UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: April 25, 2010

SUBJECT: Technical Support Document – Commonwealth of Pennsylvania – Control of 

Nitrogen Oxides from Portland Cement Kilns

/s/

FROM: Rose Quinto, Environmental Engineer

Office of Air Program Planning

TO: File

/s/

THRU: Cristina Fernandez, Associate Director

Office of Air Program Planning

A. BACKGROUND

On July 23, 2010, the Pennsylvania Department of Environmental Protection (PADEP) 

submitted a State Implementation Plan (SIP) revision pertaining to the control of nitrogen oxides 

(NOx) emissions from Portland cement kilns. Portland cement manufacturing is an energy

intensive process in which cement is made by grinding and heating a mixture of raw materials 

such as limestone, clay, sand, and iron ore in a rotary kiln. NOx emissions are generated during 

fuel combustion by oxidation of chemically-bound nitrogen in the fuel and by thermal fixation of 

nitrogen in the combustion air. This SIP revision is based on the Ozone Transport Commission 

(OTC) control measure to reduce NOx emissions from cement kilns. The OTC members include 

Pennsylvania, Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New 

Jersey, New York, Rhode Island, Vermont, Virginia, and the District of Columbia. The OTC 

was created under section 184 of the Clean Air Act (CAA) to establish regulatory programs to 

reduce ozone precursor emissions, which includes the reduction of NOx emissions from cement 

kilns.

B. STATE SUBMITTAL

The SIP revision amends the NOx emission standards in the Title 25 of the Pennsylvania Code 

(25 Pa. Code) Chapter 145, Subchapter C, “Emissions of NOx from Cement Manufacturing,” for 

Portland cement kilns during the ozone season, from May 1 through September 30, 2011, and for 

each year thereafter. 

The SIP revision added new definitions and terms: 
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1. Calcine – To heat a substance to a high temperature, but below its melting or fusing 

point, to bring about thermal decomposition or a phase transition in its physical or 

chemical constitution.

2. Long dry-process cement kiln – A Portland cement kiln that employs no preheating of the 

feed. The inlet feed to the kiln is dry.

3. Long wet-process cement kiln – A Portland cement kiln that employs no preheating of the 

feed. The inlet feed to the kiln is slurry.

4. Precalciner cement kiln – A Portland cement kiln where the feed to the kiln system is 

preheated in cyclone chambers and a second burner is used to calcine material in a 

separate vessel attached to the preheater prior to the final fusion in a kiln that forms 

clinker.

5. Preheater cement kiln – A Portland cement kiln where the feed to the kiln system is 

preheated in cyclone chambers prior to the final fusion in a kiln that forms clinker.

6. System-wide – Two or more Portland cement kilns under the common control of the same 

owner or operator, or multiple owners, in the Commonwealth.

The other definitions mentioned in this SIP revision were already approved by EPA on December 

10, 2009 (74 FR 65446): continuous emissions monitoring system (CEMS), clinker, Portland 

cement, and Portland cement kiln. Therefore, these terms are not included in this action.

Standard Requirements

Section 145.143(b) was revised to provide that the owner or operator of a Portland cement kiln 

cannot operate a Portland cement kiln that results in NOx emissions in excess of its allowable 

emissions. Section 145.143(b)(1) added a compliance date of May 1 through September 30, 

2005, and each year thereafter, the owner or operator will determine allowable emissions by

multiplying the tons of clinker produced by the Portland cement kiln for the period by 6 pounds 

per ton of clinker produced. Section 145.143(b)(2) was also revised to require the owner or 

operator of a Portland cement kiln determine allowable emissions of NOx by multiplying the 

tons of clinker produced by the Portland cement kiln for the period from May 1 through 

September 30, 2011 and for each year thereafter by: 

(1) 3.88 pounds of NOx per ton of clinker produced for long wet-process cement kilns.

(2) 3.44 pounds of NOx per ton of clinker produced for long dry-process cement kilns.
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(3) 2.36 pounds of NOx per ton of clinker produced for preheater and precalciner cement 

kilns.

A minor change was made to section 145.143(c) clarifying that the owner or operator of a 

Portland cement kiln subject to section 145.143(b)(1) will install and operate a CEMS and report 

CEMS emissions data. 

