Health Risk Assessment Based on Exposure to Chemicals in Air.

Few studies have investigated personal exposure concentrations of not only some volatile organic compounds but also more types of chemicals including acidic gases and acrolein. We measured the personal exposure concentrations of 35 chemicals including these chemicals in indoor and outdoor air in Chiba-shi, Japan, for 7 days in summer and winter to assess the associated health risks in 22 people. The personal exposure concentrations of nitrogen dioxide were higher in winter than in summer, and those of formaldehyde, -dichlorobenzene, and tetradecane were higher in summer than in winter.

Spatial Variations of Indoor Air Chemicals in an Apartment Unit and Personal Exposure of Residents.

Indoor air quality (IAQ) can greatly affect health in people spending much time indoors. However, the influence of IAQ on personal exposure to chemical compounds in Japan remains poorly investigated. Hence, this study aimed to clarify this influence thoroughly within one apartment.

Simple Ozone Scrubber Using a Glass Fiber Filter Impregnated with Hydroquinone for the Quantitative Analysis of Ambient Air Samples.

As a standard method for measuring the concentration of carbonyl compounds in air, 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by high-performance liquid chromatography (HPLC) is widely used. However, the method is often plagued by interference issues related to the ozone content in ambient air samples. Although the use of a potassium iodide (KI) scrubber circumvents these problems, the combination of a DNPH-coated silica cartridge and KI scrubber often performs poorly, particularly in high humidity.

Simple Determination of Gaseous and Particulate Compounds Generated from Heated Tobacco Products.

As a new form of cigarettes, heated tobacco products (HTPs) have been rapidly distributed worldwide. In this study, an improved method for analyzing gaseous and particulate compounds generated from HTPs is described. Smoke is collected using a GF-CX572 sorbent cartridge with 300 mg of carbon molecular sieves, that is, Carboxen 572 (CX572), and a 9 mm glass-fiber filter (GF).

Shear-thickening flow of nanoparticle suspensions flocculated by polymer bridging.

The steady-shear viscosity, dynamic viscoelasticity, and stress relaxation behavior were measured for suspensions of silica nanoparticles dispersed in aqueous solutions of poly(ethylene oxide) (PEO). The suspensions of silica with diameters of 8-25 nm show striking shear-thickening profiles in steady shear and highly elastic responses under large strains in oscillatory shear. Since the silica particles are much smaller than the polymer coils, one molecule can extend through several particles by intrachain bridging.

Viscosity behavior of silica suspensions flocculated by associating polymers.

Associating polymers are hydrophilic long-chain molecules containing a small number of hydrophobic groups, and act as flocculants in aqueous suspensions. The effects of associating and nonassociating polymers on viscosity behavior are studied for silica suspensions. Since flocculation is induced by polymer bridging, the viscosity behavior is converted from Newtonian to shear-thinning profiles.