Financial support for this study came from the National Natural Science Foundation of China (No. 41775148). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

1. PM Number Monitoring
<ol>
	<li>Use an airborne laser particle counter (see Table of Materials) to determine the total PM number. Collect the PM by the air sampling port on the top of the airborne laser particle counter. 
	NOTE: This particle counter is an automation equipment and it can work independently when the program including sampling time, interval, collection times, etc. has been set on its touch screen.
	<ol>
		<li>Equip the instrument with a sensor to monitor temperature and relative humidity. Measure and record temperature and relative humidity data simultaneously every 5 min.</li>
		<li>In total, measure and record 6 different particle size classes (0.3-0.5 &#956;m, 0.5-0.7 &#956;m, 0.7-2.5 &#956;m, 2.5-5 &#956;m, 5-10 &#956;m and &#62; 10 &#956;m) simultaneously every 5 min. Measure 4 other particle size classes (0.3-0.5 &#956;m, 0.5-1 &#956;m, 1-3 &#956;m and &#8805; 3 &#956;m).</li>
		<li>Collect the air samples though the sampling hole on the top of the sampler and use the test modules inside the sampler to measure the particle size of each PM. Then the data is stored automatically. All the processes above can be performed automatically after the relative parameters, including sampling time and counting range, are set though the mini touch displayer of the airborne laser particle counter. 
		NOTE: This particle counter is an automation equipment and it has test modules that count the number of PM of different particle size classes.</li>
	</ol>
	</li>
	<li>To assess experimental standard error, ensure that different particle size classes are counted with at least 15 replications. Ensure that readings are stored in the internal memory of the instrument and subsequently analyzed.
	<ol>
		<li>Ensure that analysis of the primary data includes PM number concentration, the ANOVA test and the percentage of PM in each size class. For example, as shown in Figure 1A, the PM number concentrations in December (237.6 particles/cm3) were significantly higher than those in October (average: 110.2 particles/cm3) (ANOVA; P-value &#60; 0.05). Figure 1B shows that the number of particles smaller than 3 &#956;m accounted for more than 99% of the total number.</li>
		<li>Use the laser particle counter to monitor the PM number concentrations and store the data automatically. Use a USB flash disk to export data in the computer and perform the ANOVA test.</li>
	</ol>
	</li>
</ol>
2. PM Collection by Cyclonic Aerosol Samplers
<ol>
	<li>Perform the PM sampling in an open area without any nearby major pollution sources at &#8764;2 m above the ground.
	<ol>
		<li>Record the position of the sampling site. For example, the campus of Beijing Institute of Technology is the following: 39&#176;57&#8217;51.0&#8217;&#8217; N; 116&#176;19&#8217;38.5&#8217;&#8217; E.</li>
	</ol>
	</li>
	<li>Use a cyclonic aerosol sampler to collect air samples. Use a sampler flow of 323 L/min, and a collection time of 6 h. 
	NOTE: The sampler flow rate is fixed and cannot be changed. The collection time is controlled by manual time-keeping as there is only a Start and Stop button on this sampler.
	<ol>
		<li>Use sterile water to wash the inside of the cyclonic aerosol sampler 3 times before collection, and use the automatic cleaning function 3 times by continuously pressing the collect button 3 times.</li>
		<li>Press the collect button to start sampling and press the pump button to stop sampling. Put the sampler on a shelf or floor with no one holding it in place.</li>
		<li>Preserve all samples in the dark at -20 &#176;C until the subsequent analyses.</li>
	</ol>
	</li>
</ol>
3. PM Collection by Filters
<ol>
	<li>Perform the PM sampling in an open area without any nearby major pollution sources at &#8764;2 m above the ground.
	<ol>
		<li>Record the position of the sampling site. For example, the campus of Beijing Institute of Technology is as follows: 39&#176;57&#8217;51.0&#8217;&#8217; N; 116&#176;19&#8217;38.5&#8217;&#8217; E.</li>
	</ol>
	</li>
	<li>Collect the PM samples on 20.32 &#215; 25.4 cm2 filters (see Table of Materials) by using a high-volume air sampler (see Table of Materials) at a flow rate of 1,000 L/min. Set the flow rate and collection time by relative auto-programming.
	<ol>
		<li>Preserve all sampled filters in the dark at -20 &#176;C until the subsequent analyses.</li>
	</ol>
	</li>
</ol>
4. Biological Composition Analysis
<ol>
	<li>For biological composition analysis, use each liquid sample from the cyclonic aerosol sampler or filter sample for DNA extraction by a multisource DNA extraction Kit (see Table of Materials) according to the manufacturer&#39;s protocols.
	<ol>
		<li>For samples from the high-volume air sampler with filters, use 1/8 of each filter sample for DNA extraction. Put the filter into a 50 mL tube with the sample facing inward and the back facing towards the tube wall. Add 10 beads in the central sites towards the side of the filter containing the sample.</li>
		<li>Vortex the tube for 15 min at room temperature. Pipette the liquid in the tube into a clean 50 mL centrifuge tube to continue the DNA extraction process.</li>
	</ol>
	</li>
	<li>Extract the DNA from the sample by the processes as follows.
	<ol>
		<li>Centrifuge the bacteria sample at 2,000 x g for 5 min, remove the supernatant, and suspend bacteria in 2 mL of sterile PBS buffer.</li>
		<li>Collect the suspension of bacteria in a 2 mL centrifuge tube and then centrifuge at 2,000 x g for 5 min to discard the supernatant solution.</li>
		<li>Add 350 &#956;L of sterile PBS buffer containing the suspended bacteria to the solution.</li>
		<li>Add 0.8 mL of RNase A.</li>
		<li>Add 150 &#956;L of Buffer CL and 8 &#956;L of proteinase K, and mix immediately by vortex shaking for 1 min. After brief centrifugation at 1,000 x g for 30 s (no residues on the wall), put the centrifugal tube in 56 &#176;C water for 10 min.</li>
		<li>Add 350 &#956;L of Buffer PD, and mix for 30 s and then centrifuge for 10 min at 12,000 x g.</li>
		<li>Place the DNA preparation tube in a 2 mL centrifuge tube, and transfer the mixture made in step 4.2.6 to the preparation tube. Then centrifuge for 1 min at 12,000 x g.</li>
		<li>Discard the filtrate, put back the contents of the preparation tube into the original 2 mL centrifuge tube, and add 50 &#956;L of Buffer W1. Centrifuge the mixture for 1 min at 12,000 x g.</li>
		<li>Discard the filtrate, put back the contents of the preparation tube into the original 2 mL centrifuge tube, and add 700 &#956;L of Buffer W2. Centrifuge the mixture for 1 min at 12,000 x g. Repeat this step to wash again with 700 &#956;L of Buffer W2.</li>
		<li>Discard the waste liquid, and put back the contents of the preparation tube into the original 2 mL centrifuge tube. Centrifuge the mixture for 1 min at 12,000 x g.</li>
		<li>Put the contents of the DNA preparation tube into another clean 1.5 mL centrifuge tube, and add 100 &#956;L of eluent or deionized water to the middle of the membrane in the preparation tube (deionized water or eluent was heated to 65 &#176;C). Allow the mixture to stand at room temperature for 1 min, and Centrifuge the mixture for 1 min at 12,000 x g.</li>
	</ol>
	</li>
	<li>Perform quantitative real-time polymerase chain reaction (Q-RT-PCR) to quantify the relative abundances of bacteria and fungi on the sampling filters.
	<ol>
		<li>Use primers as follows: for bacterial 16S rDNA, 515F (5&#8217;- GTG CCA GCM GCC GCG GTA A-3&#8217;) and 806R (5&#8217;- GGA CTA CHV GGG TWT CTA AT-3&#8217;); and for the fungal ITS, ITS1 (5&#8217;-TCC GTA GGT GAA CCT GCG G-3&#8217;) and ITS1 (5&#8217;-GCT GCG TTC TTC ATC GAT GC-3&#8217;).</li>
		<li>Run the Q-RT-PCR assays on a Real-Time PCR System (see Table of Materials). RT-PCR condition: predegeneration, 95 &#176;C, 10 min; degeneration, 95 &#176;C, 15 s; anneal and extension, 60 &#176;C, 1 min; 40 cycles from degeneration to anneal and extension.</li>
	</ol>
	</li>
	<li>For bacterial and fungal community structure analysis, amplify the V1&#8211;V3 region of the bacterial 16S rDNA and the ITS region of the fungal rRNA operon by PCR.
	<ol>
		<li>Use the primers as follows: for bacteria, V1-9F (5&#8242;-CCT ATC CCC TGT GTG CCT TGG CAG TCT CAG ACG AGT TTG ATC MTG GCT CAG-3&#8242;) and V3-541R (5&#8242;-CCA TCT CAT CCC TGC GTG TCT CCG ACT CAG-barcode-ACW TTA CCG CGG CTG CTG G-3&#8242;); and for fungi, ITS-3F (5&#8217;-CCT ATC CCC TGT GTG CCT TGG CAG TCT CAG CAC ATC GAT GAA GAA CGC AGC-3&#8217;) and ITS-4R (5&#8217;-CCA TCT CAT CCC TGC GTG TCT CCG ACT CAG-barcode-GCT CCT CCG CTT ATT GAT ATG C-3&#8217;).</li>
		<li>Ensure that the 20 &#956;L mixture of PCRs included 2 &#956;L of 2.5 mM dNTPs, 4 &#956;L of 5&#215; FastPfu Buffer, 0.8 &#956;L of each primer (5 &#956;M), 0.4 &#956;L of FastPfu Polymerase, and 10 ng of template DNA (see Table of Materials).</li>
		<li>Use the PCR program as follows: 94 &#176;C for 5 min; followed by 10 cycles of 94 &#176;C for 30 s, 55-60 &#176;C for 45 s, and 72 &#176;C for 90 s; 20 cycles of 94 &#176;C for 30 s, 55 &#176;C for 45 s and 72 &#176;C for 90 s; and a final extension at 72 &#176;C for 5 min.</li>
	</ol>
	</li>
	<li>Perform DNA purification, DNA quantification and pyrosequencing as described in a previous study 21.</li>
</ol>
5. Bioaerosol Sampling and Cultivation
<ol>
	<li>Use an international standard Andersen six-stage sampler (see Table of Materials) to sample culturable airborne bacteria and fungi at a flow rate of 28.3 L/min. Use a sampling time of 35 min. Put the culture plate in each stage of the sampler. Sufficiently disinfect the sampler with 75% ethyl alcohol after each sampling. 
	NOTE: The sampler flow rate is fixed and the collection time is controlled by manual time-keeping.
	<ol>
		<li>Sample the six stages with the Andersen six-stage sampler, which is defined by the aerodynamic diameters of the airborne particles, including stage VI (0.65&#8211;1.1 &#956;m), stage V (1.1&#8211;2.1 &#956;m), stage IV (2.1&#8211;3.3 &#956;m), stage III (3.3&#8211;4.7 &#956;m), stage II (4.7&#8211;7.0 &#956;m) and stage I (&#8805;7.0 &#956;m).</li>
		<li>Collect the bacterial particles and deposit onto the culture plate in each stage containing Soybean-Casein Digest Agar (see Table of Materials). There is a container with many air intakes on the top in each stage of the sampler.</li>
		<li>Culture the airborne bacteria collection plates at 37 &#176;C for 24-48 h; then, count the colony numbers of bacteria on the sample dish for each stage.</li>
	</ol>
	</li>
	<li>To prevent the particles collected by the Andersen six-stage sampler from overlapping, correct the number of colonies at each sampler level by the following formula: 
	<img alt="Equation" src="/files/ftp_upload/58795/58795eq1.jpg" /> 
	where Pr: corrected number of colonies at each level, 
	N: number of sampling holes of the sampler at all levels (400), and 
	r: the actual count of colonies.</li>
	<li>Calculate the unit of colonies per m3 of air as follows: 
	<img alt="Equation" src="/files/ftp_upload/58795/58795eq2.jpg" /> 
	where C: concentration (CFU/m3), 
	N1-N6: the corrected number of colonies at each level, 
	T: sampling time (min), and 
	F: sampling flow rate (28.3 L/min).</li>
	<li>Use methods from Steps 5.1 - 5.3 to study the bioaerosol in livestock farm, including four types of piggeries. 
	NOTE: The livestock farm is located in Changchun, China. The central position 2 m above the ground in each piggery was selected as sampling location.) After culture of bacteria, treat all colonies in the plates as described in Steps 6.1 - 6.2.</li>
</ol>
6. Identification of Culturable Bacteria
<ol>
	<li>After 48 h or 72 h of culturing, place the bacteria into a 2 mL centrifuge tube. Extract the DNA of these bacteria or fungi by using a multisource DNA extraction Kit (see Table of Materials). The DNA extraction process is described in section 4.2.</li>
	<li>Use 200 &#956;L DNA extraction sample for 16S rDNA sequencing. Use the same processes as described in Steps 4.2, 4.3 and 4.4 on biological composition analysis.</li>
</ol>

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+air+sampling+to+detect+exotic+Newcastle+disease+virus+in+two+California+commercial+poultry+flocks.">Environmental air sampling to detect exotic Newcastle disease virus in two California commercial poultry flocks.</a> Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 17 (2), 198-200 (2005).</li><li>Logares, R., 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=Metagenomic+16S+rDNA+Illumina+tags+are+a+powerful+alternative+to+amplicon+sequencing+to+explore+diversity+and+structure+of+microbial+communities.">Metagenomic 16S rDNA Illumina tags are a powerful alternative to amplicon sequencing to explore diversity and structure of microbial communities.</a> Environmental microbiology. 16 (9), 2659-2671 (2014).</li><li>Kogawa, M., Hosokawa, M., Nishikawa, Y., Mori, K., Takeyama, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Obtaining+high-quality+draft+genomes-+from+uncultured+microbes+by+cleaning+and+co-assembly+of+single-cell+amplified+genomes.">Obtaining high-quality draft genomes- from uncultured microbes by cleaning and co-assembly of single-cell amplified genomes.</a> Scientific reports. 8 (1), 2059 (2018).</li><li>Handelsman, J., Rondon, M. R., Brady, S. F., Clardy, J., Goodman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+biological+access+to+the+chemistry+of+unknown+soil+microbes:+a+new+frontier+for+natural+products.">Molecular biological access to the chemistry of unknown soil microbes: a new frontier for natural products.</a> Chemistry &amp; biology. 5 (10), R245-R249 (1998).</li><li>Moon, C. 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The authors have nothing to disclose.

