Inflammatory effects induced by selected limonene oxidation products: 4-OPA, IPOH, 4-AMCH in human bronchial (16HBE14o-) and alveolar (A549) epithelial cell lines.

Limonene, a monoterpene abundantly present in most of the consumer products (due to its pleasant citrus smell), easily undergoes ozonolysis leading to several limonene oxidation products (LOPs) such as 4-acetyl-1-methylcyclohexene (4-AMCH), 4-oxopentanal (4-OPA) and 3-isopropenyl-6-oxoheptanal (IPOH). Toxicological studies have indicated that human exposure to limonene and ozone can cause adverse airway effects. However, little attention has been paid to the potential health impact of specific LOPs, in particular of IPOH, 4-OPA and 4-AMCH. This study evaluates the cytotoxic effects of the selected LOPs on human bronchial epithelial (16HBE14o-) and alveolar epithelial (A549) cell lines by generating concentration-response curves using the neutral red uptake assay and analyzing the inflammatory response with a series of cytokines/chemokines. The cellular viability was mostly reduced by 4-OPA [IC50=1.6mM (A549) and 1.45mM (16HBE14o-)] when compared to IPOH [IC50=3.5mM (A549) and 3.4mM (16HBE14o-)] and 4-AMCH [IC50 could not be calculated]. As a result from the inflammatory response, IPOH [50µM] induced an increase of both IL-6 and IL-8 secretion in A549 (1.5-fold change) and in 16HBE14o- (2.8- and 7-fold change respectively). 4-OPA [50µM] treatment of A549 increased IL-6 (1.4-times) and IL-8 (1.3-times) levels, while in 16HBE14o- had an opposite effect. A549 treated with 4-AMCH [50µM] elevate both IL-6 and IL-8 levels by 1.2-times, while in 16HBE14o- had an opposite effect. Based on our results, lung cellular injury characterized by inflammatory cytokine release was observed for both cell lines treated with the selected chemicals at concentrations that did not affect their cellular viability.

Indoor air characterization of various microenvironments in the Arctic. The case of Tromsø, Norway.

The present pilot study monitored for the first time volatile organic compounds (VOCs) and aerosols in domestic and occupational microenvironments in the Arctic Region. Differences between the two categories of samples are noted with domestic environments exhibiting higher concentrations of VOCs (total VOCs ranging between 106 and 584 µg m(-3)), while total particulate matter was highest in workplace non-office environments (ranging between 132 and 284 µg m(-3)). The terpenes were the most abundant class of VOCs, while a variety of other compounds exhibited 100% frequency of occurrence (i.e. naphthalene, D5-volatile methyl siloxane). Compared to results from other studies/regions, the concentrations of VOCs are considered as relatively low. Based on the results and the knowledge of the typical characteristics of the Arctic lifestyle, some important sources are identified. As this is the first study that deals with indoor air quality in the coldest region globally, it is expected that it will trigger the interest of Authorities to proceed to more detailed studies.

Building materials. VOC emissions, diffusion behaviour and implications from their use.

Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 µg m(-3), accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h).

Evaluation of the fate of the active ingredients of insecticide sprays used indoors.

The fate of the active ingredients of insecticide sprays after use in indoor environments was investigated. Indoor air sampling was performed through two types of adsorbents, namely, TENAX TA and XAD-2 (10 L). After sampling, both adsorbents were ultrasonically extracted and analyzed by Gas Chromatography coupled to Mass Spectroscopy. The separation and analysis of the selected compounds were satisfactory and fast (duration of the chromatographic run: 40 min). The method was linear for all examined chemicals over the tested range (2 to 50 ng of absolute compound); limits of detection ranged from 0.42 to 1.32 ng of absolute compound. The method was then applied in the determination of the active ingredients of three commercially available insecticide sprays that were separately used in a full-scale environmental chamber (30 m(3)). After spraying, the fate of the active ingredients [propoxur, piperonyl butoxide (PBO) and pyrethrin insecticides] was monitored over 40 minutes, with and without ventilation. Both adsorbent materials were proven to be efficient and the differences in the concentrations deriving from sampling with both materials were in almost all cases less than 10%. All chemicals were removed in rates that exceeded 80%, after the 40 minutes of monitoring, exhibiting different decay rates. The removal of insecticides was not significantly affected by the ventilation of the chamber. The correlation analysis of propoxur, PBO and pyrethrins with the aerosols of various sizes (15 fractions, from 0.3 to > 20 microm) showed that propoxur and PBO mainly associated with the medium size aerosols (3-7.5 microm) while pyrethrins seem to link more with heavier particles (> 10 microm).

Anticrossproducts and cross divisions.

This paper defines, in the context of conventional vector algebra, the concept of anticrossproduct and a family of simple operations called cross or vector divisions. It is impossible to solve for a or b the equation axb=c, where a and b are three-dimensional space vectors, and axb is their cross product. However, the problem becomes solvable if some "knowledge about the unknown" (a or b) is available, consisting of one of its components, or the angle it forms with the other operand of the cross product. Independently of the selected reference frame orientation, the known component of a may be parallel to b, or vice versa. The cross divisions provide a compact and insightful symbolic representation of a family of algorithms specifically designed to solve problems of such kind. A generalized algorithm was also defined, incorporating the rules for selecting the appropriate kind of cross division, based on the type of input data. Four examples of practical application were provided, including the computation of the point of application of a force and the angular velocity of a rigid body. The definition and geometrical interpretation of the cross divisions stemmed from the concept of anticrossproduct. The "anticrossproducts of axb" were defined as the infinitely many vectors x(i) such that x(i)xb=axb.

VOC and carbonyl emissions from carpets: a comparative study using four types of environmental chambers.

Emissions of Volatile Organic Compounds (VOCs) and carbonyls from carpets of different type (wool, synthetic) over a time period of three days at 23 degrees C, at 45% relative humidity, 0.5 air change rate and a loading factor of 0.4 m(2) m(-3) were measured. The experiments were carried out at four different environmental chambers (volumes of 0.02/0.28/0.45/30 m(3)). For TVOCs, maximum concentrations up to 2300 microg m(-3) (for carpet with synthetic backing) were found. Aromatic compounds e.g. benzene, toluene, the xylenes and styrene are emitted in relatively low concentrations, while for 4-phenylcyclohexene and 2, 2-butoxyethoxy-ethanol concentrations up to 170 and 320 microg m(-3), respectively, were measured. In all experiments, emission rates reached the maximum value within few hours from the beginning of the experiment. The emission rates of TVOCs from the same type of carpet measured with various types of chambers (0.02/0.28/0.45/30 m(3)), exhibited differences of up to 75%. Chamber concentrations of carbonyls (formaldehyde, acetaldehyde, acetone and propanale) are of a few microg m(-3). Acetone and formaldehyde reach concentrations up to 15 and 10 microg m(-3), respectively.