Evaluation of low-VOC latex paints

Environmentally Friendly Water-Based Self-Crosslinking Acrylate Dispersion Containing Magnesium Nanoparticles and Their Films Exhibiting Antimicrobial Properties

A water-based polymeric acrylate dispersion (latex) containing MgO nanoparticles, which had been added at a concentration of 1.5% (with respect to the monomers) during the preparation procedure, was investigated as an environmentally friendly binder for sanitary interior paints. The properties of this new latex were compared to those of a reference system free of the magnesium nanoparticles, synthesized by the same route, i.e., by semi-continuous emulsion polymerization. Tests were made in order to ascertain the mechanical and chemical properties, flash corrosion resistance and antimicrobial effect of the latex films. The results revealed that the new latex containing magnesium nanoparticles provided solvent-resistant coating films having pronounced antimicrobial activity against all the tested bacterial and fungal strains. The desirable antimicrobial properties can be ascribed to the sharp-edged character of magnesium nanoparticles, the peroxidation of lipids and the formation of reactive oxygen species. Moreover, no flash corrosion was formed beneath coating films containing magnesium nanoparticles, which can be attributed to the alkaline action due to the dissolution of a fraction of MgO in latex medium. The results of all of the tests provided evidence of the superiority of the polymeric dispersion with the magnesium nanoparticles to the reference system containing no nanoparticles.

Data on formaldehyde sources, formaldehyde concentrations and air exchange rates in European housings

Formaldehyde has been discussed as a typical indoor pollutant for decades. To evaluate the current state-of-the-art in formaldehyde research and to identify the plethora of regulated and unregulated formaldehyde sources in indoor and outdoor spaces, an extensive literature search was carried out. The acquired data were analyzed with the aid of Monte-Carlo methods to calculate realistic formaldehyde concentration profiles and exposure scenarios under consideration of aging, source/sink behavior and diffusion effects. Average concentrations of formaldehyde are within 20–30 µg/m³ for European households under residential-typical conditions. The assumption of an average air exchange rate of 0.5 h⁻¹ is also plausible. Formaldehyde emission rates of materials and products for indoor use are widely spread and range from non-detectable to > 1000 µg/h. However, processes like combustion, cleaning activities, operation of air purifiers and indoor chemistry were identified as temporary but relevant formaldehyde sources, which might cause high peak concentrations.

Self-Protecting Epoxy Coatings with Anticorrosion Microcapsules

The corrosion of steel substrates causes damage that is costly to repair or replace. Current protective coatings predominately rely on environmentally harmful anticorrosive agents and toxic solvents to protect the underlying substrate. The use of lawsone (2-hydroxy-1,4-napthoquinone) together with a water-based epoxy coating provides an environmentally friendly alternative for common protective coatings. Microencapsulated lawsone embedded in an epoxy coating allows the anticorrosive agent to remain dormant until released by damage and delivered directly onto the steel substrate. UV-vis analysis confirms successful encapsulation of lawsone in a polyurethane shell wall and reveals up to 8 wt % lawsone in the capsule cores. Uniform dry film thickness and inflicted damaged are verified with ultrasound and optical microscopy. Visual and electrochemical analysis demonstrates that this self-protective scheme leads to a 70% corrosion inhibition efficiency in a neutral salt water solution.

Direct and potential risk assessment of exposure to volatile organic compounds for primary receptor associated with solvent consumption

Rapid development of industrial production has stimulated the growth of consumption of raw and auxiliary materials including organic paints, among which volatile organic compounds (VOCs) are proved harmful to the population who inhale the polluted air based on epidemiologic studies. Therefore, new types of environment-friendly paints were developed to replace solvent-based paints (SBPs). Nevertheless, new types of paints containing VOCs failed to replace SBPs entirely due to certain disadvantages. Hence, five kinds of paints were employed in simulation experiments to assess the health risk of primary receptor including three kinds of water-based paints (WBPs) and two kinds of SBPs. Conclusions showed that mean TVOC concentration in breathing zone of primary receptor ranged from 9.5 to 13.6 mg/m³ and 3.4 × 10³ to 1.4 × 10⁴ mg/m³ for WBPs and SBPs, respectively. Assessments of non-cancer risk concluded that nearly one third quantified compounds exceeded corresponding thresholds for WBPs, and the maximum risk value was 101.33; for SBPs, the maximum risk value reached 50760.20, and twenty-two compounds exceeded the reference limits. The calculation of cancer risk values showed that seventeen compounds were higher than acceptable limit amongst which 1,2-dibromoethane had maximum values of 1.27 × 10^-2 to 3.24 × 10^-2 for WBPs; for SBPs, all quantified compounds exceeded the acceptable limit, and 82.61% VOCs were distributed in a scope larger than 1 × 10^-3. Additionally, a removal efficiency of 60% was considered for primary receptor with personal protective equipment, and subsequent results confirmed its inability of lowering the risk resulted from hazardous VOCs. The calculated potential health risk could be applied to estimate the total health risk for both primary and secondary receptor based on consumed materials. The finding suggested that WBPs could improve VOCs exposure condition and reduce the direct and potential health risk significantly for primary receptor, although they might dissatisfy acceptable limit.