The other sections mentioned in this SIP revision under section 145.143 were already approved 

by EPA on December 10, 2009 (74 FR 65446): Sections 145.143(a), 145.143(b)(1), and 

145.143(d) through (h). Therefore, these sections are not included in this action.

The following sections were added to the SIP revision:

Section 145.144. Compliance Determination Requirements

By April 15, 2011, the SIP revision requires the owner or operator of a Portland cement kiln:

1. To install, operate and maintain CEMS for NOx emissions.

2. To report CEMS emissions data to PADEP in accordance with the CEMS requirements 

of 25 Pa. Code Chapter 139, Subchapter C, relating to the requirements for source 

monitoring for stationary sources.

3. Calculate actual emissions using the CEMS data reported to PADEP.

A data invalidated under 25 Pa. Code Chapter 139, Subchapter C will be substituted either by the 

highest valid 1-hour emission value that occurred under similar source operating conditions 

during the reporting quarter for an invalid data period during that quarter, or an alternative 

method of data substitution as approved by PADEP in writing. If no valid data were collected 

during the reporting quarter, the highest valid 1-hour emission value that occurred under similar 

source operating conditions during the most recent quarter for which valid data were collected, or 

the highest valid 1-hour emission value that occurred under similar source operating conditions 

during an alternative reporting period, shall be reported to PADEP.

Additionally, under this section, the owner or operator of a Portland cement kiln will submit to 

PADEP quarterly reports of CEMS monitoring data in pounds of NOx emitted per hour, in a 

format approved by PADEP, which is in compliance with 25 Pa. Code Chapter 139, Subchapter 

C. Also, the CEMS for NOx installed under the requirements of this section, must meet the 

minimum data availability requirements in 25 Pa. Code Chapter 139, Subchapter C.
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Section 145.145. Compliance Demonstration and Reporting Requirements

By October 31, 2011, and each year thereafter, the owner or operator of a Portland cement kiln 

will submit a written report to PADEP which includes the following:

1. The difference between the actual NOx emissions from the kiln during the interval 

from May 1 through September 30 and the allowable emissions for that period.

2. The calculations used to determine the difference in emissions, including the 

CEMS data and clinker production data used to show compliance with the 

allowable emission limits. The clinker production data must consist of the quality

of clinker, in tons, produced per day for each kiln.

The owner or operator of a Portland cement kiln must demonstrate compliance with the emission

requirements on a kiln-by-kiln basis, a facility-wide basis or a system-wide basis among Portland 

cement kilns. 

Section 145.146. Recordkeeping Requirements

The owner or operator of a Portland cement kiln must maintain an operating log for each 

Portland cement kiln. The operating log must contain the following on a monthly basis:

(1) The total hours of operation.

(2) The type and quantity of fuel used.

(3) The quantity of clinker produced. 

The records maintained by the owner or operator of a Portland cement kiln must include the 

following: 

(1) Source tests and operating parameters established during the initial source test and 

subsequent testing. 

(2) The date, time and duration of any start-up, shutdown or malfunction of a Portland 

cement kiln or emissions monitoring system.

(3) The date and type of maintenance, repairs or replacements performed on the kilns, control 

devices an emission monitoring systems. 

Furthermore, the owner or operator of a Portland cement kiln must maintain the records onsite 

for five years and be made available to PADEP upon request.
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C. EPA EVALUATION

This regulation will reduce emissions of NOx from cement kilns to reduce levels of ground-level 

ozone. Ground-level ozone is not directly emitted by pollution sources, but is created as a result

of a chemical reaction of NOx and volatile organic compounds (VOC) in the presence of light 

and heat. The reduction of NOx emissions will also help protect the public health from high 

levels of fine particulate matter (PM2.5), of which NOx is a precursor component. PM2.5, as well 

as ozone, is health hazards. The reduction of NOx emissions also reduces visibility impairment 

and acid deposition.

D. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

The regulation to control NOx emissions from Portland cement kilns adopted by the 

Commonwealth of Pennsylvania will result in the reduction of NOx emissions from cement kilns

and will help the Commonwealth in attaining compliance with the 8-hour ozone and PM2.5 

national ambient air quality standards (NAAQS). EPA approval of the SIP revision is 

recommended.