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Indoor and outdoor concentrations of six chlordane components (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, oxychlordane, and MC5) were measured at 157 residences, all of which were inhabited by nonsmoking individuals, in three urban areas during June 1999−May 2000. The analyses were conducted on a subset of 48 h integrated samples collected in Los Angeles County, CA, Houston, TX, and Elizabeth, NJ within the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study. Both particle-bound (PM2.5; quartz fiber filter) and vapor-phase (PUF sorbant) chlordane concentrations were separately measured by GC/EI MS after solvent extraction. The outdoor (gas + particle) total chlordane (trans-chlordane + cis-chlordane + trans-nonachlor + cis-nonachlor) concentrations ranged from 0.036 to 4.27 ng m-3 in Los Angeles County, from 0.008 to 11.00 ng m-3 in Elizabeth, and from 0.062 to 1.77 ng m-3 in Houston. The corresponding indoor total chlordane concentrations ranged from 0.037 to 112.0 ng m-3 in Los Angeles County, from 0.260 to 31.80 ng m-3 in Elizabeth, and from 0.410 to 38.90 ng m-3 in Houston study homes. Geometric mean concentrations were higher in indoor air than outdoor air (1.98 vs 0.58 ng m-3 in CA; 1.30 vs 0.17 ng m-3 in NJ; 4.18 vs 0.28 ng m-3 in TX), which suggests there are significant indoor sources of chlordane species in a subset of homes in each of the three cities. Calculated source strengths relate to home age, with the highest apparent indoor source strengths occurring in unattached single-family homes built during the period from 1945 to 1959. Principle indoor sources of chlordanes likely include volatilization from residues of indoor application of chlordanes and infiltration from subsurface and foundation application of chlordane-containing termiticides during home construction.
Subsistence and smallholder farmers in the Deccan plateau region of India struggle with a predominantly hot and dry climate and often accumulated debt due to the cost of fertilizer that they need to increase yields for profitability. While a low-cost deep-flow technique hydroponic growing system (DFT) as a supplement to soil-based agriculture could help reduce debt, the cost of electricity needed to operate the DFT makes it inaccessible to these farmers. The objective of this project was to test the viability of electricity-free DFT which would substantially reduce production costs. Two DFT systems were set up in a shade net house and prepared with identical nutrients to grow chili pepper seedlings. Each DFT system was oxygenated for 30 minutes per day, one system using an electrical air pump, and the other system was oxygenated manually. After four weeks of growth, the dry mass of the shoots of the chili pepper seedlings in each system was measured. While the pump-oxygenated DFT system produced more dry matter, the manually-oxygenated system produced a larger number of visually healthier plants. Therefore, we conclude that electricity-free DFT hydroponics may be a viable alternative to pump-oxygenated DFT hydroponics, making hydroponic farming a cost-effective option for poor farmers.
The indoor and outdoor concentrations of 30 polycyclic aromatic hydrocarbons (PAHs) were measured in 55 nonsmoking residences in three urban areas during June 1999−May 2000. The data represent the subset of samples collected within the Relationship of Indoor, Outdoor, and Personal Air study (RIOPA). The study collected samples from homes in Los Angeles, CA, Houston, TX, and Elizabeth, NJ. In the outdoor samples, the total PAH concentrations (∑PAH) were 4.2−64 ng m-3 in Los Angeles, 10−160 ng m-3 in Houston, and 12−110 ng m-3 in Elizabeth. In the indoor samples, the concentrations of ∑PAH were 16−220 ng m-3 in Los Angeles, 21−310 ng m-3 in Houston, and 22−350 ng m-3 in Elizabeth. The PAH profiles of low molecular weight PAHs (3−4 rings) in the outdoor samples from the three cities were not significantly different. In contrast, the profiles of 5−7-ring PAHs in these three cities were significantly different, which suggested different dominant PAH sources. The signatures of 5−7-ring PAHs in the indoor samples in each city were similar to the outdoor profiles, which suggested that indoor concentrations of 5−7-ring PAHs were dominated by outdoor sources. Indoor-to-outdoor ratios of the PAH concentrations showed that indoor sources had a significant effect on indoor concentrations of 3-ring PAHs and a smaller effect on 4-ring PAHs and that outdoor sources dominated the indoor concentrations of 5−7-ring PAHs.
Summary form only given. In atmospheric-pressure gas discharge system, slit discharge (SD), has been developed for the removing of biological and chemical contaminants from the ambient air. The system consists of multiple plasma grids stacked perpendicularly to the air flow. The performance of the system has been tested using the surrogates of biological and chemical warfare agents. The results of the biological testing will be presented. The experiments have been done using the "in-room" and "in-duct" scenarios, simulating the stand alone room air cleaner and the HVAC system. The efficacy of the system in removal of bacterial spores will be presented as a function of flow rate, discharge power, number of plasma grids, and concentration of the spores in the air. Sampling methods and associated challenges will be discussed. Slit discharge (SD) is a promising technology in air-cleaning. Its performance is comparable with and often exceeds that of the convectional methods, such as dilution ventilation, filtration and ultraviolet germicidal irradiation. SD is an energy efficient, high performance, and low cost technology for air decontamination with potential uses in industry, health care and household applications
Objective. To determine the range and the mode of germicidal activity of sterilants generated by a nonthermal plasma sterilization system for microorganisms. Methods. Representative bacteria, spores, viruses, bacteriophages, and fungi were exposed to the plasma cycle and the residual viability was measured in vitro. To assess the mode of lethal injury, Escherichia coli, Staphylococcus aureus, Bacillus atrophaeus, and bacteriophages were exposed to the plasma cycle, and the effects of the plasma-generated sterilants on the biological parameters were determined. Results. There were at least 4-6 log reductions in viability for all microorganisms after 10 minutes of exposure to the plasma cycle. Electron micrographs and studies of the inhibition of bacteriophage infectivity suggested that the primary injury is to the organisms' cell envelopes. The plasma cycle also denatured isolated bacterial proteins and inactivated bacteriophages, but it had no effect on isolated DNA and bacterial proteins within exposed bacteria. Conclusion. Nonthermal plasma, which is produced at atmospheric temperature and pressure, generates sterilants that kill high concentrations of microorganisms and inactivate viruses during a 10-minute exposure. The primary injury appears to be at the surface structures of the organisms. This suggests that nonthermal plasma has utility for sterilization of heat-sensitive medical materials and devices.
