Recent developments in air quality modeling make it possible to track size distribution, chemical composition, and source origin of regional particulate air quality problems in sufficient detail so that the effect of emissions controls on size and composition distribution can be represented accurately.
The Study:
*24 air parcel trajectories were passed over Claremont at each hour of the day on Aug. 28, 1987 and then were followed backward for 48 hours to their starting position over the Pacific Ocean on Aug.27, 1987. (Don't be fooled by the date, the article wasn't published until 2001, so this is relatively recent news.)
*Meteorological variables included wind speed and direction, temperature, and relative humidity.
*Source-specific chemical composition profiles and inventory were used for calculations, [inventory describes the spatial distribution and temporal variation of the gas-phase pollutants (NOx, SOx, CO, reactive organic gases) and the particulate matter mass emitted from sources within the L.A. Area].
*Each air parcel was initialized with gas and particle-phase concentrations and measured at San Nicolas Island during the study period.
*The evolution of the gases and particles injected into each parcel as the air passed over the city upwind, was followed.
*Time period: 6AM-6PM Pacific Std. Time, Aug. 28, 1987.