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Background: Millions of rural U.S. households are heated with wood stoves. Wood stove use can lead to high indoor concentrations of fine particulate matter [airborne particles [less than or equal to] 2.5 [micro]m in aerodynamic diameter ([PM.sub.2.5])] and is associated with lower respiratory tract infection (LRTI) in children. Objectives: We assessed the impact of low-cost educational and air filtration interventions on childhood LRTI and indoor [PM.sub.2.5] in rural U.S. homes with wood stoves. Methods: The Kids Air Quality Interventions for Reducing Respiratory Infections (KidsAIR) study was a parallel three-arm (education, portable air filtration unit, control), post-only randomized trial in households from Alaska, Montana, and Navajo Nation (Arizona and New Mexico) with a wood stove and one or more children RESULTS: There were 61 LRTI cases from 14,636 child-weeks of follow-up among 461 children. In the intent-to-treat analysis, children in the education arm [odds ratio (OR) = 0.98; 95% confidence interval (CI): 0.35, 2.72] and the filtration arm (OR = 1.23; 95% CI: 0.46, 3.32) had similar odds of LRTI vs. control. Geometric mean [PM.sub.2.5] concentrations were similar to control in the education arm (11.77% higher; 95% CI: -16.57, 49.72) and air filtration arm (6.96% lower; 95% CI: -30.50, 24.55). In the exposure-response analysis, odds of LRTI were 1.45 times higher (95% CI: 1.02, 2.05) per interquartile range (25 [micro]g/[m.sup.3]) increase in mean indoor [PM.sub.2.5]. Discussion: We did not observe meaningful differences in LRTI or indoor [PM.sub.2.5] in the air filtration or education arms compared with the control arm. Results from the exposure-response analysis provide further evidence that biomass air pollution adversely impacts childhood LRTI. Our results highlight the need for novel, effective intervention strategies in households heated with wood stoves. https://doi.org/10.1289/EHP9932, Introduction Nearly 13 million homes in the United States (U.S.) burn wood fuel in wood stoves or fireplaces as a primary or secondary heating source (EIA 2015). Approximately half of [...]

A three-step scheme for a miniature air purification filter for a gas chromatograph has been proposed. A method for controlling the selectivity of a new ion gas chromatography detector has been considered using a simulating model. The possibility of determining explosive traces by a gas chromatograph with air as a carrier gas has been demonstrated. Keywords: gas chromatography, air carrier gas, air purification, ion filter, detection, explosives DOI: 10.1134/S1061934813110026, The solution of a number of safety problems depends on the availability of timely information on the source of contamination, substances, and contamination level. This requires rapid instruments of infield [...]

ABSTRACT A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to [...]

A kinetic model for a cycling adsorbent/photocatalyst combination for formaldehyde removal in indoor air (Chin et al. J. Catalysis 2006, 237, 29-37) was previously developed in our lab, demonstrating agreement with lab-scale batch operation data of other researchers (Shiraishi et al. Chem. Engineer. Sci. 2003, 58, 929-934). Model parameters evaluated included adsorption equilibrium and rate constants for the adsorbent (activated carbon) honeycomb rotor, and catalytic rate constant for pseudo-first-order formaldehyde destruction in the titanium dioxide photoreactor. This paper explores design consequences for this novel system. In particular, the batch parameter values are used to model both adsorbent and photocatalyst behavior for continuous operation in typical residential home challenges. Design variables, including realistic make-up air fraction, adsorbent honeycomb rotation speed, and formaldehyde source emission rate, are considered to evaluate the ability of the system to achieve World Health Organization pollutant guidelines. In all circumstances, the size of the required rotating adsorbent bed and photoreactor for single-stage operation and the resultant formaldehyde concentration in the home are calculated. The ability of how well such a system might be accommodated within the typical dimensions of commercial ventilation ducts is also considered., INTRODUCTION Indoor air quality (IAQ) has been a health hazard concern since the early 1990s. The primary causes for IAQ problems in residential homes are gas and particle release from [...]

Dielectric barrier discharge plasma has been known to inactivate many different microorganisms on surfaces when treatment times are on the order of seconds or minutes in duration. In this paper, a unique plasma air cleaning facility was created which combines a dielectric barrier grating discharge (DBGD) with a filterless laboratory-scale ventilation system and is used to treat concentrated bacterial bioaerosol in a moving air stream at air flow rates of 25 L/s. Results indicate that plasma treatment times on the order of milliseconds corresponding to one pass through the DBGD device can achieve 1.5-log reduction in culturable E. coli immediately after contact with plasma and 5-log reduction totally following in the minutes after the plasma treatment. A numerical characterization study was performed to help predict and understand the mechanism of bacteria inactivation in the DBD plasma from a variety of plasma factors. Index Terms--Airborne microorganism, air sterilization, dielectric barrier discharge, E. coli, nonthermal plasma.

Ventilation systems often host bacteria and fungi that may be dangerous for the health of exposed people. Essential oils are one means among others to prevent microbial development. Used as a basis for many traditional therapies, these odorant plant extracts have been studied extensively in the medical domain and their effectiveness in the treatment of numerous pathologies has been demonstrated. As opposed to most antimicrobial agents currently used for air disinfection, essential oils are low in toxicity. With a view to proposing an indoor air purification method based on the germicidal and odorant properties of essential oils, we selected a pathogenic test strain and followed the AFNOR NF T72-281 standard. This protocol evaluates on a surfaces level, the disinfection efficacy of volatile antimicrobial agents on airborne contaminations such as bacteria, fungi and spores. The protocol was applied to one of the most active essential oils, mountain savory, and also to a solution of formaldehyde at a concentration of 40% called formol, a chemical reference in hospitals. We demonstrated that the gaseous phase of the essential oil of savory has a lethal effect on Staphylococcus aureus and it has a satisfying bacteria reduction rate close to the total disinfection achieved with evaporated formol. KEYWORDS Indoor air; Ventilation systems; Airborne microorganisms; Essential oils

This study focused on modeling and optimization of a photoreactor packed with parallel glass plates coated with sol--gel Ti[O.sub.2] thin films on both sides. The photoreactor design has great potential for solar photocatalytic air purification. Borosilicate glass substrate was selected because its high transmissivity facilitated the transmission and distribution of exterior solar radiation onto interior immobilized photocatalyst. Flat-plate configuration was adopted because a Ti[O.sub.2]-coated plate could be easily set up for effective ion implantation treatment to extend the activating spectral range from UV to visible light for a higher solar photonic efficiency. In the analytical study of this research, a semi-empirical correlation model was formulated for prediction of the photoreactor performance. The correlation coefficients were obtained based on the results of photocatalytic air purification experiments conducted. Additional experimental tests were carried out for validation of the model. In the photoreactor design optimization analysis, the semi-empirical correlation model was used as an optimizer to determine the number of parallel Ti[O.sub.2]-coated plates needed for efficient photocatalytic air purification. It was found that the optimal number of plates was dependent of the incident irradiance. The modeling and optimization methods developed for solar photocatalytic air purification are equally applicable for solar photocatalytic water purification. Keywords: Solar; Photocatalytic; Parallel-plate photoreactor; Design optimization

Nonthermal plasma created by high-voltage dc power supply can be used to collect precharged suspended particulates, whereas nonthermal plasma generated by high-voltage pulsed power supply is used to remove harmful gases in the air, but how to increase the efficiency is not clear. In this paper, it is novel to apply magnetic field to air purification to increase the purification efficiency. Effect of magnetic field is analyzed. It can be concluded that purification efficiency can be improved significantly along with the application of magnetic field. Index Terms--Magnetic field, nonthermal plasma, purification efficiency.