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This is Part II of a review covering the wide range of issues associated with all aspects of the use and responsible disposal of foam and plastic wastes containing toxic or potentially toxic flame retardants. We identify basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes. In Part II, we explore alternative technologies for the management of halogenated flame retardant (HFR) containing wastes, including chemical, mechanical, and thermal processes for recycling, treatment, and disposal.

Electron paramagnetic resonance (EPR) spectroscopy was used to measure the free radicals in the particulate matter (PM) emissions from wood and coal combustion. The intensity of radicals in PM dropped linearly within two months of sample storage and stabilized after that. This factor of storage time was adjusted when comparing radical intensities among different PM samples. An inverse relationship between coal rank and free radical intensities in PM emissions was observed, which was in contrast with the pattern of radical intensities in the source coals. The strong correlation between intensities of free radical and elemental carbon in PM emissions suggests that the radical species may be carbon-centered. The increased g-factors, 2.0029-2.0039, over that of purely carbon-centered radicals may indicate the presence of vicinal oxygen heteroatom. The redox and biology activities of these carbon-centered radicals are worthy of evaluation.

Rural kitchens of solid-fuel burning households constitute the microenvironment responsible for the majority of human exposures to health-damaging air pollutants, particularly respirable particles and carbon monoxide. Portable nephelometers facilitate cheaper, more precise, time-resolved characterization of particles in rural homes than are attainable by gravitational methods alone. However, field performance of nephelometers must contend with aerosols that are highly variable in terms of chemical content, size, and relative humidity. Previous field validations of nephelometer performance in residential settings explore relatively low particle concentrations, with the vast majority of 24-hour average gravitational PM2.5 concentrations falling below 40 μg/m3. We investigate relationships between 24-hour gravitational particle measurements and nephelometric data logged by the personalDataRAM in highly polluted rural Chinese kitchens, where gravitationally determined 24-hour average respirable particle concentrations were as high as 700 μg/m3. We find that where relative humidity remained below 95%, nephelometric response was strongly linear despite complex mixtures of aerosols and variable ambient conditions. Where 95% relative humidity was exceeded for even a brief duration, nephelometrically determined 24-hour mean particle concentrations were nonsystematically distorted relative to gravitational data, and neither concurrent relative humidity measurements nor use of robust statistical measures of central tendency offered means of correction. This nonsystematic distortion is particularly problematic for rural exposure assessment studies, which emphasize upper quantiles of timeresolved particle measurements within 24-hour samples. Precise, accurate interpretation of nephelometrically resolved short-term particle concentrations requires calibration based on short-term gravitational sampling.

Rural kitchens of solid-fuel burning households constitute the microenvironment responsible for the majority of human exposures to health-damaging air pollutants, particularly respirable particles and carbon monoxide. Portable nephelometers facilitate cheaper, more precise, time-resolved characterization of particles in rural homes than are attainable by gravitational methods alone. However, field performance of nephelometers must contend with aerosols that are highly variable in terms of chemical content, size, and relative humidity. Our investigation of relationships between 24-hour optical and gravitational particle measurements in rural Chinese kitchens depicts that where relative humidity remained below 95%, nephelometric response was strongly linear despite complex mixtures of aerosols. Where 95% relative humidity was exceeded for even a brief duration, nephelometric data were nonsystematically distorted, and neither concurrent relative humidity measurements nor use of robust statistical measures of central tendency offered means of correction. This nonsystematic distortion is particularly problematic for rural exposure assessment studies, which emphasize upper quantiles of timeresolved particle measurements both within and between samples. Precise, accurate interpretation of optically resolved short-term particle concentrations requires short-term gravitational sampling concurrent with optical methods.

The photochemical interaction of 193 nm light with polystyrene nanospheres is used to produce particles with a controlled size and morphology. The result shows that irradiated particles have a smaller mean diagram and a number concentration more than an order of magnitude higher than nonirradiated particles and the particles are formed by nucleation of gas-phase species produced by decomposition of nanospheres.

