Soluble metals in the atmosphere and their biological implications. A study to identify important aerosol components by statistical analysis of PIXE data

Analysis of anions in ambient aerosols by microchip capillary electrophoresis

We describe a microchip capillary electrophoresis method for the analysis of nitrate and sulfate in ambient aerosols. Investigating the chemical composition of ambient aerosol particles is essential for understanding their sources and effects. Significant progress has been made towards developing mass spectrometry-based instrumentation for rapid qualitative analysis of aerosols. Alternative methods for rapid quantification of selected high abundance compounds are needed to augment the capacity for widespread routine analysis. Such methods could provide much higher temporal and spatial resolution than can be achieved currently. Inorganic anions comprise a large percentage of particulate mass, with nitrate and sulfate among the most abundant species. While ion chromatography has proven very useful for analyzing extracts of time-integrated ambient aerosol samples collected on filters and for semi-continuous, on-line particle composition measurements, there is a growing need for development of new compact, inexpensive approaches to routine on-line aerosol ion analysis for deployment in spatially dense, atmospheric measurement networks. Microchip capillary electrophoresis provides the necessary speed and portability to address this need. In this report, on-column contact conductivity detection is used with hydrodynamic injection to create a simple microchip instrument for analysis of nitrate and sulfate. On-column contact conductivity detection was achieved using a Pd decoupler placed upstream from the working electrodes. Microchips containing two Au or Pd working electrodes showed a good linear range (5-500 microM) and low limits-of-detection for sulfate and nitrate, with Au providing the lowest detection limits (1 microM) for both ions. The completed microchip system was used to analyze ambient aerosol filter samples. Nitrate and sulfate concentrations measured by the microchip matched the concentrations measured by ion chromatography.

Short-term effects of air pollution on mortality in nine French cities: a quantitative summary

Between 1990 and 1995, 9 French cities provided data on daily air pollution, total mortality, cardiovascular mortality, and respiratory mortality. Personnel in individual cities performed Poisson regressions, controlling for trends in seasons, calendar effects, influenza epidemics, temperature, and humidity, to assess the short-term effects of air pollution. The authors describe results obtained from the quantitative pooling of these local analyses. When no heterogeneity could be detected, a fixed-effect model was used; otherwise, a random-effect model was used. Significant and positive associations were found between total daily deaths in these cities and the 4 air pollution indicators studied: (1) Black Smoke, (2) sulfur dioxide, (3) nitrogen dioxide, and (4) ozone. A 50-microg/m3 increase in Black Smoke (24 hr), sulfur dioxide (24 hr), nitrogen dioxide (24 hr), or ozone (8 hr) was associated with increases in total mortality of 2.9% (95% confidence interval [CI]) = 1.3, 4.4), 3.6% (95% CI = 2.1, 5.2), 3.8% (95% CI = 2.0, 5.5), and 2.7% (95% CI = 1.3, 4.1), respectively. Similar results were obtained for cardiovascular mortality. Except for sulfur dioxide, positive--but not significant--associations were found with respiratory mortality. The internal consistency among the cities studied, as well as consistency with previously published results, favors a causal interpretation of these associations.

Use of nuclear analytical techniques in bioenvironmental studies

Bioenvironmental studies remain to be one of the most important fields of applied analytical chemistry. At present time, more than 50% of nuclear analytical studies deal with bioenvironmental investigations. The first period of utilizing nuclear analytical methods in bioenvironmental sciences could be characterized as "purely analytical," in which these methods were used for determination of sample composition in competition with other non-nuclear methods. Later, the outstanding advantages of the former methods were used for more detailed description of systems to be studied, including element speciation, spatial distribution, and so forth. The present period not only develops approaches of previous periods but also considers the bioenvironmental processes more widely and is focused on their dynamics. In this field, a large extent of utilizing various nuclear analytical techniques can be expected as well.