A5069195507- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Combustion and Detonation Processes
- Catalytic Processes in Materials Science
- Brake Systems and Friction Analysis
- Vehicle emissions and performance
- Atmospheric aerosols and clouds
- Asphalt Pavement Performance Evaluation
- Environmental Policies and Emissions
- Environmental and biological studies
- Geography and Environmental Studies
- Advanced Combustion Engine Technologies
- Tribology and Wear Analysis
- Atmospheric Ozone and Climate
University of California, Irvine
2020-2025
Although the last several decades have seen a dramatic reduction in emissions from vehicular exhaust, nonexhaust (e.g., brake and tire wear) represent an increasingly significant class of traffic-related particulate pollution. Aerosol particles emitted wear automotive pads contribute roughly half particle mass attributed to sources, while their relative contribution urban air pollution overall will almost certainly grow coinciding with vehicle fleet electrification transition alternative...
Particulate matter (PM) emitted from road traffic causes adverse health effects upon inhalation and respiratory deposition. Non-exhaust emissions will eventually become the dominant source of PM transition to electric vehicles; however, non-tailpipe is currently unregulated as its impacts are still unclear. In this study, we generated brake wear particles (BWPs) with non-asbestos organic, ceramic, semimetallic pads using custom dynamometers measured aqueous-phase formation reactive oxygen...
Motor vehicles are among the major sources of pollutants and greenhouse gases in urban areas a transition to "zero emission vehicles" is underway worldwide. However, emissions associated with brake tire wear will remain. We show here that previously unrecognized volatile semi-volatile organic compounds, which have similarity biomass burning emitted during braking. These include or, these classified as Hazardous Air Pollutants, well nitrogen-containing organics, nitrogen oxides ammonia. The...
Abstract. Reports on the composition of ultrafine particles (<100 nm in diameter) Amazon are scarce, due part to fact that new-particle formation has rarely been observed near ground level. Ultrafine surface have nevertheless observed, leaving open questions regarding sources and chemistry their growth, particularly as these vary across seasons. Here, we present measurements collected Tapajós National Forest (2.857° S, 54.959° W) during three different seasonal periods: 10–30 September...
As worldwide trends move toward replacing combustion transportation modes with electric vehicles, characterizing non-tailpipe emissions, such as those from brake wear, becomes increasingly important. Nitrous acid (HONO), nitryl chloride (ClNO2), and dinitrogen pentoxide (N2O5) are important sources of radical oxidants (e.g., •OH, •Cl, •NO3) nitrogen oxides (NOx) in the atmosphere, driving chemistry that leads to air quality degradation. Discrepancies between measurements model predictions...
Abstract. Reports on the composition of ultrafine (<100 nm in diameter) particles Amazon are scarce, due part to fact that new particle formation has rarely been observed near ground level. Ultrafine surface have nevertheless observed, leaving open questions regarding sources and chemistry their growth, particularly as these vary across seasons. Here we present measurements collected Tapajos National Forest (2.857° S, 54.959° W) during three different seasonal periods: 10–30 September...
We conducted laboratory chamber experiments to probe the gas- and particle-phase composition of oxidized organics secondary organic aerosol (SOA) formed from α-thujene ozonolysis under different chemical regimes. The formation low-volatility compounds was observed using ionization mass spectrometry with nitrate (NO3-) iodide (I-) reagent ions. contribution measured particle growth predicted a simple condensational model found underpredict rates in our (on order several nm min-1). yields SOA...