In this study, we provided some representative results that were obtained during hazy days and in livestock farms. The results from bioaerosol samples taken during Beijing hazy days facilitated a better understanding of the biological compositions of the biological composition of PM without PM present during Beijing hazy days. The results from samples taken from livestock farms will also provide basic data for environmental air quality control in piggeries and a theoretical foundation and technical support for healthy breeding and safe production in livestock farms. Many environmental factors, such as temperature, humidity and wind speed, might contribute to the distribution of aerosol particles in the cow house (Figure 1). Previous studies have revealed that the PM in livestock farms mainly comes from the fodder, feces, fur and feather, which may be related to the animal activities. The environmental factors can affect not only animal activities, but also the aggregation and diffusion of PM in a relatively closed cow house. Therefore, we detect different concentrations and size distributions of PM in four different months. Besides, the sanitary condition, feeding method and animal activity were different between the four types of piggeries, which might also affect their community structure of culturable bacteria in the air (Figure 4).
However, in this study, we mainly focused on the available methods that we could use to study the composition and distribution of bioaerosols under different environmental conditions. Compared with other microbial samples, those of airborne microorganisms have very low concentrations and are mixed with a large number of impurities, such as inorganic dust particles, which introduce certain difficulties during the collection and detection of such microorganisms21. Therefore, appropriate methods of collection and detection should be selected for microbial aerosols. The collection of microbial aerosol samples is generally performed by using the precipitation method or specialized equipment to collect the microorganisms in liquid, semi-solid or solid sampling medium22,23,24. Then, some corresponding technical treatment and specific testing and analysis are subsequently carried out25. The sampling medium should keep microorganisms intact to reduce the error associated with detection and analysis26. However, different aerosol microorganism samplers have different effects on the integrity of samples due to their different sampling principles and media. People have designed many kinds of bioaerosol samplers that use different sampling principles, such as inertial impaction, filtration resistance, and electrostatic precipitation27.
Impacting samplers can push airborne PM into the sampling medium at high speed by using extraction equipment. There are two types of impacting samplers: solid and liquid.Solid impacting samplers can be used to sample bioaerosols at a low concentration and can be almost impervious to air flow28. Aerosol particles of different sizes can be preliminarily screened, and microbes can be sampled directly into the culture medium, which increases the survival rate of culturable microorganisms10. Due to inertial impact, microbial aerosol particles easily collide at the same site, and colonies may overlap easily after culture. At present, the most common solid impacting sampler is the Andersen-6 microbial aerosol sampler. In this study, we used an Andersen six-stage sampler to study the culturable bacteria distributed in airborne PM of different sizes.
Cyclonic aerosol samplers use cyclones to spiral air at high speed into a cylinder or cone. Bioaerosol particles can be separated from the airflow by centrifugal force, which means that microbes can bump into the inner wall of the sampler and then be collected by the sampling buffer. This method is convenient and can be used for long sampling times in large flow and sampling operations. However, this method cannot be implemented at low temperatures because the operation is dependent on liquid. The cyclonic aerosol sampler used in this study is a cyclonic wetted-wall aerosol sampler that can extract and transfer airborne pathogens and particles from sampled air into a small volume of water for analysis29.
Filter samplers can work under low temperature conditions and can sample particles above a certain size. However, they have a great impact on microbial activity and are prone to damage, which will greatly influence subsequent studies on sampling activity. In this study, bioaerosol samples from Beijing hazy days were collected by using both a high-volume air sampler with filters and a cyclonic aerosol sampler. The aim of this experiment was to analyses the biological composition of PM without the separation and culturing of airborne microbes. Therefore, these two sampling methods were suitable for this study. For the cyclonic aerosol sampler method, airborne microbes at a low concentration can be easily extracted into the running buffer and then can be analyzed conveniently without the additional treatment that is commonly used for filter samples. In this study, these two sampling methods, cyclonic aerosol sampler and filter sampler, showed different sampling efficiency. The additional treatment that is commonly used for filter samples, such as recovering the sample from the filter, is one of the main differences between these two methods. Besides, the air samples were collected directly into the running buffer by cyclonic aerosol sampler while the other method collected samples on filters. The characteristics of different type of sampling method might contribute to this different sampling efficiency. We can assume that the cyclonic aerosol sampler is the better choice for microorganism collection, and this assumption needs further confirmation.
In this study, bacterial 16S rDNA and fungal ITS region sequencing were used to perform the biological analysis of bioaerosols. 16SrDNA sequencing is the determination of 16S rDNA segments in the microbial genome30. 16S rDNA widely exists in prokaryotes with high conservation and specificity, which makes it useful for the identification of microbial species31. Whole-genome sequencing requires only the extraction of genomic DNA and subsequent sequencing. In addition to producing a large amount of data, this process also allows for a more comprehensive analysis of microbial community structure. Besides, metagenomics can also be used in this field of study by providing more information in the future. Handelsman et al. first proposed the concept of the metagenome in a 1998 paper on microbes in soil32. In subsequent studies, the concept of the metagenome was gradually accepted, and much research was carried out on the microbes included in the human gut, ocean and soil33,34,35. With the support of high-throughput sequencing technology, metagenomics has developed rapidly, and it plays an increasingly important role in the study of pathogen detection. Traditional microbial research methods mainly rely on culture for separation and purification. However, many studies cannot be carried out because more than 99% of microbes cannot be cultured. In contrast to traditional methods, metagenomics can take the genetic information of all the microbes in the environment as a whole without the need to separate individual organisms36. A comprehensive analysis of all the resulting microorganisms can be conducted directly.
In summary, this study showed several detection, sampling and analysis methods that could be used for studies on the biological composition of environmental PM, including PM monitoring; PM sampling by an Andersen six-stage sampler, a high-volume air sampler with filters or cyclonic aerosol sampler; and subsequent biological analysis based on DNA sequencing. In practice, these methods can be used under different environmental conditions, such as many types of livestock farms. Our protocols and results may help other researchers all over the world further explore the health impacts of fungal and bacterial bioaerosols in the environment.

