Name: assessing the particulate matter removal abilities of tree leaves
Uploaded: 2018-10-07T15:00:00
Description: Watch this Scientific Journal Video about Assessing the Particulate Matter Removal Abilities of Tree Leaves at JoVE.com

This work was supported by the Fundamental Research Funds for the Central Universities (2017ZY21) and the National Natural Science Foundation of China (21607038).

1. Leaf Collection, Elution and Mass Measurement of PM
<ol>
	<li>Select five healthy individual trees (i.e., five replicates) of each tree species with similar diameter at breast height. Collect four larger branches randomly from four directions of the outer canopy in the middle canopy layer and cut off all intact leaves. 
	NOTE: All plants for leaf sampling should be located closely in a greening strip with length and width of about 250 and 60 m, respectively, to ensure that the environment conditions (w...

<ol>
	<li>Baidurela, A., Halik, U., Aishan, T., Nuermaimaiti, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maximum+dust+retention+of+main+greening+trees+in+arid+land+oasis+cities,+Northwest+China.">Maximum dust retention of main greening trees in arid land oasis cities, Northwest China.</a> Scientia Silvae Sinicae. 51, 57-63 (2015).</li><li>Fan, S. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dust+capturing+capacities+of+twenty-six+deciduous+broad-leaved+trees+in+Beijing.">Dust capturing capacities of twenty-six deciduous broad-leaved trees in Beijing.</a> Chinese Journal of Plant Ecology. 39, 736-745 (2015).</li><li>Dzierzanowski, K., Gawro&#324;ski, S. 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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploration+of+a+quantitative+methodology+to+characterize+the+retention+of+PM2.5+and+other+atmospheric+particulate+matter+by+plant+leaves:+Taking+Populus+tomentosa+as+an+example.">Exploration of a quantitative methodology to characterize the retention of PM2.5 and other atmospheric particulate matter by plant leaves: Taking Populus tomentosa as an example.</a> Chinese Journal of Applied Ecology. 25, 2238-2242 (2014).</li><li>Zhang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+the+Existing+Shrubs+of+the+Road+in+Changchun+and+the+Dust+Retention+Capacity+of+the+Three+Shrubs.">Studies on the Existing Shrubs of the Road in Changchun and the Dust Retention Capacity of the Three Shrubs.</a> Jilin Agricultural University. , (2013).</li><li>Beckett, K. P., Freer-Smith, P., Taylor, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effective+tree+species+for+local+air-quality+management.">Effective tree species for local air-quality management.</a> Journal of Arboriculture. 163, 12-19 (2000).</li><li>Wang, H. X., Shi, H., Wang, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+the+captured+quantity+of+particulate+matter+by+plant+leaves+under+typical+weather+conditions.">Dynamics of the captured quantity of particulate matter by plant leaves under typical weather conditions.</a> Acta Ecologica Sinica. 35, 1696-1705 (2015).</li><li>Wang, Z. H., Li, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capacity+of+dust+uptake+by+leaf+surface+of+Euonymus+Japonicus+Thunb.+and+the+morphology+of+captured+particle+in+air+polluted+city.">Capacity of dust uptake by leaf surface of Euonymus Japonicus Thunb. and the morphology of captured particle in air polluted city.</a> Ecology &amp; Environment. 15, 327-330 (2006).</li><li>Liu, H. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+Role+of+Ultrasonic+Cleaning+in+Quantitative+Evaluation+of+the+Retention+of+Tree+Leaves+to+Atmospheric+Particles:+A+Case+Study+with+Ginkgo+biloba.">Analysis of the Role of Ultrasonic Cleaning in Quantitative Evaluation of the Retention of Tree Leaves to Atmospheric Particles: A Case Study with Ginkgo biloba.</a> Scientia Silvae Sinicae. 52 (12), 133-140 (2016).</li><li>Chen, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dust+absorption+effect+of+urban+conifers+in+Northeast+China.">Dust absorption effect of urban conifers in Northeast China.</a> Chinese. Journal of Applied Ecology. 14 (12), 2113-2116 (2003).</li><li>Li, H., Yang, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+of+suspended+particulates+adhering+to+salt+marsh+plants.">Changes of suspended particulates adhering to salt marsh plants.</a> Acta Oceanolo Giga Sinica. 32 (1), 114-119 (2010).</li><li>Nguyen, T., Yu, X. X., Zhang, Z. M., Liu, M. M., Liu, X. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+types+of+urban+forest+and+PM2.5+capture+at+three+growth+stages+of+leaves.">Relationship between types of urban forest and PM2.5 capture at three growth stages of leaves.</a> Journal of Environmental Sciences. 27 (1), 33-41 (2015).</li><li>Fan, S. X., Li, X. P., Han, J., Cao, Y., Dong, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Field+assessment+of+the+impacts+of+landscape+structure+on+different-sized+airborne+particles+in+residential+areas+of+Beijing,+China.">Field assessment of the impacts of landscape structure on different-sized airborne particles in residential areas of Beijing, China.</a> Atmospheric Environment. 166, 192-203 (2017).</li><li>Liu, J. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonic+based+investigation+on+particulate+size+distribution+and+retention+efficiency+of+particulate+matters+retained+on+tree+leaves-Taking+Ginkgo+biloba+and+Pinus+tabuliformis+as+examples.">Ultrasonic based investigation on particulate size distribution and retention efficiency of particulate matters retained on tree leaves-Taking Ginkgo biloba and Pinus tabuliformis as examples.</a> Chinese Journal of Applied Ecology. 40, 798-809 (2016).</li><li>Yao, X. Y., Hu, Y. S., Liu, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dust-retention+effect+of+8+common+greening+Tree+Species+in+Beijing.">Dust-retention effect of 8 common greening Tree Species in Beijing.</a> Journal of Northwest Forestry University. 29, 92-95 (2014).</li><li>Wang, H. X., Shi, H., Wang, Y. H., Duan, J., Wang, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+surface+structure+on+the+particle+size+distribution+captured+by+Ligustrum+lucidum.">Influence of surface structure on the particle size distribution captured by Ligustrum lucidum.</a> Journal of Safety &amp; Environment. 1, 258-262 (2015).</li></ol>

