SoCalGas - Potential to Emit (PTE) Calculator
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Potential to Emit (PTE) Calculator

Southern California Gas Company (SoCalGas) has prepared a simple MS® Excel™ spreadsheet to help you estimate the potential to emit (PTE) emissions of your stationary engine(s) and to compare these emissions to Title V emission thresholds for San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD). These values may be used for your information, but you should always confirm your calculations and facility's PTE status with the SJVUAPCD staff.

The PTE Calculator has been created as a simple tool for the farming industry to use to perform a quick criteria pollutant PTE estimate for engines. If the facility has other equipment that emits criteria pollutants such as oxides of nitrogen, oxides of sulfur, particulates, volatile organic compounds, and/or carbon monoxide, the emissions from that equipment needs to be accounted for as well. This calculator, however, is only an estimate for pump engines or other internal combustion engines. The user needs to perform a thorough investigation of all operations at the facility to capture all equipment.

This Calculator is for Emissions Estimation purposes only and should not be solely relied upon or used as an endorsement, approval or guaranty of compliance with Title V or any other air quality regulations. All Calculated results should be reviewed with SJVUAPCD staff to ensure that all inputs reflect the most up to date air district policies and regulations. Use of the information and data from this Calculator is at your sole risk. SoCalGas makes no representations or warranties, whether expressed or implied, and shall not assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information, data or process disclosed or derived from the use of this Calculator. Contact the SJVUAPCD for more detailed information.

This calculator was prepared by Yorke Engineering LLC for the Southern California Gas Company.

Criteria Pollutants

The US EPA regulates five criteria pollutants listed below:

  • VOC = Volatile Organic Compounds
  • NOX = Nitrogen Oxides
  • SOX = Sulfur Oxides
  • CO = Carbon Monoxide
  • PM = Particulate Matter

This document and the PTE Calculator only consider criteria pollutants.

Hazardous Air Pollutants

The US EPA also regulates Hazardous Air Pollutants (HAPs), since they contribute to health risks. For example, diesel engines emit both criteria pollutants and HAPs. To prepare a complete Title V applicability analysis, the Hazardous Air Pollutant potential to emit should also be examined.

What is Title V?

Title V is a federal operating permit program. Federal Title V permits are required for large "major" sources of air pollution. If your agricultural operation is determined to be a major source, the District must issue a Title V permit instead of the standard District permit. Title V permits are subject to the Environmental Protection Agency (EPA) and public review and generally contain more monitoring, recordkeeping, and reporting requirements based on federal regulations.

The US EPA uses a facility's "Potential to Emit" (PTE) to determine whether that facility is subject to Title V permit regulations. The Potential to Emit is a facility's emission level if it operated at maximum capacity. It is the maximum amount of emissions that a facility can emit; it is not the facility's actual emissions. One of the first steps that any facility needs to do is calculate its PTE to find out whether it is subject to EPA Title V air permits.

To calculate your operation's Potential to Emit, you must consider all sources of air emissions. One of these is the emissions from engines. Other sources may include pesticide use, gasoline dispensing, etc. The PTE Calculator is designed to assist you in quantifying your engine criteria pollutant emissions. These emissions should then be added to the emissions from other sources to obtain your facility's total emissions.

What causes a facility to be subject to Title V?

  1. If a facility reports actual emissions that are greater than 50% of the major source thresholds, it may be subject to Title V and should calculate PTE. Note that SJVUAPCD requires a District permit for equipment with reported emissions that are greater than 50% of the major source thresholds.
  2. If the potential to emit (PTE) (of any criteria pollutant or hazardous air pollutants) of all the sources in a facility are greater than the major source PTE thresholds, the facility is subject to Title V permitting requirements. The SJVAPCD currently assumes a 65% load factor and 6000 hours/year as default values to represent an agricultural operation at maximum capacity. Note that an operator can take permit limits to limit maximum hours of operation (less than the default value of 6,000 hours) to reduce the PTE.
Pollutant "Severe"
Attainment Status
VOC 25 10
NOx 25 10
CO 100 50
PM10 70 70
SOx 70 70

What is "Attainment Status" and why does it matter?

Attainment status is a rating or categorization assigned to an air district based on how close it is to meeting the ambient clean air standards. San Joaquin Valley APCD recently petitioned CARB to change it's designation from "Severe" to "Extreme” non-attainment. The move to "Extreme" rating will not go into effect until SJVUAPCD amends its rules to reflect this change. The major source thresholds vary by attainment status; see the table above.

How do I use the PTE Calculator?

Continue to the PTE Calculator.

Updated 12/2010

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