png AER,BC,BCPOM,DMS,DUST,METEO,POM,SO2,SO4,SS AERH2O,AVE,BUD,CFREE,CONC1000,CONC500,CONCZON,EC550ZON,EMI,ER3D1000,ER3D500,ERGT053D1000,ERGT053D500,ERLT053D1000,ERLT053D500,LOAD,LOAD05,LOAD125,LOADCOA,MEC550,OD550,OD865,RH1000,RH500,SEDDRY,WET an1996,an2000 mALLYEAR ps