Evaluation of time-resolved PM2.5 data in urban/suburban areas of New Jersey.

Time-resolved data is needed for public notification of unhealthful air quality and to develop an understanding of atmospheric chemistry, including insights important to control strategies. In this research, continuous fine particulate matter (PM2.5) mass concentrations were measured with tapered element oscillating microbalances (TEOMs) across New Jersey from July 1997 to June 1998. Data features indicating the influence of local sources and long-distance transport are examined, as well as differences between 1-hr maxima and 24-hr average concentrations that might be relevant to acute health effects. Continuous mass concentrations were not significantly different from filter-collected gravimetric mass concentrations with 95% confidence intervals during any season. Annual mean PM2.5 concentrations from July 1997 to June 1998 were 17.3, 16.4, 14.1, and 15.3 micrograms/m3 at Newark, Elizabeth, New Brunswick, and Camden, NJ, respectively. Monthly averaged 24- and 1-hr daily maximum PM2.5 concentrations suggest the existence of a high PM2.5 (May-October) and a low PM2.5 (November-April) season. PM2.5 magnitudes and temporal trends were very similar across the state during high PM2.5 events. In fact, the between-site coefficients of determination (R2) for daily PM2.5 measurements were 84-98% for June and July. Additionally, during the most pronounced PM2.5 episode, PM2.5 concentrations closely tracked the daily maximum 1-hr O3 concentrations. These observations suggest the importance of transport and atmospheric chemistry (i.e., secondary formation) to PM2.5 episodes in New Jersey. The influence of local sources was observed in diurnal concentration profiles and annual average between-site differences. Urban wintertime data illustrate that high 1-hr maximum PM2.5 concentrations can occur on low 24-hr PM2.5 days.

The determination of lead in total suspended air particulates by x-ray fluorescence spectroscopy.

A method has been developed for the measurement of lead in air particulates collected on glass fiber filter paper with wavelength-dispersive x-ray fluorescence spectroscopy (WDXRF). Analyses conducted by both WDXRF and an EPA-approved procedure that employs acid sonication followed by analysis of the extract by atomic-absorption spectroscopy (AAS) shows excellent agreement between the two methods. WDXRF calibration was accomplished with standards prepared from known additions of Pb to unexposed glass fiber filter discs. Method equivalency has also been demonstrated by the analysis of several reference materials and the statistical analysis of quality control data. The WDXRF procedure has also been used to evaluate the distribution of Pb in the particulates across the surface of the filter.

The Total Human Environmental Exposure Study (THEES) to benzo(a)pyrene: comparison of the inhalation and food pathways.

The assessment of human exposure to an environmental contaminant requires the measurement of levels present in each pathway of possible contact. In this paper, the design considerations and Phase I results of a human exposure study focused on Benzo(a)pyrene (BaP) are discussed. This study site, located in Phillipsburg, New Jersey, is a city that contains a metal pipe foundry, which is a suspected major source of BaP. Three outdoor PM-10 samplers (used to collect BaP-containing particles with an aerodynamic size of less than or equal to 10 micron) were located in residential areas surrounding the foundry. Ten homes were sampled indoors for PM-10. Some homes have indoor combustion sources, e.g., cigarette smoke or a coal burning stove. The indoor and outdoor samples were 24 hr in duration. The mean outdoor concentration of BaP was 0.9 ng/m3, and the indoor concentrations ranged from 0.1-8.1 ng/m3. Food samples were acquired from family meals each day. They represented a one-third portion of each meal eaten at home. The range of BaP per gram of wet weight of food was between 0.004 and 1.2 ng/g. Of the 20 wk of exposure (10 x 2 wk), 10 had higher food exposures and the other 10 had higher inhalation exposures. Of the two groups, the higher food exposures usually had a greater number of ng of BaP/wk. The dominance of one or the other pathway appeared to depend upon personal eating habits and indoor combustion source use. In some instances, outdoor air pollution led to a major portion of indoor air BaP exposures. Water appears to be a minor source of BaP exposures in the study area.

Exploring data quality for some inorganic and organic constituents of inhalable particulate matter (PM10).

Quality assurance (QA) assessments of air pollution data sets provide a basis for evaluating the significance of various substances in the atmosphere. For non-criteria pollutants, QA results are seldom reported in the technical literature and are often difficult to estimate. The present report provides a summary of QA results such as recovery, precision and accuracy data. Of the six trace elements and nine organic constituents compared in detail, recoveries, laboratory precision and laboratory accuracy values were 100%, ±3% to ±19% and-2 to-13% for the former group and 69% to 98%, ±7% to 23% and-15 to-34% for the later group. System precision varied from ±22% to ±47% for the trace elements and ±42% to ±83% for the organic constituents. Limitations in the interpretation of non-criteria particulate-phase pollutant data bases are discussed with some emphasis placed on receptor-modelling and risk assessment applications. Finally, the relevance of NBS certified materials for QA estimates in non-criteria air pollutant studies is also reviewed.