Development and application of three-dimensional potential source contribution function (3D-PSCF)

Abstract

A potential source contribution function (PSCF) can indicate the source areas of high air pollutant concentrations using backward trajectories. However, the conventional two-dimensional PSCF (2D-PSCF) cannot consider the emission and transport height of air pollutants. That missing information might be critical because injection height varies depending on the source type, such as with biomass burning. We developed a simple algorithm to account for the height of trajectories with high concentrations and combined it with the conventional PSCF to devise 3D-PSCF. We demonstrate the applicability of the 3D-PSCF by applying it to particulate PAH data collected from September 2006 to August 2007 in Seoul. We found variation in the results from 3D-PSCF with threshold heights from 3,000 to 1,500 m. Applying 2,000 m as the threshold height in the PSCF calculation most clearly determined the possible source areas of air pollutants from biomass fuel burning that were affecting the air quality in Seoul.

Sources and Geographical Origins of PM10 in Metz (France) Using Oxalate as a Marker of Secondary Organic Aerosols by Positive Matrix Factorization Analysis

“…Wet deposition was estimated by "cutting" the trajectory where significant precipitation occurred (endpoint with associated rainfall higher than 1 mm/h). Similarly to the work of Reference [35], an altitude threshold was set at 2000 m agl.…”

A Study on Elevated Concentrations of Submicrometer Particles in an Urban Atmosphere

“…The RTA value for each grid cell (0.2 • latitude × 0.2 • longitude) was calculated using the number of endpoints passing over the grid cell (i.e., the number of endpoints is the residence time of the air mass in each grid cell). Additionally, a PSCF method was applied to find the source regions of the chemical constituents in PM 1 [29][30][31] (i.e., elevated concentrations of chemical constituents at a receptor site can be related to the air mass trajectory). The PSCF value for each grid cell was calculated using the ratio of the number of endpoints passing over the grid cell when the concentration of specific chemical constituents was within the upper 35% level to the total number of endpoints passing over the grid.…”

Potential Source Density Function: A New Tool for Identifying Air Pollution Sources

“…Mean or median can change with data set, so PSCF values with different criteria cannot be quantitatively compared. Several researches extend and modify the conventional models to reduce the limitation of PSCF and to enhance the application of trajectories (Stohl et al, 2002;Lin et al,2003;Kim et al, 2016;Kim et al, 2019).…”

“…The hyperparameters for the PSDF model can be specified by the ML-II approximation with the two variables ℓ and r. However, in most practical applications of the PSDF model, we can reduce the number of hyperparameters even further. Other models utilizing ambient data and backward trajectories divide the domain into a 0.5˚ by 0.5˚ grid (Zhang et al, 2015;Kim et al, 2016). Also, the typical spatial scale in atmospheric chemical transport models ranges from 20 km to 80 km for regional and continental scale (Seinfeld and Pandis, 2016).…”