Accurate and proper collection of the PM retained on leaf surfaces is the basis for assessing the PM removal abilities of different tree species. However, the conventional cleaning method (WC or plus BC) cannot completely remove the dust on leaf surfaces, which has been confirmed by scanning electron microscopy10. This was further demonstrated clearly by the present study (Figure 1, Figure 2,&#160;Fig...

The abilities of different tree species to remove PM from ambient air can be assessed through quantifying the mass of PM retained on leaf surfaces. To achieve this objective, the subtraction method1,2, the membrane filter method3,4,5, and the elution-weighing method coupled with particle size analysis6 have been applied to quantitatively estimate the mass of PM2.5 (diameter &#8804; 2.5 &#181;m), PM10 (diameter &#8804; 10 &#181;m) or total suspended particulate (TSP) retained on leaves. However, the accuracy of these methods basically depends on their performance in collecting PM retained on the leaf surfaces. At present, the conventional leaf cleaning method used in related studies often includes one or two steps, namely only water washing (soak and rinse leaves using deionized water)3,7 or plus brushing5,8,9. However, some studies10,11 have demonstrated that PM on leaf surfaces could not be completely eluted by the conventional cleaning method. As ultrasonic cleaning has the advantages of high speed, high quality, and little damage to the surface of the object, it has great potential to be used to collect the PM retained on leaf surfaces with complex microstructures. At present, ultrasonic cleaning has been applied in some studies to collect PM retained on leaf surfaces (i.e., put the leaves into deionized water, and use the ultrasonic cleaner to elute PM)12,13. However, this method is only used as a supplement to a leaf cleaning method, while it is not known whether the ultrasonic cleaning has a positive effect on collecting PM from leaf surfaces and its optimum operating parameters are also not clear. Our previous research has shown that the PM retained on Ginkgo biloba leaf surface could be completely eluted without destroying the leaf surfaces, if a proper ultrasonic cleaning procedure was supplemented to the conventional cleaning method11. However, the stability and general applicability of the ultrasonic cleaning parameters (ultrasonic power, time, and other information) to different plant species experiencing different dust retention periods are still not clear.
Currently, the mass of PM2.5, PM10, or TSP on unit leaf area has often been utilized to evaluate the abilities of different tree species to remove PM from ambient air14,15. Under the natural condition, the PM retained on leaf surfaces can be classified into two parts: the first part is the PM that can fall off leaves due to the effects of wind and rainfall, while the other part is the PM that is tightly adhered to leaf surfaces and cannot be easily washed off by rainfall. However, few studies have focused on the mass of both types of PM on leaf surfaces. In addition, the PM retention periods of leaves in different studies differ enormously. Thus, the comparability of the results of these studies will be poor, if the mass of PM retained on unit leaf area is adopted to assess the PM removal abilities of trees16. Consequently, the PM retention efficiency (the mass of PM retained on unit leaf area per unit time), as an alternative, was proposed to evaluate the PM purification effects of urban trees5,17. In general, there is still a lack of research in this aspect. It is extremely necessary to carry out relevant studies for different tree species to provide methodological basic and data support for assessing the PM removal abilities of different tree species accurately.
