(Adopted 9-1-1974; Revised 9-15-1993; 10-16-1996; and 3-22-2000)






1.1 Purpose
The purpose of this Rule is to provide limits for the emissions of sulfur compounds, nitrogen oxides and nitrogen dioxide from sources within the District.

1.2 Applicability
The provisions of this Rule shall apply to sources of sulfur compounds, nitrogen oxides, nitrogen dioxide subject to District Rule 200 (Permits Required).

1.3 Exemptions

1.3.1 Electric power boilers subject to the emission limits of District Rule 431 (Emissions from Electric Power Boilers) shall not be subject to Subsection 3.1.3 of this Rule.
1.3.2 Any source subject to an emission limit imposed by the BACT requirements of Section 4.1 or 5.2 of District Rule 207 (Review of New or Modified Sources) shall not be subject to Section 3.1 of this Rule for the same pollutant.
Rule 404 does not apply to:
1.3.3 Fires set by or permitted by a public officer if such fire is set or permission given in the performance of the official duty of such officer, and such fire in the opinion of such officer is necessary: for the purpose of the prevention of a fire hazard which cannot be abated by other means, or the instruction of public employees in methods of fighting fires.

1.3.4 Fires set pursuant to a permit on property used for industrial purposes for the purpose of instruction of employees in methods of fighting fire.
1.3.5 Agricultural operations necessary for the growing of crops or raising of fowl or animals, or
1.3.6 The use of an orchard, field crop, or citrus grove heater which does not produce unconsumed solid carbonaceous material at a rate in excess of that allowed by State law, i.e., no more than 1 gram per minute of unconsumed solid carbonaceous material. {California Health and Safety Code (HSC) Sections 41860 and 41704 (f)}

1.4 Effective Dates
This Rule as most recently revised, is effective on March 22, 2000.

1.5 References and Related Rules

1.5.1 The requirements of this Rule arise from the provisions of the California Clean Air Act and amendments (California Health and Safety Code Section 40910 et seq.) and the Federal Clean Air Act and amendments (42 U.S.C. Section 7401 et seq.)
1.5.2 Related District Rules include:


2.1 British Thermal Unit (Btu)
The quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit (oF) at or near 39.2o F.

2.2 Nitrogen Oxides
The sum of the molecular forms of nitrogen oxide and nitrogen dioxide. When measured or calculated, the total of the two molecular forms are collectively expressed as nitrogen dioxide.


3.1 Emission Limits
Any person shall not discharge from any single emission unit any one or more of the following contaminants in any state or combination thereof, exceeding in concentration or amount at the point of discharge to the atmosphere;

3.1.1 sulfur compounds calculated as sulfur dioxide (SO2), 0.2 percent by volume;

3.1.2 nitrogen oxides, calculated as nitrogen dioxide (NO2), 140 pounds per hour from any new or expanded boiler, furnace, jet engine, or similar fuel burning equipment used for the production of power or heat;

3.1.3 from fuel burning equipment having a maximum heat input rate of more than 1-1/2 billion Btu per hour (gross), flue gas having a concentration of nitrogen oxides calculated as nitrogen dioxide (NO2) in parts per million parts of flue gas (ppm) by volume at 3 per cent oxygen, 225 ppm with natural gas, liquid or solid fuel; or,

3.1.4 from sources other than combustion sources, nitrogen oxides, calculated as nitrogen dioxide (NO2), 250 parts per million by volume.

3.2 Measurement Methods

3.2.1 For determination of SO2 emissions concentrations in stack gases during stationary source tests, 40 Code of Federal Regulations (CFR) Part 60, App. A, Methods 6 or 6C (EPA Methods 6 or 6C, "Determination of Sulfur Dioxide Emissions from Stationary Sources"), or California Air Resources Board (ARB) Method 100, "Procedures for Continuous Gaseous Emission Stack Sampling", shall be performed.

3.2.2 For determination of NOx emissions concentrations in stack gases during stationary source tests, 40 CFR Part 60, App. A, Method 7E (EPA Method 7E, "Determination of Nitrogen Oxides Emissions from Stationary Sources (Instrumental Analyzer Procedure)"), or ARB Method 100, "Procedures for Continuous Gaseous Emission Stack Sampling", shall be performed.

3.3 Record-keeping Requirements
For any source subject to this Rule, permanent records, or records in a District-approved electronic format, shall be maintained for a period of five years after creation and shall be made available for inspection by the Air Pollution Control Officer upon request. The records shall include, but are not limited to, the date and time of testing, the parameters which were measured and the contaminant concentrations or emission rates in the same units as the emission limits.

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