A two-laser technique is used to study laser--particle interactions and the disintegration of soot by high-power UV light. Two separate 20 ns laser pulses irradiate combustion-generated soot nanoparticles with 193 nm photons. The first laser pulse, from 0 to 14.7 J/[cm.sup.2], photofragments the soot particles and electronically excites the liberated carbon atoms. The second laser pulse, held constant at 13 J/[cm.sup.2], irradiates the remaining particle fragments and other products of the first laser pulse. The atomic carbon fluorescence at 248 nm produced by the first laser pulse increases linearly with laser fluence from 1 to 6 J/[cm.sup.2]. At higher fluences the signal from atomic carbon saturates. The carbon fluorescence from the second laser pulse decreases as the fluence from the first laser increases, suggesting that the particles fully disintegrate at high laser fluences. We use an energy balance parameter, called the photon/atom ratio, to aid in understanding laser--particle interactions. These results help define the regimes where photofragmentation fluorescence methods quantitatively measure total soot concentrations. OCIS codes: 120.1740, 300.6280.

Researchers from the University of California, Berkeley, investigated how the environmental implications of the Clean Air Act Amendments of 1990 which allowed the use of MTBE (methyl tert-butyl ether) as an additive to gasoline.

We detect chlorinated hydrocarbons (CHC's) in gas mixtures by dissociating the CHC's with a 193-nm laser and measuring the subsequent concentration of the CCl fragmentation by means of laser-induced fluorescence. Sub-ppm detection, where ppm indicates parts in [10.sup.6], is achieved for [C.sub.2][H.sub.5] Cl with a 10-[mm.sup.3] measurement volume and integration over 50 laser shots. Every other CHC tested is also detectable, with the same or better detection limits. The CCl forms promptly during the fragmentation laser pulse through unimolecular dissociation of the parent CHC's. The technique should be a useful diagnostic for CHC incineration systems.

Abstract Background The Pearl River Origin area, Qujing District of Yunnan Province, has one of the highest female lung cancer mortality rates in China. Smoking was excluded as a cause of the lung cancer excess because almost all women were non-smokers. Crystalline silica embedded in the soot emissions from coal combustion was found to be associated with the lung cancer risk in a geographical correlation study. Lung cancer rates tend to be higher in places where the Late Permian C1 coal is produced. Therefore, we have hypothesized the two processes: C1 coal combustion --> nanoquartz in ambient air --> lung cancer excess in non-smoking women. Methods/Design We propose to conduct a retrospective cohort study to test the hypothesis above. We will search historical records and compile an inventory of the coal mines in operation during 1930–2009. To estimate the study subjects' retrospective exposure, we will reconstruct the historical exposure scenario by burning the coal samples, collected from operating or deserted coal mines by coal geologists, in a traditional firepit of an old house. Indoor air particulate samples will be collected for nanoquartz and polycyclic aromatic hydrocarbons (PAHs) analyses. Bulk quartz content will be quantified by X-ray diffraction analysis. Size distribution of quartz will be examined by electron microscopes and by centrifugation techniques. Lifetime cumulative exposure to nanoquartz will be estimated for each subject. Using the epidemiology data, we will examine whether the use of C1 coal and the cumulative exposure to nanoquartz are associated with an elevated risk of lung cancer. Discussion The high incidence rate of lung cancer in Xuan Wei, one of the counties in the current study area, was once attributed to high indoor air concentrations of PAHs. The research results have been cited for qualitative and quantitative cancer risk assessment of PAHs by the World Health Organization and other agencies. If nanoquartz is found to be the main underlying cause of the lung cancer epidemic in the study area, cancer potency estimates for PAHs by the international agencies based on the lung cancer data in this study setting should then be updated.

The interaction of nanoscale NaCl particles with 193-nm photons is studied to better understand particle disintegration and production by ultraviolet photofragmentation. The particles are irradiated in a constrained air stream with laser fluences from 0.08 to 0.23 J/cm2 with single and multiple pulses striking the particles. The resulting particle size distributions are measured with a scanning mobility particle sizer and the morphology is analyzed qualitatively by scanning electron microscopy (SEM). Photofragmentation of NaCl particles at 193 nm produces gas-phase species as well as small solid-phase fragments without significantly heating the particles or creating a plasma. The irradiated particles have a mean diameter from 20 to 55 nm (depending on the photon energy) and a number concentration an order of magnitude higher than the 118-nm mean diameter nonirradiated particles. The SEM images before and after 193-nm irradiation reveal that the irradiated particles are less fractal and more spherical. [ABSTRACT FROM AUTHOR]