The general rule under Louisiana law has long been that any activity that results in emissions of air pollutants must obtain an air permit from the Louisiana Department of Environmental Quality (LDEQ) unless a specific exemption applies. There are a few broad statutory and regulatory exemptions, such as activities conducted on residential property (with minor exceptions), the distribution or application of pesticides, and emissions from mobile sources such as automobiles, trucks, boats and aircraft, controlled burning of agricultural by-products in the field or of cotton gin agricultural wastes or controlled burning in connection with timber stand management, or pastureland or marshland in connection with trapping or livestock production. The most useful exemption for businesses and non-residential activities has long been the “Small Source Exemption” found in LAC 33:III.501.B.2.d, which exempts any source that emits less than the Minimum Emission Rate of any Louisiana Toxic Air Pollutant and less than 5 tons per year of any single “criteria pollutant” and 15 tons per year of all criteria pollutants in the aggregate.

Until this year, there was no specific requirement for sources exempt from permitting under this Small Source Exemption to document or keep records to verify they met the conditions of the exemption. On March 20, 2017, LDEQ published notice of a final rule amending the Small Source Exemption rule to require that either the owner or the operator of a source claiming exemption under this provision to: 1) make a written determination assessing its maximum potential annual emissions to show the exemption criteria are met; 2) keep such records available for LDEQ inspection; and 3) make a revised determination and document such any time there is a modification to the source or activity that could change the initial calculations, such as an increase in production rate or an increase in hours of operation. When determining the maximum potential emissions, the owner or operator may take into account any physical limitation on the capacity of a source to emit an air pollutant, including air pollution control equipment that is used.

Unfortunately, LDEQ made the rule effective immediately upon promulgation (the March 20, 2017 Louisiana Register publication date), and did not provide a time period for allowing facilities to prepare such documentation. Thus, sources relying on the Small Source Exemption should take steps to prepare such documentation as soon as possible.

A list of the Louisiana Toxic Air Pollutants and their Minimum Emission Rates can be found in Table 51.1, LAC 33:III.Chapter 51.[i] Criteria air pollutants are Volatile Organic Compounds (VOC), Nitrogen Oxides (NOx), Carbon Monoxide (CO), Sulfur Dioxide (SO2), Particulate Matter (PM10 diameter < 10 microns and PM2.5 diameter < 2.5 microns), and Lead. Many sources may need a consultant to assist with preparation of such calculations; however, a standard reference is the Environmental Protection Agency’s (EPA) publication AP-42, A Compilation of Air Emission Factors,”[ii] which provides standard emission factors for a wide variety of commercial and industrial activities and sources. LDEQ does have a Small Business / Community Assistance program which can help to address these requirements (without enforcement action in most cases).[iii]

It should also be noted that there are other specific exemptions from air permitting that may be applicable to individual circumstances. Also, if a source does not qualify for an exemption, there are a wide variety of potentially applicable types of air permits, including minor source permits, standard oil and gas minor permits, portable source permits, temporary source permits, general permits, regulatory permits, and major source permits. If an owner or operator of a source of air emissions determines that it does not qualify for an exemption, it should seek to obtain the appropriate air permit as soon as possible to minimize the potential for and/or magnitude of enforcement action.


[i] Available at:

[ii] Available at:

[iii] See: