5Huang S, Rahn K A, Arimoto R. Testing and Optimizing two factor-analysis techniques on aerosol at Narragansett, Rhode Island. Atmos Environ, 1999,33:2169-2185.
6Eddie Lee, Chak K Chan, Pentti Paatero. Application of positive matrix factorization in source apportionment of particulate pollutants in Hong Kong. Atmos Environ, 1999, 33: 3201- 3212.
7Prendes P,Andrade J M, Lopez Mahia P, et al. Source apportion of inorganic ions in airborne urban particles from Coruna city (N. W. of Spain) using positive matrix factorization. Talanta, 1999, 49: 165-178,
8Xie Y L, Hopke P K, Paatero P, etal. Identification of source nature and seasonal variation of Arctic aerosol by positive matrix factorization. J Atmos Sci, 1999, 56:249-260.
9Chueinta W, Hopke P K, Pzacero P. Investigation of source of atmospheric aerosol et urban and suburban residential areas in Thailand by positive matrix factorization. Atmos Environ, 2000,34 : 3319-3329.
10US Environmental Protection Agency. National Ambient Air Quality Standards. 1997.