THE OCCURRENCE OF ATMOSPHERIC AEROSOLS IN THE NORTHEASTERN UNITED STATES^*

The New Jersey Project on Airborne Toxic Elements and Organic Substances (ATEOS): A Summary of the 1981 Summer and 1982 Winter Studies

“…As shown by Lioy et al, 12 the periodic increases in sulfate in the summer, in excess of 25 jug/m 3 , were recorded simultaneously at all sites and were associated with the passage of high pressure systems. This observation is consistent with previous work of Wolff et al , 17 Mueller et al , 18 and Lioy et al 19 The summertime peaks occurred on July 19, August 4, and August 9-10, during the most severe portions of these episodes. The wintertime levels, by contrast, never exceeded 20 /*g/m 3 at any of the sites, and in fact the levels never went below 5.5 yug/m 3 on any given day at the urban sites.…”

Visibility: Science and Regulation

“…It overlooks, however, the simple option of diurnally resolved filter sampling, which has long been available. Early haze monitoring programs that collected 2-to 12-hr samples include the Tri-City Study, 102 RAPS, 107 SURE, 108 ERAQS, 109 WRAQS, 110 and SCENES. 111 Figure 14 shows some daytime-only observations made in Los Angeles more than 30 years ago.…”

Advances in Integrated and Continuous Measurements for Particle Mass and Chemical Composition

“…Several analytical methods have been applied to filter samples. These include: (1) mass by gravimetry 14,15,59 ; (2) light transmission (b abs ) by densitometer or reflectance 60 ; (3) elements by X-ray fluorescence (XRF), 61 proton-induced X-ray emission (PIXE), 62 instrumental neutron activation analysis (INAA), 63 atomic absorption spectroscopy (AAS) 64 and inductivelycoupled plasma/MS (ICP/MS) 65 ; (4) 67 ion-selective electrodes (ISE), 68 and Fourier transform infrared spectrometry (FTIR) 69 ; and 7) carbon (OC and EC) by thermal/optical reflectance (TOR) and transmittance (TOT) methods. 70 -78 Table 4 shows that these methods typically report 2-5% accuracy, 5-10% precision for mass, elements, ions, and total carbon (TC), and 10 -20% precision for OC and EC.…”