Formaldehyde emissions for the old wood paneling with new and old polish, and the drywall were all similar ranging from 10 µg/m2 /h to 22 µg/m2 /h . For the new wood, the formaldehyde emissions were approximately an order of magnitude higher than the other materials for both the polished and unfinished surfaces. The emission results for formaldehyde are illustrated in Figure 4 showing that the polish coating does not seem to significantly change the measured emission factors when the age of the wood paneling is taken into consideration. For old wood, the new polish slightly reduces the emission factor while for new wood the polish increases the emission factor slightly but the difference is likely more a function of the age of the wood than the polish. For example, given the old wood where the emissions are already low, adding the new polish may provide an apparent sink for the formaldehyde as it accumulates in the coating. In contrast, for the new wood, the initial emission rate is high and the coating may simply add a diffusion layer that increases the time that the emission from the wood paneling takes to drop to a constant level. With or without the coating,vertical greenhouse the new wood is clearly the major source of formaldehyde emissions among the materials tested. The aging of the formaldehyde emissions and the affect of the polish coating were tested further by removing the backing plate from the new wood with new polish after the initial conditioning and testing period was complete and reversing the material to expose the unfinished face.

Our premise was that the formaldehyde diffuses to and accumulates at the surface of the material when the surface is covered so the initial emissions after uncovering the surface are expected to be high then drop with time towards an constant value. The results are illustrated in Figure 5. The initial test of the polished side was repeated 4 times over 15 days. To test the emissions of aldehydes from the unfinished side of the same new wood material, the sample was flipped to expose the unfinished side and the polished side was sealed and the sample was returned to the test chamber to test the unfinished face. The first measurement found formaldehyde emissions from the unfinished face significantly in excess of the polished side but the emissions decreased rapidily over the next week. The material was flipped again exposing the poished side again that had been sealed for a week and the emission factor doubled but resumed dropping over the next day. Overall, the results indicate that the emission factor of formaldehyde from the new wood with new polish is approaching that of the new wood with no applied polish over time. The standard emission factors for formaldehyde from each of the main wall surface materials listed in Table 3 are compared to field measured values for the PBC building that were collected previously using Equation 3 along with the building parameters listed in Table 4. The results are listed in Table 5 for each material and each floor as a range of concentrations estimated with ACH values representing the maximum and 50% of the maximum accounting for the fact that the demand response system will likely run the ventilation at less than the maximum value. These ranges are summed for the total wall area based on loading factors for each material and the range of total concentraions are compared to the measurements in the last row of the table.

Assuming no other significant loss pathways for formaldehyde, the three primary wall materials can easily account for the measured concentrations. To probe the effects of SPIONs on the soybean chlorophyll, highly uniform SPIONs with core size of 9 nm, and either plain, or dextran based negative or positive surface charges were synthesized.Dynamic light scattering and ζ potential measurements show that the electrokinetic potential and average sizes of the SPIONs in different solutions are highly dependent on the surface charges of the SPIONs. The average DLS sizes of the SPIONs with different coatings are 18.9 and 20.3 nm in DI water and phosphate buffered saline , respectively. The DLS results are in good agreement with TEM data. It is essential to plant research had monodisperse NPs, with same physicochemical properties for evaluation real interaction effects with plants. In this study, magnetite NPs was synthesized monodisperse and suitable magnetic properties.There are no specific testing manual for nanomaterials phytotoxicity. The U.S. EPA and OECD are guidelines for testing of chemicals, frequently applied to nanotoxicity assay for plant recommended by these guidelines.19 The plant species recommended have different germination time so exposure to nanomaterials at different stage of growing in the same time. In this study, it was used the TZ method because measurement of seed germination percent in this method is not time-dependent. The plants were treated with NPs and the effects on germination index and root elongation were probed. According to the results, various concentrations of SPIONs, with different charges, do not have significant effects on the germination index . Interestingly, positive and negative SPIONs show significant positive influence on root elongation, where as plain SPIONs have no significant effect; more specifically, plain SPIONs slightly inhibit . This may happened due to the lower protective effect of the polymeric shell in plain SPIONs, compared to the negative and positive SPIONs, resulting in release of more Fe2+ ions in the treatment.

