Biocidal spray product exposure: Measured gas, particle, and surface concentrations compared with spray model simulations.

The purpose of the study was to compare measured air and surface concentrations after application of biocidal spray products with concentrations simulated with the ConsExpo Web spray simulation tool. Three different biocidal spray products were applied in a 20 m3 climate test chamber with well-controlled environmental conditions (22 ± 1 °C, 50 ± 2% relative humidity, and air exchange rate of 0.5 h-1). The products included an insect spray in a pressurized spray can, another insect spray product, and a disinfectant, the latter two applied separately with the same pumped spray device. The measurements included released particles, airborne organic compounds in both gas and particle phase, and surface concentrations of organic compounds on the wall and floor in front of the spraying position and on the most remote wall. Spraying time was a few seconds and the air concentrations were measured by sampling on adsorbent tubes at 9-13 times points during 4 hr after spraying. The full chamber experiment was repeated 2-3 times for each product. Due to sedimentation the concentrations of the particles in air decayed faster than explained by the air exchange rate. In spite of that, the non-volatile benzalkonium chlorides in the disinfectant could be measured in the air more than 30 min after spraying. ConsExpo Web simulated concentrations that were about half of the measured concentrations of the active substances when as many as possible of the default simulation parameters were replaced by the experimental values. ConsExpo Web was unable to simulate the observed faster decay of the airborne concentrations of the active substances, which might be due to underestimation of the gravitational particle deposition rates. There was a relatively good agreement between measured surface concentrations on the floor and calculated values based on the dislodgeable amount given in the selected ConsExpo Web scenarios. It is suggested to always supplement simulation tool results with practical measurements when assessing the exposure to a spray product.

Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization.

A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection of mixtures of common volatile organic compounds. Amounts down to ca. 0.5 ng (on column) could be detected for most compounds and with a chromatographic performance comparable to that of GC/EIMS. In the positive mode, LTP ionization resulted in a compound specific formation of molecular ions M(+•), protonated molecules [M + H](+), and adduct ions such as [(M + O) + H](+) and [M + NO](+). The ion patterns seemed unique for each of the analyzed compound classes and can therefore be useful for identification of functional groups. A total of 20 different compounds within 8 functional groups were analyzed.

Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment.

We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85-89%) or low (<10%) relative humidity, respectively for 48h prior to a 60-min exposure to either 0.4, 1.8 or about 5ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the "scrubber effect" in the nose, consequently protecting the conducting and lower airways.

Characterization of the aerosol release from spray cleaning and disinfection products - Spray scenarios in a climate chamber.

Cleaning work using spray products has been associated with adverse respiratory effects but little is known of the exposure concentrations. The purpose of this study was to characterize aerosol generation at spray scenarios in a controlled climate chamber. Spraying on vertically and horizontally oriented surfaces, as well as spraying on a cloth, was investigated. Furthermore, the effect of nozzle geometry was tested. The average mass generation rates of six pressurized spray cans and 13 trigger sprays were about 1.7 g/s and did not differ significantly, but the average values of the individual sprays had large variations (0.5-3.1 g/s). The time required to halve the air concentration of aerosol particles, the half-life time, was determined for all spray products. The average half-life time of the total particle mass concentration (TPMC) of the pressurized spray cans was 0.5 h versus 0.25 h for trigger sprays. Gravimetrically determined airborne fractions of pressurized spray cans tended to be higher than those of trigger sprays. However, airborne fractions based on the measured peak TPMC were up to three orders of magnitude smaller. A comparison of different trigger spray nozzles when spraying the same product showed that the TPMC can be up to 18 times higher for the largest emitting nozzle. The distance of the nozzle to a cloth should be 1 cm to significantly reduce the concentration of the generated aerosols. ConsExpo modeling predicted the measured peak TPMC well but less well the decay.

Influence of temperature on the emission of di-(2-ethylhexyl)phthalate (DEHP) from PVC flooring in the emission cell FLEC.

Emissions of di-(2-ethylhexyl) phthalate (DEHP) from one type of polyvinylchloride (PVC) flooring with approximately 13% (w/w) DEHP as plasticizer were measured in the Field and Laboratory Emission Cell (FLEC). The gas-phase concentrations of DEHP versus time were measured at air flow rate of 450 mL·min(-1) and five different temperatures: 23 °C, 35 °C, 47 °C, 55 °C, and 61 °C. The experiments were terminated two weeks to three months after steady-state was reached and the interior surface of the FLECs was rinsed with methanol to determine the surface concentration of DEHP. The most important findings are (1) DEHP steady-state concentrations increased greatly with increasing temperature (0.9 ± 0.1 µg·m(-3), 10 ± 1 µg·m(-3), 38 ± 1 µg·m(-3), 91 ± 4 µg·m(-3), and 198 ± 5 µg·m(-3), respectively), (2) adsorption to the chamber walls decreased greatly with increasing temperature (measured partition coefficient between FLEC air and interior surface are: 640 ± 146 m, 97 ± 20 m, 21 ± 5 m, 11 ± 2 m, and 2 ± 1 m, respectively), (3) gas-phase DEHP concentration in equilibrium with the vinyl flooring surface is close to the vapor pressure of pure DEHP, and (4) with an increase of temperature in a home from 23 to 35 °C, the amount of DEHP in the gas- and particle-phase combined is predicted to increase almost 10-fold. The amount in the gas-phase increases by a factor of 24 with a corresponding decrease in the amount on the airborne particles.

Occupational Exposure and Environmental Release: The Case Study of Pouring TiO2 and Filler Materials for Paint Production.