The effect of low-volatile organic compounds, water-based paint on aggravation of allergic disease in schoolchildren

Whether indoor painting aggravates preexisting allergic diseases remains unclear. We aimed to evaluate the impact of new classroom painting on aggravation of asthma, allergic rhinitis (AR), and atopic dermatitis (AD) in children. Studied school was previously painted with conventional water-based paint 20 years ago and had natural ventilation system. We identified a total of 172 children aged 10-12 years with allergic diseases in 17 classrooms, which were allocated to newly painted rooms with low-volatile organic compounds (VOC), water-based paint, or existing rooms. After painting, there was no intervention or internal airflow to influence indoor air environment in both classrooms. We prospectively assessed the symptom severity and serious events of allergic diseases between both classrooms at baseline and after one and eight weeks after painting. At one and eight weeks, there were no significant changes in the Childhood Asthma Control Test scores, the fractional nitric oxide levels, lung function in asthmatic children in either classroom. There were also no significant changes in the severity score of AR or AD, or serious events in all allergic diseases. These findings suggest classroom painting with this new paint at the levels encountered in this study might not be a major aggravating factor for school-aged children with allergic diseases.

Síntese de látices com baixa concentração de compostos orgânicos voláteis (COVs): efeito das técnicas de redução dos COVs nas propriedades dos látexes e das tintas

A redução dos compostos orgânicos voláteis (COVs) nos látices produzidos via polimerização em emulsão é uma opção viável, mas em algumas situações pode comprometer a qualidade do látex. Diferentes técnicas de redução da concentração dos monômeros e dos COVs foram estudadas com o objetivo de entender o efeito destas técnicas e da concentração dos COVs nas propriedades de aplicação dos látices e das tintas. Os látices de estireno com acrilato de 2-etil hexila funcionalizados com ácido acrílico e acrilamida foram produzidos via polimerização em emulsão, seguido por remoção química, física e a combinação de ambas as técnicas de redução dos monômeros e dos COVs. Os parâmetros relacionados à técnica de redução dos COVs, ao tipo de iniciador, ao agente de redução e à introdução de nitrogênio saturado com vapor de água foram estudados e correlacionados com as propriedades de aplicação das tintas. A combinação da técnica química com a técnica física foi mais eficiente na redução dos monômeros e dos COVs nos látices. As técnicas utilizadas na redução dos COVs tiveram influência negativa nas propriedades de aplicação dos látices. A resistência à abrasão dos filmes de tinta foi dependente da técnica empregada e da concentração dos COVs.

Better IVF outcomes following improvements in laboratory air quality

BACKGROUND

It has been proved that air quality is crucial for the success of IVF because of the presence of volatile organic compounds (VOCs), microbes, and perfumes, all of which can be harmful to embryo development in vitro. Therefore IVF laboratories are equipped with high efficiency particulate air (HEPA), and activated carbon filters plus positive pressure for air particulate control, with or without CODA system. Here we introduce a new technology using specially treated Honeycomb matrix media aligned in the Landson ™ series system for our laboratory air purification and its impact on IVF outcome.

METHODS

Air samples were collected outside and inside the laboratory, and intra-incubator at three different time points, before and after changing carbon filters and after Landson system installation, and we correlated air compounds measure variation with IVF outcome from 1403 cycles.

RESULTS

An improvement of air quality was confirmed with passages of total VOCs from 0.42 mg/m(3), 30.48 mg/m(3), 9.62 mg/m3, to 0.1 mg/m(3), 2.5 mg/m(3), 2.19 mg/m(3) through 0.07 mg/m(3), 0.16 mg/m(3), 0.29 mg/m(3), outside the laboratory, inside laboratory and intra-incubator respectively at three separated air sampling times. A clear decrease was observed in some VOCs such as formaldehyde, ethylene, acethylene, propylene, SO2, pentane, NOx, benzene, Hallon-1211, CFC and alcohol. At the same time a significant difference (P<0.05) was found between the third testing time TT3 after carbon filter change and Landson system installation and the first testing time TT1 before carbon filter change in fertilization rate 83.7 % vs 70.1 %, embryo cleavage rate 97.35 % vs 90.8 %, day 5 blastocyst formation rate 51.1 % vs 41.7 %, and pregnancy/implantation rates 54.6 %, 34.4 % vs 40.6 %, 26.4 %.

CONCLUSION

Air purification by the new technology of Landson ™ series significantly improved IVF laboratory air quality, and embryo quality, thus increased pregnancy and implantation rates.

Wall finish selection in hospital design: a survey of facility managers

OBJECTIVE

This paper seeks to analyze healthcare facility managers' perceptions regarding the materials used for interior wall finishes and the criteria used to select them. It also examines differences in wall finish materials and the selection process in three major hospital spaces: emergency, surgery, and in-patient units. These findings are compared with healthcare designers' perceptions on similar issues, as currently documented in the literature.

