Emission Characteristics of Hazardous Air Pollutants from Construction Equipment

Abstract

The emission characteristics of mobile air pollution sources belonging to the non-road sector have yet to be thoroughly investigated, especially when compared to those of on-road vehicles. Hence, the present study employed an engine dynamometer to evaluate the emissions of a diesel engine complying with Tier 3 standards during various driving modes (KC1-8, NRSC, and NRTC) and a portable emissions measurement system (PEMS) to assess those of two excavators, one complying with Tier 3 and the other with Tier 4 standards, during real-world working and driving conditions. The characteristics and chemical composition of the emitted regulated pollutants (carbon monoxide (CO), non-methane hydrocarbon (NMHC), nitrogen oxide (NO x), and particulate matter (PM)) and hazardous air pollutants (HAPs), e.g., volatile organic compounds (VOCs), aldehydes, and polycyclic aromatic hydrocarbons (PAHs), were then determined. For the regulated pollutants, NRTC mode generated the highest emissions owing to the rapid changes in engine load and speed during transitions. As a result of the after-treatment systems, which utilized a diesel oxidation catalyst (DOC) and selective catalytic reduction (SCR), CO, NMHC, and NO x emissions from the Tier 4-compliant excavator were lower than those from the Tier 3compliant diesel engine and excavator. The operating conditions of the diesel engine and construction equipment as well as the after-treatment systems significantly affected the composition of the non-methane volatile organic compound (NMVOC) emissions, which were dominated by alkanes that comprised 23 detected species. Sampling the particle-phase PAHs, we found phenanthrene, fluoranthene, and naphthalene; furthermore, we estimated the concentrations of the gas-phase PAHs with models to obtain the total PAH concentrations. Formaldehyde, which contributed the largest fraction of the aldehydes, was more abundant than the other species. Thus, emissions from non-road sources, including construction equipment, must be controlled because of the considerable health risks from pollutants such as formaldehyde and benzene. Our results will aid in the establishment of a national emission inventory for HAPs.

Emission Characteristics of Hazardous Air Pollutants from Medium-Duty Diesel Trucks Based on Driving Cycles

“…In addition, the higher loading of a diesel engine has a significant relationship with endocrine disruption [12] due to their emission of polycyclic aromatic compounds (PAHs). Many studies [13][14][15][16][17] have explored the characterization of PAHs in particles from diesel vehicles. A recent study reported that the PAH concentration in terms of toxic equivalency quantity (TEQ) associated with benzene ring number demonstrated two peak concentrations with respect to smaller ultrafine (> 66 nm) and quasiaccumulation (170-330 nm) size ranges [18].…”

Emission Characteristics of Hazardous Air Pollutants from Medium-Duty Diesel Trucks Based on Driving Cycles

“…In addition, the higher loading of a diesel engine has a significant relationship with endocrine disruption [12] because of their emission of PAHs. Many studies [13][14][15][16][17] have explored the characterization of PAHs in particles from diesel vehicles. A recent study reported that the PAH concentration in terms of the toxic equivalency quantity (TEQ) associated with the benzene ring number demonstrated two peak concentrations with respect to smaller ultrafine (>66 nm) and quasiaccumulation (170-330 nm) size ranges [18].…”

Enhanced removal of ultrafine particles from kerosene combustion using a dielectric barrier discharge reactor packed with porous alumina balls

“…However, the UFPs removal efficiencies are depended on the size distribution of the UFPs [19,20]. Electrostatic precipitators (ESPs) have also been successfully used in industry to collect the particles from exhaust gases, such as in coal power generation [21][22][23]. The total PM removal efficiency by using ESP technology was above 95% based on mass.…”