Pulmonary exposure to micro- and nanoscaled particles has been widely linked to adverse health effects and high concentrations of respirable particles are expected to occur within and around many industrial settings. In this study, a field-measurement campaign was performed at an industrial manufacturer, during the production of paints. Spatial and personal measurements were conducted and results were used to estimate the mass flows in the facility and the airborne particle release to the outdoor environment. Airborne particle number concentration (1 × 103-1.0 × 104 cm-3), respirable mass (0.06-0.6 mg m-3), and PM10 (0.3-6.5 mg m-3) were measured during pouring activities. In overall; emissions from pouring activities were found to be dominated by coarser particles >300 nm. Even though the raw materials were not identified as nanomaterials by the manufacturers, handling of TiO2 and clays resulted in release of nanometric particles to both workplace air and outdoor environment, which was confirmed by TEM analysis of indoor and stack emission samples. During the measurement period, none of the existing exposure limits in force were exceeded. Particle release to the outdoor environment varied from 6 to 20 g ton-1 at concentrations between 0.6 and 9.7 mg m-3 of total suspended dust depending on the powder. The estimated release of TiO2 to outdoors was 0.9 kg per year. Particle release to the environment is not expected to cause any major impact due to atmospheric dilution.

Thermogravimetry and Mass Spectrometry of Extractable Organics from Manufactured Nanomaterials for Identification of Potential Coating Components.

Manufactured nanomaterials (MNMs) often have a surface-chemical modification in order to tailor their physicochemical properties, including also powder properties and miscibility. Surface-chemical modifications may influence the toxicological properties of the MNM, but the specific chemistry and extent are rarely described in detail in suppliers' technical data sheets. Chemical and quantitative information on any surface-chemical treatment, coating and functionalization are required for chemicals registration in Europe. Currently there is no globally accepted and documented approach to generate such data. Consequently, there is a continued research need to establish a structured approach to identify and quantify surface-chemical modifications. Here we present a tiered approach starting with screening for mass-loss during heating in a furnace or thermogravimetric analysis (TGA) followed by solvent extraction, and analysis by several mass spectrometry (MS) techniques depending on the target analytes. Thermal treatment was assumed to be able to quantify the amount of organic coating and MS was used to identify the extractable organic coatings after pressurized liquid extraction (PLE) using methanol at 200 °C. Volatile organic compounds in extracts were identified with gas chromatography and MS (GC-MS), non-volatile organic compounds with liquid chromatography MS (LC-MS), and polymeric compounds with matrix-assisted laser desorption ionization time-of-flight MS (MALDI-TOF-MS). The approach was demonstrated by analysis of 24 MNM, comprising titanium dioxide, synthetic amorphous silica, graphite, zinc oxide, silver, calcium carbonate, iron oxide, nickel-zinc-iron oxide, and organoclay. In extracts of 14 MNMs a range of organic compounds were identified and the main groups were silanes/siloxanes, fatty acids, fatty acid esters, quaternary ammonium compounds and polymeric compounds. In the remaining 10 MNMs no organic compounds were detected by MS, despite the fact an organic coating was indicated by TGA.

Experimental estimation of migration and transfer of organic substances from consumer articles to cotton wipes: Evaluation of underlying mechanisms.

The aim of this work was to identify the key mechanisms governing transport of organic chemical substances from consumer articles to cotton wipes. The results were used to establish a mechanistic model to improve assessment of dermal contact exposure. Four types of PVC flooring, 10 types of textiles and one type of inkjet printed paper were used to establish the mechanisms and model. Kinetic extraction studies in methanol demonstrated existence of matrix diffusion and indicated the presence of a substance surface layer on some articles. Consequently, the proposed substance transfer model considers mechanical transport from a surface film and matrix diffusion in an article with a known initial total substance concentration. The estimated chemical substance transfer values to cotton wipes were comparable to the literature data (relative transfer ∼ 2%), whereas relative transfer efficiencies from spiked substrates were high (∼ 50%). For consumer articles, high correlation (r(2)=0.92) was observed between predicted and measured transfer efficiencies, but concentrations were overpredicted by a factor of 10. Adjusting the relative transfer from about 50% used in the model to about 2.5% removed overprediction. Further studies are required to confirm the model for generic use.

Human reference values for acute airway effects of five common ozone-initiated terpene reaction products in indoor air.

Ozone-initiated monoterpene reaction products have been hypothesized to cause eye and airway complaints in office environments and some have been proposed to cause skin irritation and sensitization. The respiratory effects of 60 min exposures to five common oxidation products from abundant terpenoids (e.g. limonene), used as solvent and fragrance in common household products or present in skin lipids (e.g. squalene), were studied in a head out mouse bioassay. This allowed determination of acute upper airway (sensory) irritation, airflow limitation in the conducting airways, and pulmonary irritation in the alveolar region. Derived human reference values (RFs) for sensory irritation were 1.3, 0.16 and 0.3 ppm, respectively, for 4-acetyl-1-methylcyclohexene ( 0.2 ppm) [corrected], 3-isopropenyl-6-oxo-heptanal (IPOH), and 6-methyl-5-heptene-2-one (6-MHO). Derived RFs for airflow limitation were 0.8, 0.45, 0.03, and 0.5 ppm, respectively, for dihydrocarvone (DHC), 0.2 ppm [corrected], 4-oxo-pentanal (0.3 ppm) [corrected], and 6-MHO. Pulmonary irritation was unobserved as a critical effect. The RFs indicate that the oxidation products would not contribute substantially to sensory irritation in eyes and upper airways in office environments. Reported concentrations in offices of 6-MHO and 0.3 ppm [corrected]would not result in airflow limitation. However, based upon the RFs for IPOH and 0.3 ppm [corrected], precautionary actions should be considered that disfavor their formation in excess.