To evaluate this hypothesis, the measured Fe2+concentrations in the growth medium containing SPIONs with and without soybean cultured condition were measured by the Snell 2007 method at 510 nm. Results confirm that the concentration of Fe2+ in the growth medium is increased by the cultivating soybean. The NPs accumulate on the root and seed surface and occlude some water and ion channels. Nanomaterial phytotoxicity is related to its dimensions, chemical composition, surface properties, and ionization of the surface.42,43 To remove the slight observed toxicity of SPIONs, lower concentrations are employed for the further stages.Selected VSM measurement results of various soybean tissues treated with 0.06 mg/mL of SPIONs, with various charges, are shown in Figure 3. It is important to mention that there is no trace of the magnetization signal in the control plant tissue. Because of the accumulation of SPIONs in the root, stem, crown, and leaf, regardless of surface charge of the SPIONs, in all sub apical leaf of treatment plants were detected magnetization signal. The weakest magnetic signal was detected from stem tissue in all treatment. The highest magnetic signal in aerial tissue is detected in the crown, where the root vascular systems change to stem and where we observed the maximum accumulation of NPs. The strongest magnetizations are observed in the roots for soybeans cultured in nutrient solution with plain SPIONs; this may happen because the majority of SPIONs may be absorbed/trapped on the root tissue. It is now well recognized that the surface of NPs are covered by various macromolecules, upon their entrance into the fluids containing bio-molecules.Thus, the abundance of magnetic signal in the root tissue clearly indicates that the absorbance of root exudates macromolecules at the surface of NPs caused SPIONs accumulation on the root surface; this result was completely in agreement with the previous reports on the surface of gold NPs could varies their physicochemical properties and affect their uptakes and traslocations into rizhospher and xylem sap25. It is now well-recognized that NPs surfaces are affected by various chemical and biological elements in biological media.The biological identity of NPs changes in biological milieu with absorption of bio-molecules.According to the magnetization results , it is confirmed that positive and negative SPIONs can penetrate well from growth medium into various soybean tissues, rather than plain NPs; furthermore, positive and negative SPIONs can traverse to stem and leaf and less aggregated in aerial plant tissue, compared to the plain NPs. Zhu et al. investigated uptake and translocation of Fe3O4 NPs by pumpkin in hydroponic conditions by using a vibrating sample magnetometer. The study showed similar result that magnetic signals were detected in root, stem, and leave of plant grown in medium with magnetite NPs.On the other hand, Wang et al.did not observe any uptake of 25 nm Fe3O4 NPs by pumpkin plants. It is hypothesized that it is difficult for the larger size NPs to penetrate through the cell walls and transport across the plasma membranes.Figure 4 shows how SPIONs penetrate into the root, traverse to the xylem,vertical grow towers and translocate into the shoot. Figure 4A indicates that accumulation of SPIONs inside the root tissue is much broader than the aerial part of the plant. The largest amount of agglomerated SPIONs cannot be uptaken by the plant cells and a number of them is incorporated into the cell wall. Figure 4B confirms that SPIONs are diffused toward the interior of the stem parenchyma. Since SPIONs dimension have significant smaller size compared to the cell wall pore and the plasmodesmata width, the SPIONs traverse through the biomembranes and other plant pathways. Figure 4C displays SPIONs infiltrated into the mesotome and parenchyma cell from the leaf veins. SPIONs diffuse from xylem’s sap to aerial tissue with apoplastic flow and symplastic transport.

Transpiration and evaporation stream of water from stomata leaf are responsible for accumulated of SPIONs in the margin of leaves. However, the mechanisms underlying these processes are not understood. Nowack and Bucheli50 speculated NPs may enter plant roots through osmotic pressure, capillary forces, through pores in cell walls and intercellular plasmodesmata, or via the highly regulated symplastic route. Plants have selective uptake and translocation of NPs. The NPs could also diffuse into the intercellular space, the apoplast, and then be adsorbed or incorporated into chelates.The properties of NPs, such as composition, size, shape, and surface charge may affect the uptake and translocation inside plant.Enhancement of chlorophyll content in subapical leaves of soybean is depended on the concentration SPIONs in the growth medium and surface charge of NPs. The mean chlorophyll concentration in the soybean fresh weight exposed to SPIONs is significantly lower than those treated with Fe-EDTA at the same concentration . There is no significant difference in the ratio of chlorophyll a/b in all treatments. For these reasons we suggest that the biosynthesis of chlorophyll a is  influenced differently in comparison to that of chlorophyll b. A suitable linear correlation between chlorophyll a and b, with correlation coefficient over 0.9, suggests that the biosynthesis of main photosynthetic pigments is affected by SPIONs. In this experiment, the SPIONs are sole source of iron in the treatment. The soybean rhizosphere is acidified by protons for releassing of Fe ions from SPIONs and then the iron ions are used inside the plant. But iron ions concentrations are not adequate for soybean growth . The SPIONs could provide iron ions with redox reactions involved in the chloroplast. The biochemical reactions in chloroplast stroma, siderophore in the tylakoidal membranes,and photocatalytic reaction are suggested as factors for iron availability from SPIONs. Other results of previous investigations show low ferrofluid concentrations increase chlorophyll level in bean plantlets.The SPIONs effects on the soybean photosynthesis performance may have not only a biochemical influence but also a magnetic field of the particle  influence on the enzymatic structures in the different stages of the photosynthesis reactions.The effect of magnetic NPs coated with tetra methyl ammonium hydroxide with super paramagnetic properties could  influence the ion flows by changing ion channels properties.Chlorophyll a and b concentrations at subapical leaves of soybean are diminished at more than 45 mg·L−1 of plain SPIONs in the growth medium . The ratio of chlorophyll a to b in all treatments indicates that there is no significant difference on the photosynthesis efficiency between Fe-EDTA and SPIONs as sources of iron. We notice toxicity symptoms lead to brown spots covering the leaf surface in the plants for a culture medium with 60 mg·L−1 Fe-EDTA and plain SPIONs. Iron excess in this treatment could be generating oxidative stress in the leaf cells.Nitrogen is the mineral element that most often limits plant growth and primary productivity in natural and agricultural systems. Plants usually acquire N from the soil in the forms of ammonium and nitrate , and management of these forms is vital to agriculture.