Here, three broadleaf tree species (G. biloba, Sophora japonica, and Salix babylonica) and two needleleaf tree species (Pinus tabuliformis and Sabina chinensis) were selected to evaluate their PM removal abilities under two PM retention periods. The leaf sampling site was in Xitucheng Park (39.97&#176; N, 116.36&#176; E), located in an area with heavy pollution in Beijing. The three specific objectives of this study were: (1) to assess the efficiency of different leaf cleaning methods (water cleaning (WC), brush cleaning (BC), and ultrasonic cleaning (UC)) in eluting the PM on leaves, (2) to verify the effect of ultrasonic cleaning on eluting PM, and (3) to assess the retention efficiency of different tree species to PM1, PM2.5, PM5, PM10, and TSP.

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		<tr height="21">
			<td height="21" style="height:21px;width:349px;">MSA2258-1CE-DU ten-thousandth scale</td>
			<td style="width:328px;">Sartorius Scientific Instruments (Beijing) Co., Ltd.</td>
			<td style="width:153px;">MSA2258-1CE-DU</td>
			<td style="width:688px;">precision: 0.01 mg</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">The IS13320 laser granularity instrument</td>
			<td>Beckman Coulter, Brea, USA</td>
			<td>IS13320</td>
			<td>working conditions: liquid/power samples; particle size range of measurement: 0.017-2000 &#956;m</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Epson Twain Pro high-quality scanner</td>
			<td>Seiko Epson, Nagano, Japan</td>
			<td>expression1680</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Automatic image analysis software WinRHIZO</td>
			<td>Regent Instruments Inc., Quebec, Canada</td>
			<td>WinRHIZO Pro 2013a</td>
			<td></td>
		</tr>
	</tbody>
</table>

assessing the particulate matter removal abilities of tree leaves

Based on the conventional cleaning methods (water cleaning (WC) + brush cleaning (BC)), this study evaluated the influence of ultrasonic cleaning (UC) on collecting various sized particulate matter (PM) retained on leaf surfaces. We further characterized the retention efficiency of leaves to various sized PM, which will help to assess the abilities of urban trees to remove PM from ambient air quantitatively. 
Taking three broadleaf tree species (Ginkgo biloba, Sophora japonica, and Salix babylonica) and two needleleaf tree species (Pinus tabuliformis and Sabina chinensis) as the research objects, leaf samples were collected 4 days (short PM retention period) and 14 days (long PM retention period) after the latest rainfall. PM retained on the leaf surfaces was collected by means of WC, BC, and UC in sequence. Then, retention efficiencies of leaves (AEleaf) to three types of the various sized PM, including easily removable PM (ERP), difficult-to-remove PM (DRP), and totally removable PM (TRP), were calculated. Only around 23%-45% of the total PM retained on leaves could be cleaned off and collected by WC. When the leaves were cleaned through WC+BC, the underestimation of the PM retention capacity of different tree species was in the range of 29%-46% for various sized PM. Almost all PM retained on leaves could be removed if UC was supplemented to WC+BC. 
In conclusion, if the UC was complemented after the conventional cleaning methods, more PM on leaf surfaces could be eluted and collected. The procedure developed in this study can be used for assessing the PM removal abilities of different tree species.