BACKGROUND

Hospital design and the materials used for hospital construction have a considerable effect on the environment and health of patients. A 2002 survey revealed which characteristics healthcare facility designers consider when selecting materials for healthcare facilities; however, no similar study has examined the views of facility managers on building finish selection.

METHODS

A 22-question survey questionnaire was distributed to 210 facility managers of metropolitan, for-profit hospitals in Texas; IRB approval was obtained. Respondents were asked to rank 10 interior wall finish materials and 11 selection criteria for wall finishes. Data from 48 complete questionnaires were analyzed using descriptive statistics and nonparametric statistical analysis methods.

RESULTS

The study found no statistically significant differences in terms of wall finish materials or the characteristics for material selection in the three major spaces studied. It identified facility managers' four most-preferred wall finish materials and the five-most preferred characteristics, with a statistical confidence level of greater than 95%.

CONCLUSIONS

The paper underscores the importance of incorporating all perspectives: facility designers and facility managers should work together toward achieving common organizational goals.

Housing characteristics and indoor concentrations of nitrogen dioxide and formaldehyde in Quebec City, Canada

Concentrations of nitrogen dioxide and formaldehyde were determined in a study of 96 homes in Quebec City, Canada, between January and April 2005. In addition, relative humidity, temperature, and air change rates were measured in homes, and housing characteristics were documented through a questionnaire to occupants. Half of the homes had ventilation rates below 7.5 L/s person. Nitrogen dioxide (NO2) and formaldehyde concentrations ranged from 3.3 to 29.1 microg/m3 (geometric mean 8.3 microg/m3) and from 9.6 to 90.0 microg/m3 (geometric mean of 29.5 microg/m3), respectively. The housing characteristics documented in the study explained approximately half of the variance of NO2 and formaldehyde. NO2 concentrations in homes were positively correlated with air change rates (indicating a significant contribution of outdoor sources to indoor levels) and were significantly elevated in homes equipped with gas stoves and, to a lesser extent, in homes with gas heating systems. Formaldehyde concentrations were negatively correlated with air change rates and were significantly elevated in homes heated by electrical systems, in those with new wooden or melamine furniture purchased in the previous 12 months, and in those where painting or varnishing had been done in the sampled room in the previous 12 months. Results did not indicate any significant contribution of indoor combustion sources, including wood-burning appliances, to indoor levels of formaldehyde. These results suggest that formaldehyde concentrations in Quebec City homes are caused primarily by off-gassing, and that increasing air change rates in homes could reduce exposure to this compound. More generally, our findings confirm the influence of housing characteristics on indoor concentrations of NO2 and formaldehyde.

Levels and determinants of formaldehyde, acetaldehyde, and acrolein in residential indoor air in Prince Edward Island, Canada

This study was undertaken to determine the concentrations of formaldehyde, acetaldehyde, and acrolein in air samples taken in some Canadian houses and to determine the association between aldehyde levels and housing characteristics. Concentrations of formaldehyde, acetaldehyde, and acrolein were measured in 59 homes in Prince Edward Island, Canada, during the winter of 2002. Housing characteristics were documented through inspection and by interviews of occupants. Formaldehyde, acetaldehyde, and acrolein concentrations ranged from 5.5 to 87.5 microg/m(3) (median, 29.6 microg/m(3)), from 4.4 to 79.1 microg/m(3) (median, 18.9 microg/m(3)), and from 0.1 to 4.9 microg/m(3) (median, 0.9 microg/m(3)), respectively. Formaldehyde levels were elevated in homes built after 1970. Acetaldehyde and acrolein levels were elevated in homes inhabited by at least one smoker and in homes built 1970--1985 and were correlated with absolute humidity and carbon dioxide, two variables likely to be surrogates for lower air exchange rates. In conclusion, lower air exchange rates appear to be important determinants of formaldehyde, acetaldehyde, and acrolein levels in homes. These data also confirm that smoking is a significant source of acetaldehyde and acrolein and indoor air.

INDOOR AIR QUALITY FACTORS IN DESIGNING A HEALTHY BUILDING

▪ Abstract  Current guidelines for green buildings are cursory and inadequate for specifying materials and designing ventilation systems to ensure a healthful indoor environment, i.e. a “healthy building,” by design. Public perception, cultural preferences, litigation trends, current codes and regulations, and rapid introduction of new building materials and commercial products, as well as the prevailing design-build practices, pose challenges to systems integration in the design, construction and operation phases of modern buildings. We are on the verge of a paradigm shift in ventilation design thinking. In the past, thermal properties of air within a zone determined heating, ventilating, and air-conditioning specifications. In the future, occupant-specific and highly responsive systems will become the norm. Natural ventilation, displacement ventilation, and microzoning with subfloor plenums, along with the use of point-of-source heat control and point-of-use sensors, will evolve to create a “smart,” responsive ventilation-building dynamic system. Advanced ventilation design tools such as the modeling of computational fluid dynamics (CFD) will be used routinely. CFD will be integrated into air quality and risk assessment models.