Abstract
Coarse and fine PM10 were collected in Hanoi from January 2001 to July 2002 and were analysed for water-soluble ions (WSI) and chemical elements. Factor analysis in the form of Positive Matrix Factorization was used to derive and characterize emission sources. For the coarse fraction, five sources accounting for 91% of the average coarse mass (37,8 mg m-3) were resolved, namely soil dust (46%), coal fly ash (20%), marine aerosols (14%), coarse nitrate (10%) and local ammonium sulphate (8%). Six sources of fine PM10 accounting for 97% of the average fine mass concentration (31.1 mg m-3) were resolved including long range transport (46%), coal (17%), soil dust (16%), vehicles (10%), biomass (6%) and Cl-depleted marine aerosols (5%).
The source contributions are much larger in winter than in summer, reflecting the contrast in characteristics of air masses and their trajectories governing the monsoon regime in northern Vietnam. The results showed that soil dust and coal burning are the two high priority issues that should be addressed in order to improve the air quality in Hanoi.
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