1. Please go to next page Fig 1. Ambient aerosols observations in Oct and Nov 2002.

2. Please go to next page Fig 2. Rad-Res-Nephs comparison at Fazenda with ambient aerosols and NaCl particles.

3. 1.TSI nephs observed lower values than Rad Res neph Zeppo which was operated at ambient conditions. 2. Total scattering of TSI-neph-IAG is 20% lower than TSI-neph-LFA at 550 nm. 3. It is interesting that there is no offset in the slops, only factor is applicable. 4. Rad-Research-Nephs were calibrated and intercompared at fazenda in parallel configurations (Fihure2). The results shown above are after applying all the corrections i.e. (calibration with zero air and CO2; intercomparison with ambient air and NaCl particles, the truncation correction based on the Guyan et al 2003). Using all the analysis an offset of 1(Mm-1) is added in zeppo observations and all the data are increase by 2% i.e. a factor of 1.02. 5. The the Rad-research-Neph-Zeppo (sampling ambient aerosols) observes higher than the Rad-Res-neph-Groucho (sampling dry aerosols with impactor cut off at about 1 micro meter). This difference is expected. We need to resolve (1)Why the TSI nephs show lower values than Rad Res neph zeppo. (2)Why the two TSI are not matching (20% different in each other). The calibration data for the two TSI nephs can help to resolve these issues.