The Lower Fraser Valley of British Columbia (LFV) is currently experie
ncing rapid population growth and is perceived to suffer from reduced
air quality, specifically, elevated ozone concentrations and impaired
visibility. It is necessary to identify the sources of visibility-degr
ading aerosols in order to develop strategies to prevent further degra
dation and to institute measures to improve air quality in this region
. Although chemical mass balance analyses have typically been used in
such studies, herein, a P-mode principal component analysis (PCA) is p
erformed upon the ambient aerosol species at one polluted site in the
LFV, and source profiles are inferred from the resulting component loa
dings. The loading coefficients on the five significant components (wh
ich account for over 70% of the variance in the fine aerosol speciatio
n dataset) are used to assess the contribution of these sources to par
ticulate light scattering (b(sp)). Automobile emissions and wood burni
ng are found to contribute most to b(sp) at this site.