API Publ 4720 is a technical API document focused on the comparison of API and EPA toxic air pollutant emission factors for combustion sources. For buyers evaluating environmental and compliance references, it provides a practical way to review how emission factors are presented and compared for combustion-related activities. API Publ 4720 can support technical teams that need a documented basis for emission-related review, internal assessment, or regulatory alignment in petroleum and process operations. The 2002 edition offers a dated but relevant reference point for organizations handling air emissions data and technical documentation.

Purpose of API Publ 4720

The purpose of API Publ 4720 is to serve as an API reference document on toxic air pollutant emission factors, with particular attention to combustion sources and the comparison between API and EPA approaches. As an API Document, it is best understood as a technical background and reference resource rather than an operating manual. It may help engineering, environmental, and compliance-related personnel evaluate emission-factor basis, support internal technical review, and maintain consistency when comparing methods used for air emissions work in industrial facilities.

Common use cases of API Publ 4720

API Publ 4720 is commonly relevant in oil and gas, refining, and other process facilities where combustion sources are part of routine operations and emissions management. It may be used by environmental teams, engineering staff, procurement reviewers, and operations personnel who need a reliable technical reference during permit support, project planning, or emissions documentation. The document can also help with internal comparisons of API and EPA factors when preparing reports, reviewing facility data, or supporting compliance-focused technical work.

Why API Publ 4720 matters

This document matters because it gives teams a structured reference for understanding and comparing emission factors that may affect air emissions reporting and technical decision-making. For day-to-day use, API Publ 4720 can improve consistency in environmental documentation, reduce uncertainty during technical review, and support clearer communication between engineering, operations, and compliance functions. It is especially useful where combustion-related emissions must be assessed against recognized API and EPA references in a controlled, defensible way.

• Comparison of API and EPA emission factors
• Combustion source focus
• Environmental and compliance reference use
• Engineering and operations support
• Technical review for emissions documentation