The PM retained on leaf surfaces had two types under natural conditions. The PM falls off easily by rainfall and wind under natural conditions is defined as the easily removable particulate matter (ERP). This type of PM was represented by the PM eluted by WC in this study. The PM that tightly adheres to leaf surfaces and cannot be easily washed off by BC and UC is defined as the difficult-to-remove particulate matter (DRP). This kind of PM cannot be eluted by natural rainfall and wind.</p...

Watch this Scientific Journal Video about Assessing the Particulate Matter Removal Abilities of Tree Leaves at JoVE.com

Assessing the Particulate Matter Removal Abilities of Tree Leaves

The ultrasonic cleaning method was applied to elute the particulate matter (PM) retained on leaf surfaces after PM was eluted by the conventional cleaning methods (water cleaning only or water cleaning plus brush cleaning). The methodology can help to improve the estimation accuracy for PM retention capacity of leaves.

Based on the conventional cleaning methods (water cleaning (WC) + brush cleaning (BC)), this study evaluated the influence of ultrasonic cleaning (UC) on ...

This method can help answer key questions in the relationship between urban forests and particulate matter pollution field, such as how to select tree species with high particulate matter removal abilities. The main advantage of this technique is that the PM removal abilities of trees can be assessed accurately and quantitatively by collecting the PM retained on leaf surface completely. To begin, select five healthy individual trees with similar diameter at breast height of each tree species.Then, randomly collect four larger branches from four directions of the out canopy in the middle canopy layer, and cut off all intact leaves. Place the leaves in labeled valve bags before transporting the bags to the laboratory and storing them in the fridge. Next, wash and dry beakers in an oven set to 80 degrees Celsius.Equilibrate the beakers to room temperature and humidity before weighing them. After this, place randomly selected leaves into one of the large beakers. Then, add 270 milliliters of DI water to beaker A, and immerse the leaves completely.Stir the water for 60 seconds in one direction with a glass rod. Then, evenly pour the eluent into three smaller beakers. Next, add 270 milliliters of DI water to a different large beaker, and immerse the leaves in water once more.Using a nylon brush, scrub the leaf surfaces with the DI water, taking care to avoid destroying the leaf microstructure. Next, wash the leaves in DI water with a squeezable bottle with a fine tip, and transfer them to a new large beaker. After this, pour the eluent into a clean set of three smaller beakers.Add 270 milliliters of DI water to the large beaker, and immerse the leaves in water again. Then, place the beaker in an ultrasonic cleaning machine for three to 10 minutes, and stir the leaves in one direction with a glass rod. Then, transfer the leaves to a new large beaker.Next, pour the eluent into a new set of three small beakers. Cover each of the sets of three small beakers with clean filter paper, and dry the beakers in the drying oven for five days or until the mass of the beakers becomes constant. After this, put the beakers on a laboratory bench for 30 minutes, and measure the mass of each beaker.First, add 50 milliliters of DI water to each of the small beakers. Then, place the beakers in the ultrasonic cleaning machine for 30 minutes until the PM disperses in the liquid. Add the supernatant from the beakers to a laser granularity instrument, and measure the size distribution of the PM eluted in the various cleaning steps.Next, spread the leaves on a plastic board, and scan the leaves with a scanner. Finally, use image analysis software to estimate the surface area and projected area of the leaves. In this study, PM was eluted from the leaves of five species of trees via different cleaning methods.A large number of different-sized PM were eluted from leaf surfaces after supplement ultrasonic cleaning to water cleaning plus brush cleaning. The average eluted proportions of various-sized PM of the five tree species by ultrasonic cleaning were 41%and 36%under the short dust retention and long dust retention periods, respectively. While attempting this procedure, it's important to remember to control the ultrasonic pulse and ultrasonic time strictly.Following this procedure, other methods like collecting the PM retained in waxy layer of leaves can be performed in order to answer additional questions, like the production of the mass of PM on surface and in waxy layer of leaves. After its development, this technique paved the way for research in the field of forest and particulate matter pollutions to explore the particulate matter retained on leaves in selecting tree species with how particulate matter removal abilities.

