In September 2026, the Georgia Environmental Protection Division (EPD) updated Appendix A of its Guideline for Ambient Impact Assessment of Toxic Air Pollutant Emissions, increasing the formaldehyde minimum emission rate (MER) from 22.1 to 34 lb/yr. Because Appendix A establishes acceptable ambient concentrations (AACs) and MERs for toxic air pollutants (TAPs), the revision may eliminate formaldehyde dispersion-modeling requirements for some facilities. The update partially reverses the substantially more stringent formaldehyde values EPD adopted earlier in 2026.
What Changed
EPD revised the long-term annual formaldehyde AAC to 0.14 µg/m³ based on EPA’s Regional Screening Level Calculator and adjusted the corresponding MER to 34 lb/yr, as shown in Table 1. The short-term 15-minute AAC remains unchanged at 245 µg/m³ and continues to be based on OSHA’s short-term exposure limit.
Table 1. Formaldehyde AAC and MER Updates
| Prior Value (March 2026 Update) | New Value
(September 2026 Update) |
| Annual AAC (µg/m³) | 0.0909 | 0.14 |
| 15-Minue AAC (µg/m³) | 245 | 245 |
| MER (lb/yr) | 22.1 | 34 |
How Georgia’s Formaldehyde MER Changed in 2026
For years, Georgia’s formaldehyde MER was 267 lb/yr. EPD reduced it to 22.1 lb/yr in March 2026—a decrease of more than 90 percent—which meant that many facilities previously below the screening threshold had to perform formaldehyde dispersion modeling. In September 2026, EPD increased the MER by approximately 54 percent, from 22.1 to 34 lb/yr. Although the latest update provides some relief, the current MER remains substantially below the long-standing 267 lb/yr value.
Who Is Affected
Formaldehyde is a common combustion byproduct and may also be emitted by a range of industrial processes. Any Georgia facility that emits formaldehyde should evaluate the revised values, but facilities with the following emission sources are especially likely to be affected:
- Sites with stationary engines, turbines, or boilers
- Wood products, panel, and pulp and paper mills
- Resin, adhesive, and coating manufacturers and users
- Thermal oxidizers and other combustion-based control devices
What Should Facilities Do Now
Facilities should review their formaldehyde emissions, modeling, permit applications, and compliance tools against the September 2026 values to determine whether the revised MER and AAC affect current or pending obligations:
- Re-screen against the new MER. If your site-wide formaldehyde emissions fall between 22.1 and 34 lb/yr, modeling may no longer be required.
- Revisit recent demonstrations. Review toxics analyses prepared using the March 2026 values to confirm the additional margin available under the revised annual AAC of 0.14 µg/m³.
- Check pending applications. Make sure permit applications under EPD review use the current Appendix A.
- Update your tools. Replace older AAC and MER values in emission calculators, templates, and compliance spreadsheets.
How Can Trinity Help
Trinity’s Atlanta office helps Georgia facilities evaluate TAP applicability, update emissions calculations, perform dispersion modeling, and address air-permitting implications. To discuss how the revised formaldehyde AAC and MER may affect your facility or a pending permit application, contact Chris Pool.