In natural environments, various kinds of microorganisms exist in bioaerosols, including fungi, bacteria, viruses and other microorganisms1. Airborne microorganisms, which can be emitted from some human activities such as animal feeding operations in livestock farms, are the important contents of the atmospheric environment2. These microorganisms may not only play important roles in the atmospheric environment but also have significant impacts on human health and diseases spread.
As an important way of spreading diseases, microbial aerosols have attracted wide attention throughout the world. In recent studies, many human diseases were found to be associated with the complex composition of environmental particulate matter (PM) in different locations, such as chemical factories, livestock farms and smoggy cities3,4. The biological composition of PM may contribute to some respiratory and cardiovascular diseases in PM-exposed humans5. Different body regions, such as the mucosa, skin, digestive tract and respiratory tract, can be potential targets of microbes attached to PM6,7. An increased risk of lung cancer might be caused by prolonged exposure to PM2.58.
Airborne bacteria have been surveyed at various locations in several countries around the world, including in subway stations, veterinary hospitals, slaughterhouses, composting facilities, tanneries, milk-processing facilities, coal mines, dental clinics and indoor environments9,10,11,12,13,14,15,16,17, generating a large number of reports about biological aerosols. Crowded places associated with campuses, livestock farms and large cities during hazy days are three particularly important public conditions for which we need to explore the connections between human health and the potential effects of PM exposure. Furthermore, during winter days in the northern cities of China, high PM2.5 values may affect human health. Although PM2.5 can generate toxic effects by targeting respiratory surfaces and dissolving into blood18, it is still not clear whether and how the microbes attached to PM2.5 could potentially affect human health19,20. Livestock farms are one of the main sources of PM and microbial aerosols in the air. The large numbers of pathogens, such as influenza virus and Brucella melitensis, that are carried by aerosols in the fields around livestock farms are important factors causing respiratory diseases in both livestock and poultry workers.
In this study, we explored multiple types of analyses of bioaerosols, including PM number monitoring, bioaerosol collection and biological composition analysis. Air samples were collected by a cyclonic aerosol sampler, a high-volume air sampler with filters and an Andersen six-stage sampler. Then, the samples collected by these three samplers were analyzed by biological analysis including bacterial 16S rDNA and fungal ITS sequencing to determine their biological compositions. Herein, we show representative results from the bioaerosol samples collected during Beijing hazy days and from livestock farms indicating that bioaerosols might have great impacts on human and animal health. The comparison between liquid and filter sampling methods were also explored in this study mainly based on the data from 16S DNA and fungal ITS sequencing.