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Research

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Environment

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We provide a technique to preserve intact tree phloem and prepare it for observation. We create an apparatus called a phloem sandwich that allows for the introduction and observation of arthropods, microbes, and other organisms that inhabit phloem tissues.

Phloem tissues of pine are habitats for many thousands of organisms.  Arthropods and microbes use phloem and cambium tissues to seek mates, lay eggs, rear ...

Transcript and Metabolite Profiling for the Evaluation of Tobacco Tree and Poplar as Feedstock for the Bio-based Industry

The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article.

Plant biomass offers a renewable resource for multiple products, including fuel, feed, food, and a variety of materials. In this paper we investigate the properties of tobacco tree (Nicotiana glauca) and poplar as suitable sources for a biorefinery pipeline.

The global demand for food, feed, energy, and water poses extraordinary challenges for future generations. It is evident that robust platforms for the ...

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Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and detritus, and excreting particulate and dissolved compounds, they serve as important agents for benthic-pelagic coupling. Accurately measuring the compounds removed and excreted by suspension feeders (such as sponges, ascidians, polychaetes, bivalves) is crucial for the study of their physiology, metabolism, and feeding ecology, and is fundamental to determine the ecological relevance of the nutrient fluxes mediated by these organisms. However, the assessment of the rate by which suspension feeders process particulate and dissolved compounds in nature is restricted by the limitations of the currently available methodologies. Our goal was to develop a simple, reliable, and non-intrusive method that would allow clean and controlled water sampling from a specific point, such as the excurrent aperture of benthic suspension feeders, in situ. Our method allows simultaneous sampling of inhaled and exhaled water of the studied organism by using minute tubes installed on a custom-built manipulator device and carefully positioned inside the exhalant orifice of the sampled organism. Piercing a septum on the collecting vessel with a syringe needle attached to the distal end of each tube allows the external pressure to slowly force the sampled water into the vessel through the sampling tube. The slow and controlled sampling rate allows integrating the inherent patchiness in the water while ensuring contamination free sampling. We provide recommendations for the most suitable filtering devices, collection vessel, and storing procedures for the analyses of different particulate and dissolved compounds. The VacuSIP system offers a reliable method for the quantification of undisturbed suspension feeder metabolism in natural conditions that is cheap and easy to learn and apply to assess the physiology and functional role of filter feeders in different ecosystems.

VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders

We introduce the VacuSIP, a simple, non-intrusive, and reliable method for clean and accurate point sampling of water. The system was developed and evaluated for the simultaneous collection of the water inhaled and exhaled by benthic suspension feeders in situ, to cleanly measure removal and excretion of particulate and dissolved compounds.

Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and ...

Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

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Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems

Dissolved organic matter provides an important source of energy and nutrients to stream ecosystems. Here we demonstrate a field-based method to manipulate the ambient pool of dissolved organic matter in situ through easily replicable nutrient pulses.

Dissolved organic matter (DOM) is a highly diverse mixture of molecules providing one of the largest sources of energy and nutrients to stream ecosystems. ...

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This paper describes the operation procedure for the flow tube reactor and related data collection. It shows the protocols for setting the experiments, recording data and generating the number-diameter distribution as well as the particle mass information, which gives useful information about chemical and physical properties of the organic aerosols.

