Study on real-world power-based emission factors from typical construction machinery

Area of Science:

• Environmental Science
• Mechanical Engineering
• Atmospheric Chemistry

Background:

• Construction machinery is a major source of non-road emissions.
• Understanding real-world emissions is crucial for effective pollution control.

Purpose of the Study:

• To measure real-world engine performance and emission factors of excavators and wheel loaders.
• To compare emissions across different operating modes and machine types.
• To evaluate the accuracy of current emission standards and inventory guidelines.

Main Methods:

• Conducted real-world emission tests on 16 excavators and 19 wheel loaders.
• Utilized a portable emission measurement system (PEMS).
• Categorized operating modes into idling, moving, and working.

Main Results:

• Working mode resulted in high engine load and fluctuating CO, HC, NO_x, and particle number (PN) emissions.
• Wheel loaders exhibited significantly higher CO, HC, and NO_x emission factors than excavators under China III standards.
• Measured NO_x emission factors were higher than guideline values, indicating underestimation in current inventories.

Conclusions:

• Wheel loaders contribute more significantly to air pollution than excavators.
• Stricter emission standards have led to decreased CO, HC, and NO_x emissions.
• National emission inventory guidelines may overestimate CO and HC but underestimate NO_x for construction machinery.