Air Quality Services

Federal New Source Review (NSR) Permits

Prevention of Significant Deterioration (PSD) & Non-Attainment NSR Permits (NNSR) 

Under Title I of the 1990 Clean Air Act Amendments, there are National Ambient Air Quality Standards (NAAQS) for the six criteria air pollutants listed below. The United States is divided into attainment and nonattainment areas for each pollutant with respect to these NAAQS standards. A federal PSD permit may be required for major sources of pollutants in areas that are in attainment of the NAAQS and that meet certain other criteria. The PSD program is designed to maintain good air quality with some allowances for economic growth.

A non-attainment NSR permit may be required for major sources of pollutants in nonattainment areas that meet certain other criteria. Emissions increases must be offset and controls must be installed which meet the lowest achievable emission rates.

Criteria Pollutants:

  • ozone (associated with VOCs and NOx)
  • carbon monoxide (CO)
    particulate matter (PM10, PM2.5)
  • sulfur oxides (SOx)
  • nitrogen dioxide (NO2)
  • lead

State Permits, Amendments, & Renewals

States may have their own air permitting programs. In addition, several federal permitting programs have been delegated to the states. These include PSD & Non-Attainment NSR Permits , as well as Title V Operating Permits. See links to various state environmental agencies. Environmental Links
Facilities that produce air emissions above a certain level may require a state permit. Requirements vary by state and location within the state. If an air permit is already in place, modifications to equipment and/or processes including increased production rates above current permit allowable rates, may require a permit amendment. An air permit has a specified lifetime (usually 5 years) after which it must be renewed.

The permitting process includes an evaluation of air emissions generating processes and equipment, including control equipment, to identify and quantify emissions. EPA and state-approved calculation methods are used. Area maps, process flow diagrams and process descriptions are typically required.

Exemptions from Permitting

Most states have mimimum air emissions threshold levels, below which an air permit is not required. In addition, certain activities may be listed as “de minimus” with respect to air emissions and not require an air permit. In some instances registration with the state agency may still be required and documentation that demonstrates eligibility for exemption status must be maintained.

TCEQ Permits By Rule and Standard Permits

A Permit By Rule or Standard Permit are simplified air emissions authorizations for facilities that meet certain criteria that varies by industry.
Information required to claim a Permit By Rule or Standard Permit may include:
Completion of specific forms and checklists
Regulatory Compliance Review
Emission calculations
Supporting documentation, such as equipment specifications, analytical data, process description, site area map and plot plan

Title V Operating Permits

A Title V Operating Permit is a Federal Permit required for sources with the potential to emit air contaminants at or above the major source threshold limits. The Title V Permit is intended to list all applicable air-quality related regulatory requirements in one permit along with the method to demonstrate compliance.

The major source emission levels which trigger Title V are based on a facility’s potential to emit (PTE) at maximum capacity:

Areas in Attainment of NAAQS
10 tons per year of any Hazardous Air Pollutant (HAP)
25 tons per year of any combination of HAPs
100 tons per year or more of any air pollutant

Areas Not in Attainment of NAAQS
Emission threshold levels vary depending on the severity of the non-attainment area and specific pollutant.

Air Dispersion Modeling

Air Dispersion modeling is usually performed as part of the permitting process to demonstrate compliance with state and federal ambient air quality standards and/or health effects guidelines. Regulatory models utilize various mathematical algorithms to predict ground level concentrations of pollutants at and beyond the plant property or fence line. The model input includes meteorological data, terrain elevation data, and specific source parameter data.

Model input parameters are developed to model each applicable pollutant at specified averaging periods.
The EPA refined AERMOD or SCREEN3 Air Dispersion Models are usually used to predict pollutant concentrations.
If ambient standards for pollutants are not being met, process/equipment modifications that will lower the predicted pollutant concentrations may be required.

Pollution Control Technology Evaluations

Technical review of emission controls and analysis of the appropriate Pollution Control Technology is typically required as part of permitting process. The following terms refer to specific regulatory control requirements.
Best Available Control Technology (BACT)
Lowest Achievable Emission Rates (LAER)
Reasonable Available Control Technology (RACT)
Maximum Available Control Technology (MACT)
Facilities are required to meet a certain level of pollution control technology depending on their industry and emission levels.

Emissions Inventories

Air emissions inventories are performed to identify and quantify actual emissions from plant equipment and operations. The emissions data that is developed may be used for regional modeling. In addition, companies may use the emissions informaiton for permit and regulatory compliance evaluations, or to meet air release reporting requirements such EPA TRI Form R, CERCLA Continuous Release Reporting or other purposes.

State requirements for Emissions Inventories vary. 

Development of Credible Emission Factors

Emission Factors are established to correlate production volumes or other operational parameters with air emissions. Emission factors are most often based on actual source test data conducted during maximum production scenarios. Available emission factors are from EPA (e.g., Compilation of Air Pollutant Emissions Factors-AP-42) and industry organizations as well as state approved factors for various operations. Often AP-42 factors are very conservative and overestimate emissions. This may be acceptable unless there are regulatory concerns related to the “overestimated” emissions.

Emission factors may be developed for emissions calculations based on site-specific information.
If necessary, stack testing may be conducted.
Regulatory agencies and industry groups often recommend preferred estimation methods and helpful tools.

Record Keeping Development & Maintenance

Record keeping is often required to demonstrate compliance with various air permit provisions and emission thresholds. Record keeping is developed for each facility to best meet its record keeping needs. The record keeping system should be revised on a regular basis to ensure that emissions and/or other parameters are being accurately monitored.

Process Assessment: locate and quantify emissions sources and develop the most suitable calculation methodology.
Develop a record keeping system that meets the needs of your facility as well as regulatory requirements.

Hazardous Air Pollutant (HAP) and Air Toxics Related Projects

Title III of the Clean Air Act Amendments of 1990 regulate air pollutants classified as hazardous. In addition, there are various federal and state air quality regulations which govern the release of hazardous air pollutants.

A federal Title V Operating Permit is required for major sources of HAPs. For major sources of HAPs the Clean Air Act Amendments require industries to meet maximum available control technologies (MACT).

Evaluate equipment and processes and identify potential hazardous or toxic constituent emissions. Speciate raw materials, intermediates, and final products to identify potential air contaminants.
Review applicable federal, state, and local regulations with respect to toxic or hazardous air emissions to ensure compliance.
Air dispersion modeling may be performed to predict maximum ground level concentrations of hazardous constituents, evaluate potential health effects, and ensure compliance with air toxics regulations and guidelines.

Visual Determination of the Opacity of Emissions from Stationary Sources

Many air quality reglulations contain opacity standards regulating the visibility of emissions from stationary sources. One method that is commonly required by the regulations to determine the opacity of air emissions is EPA Method 9 – Visual Determination of the Opacity of Emissions from Stationary Sources. The procedure for conducting EPA Method 9 involves using a qualified observer to visually determine the opacity of air emissions. Liaise Environmental, Inc. is certified to perform EPA Method 9.

Close Menu