Organic particulate matter (PM) is increasingly recognized as important to the Earth's climate system as well as public health in urban regions, and the ...

Production and Measurement of Organic Particulate Matter in the Harvard Environmental Chamber

The production and the evolution of atmospheric organic particulate matter (PM) are insufficiently understood for accurate simulations of atmospheric chemistry and climate. The complex production mechanisms and reaction pathways make this a challenging research topic. To address these issues, an environmental chamber, providing enough residence time and close-to-ambient concentrations of precursors for secondary organic materials, is needed. The Harvard Environmental Chamber (HEC) was built to serve this need, simulating the production of gas and particle phase species from volatile organic compounds (VOCs). The HEC has a volume of 4.7 m3 and a mean residence time of 3.4 h under typical operating conditions. It is operated as a completely mixed flow reactor (CMFR), providing the possibility of indefinite steady-state operation across days for sample collection and data analysis. The operation procedures are described in detail in this article. Several types of instrumentation are used to characterize the produced gas and particles. A High-Resolution Time-of-Fight Aerosol Mass Spectrometer (HR-ToF-AMS) is used to characterize particles. A Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) is used for gaseous analysis. Example results are presented to show the use of the environmental chamber in a wide variety of applications related to the physicochemical properties and reaction mechanisms of organic atmospheric particulate matter.

This paper describes operation procedures for the Harvard Environmental Chamber (HEC) and related instrumentation for measuring gaseous and particle species. The environmental chamber is used to produce and study secondary organic species produced from the organic precursors, especially related to atmospheric organic particulate matter.

The production and the evolution of atmospheric organic particulate matter (PM) are insufficiently understood for accurate simulations of atmospheric ...

Improving Infrared Spectroscopy Characterization of Soil Organic Matter with Spectral Subtractions

Soil organic matter (SOM) underlies numerous soil processes and functions. Fourier transform infrared (FTIR) spectroscopy detects infrared-active organic bonds that constitute the organic component of soils. However, the relatively low organic matter content of soils (commonly &#60; 5% by mass) and absorbance overlap of mineral and organic functional groups in the mid-infrared (MIR) region (4,000-400 cm-1) engenders substantial interference by dominant mineral absorbances, challenging or even preventing interpretation of spectra for SOM characterization. Spectral subtractions, a post-hoc mathematical treatment of spectra, can reduce mineral interference and enhance resolution of spectral regions corresponding to organic functional groups by mathematically removing mineral absorbances. This requires a mineral-enriched reference spectrum, which can be empirically obtained for a given soil sample by removing SOM. The mineral-enriched reference spectrum is subtracted from the original (untreated) spectrum of the soil sample to produce a spectrum representing SOM absorbances. Common SOM removal methods include high-temperature combustion (&#39;ashing&#39;) and chemical oxidation. Selection of the SOM removal method carries two considerations: (1) the amount of SOM removed, and (2) absorbance artifacts in the mineral reference spectrum and thus the resulting subtraction spectrum. These potential issues can, and should, be identified and quantified in order to avoid fallacious or biased interpretations of spectra for organic functional group composition of SOM. Following SOM removal, the resulting mineral-enriched sample is used to collect a mineral reference spectrum. Several strategies exist to perform subtractions depending on the experimental goals and sample characteristics, most notably the determination of the subtraction factor. The resulting subtraction spectrum requires careful interpretation based on the aforementioned methodology. For many soil and other environmental samples containing substantial mineral components, subtractions have strong potential to improve FTIR spectroscopic characterization of organic matter composition.

SOM underlies many soil functions and processes, but its characterization by FTIR spectroscopy is often challenged by mineral interferences. The described method can increase the utility of SOM analysis by FTIR spectroscopy by subtracting mineral interferences in soil spectra using empirically obtained mineral reference spectra.

Soil organic matter (SOM) underlies numerous soil processes and functions. Fourier transform infrared (FTIR) spectroscopy detects infrared-active organic ...