<table>
	<tbody>
		<tr>
			<td>airborne laser particle counter</td>
			<td>TSI Inc, MN, USA</td>
			<td>model 9306</td>
			<td></td>
		</tr>
		<tr>
			<td>Andersen six-stage sampler</td>
			<td>Tisch Inc, USA</td>
			<td>TE-20-600</td>
			<td></td>
		</tr>
		<tr>
			<td>AxyPrep multisource DNA Miniprep Kit</td>
			<td>Axygen, NY, USA</td>
			<td>AP-MN-MIS-GDNA-50G</td>
			<td></td>
		</tr>
		<tr>
			<td>FastPfu Polymerase</td>
			<td>TransGen Inc., Beijing, China</td>
			<td>AP221-01</td>
			<td></td>
		</tr>
		<tr>
			<td>High-volume air sampler</td>
			<td>Beijing HuaRui HeAn Technology Co., Ltd., China</td>
			<td>HH02-LS120</td>
			<td></td>
		</tr>
		<tr>
			<td>Real-Time PCR System</td>
			<td>Thermo Fisher Scientific, USA</td>
			<td>Applied Biosystems&#174; 7500</td>
			<td></td>
		</tr>
		<tr>
			<td>Soybean-Casein Digest Agar</td>
			<td>Becton, Dickinson and company, MD, USA</td>
			<td>211043</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissuquartz filters</td>
			<td>Pall, NY, USA</td>
			<td>7204</td>
			<td></td>
		</tr>
		<tr>
			<td>Wetted-Wall Air Sampler</td>
			<td>Research International, Inc. 17161 Beaton Road SE 
			Monroe, Washington 98272-1034 USA</td>
			<td>SASS 2300</td>
			<td></td>
		</tr>
	</tbody>
</table>

composition and distribution analysis of bioaerosols under different environmental conditions

