Emissions from gasoline and diesel engines vary on time scales including diurnal, weekly, and decadal. Temporal patterns differ for these two engine types that are used predominantly for passenger travel and goods movement, respectively. Rapid growth in diesel fuel use and decreasing NOx emission rates from gasoline engines have led to altered emission profiles. During the 1990s, on-road use of diesel fuel grew 3 times faster than gasoline. Over the same time period, the NOx emission rate from gasoline engines in California was reduced by a factor of approximately 2, while the NOx emission rate from diesel engines decreased only slightly. Diesel engines therefore grew in both relative and absolute terms as a source of NOx, accounting for about half of all on-road NO, emissions as of 2000. Diesel truck emissions decrease by 60-80% on weekends. Counterintuitive responses to these emission changes are seen in measured concentrations of ozone. In contrast, elemental carbon (EC) concentrations decrease on weekends as expected. Weekly and diurnal patterns in diesel truck activity contribute to variability in the ratio of organic carbon (OC) to EC in primary source emissions, and this could be a source of bias in assessments of the importance of secondary organic aerosol.
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http://dx.doi.org/10.1021/es048172+ | DOI Listing |
J Environ Manage
January 2025
School of the Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China.
The effectiveness of protected areas in mitigating human impacts remains uncertain due to limited in-situ data; however, atmospheric micropollutant deposition in alpine lakes may provide a quantitative approach to evaluate anthropogenic pressures and threats. In this study, the temporal changes of polycyclic aromatic hydrocarbons (PAHs) inside/outside the Siling Co protected area, Tibet were reconstructed. The varying anthropogenic impact history suggested that, unlike the dominance of residential activities (i.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, 1084 Columbia Avenue, Riverside, California 92507, United States.
We assessed the real-world particulate emissions of a goods movement diesel vehicle, with an emphasis on total particle number and solid particle number emissions at different cutoff sizes. The vehicle was tested on routes in the South Coast Air Basin (SCAB) of California, representative of typical goods movement operation between the ports to warehouses and logistic centers with a mixture of urban and highway driving, as well as elevation change. We evaluated emissions during normal vehicle operation and diesel particulate filter (DPF) active regeneration events.
View Article and Find Full Text PDFSci Rep
January 2025
Parul Institute of Engineering and Technology, Parul University, Vadodara, Gujarat, India.
Maintaining stable voltage and frequency regulation is critical for modern power systems, particularly with the integration of renewable energy sources. This study proposes a coordinated control strategy for voltage and frequency in a deregulated power system comprising six Generation Companies (GENCOs) and six Distribution Companies (DISCOs). The system integrates thermal, diesel, wind, solar photovoltaic (PV), and hydroelectric sources.
View Article and Find Full Text PDFMol Biol Res Commun
January 2025
Department of Soil Science, College of Agriculture, Razi University, Kermanshah, Iran.
The bioremediation method is considered an economical and environmentally friendly strategy for the remediation of oil-contaminated soils. However, some oil field areas have extreme environmental conditions that make it difficult to establish microbes for bioreme-diation. In this study, bacteria were isolated from oil-contaminated soils of the Dehloran oil fields, which have very harsh soil and weather conditions.
View Article and Find Full Text PDFScientificWorldJournal
December 2024
Department of Mechanical Engineering, Dream Institute of Technology, Kolkata, 700104, India.
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