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem production, NEP), in non-typical ecosystems, on a currently reforested windthrow area in Poland. After a tornado event, a relatively narrow &#8220;corridor&#8221; was created within surviving forest stands, which complicates such kind of experiments. The application of other measuring techniques, such as the chamber method, is even more difficult under these circumstances, because especially at the beginning, fallen trees and in general great heterogeneity of the site provide a challenging platform to perform flux measurements and then to properly upscale obtained results. In comparison with standard EC measurements carried out in untouched forests, the case of windthrow areas requires special consideration when it comes to the site location and data analysis in order to ensure their representativeness. Therefore, here we present a protocol of real-time, continuous CO2 flux measurements at a dynamically changing, non-ideal EC site, which includes (1) site location and instrumentation setup, (2) flux computation, (3) rigorous data filtering and quality control, and (4) gap filling and net fluxes partitioning into CO2 respiration and absorption. The main advantage of the described methodology is that it provides a detailed description of the experimental setup and measurement performance from scratch, which can be applied to other spatially limited ecosystems. It can also be viewed as a list of recommendations on how to deal with unconventional site operation, providing a description for non-specialists. Obtained quality-checked, gap filled, half-hour values of net CO2, as well as absorption and respiration fluxes, can be finally aggregated into daily, monthly, seasonal or annual totals.

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

The presented protocol uses the eddy covariance method at non-typical locations, applicable to all types of short-canopy ecosystems with limited area, on a currently reforested windthrow site in Poland. Details of measuring site setup rules, flux calculations and quality control, and final result analysis, are described.

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem ...

Investigation of Xenobiotics Metabolism In Salix alba Leaves via Mass Spectrometry Imaging

The method presented uses mass spectrometry imaging (MSI) to establish the metabolic profile of S. alba leaves when exposed to xenobiotics. Using a non-targeted approach, plant metabolites and xenobiotics of interest are identified and localized in plant tissues to uncover&#160;specific distribution patterns. Then, in silico prediction of potential metabolites (i.e., catabolites and conjugates) from the identified xenobiotics is performed. When a xenobiotic metabolite is located in the tissue, the type of enzyme involved in its alteration by the plant is recorded. These results were used to describe different types of biological reactions occurring in S. alba leaves in response to xenobiotic accumulation in the leaves. The metabolites were predicted in two generations, allowing the documentation of successive biological reactions to transform xenobiotics in the leaf tissues.

Investigation of Xenobiotics Metabolism In Salix alba Leaves via Mass Spectrometry Imaging

This method uses mass spectrometry imaging (MSI) to understand metabolic processes in S. alba leaves when exposed to xenobiotics. The method allows the spatial localization of compounds of interest and their predicted metabolites within specific, intact tissues.

The method presented uses mass spectrometry imaging (MSI) to establish the metabolic profile of S. alba leaves when exposed to xenobiotics. Using a ...

Assessing Intertidal Populations of the Invasive European Green Crab

Invasive species have caused major disruptions to ecosystems worldwide. The European green crab invaded North America in the 1800s and is considered one of the world&#8217;s 100 worst invaders by the IUCN. Observations of spatiotemporal green crab population dynamics are essential for predicting and managing the ecological and economic impacts of this harmful invasive species. This protocol was developed in an effort to create a standardized method for assessing green crab population dynamics in the rocky intertidal zone of New England and Atlantic Canada. The protocol was designed to be accessible to multiple users including researchers, educators, students, and citizen scientists. Although it was designed for surveying crab populations, this protocol is easy to adapt and could be used for any number of intertidal species. The resulting data collected using this protocol has a wide range of uses, including to inform ecological research, conservation efforts, mitigation strategies, and fishery development, as well as for educational outreach purposes.

Understanding spatiotemporal patterns in green crab population dynamics is essential for predicting and managing the ecological and economic impacts of this harmful invasive species. This protocol was developed in an effort to create a standardized method for assessing green crab populations in the rocky intertidal zone of the Northwest Atlantic.

Invasive species have caused major disruptions to ecosystems worldwide. The European green crab invaded North America in the 1800s and is considered one ...