stds before the Mar 28 comment deadline @sltrib @Deseret @abc4utah @KUTV2News @KSLcom @RobertGehrke @brianmaffly @Amyjoi16 @cwilliamsKSL @jedboal

If you'd like to know more about Utah's #AirQuality history, I published a paper on that last summer. Here's a thread on our history w/ links to the paper:

https://twitter.com/loganemitchell/status/1556816559686840320