Particle Size and Temporal Characteristics of Aerosol Composition near Coal-Fired Electric Power Plants of the Eastern Transvaal

Multimodal size spectra of submicrometer particles bearing various elements in rural air

“…Samples 21-24 were collected concurrently with dichotomous filter samplers run nearby as described by Vossler et al (26). Concentrations measured by both samplers generally agreed quite well; however, concentrations of Ca (samples 21 and 22), Co (samples [22][23][24], Cr (samples [21][22][23][24], and Cl (samples 21,22 and possibly 23) measured with the MOI were much too large to be valid, and therefore, we report results for these elements only when the two measurements agreed within 25%. In addition, concentrations of Br determined by INA were more than 30% less than those determined by XRF and nearly half those obtained measured on the dichotomous filter samples.…”

“…For CFPPs burning pulverized coal for example, from «10 to «90% of the aerosol mass is emitted in narrow peaks with modal diameters ranging from «0.1 to 0.33 µ , depending largely on the type of particulate control device (7-10, 18-20). These accumulation aerosol peaks have been observed at ground level in plumes in the vicinity of single CFPPs (21,22). Here we used microorifice impactors (MOI; refs 23 and 24) to collect size-classified samples of submicrometer aerosol particles for trace-element analyses at Deep Creek Lake, a rural recreational area in western Maryland, influenced by refineries, incinerators, motor vehicles, and many CFPPs (23).…”

“…The rather prominent O.l-µ peaks for Ce and La in the spectra for samples [22][23][24] are more interesting as these elements are enriched in fine particles emitted by refineries and OFPPs (49). This is especially intriguing in view of the V source observed to be in close proximity to DCL by Vossler et al (26), because Ce and La are coemitted with V by refineries and oil-fired power plants.…”

“…For example, most of the mass of Ce and La in samples 22 and 23 is contained on stage 5 and estimates of the for these peaks averaged 1.27 ± 0.05. These surely represent primary particulate emissions from high-temperature combustion sources that have undergone little if any growth during transport.…”

System for Precise Control of Volumetric Flow Rate during Sampling with a Cascade Impactor

“…In addition to permitting determination of size distributions of aerosol properties, impactor measurements are used in combination with other measurements to infer size-dependent aerosol behavior, e.g., deposition velocities (Lin et al 1994;Caffrey et al 1998;Hoff et al 1998). Changes in size distributions of mass and various constituent species have been used to infer temporal characteristics (Annegarn 1983), particle deposition gradients (Paode et al 1998), atmospheric growth laws (Hering and Friedlander 1982;McMurry and Wilson 1983), hygroscopic growth (Ahlberg and Winchester 1978;Koutrakis et al 1989;Divita et al 1995;Divita et al 1996;Hitzenberger et al 1997), and atmospheric transformations and secondary aerosol formation processes (McMurry and Wilson 1983;John et al 1990;Venkataraman and Friedlander 1994;Berner et al 1996). The sensitivity to which such information can be inferred, however, depends on the ability to accurately determine changes in mass observed on the various impactor stages and, thus, on noise and bias errors in sampling and on measurement uncertainties.…”