Precision of an ambient sequential acid aerosol sampling system.
Jaques-PA; Thurston-GD; Kinney-PL; Gorczynski-JE Jr.
Appl Occup Environ Hyg 1993 Apr; 8(4):313-316
A study of the precision of an ambient sequential acid aerosol sampling system was conducted. Two identical automated sequential acid aerosol sampling systems were placed side by side on the roof of an air monitoring site in White Plains, New York and operated for 6 weeks. The systems consisted of impactors and filter units that sampled particulate matter containing hydrogen ions (H+), ammonium ions, and sulfate ions. Forty one pairs of daily filter samples were collected during the sampling period. The precision of the two systems was evaluated by determining the variation of daily paired differences in the H+, ammonium, and sulfate data and was reported as the relative coefficient of variation (RCV). The overall mean concentrations of the ions measured during the sampling period were: H+, 51.2 nanomoles/cubic meter (nmol/m3); sulfate, 87.0nmol/m3; and ammonium, 111nmol/m3. The mean paired differences in the ion concentrations were 6.0, 1.9, and -1.5nmol/m3 for H+, sulfate, and ammonium, respectively. Only the mean paired difference in the H+ data was statistically significant. The RCVs in the H+, sulfate, and ammonium data were 19, 7.7, and 13%, respectively. Scatter plots of the data showed that all ion concentrations measured by the two sampling systems were highly linearly correlated; correlation coefficients were greater than or equal to 0.93. The authors conclude that the analysis shows that the sequential acid aerosol sampling system appears to be a reliable technique for determining particulate ion concentrations in ambient environments.
NIOSH-Publication; NIOSH-Grant; Training; Particulates; Air-contamination; Aerosol-sampling; Acidity; Statistical-analysis; Environmental-pollution
Community Medicine MT Sinai School of Medicine Fifth Avenue and 100Th Street New York, N Y 10029
Applied Occupational and Environmental Hygiene
Mount Sinai School of Medicine, New York, New York