-pinene reactions in the presence of sunlight, ozone (O3), and oxides of nitrogen (NOx). Reaction products and aerosol formation from the kinetic model were compared to outdoor smog chamber experiments conducted under natural sunlight in the presence of NOx and in the dark in the presence of O3. The gas-particle partitioning of semivolatile organics generated in the gas phase was treated as an equilibrium process between particle absorption and desorption. Models vs experimental aerosol yields illustrate that reasonable predictions of secondary aerosol formation are possible from both dark ozone and light NOx/-pinene systems over a variety of different outdoor conditions. On average, measured gas- and particle-phase products accounted for ~54-72% of the reacted -pinene carbon. Model predictions suggest that organic nitrates account for another ~25% of the reacted carbon, and most of this is in the gas phase. Measured particle-phase products accounted for 60-100% of the particle filter mass, with pinic acid and pinonic acid being the primary aerosol-phase products. In the gas phase, pinonaldehyde and pinonic acid are major products. Model simulations of these and other products show generally reasonable fits to the experimental data from the perspective of timing and concentrations. These results are very encouraging for a compound such as pinonaldehyde, since it is being formed from OH attack on -pinene and is also simultaneously photolyzed and reacted with OH. " /> MODELING AEROSOL FORMATION FROM ALPHA-PINENE + NOX IN THE PRESENCE OF NATURAL SUNLIGHT USING GAS PHASE KINETICS AND GAS-PARTICLE PARTITIONING THEORY. (R826771) | Science Inventory | US EPA

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MODELING AEROSOL FORMATION FROM ALPHA-PINENE + NOX IN THE PRESENCE OF NATURAL SUNLIGHT USING GAS PHASE KINETICS AND GAS-PARTICLE PARTITIONING THEORY. (R826771)

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Citation:

Kamens, R. M. AND M. Jaoui. MODELING AEROSOL FORMATION FROM ALPHA-PINENE + NOX IN THE PRESENCE OF NATURAL SUNLIGHT USING GAS PHASE KINETICS AND GAS-PARTICLE PARTITIONING THEORY. (R826771). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 35(7):1394-1405, (2001).

Description:

A kinetic mechanism was used to link and model the gas-phase reactions and
aerosol accumulation resulting from src="/ncer/pubs/images/alpha.gif">-pinene reactions in the presence of sunlight,
ozone (O3), and oxides of nitrogen
(NOx). Reaction products and aerosol formation from
the kinetic model were compared to outdoor smog chamber experiments conducted
under natural sunlight in the presence of NOx and
in the dark in the presence of O3. The gas-particle partitioning of
semivolatile organics generated in the gas phase was treated as an equilibrium
process between particle absorption and desorption. Models vs experimental
aerosol yields illustrate that reasonable predictions of secondary aerosol
formation are possible from both dark ozone and light
NOx/src="/ncer/pubs/images/alpha.gif">-pinene systems over a variety of different
outdoor conditions. On average, measured gas- and particle-phase products
accounted for ~54-72% of the reacted src="/ncer/pubs/images/alpha.gif">-pinene carbon. Model predictions suggest that
organic nitrates account for another ~25% of the reacted carbon, and most of
this is in the gas phase. Measured particle-phase products accounted for 60-100%
of the particle filter mass, with pinic acid and pinonic acid being the primary
aerosol-phase products. In the gas phase, pinonaldehyde and pinonic acid are
major products. Model simulations of these and other products show generally
reasonable fits to the experimental data from the perspective of timing and
concentrations. These results are very encouraging for a compound such as
pinonaldehyde, since it is being formed from OH attack on src="/ncer/pubs/images/alpha.gif">-pinene and is also simultaneously photolyzed
and reacted with OH.


Record Details:

Record Type:DOCUMENT( JOURNAL/ PEER REVIEWED JOURNAL)
Product Published Date:01/01/2001
Record Last Revised:12/22/2005
Record ID: 68777