Rethinking organic aerosols: semivolatile emissions and photochemical aging

Science. 2007 Mar 2;315(5816):1259-62. doi: 10.1126/science.1133061.

Abstract

Most primary organic-particulate emissions are semivolatile; thus, they partially evaporate with atmospheric dilution, creating substantial amounts of low-volatility gas-phase material. Laboratory experiments show that photo-oxidation of diesel emissions rapidly generates organic aerosol, greatly exceeding the contribution from known secondary organic-aerosol precursors. We attribute this unexplained secondary organic-aerosol production to the oxidation of low-volatility gas-phase species. Accounting for partitioning and photochemical processing of primary emissions creates a more regionally distributed aerosol and brings model predictions into better agreement with observations. Controlling organic particulate-matter concentrations will require substantial changes in the approaches that are currently used to measure and regulate emissions.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aerosols
  • Air Pollutants / chemistry*
  • Computer Simulation
  • Hydrocarbons / chemistry
  • Mathematics
  • Models, Chemical
  • Organic Chemicals / chemistry*
  • Oxidation-Reduction
  • Particulate Matter / chemistry*
  • Phase Transition
  • Photochemistry
  • Ultraviolet Rays
  • Vehicle Emissions / analysis*
  • Volatilization

Substances

  • Aerosols
  • Air Pollutants
  • Hydrocarbons
  • Organic Chemicals
  • Particulate Matter
  • Vehicle Emissions