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, we described a protocol for multiple analyses of the biological compositions in environmental PM. Five experiments are presented: (1) PM number monitoring by using a laser particle counter; (2) PM collection by using a cyclonic aerosol sampler; (3) PM collection by using a high-volume air sampler with filters; (4) culturable microbes collection by the Andersen six-stage sampler; and (5) detection of biological composition of environmental PM by bacterial 16SrDNA and fungal ITS region sequencing. We selected hazy days and a livestock farm as two typical examples of the application in this protocol. In this study, these two sampling methods, cyclonic aerosol sampler and filter sampler, showed different sampling efficiency. The cyclonic aerosol sampler performed much better in terms of collecting bacteria, while these two methods showed the same efficiency in collecting fungi. Filter samplers can work under low temperature conditions while cyclonic aerosol samplers have a sampling limitation for temperature. A solid impacting sampler, such as an Andersen six-stage sampler, can be used to sample bioaerosols directly into the culture medium, which increases the survival rate of culturable microorganisms. However, this method mainly relies on culture while more than 99% of microbes cannot be cultured. DNA extracted from the culturable bacteria collected by the Andersen six-stage sampler and samples collected by cyclonic aerosol sampler and filter sampler were detected by bacterial 16S rDNA and fungal ITS region sequencing.All the methods above may have wide application in many fields of study, such as environmental monitoring and airborne pathogen detection. From these results, we can conclude that these methods can be used under different conditions and may help other researchers further explore the health impacts of environmental bioaerosols.

In this study, we performed an assessment of the overall PM distribution and a comprehensive analysis of the bioaerosols in a dairy farm from September to December. Many environmental factors contribute to the distribution of aerosol particles. We studied the concentration and size distributions of PM in a cow house by using a TSI laser particle counter. As shown in Figure 1A, the concentration of aerosol particles was highest in December and lowest in October, which might be caused by changes in temperature and humidity (Table 1). The concentration of inhalable aerosol particles (0.3-3.0 &#181;m) accounted for more than 99% of the total particle concentration (Figure 1B), and the particles in this range could reach the deep respiratory tract, causing serious hazards for humans and animals.
Biological composition analysis of samples can be performed by DNA extraction, bacterial 16SrDNA and fungal ITS region sequencing instead of microorganism culture. From the biological analysis of bioaerosol samples collected by using a cyclonic aerosol sampler or a high-volume air sampler with filters, we can preliminarily compare the efficiencies of these two methods in collecting bacteria and fungi. Figure 2 showed the analysis results of the bioaerosol samples collected during Beijing hazy days in the campus of Beijing Institute of Technology in December 20, 2016. For bacteria collection, the results indicated that the cyclonic aerosol sampler collected many more genera than the high-volume air sampler with filters (Figure 2A). For fungi collection, these samplers showed equal collection efficiencies and almost the same genus abundances (Figure 2B). From the results presented in Figure 2, we were able to measure the different collection efficiencies of these two methods for bacteria and fungi. For bacteria collection, the cyclonic aerosol sampler performed much better than the high-volume air sampler with filters because the samples from the former showed a higher genus abundance (Figure 2A). However, the fungal sequencing analysis of the two samples from different sampling methods showed nearly identical community structures (Figure 2B).
We studied airborne culturable bacteria by using an Andersen six-stage sampler. As shown in Figure 3, the colony numbers of culturable bacteria for stage I-VI particles was reduced. Stage I particles (particle size &#62; 8.2 &#181;m) had the highest numbers of culturable bacteria colonies. The percentage of stage I colonies in four different types of piggeries including farrowing house, pregnant sow house, fattening house and weaning house was 33%, 30%, 26% and 34%, respectively. The percentage of stage II colonies in four different types of piggeries was 20%, 22%, 19% and 20% respectively. The percentage of stage III colonies in four different types of piggeries was 18%, 18%, 18% and 19% respectively. The percentage of stage IV colonies in four different types of piggeries was 17%, 16%, 16% and 16% respectively. The percentage of stage V colonies in four different types of piggeries was 10%, 10%, 14% and 6% respectively. Stage VI particles (particle size &#60; 1.0 &#181;m) had the lowest numbers of culturable bacteria colonies. The percentage of stage VI colonies in the four different types of piggeries was 3%, 5%, 6% and 5%, respectively.
The air samples were collected in four different types of piggeries by using an Andersen six-stage sampler and then cultured under suitable conditions. The whole-genome DNA of the culturable bacteria collected from each particle stage was extracted and detected by bacterial 16S rDNA and fungal ITS region sequencing. A total of 91 genera and 158 species of bacteria were identified in the culturable bacteria in piggeries. The culturable bacteria community structures in four different types of piggeries, including farrowing house, pregnant sow house, fattening house and weaning house are shown in Figure 4 with data from stage I to stage VI. The content of different predominant bacterial genera is not the same among different piggeries.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58795/58795fig1v4.jpg" /> 
Figure 1: The concentration and size distribution of PM in four different months. (A) Boxplot of PM number during the study period. Each boxplot includes the Maximum, minimum, median, two quartiles and abnormal value of the database. (B) Average size distribution maps of PM. There were eighty cows in the house from September to December.&#160;The percentage of PM (&#8805; 3 &#181;m) in four months (September, October, November and December) was 0.005, 0.005, 0.002 and 0.002 respectively. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58795/58795fig1v4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58795/58795fig2v4.jpg" /> 
Figure 2: Biological analysis of bioaerosol samples collected by two samplers. (A) and (B) show the abundances of bacterial or fungal genera in bioaerosol samples obtained with different collection methods. Wetted-Wall Air Sampler represents the cyclonic aerosol sampler. Quartz Filters represents the high-volume air sampler with filters. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58795/58795fig2v4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58795/58795fig3v4.jpg" /> 
Figure 3: Average hierarchical distribution maps of culturable bacteria in four types of piggeries. The four types of piggeries are&#160;farrowing house, pregnant sow house, fattening house and weaning house. S1 to S6 represent the six particle stages (I to VI) collected by the Andersen six-stage sampler. The stages were defined by the aerodynamic diameters of the airborne particles, including stage VI (0.65-1.1 &#181;m), stage V (1.1-2.1 &#181;m), stage IV (2.1-3.3 &#181;m), stage III (3.3-4.7 &#181;m), stage II (4.7-7.0 &#181;m) and stage I (7.0 &#181;m). <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58795/58795fig3v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58795/58795fig4v3.jpg" /> 
Figure 4: Bacterial community structures with different abundances in the air samples. The air samples were collected in four different types of piggeries by using an Andersen six-stage sampler and then cultured under suitable conditions. The whole-genome DNA of the culturable bacteria in each particle stage collected by the Andersen six-stage sampler was extracted and detected by bacterial 16S rDNA sequencing. The numbers 1 to 6 in each type of piggery represent particle stages I to VI measured by the Andersen six-stage sampler. The text on the right side includes the genus name for each bacterium. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58795/58795fig4v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions at JoVE.com

Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions

Understanding the biological composition of environmental particulate matter is important for the study of its significant impacts on human health and disease spread. Here, we used three types of bioaerosol sampling methods and a biological analysis of airborne microbes to better explore airborne microbial communities under different environmental conditions.

Variable microorganisms in particulate matter (PM) under different environmental conditions may have significant impacts on human health. In this study, ...

composition-distribution-analysis-bioaerosols-under-different

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Environment

10.5K Views.  Academy of Military Medical Sciences. Understanding the biological composition of environmental particulate matter is important for the study of its significant impacts on human health and disease spread. Here, we used three types of bioaerosol sampling methods and a biological analysis of airborne microbes to better explore airborne microbial communities under different environmental conditions.

Video: Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions

Analysis of Fatty Acid Content and Composition in Microalgae

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of microalgal biomass. These fatty acids can be present in different acyl-lipid classes. Especially the fatty acids present in triacylglycerol (TAG) are of commercial interest, because they can be used for production of transportation fuels, bulk chemicals, nutraceuticals (&omega;-3 fatty acids), and food commodities. To develop commercial applications, reliable analytical methods for quantification of fatty acid content and composition are needed. Microalgae are single cells surrounded by a rigid cell wall. A fatty acid analysis method should provide sufficient cell disruption to liberate all acyl lipids and the extraction procedure used should be able to extract all acyl lipid classes.
With the method presented here all fatty acids present in microalgae can be accurately and reproducibly identified and quantified using small amounts of sample (5 mg) independent of their chain length, degree of unsaturation, or the lipid class they are part of.
This method does not provide information about the relative abundance of different lipid classes, but can be extended to separate lipid classes from each other.
The method is based on a sequence of mechanical cell disruption, solvent based lipid extraction, transesterification of fatty acids to fatty acid methyl esters (FAMEs), and quantification and identification of FAMEs using gas chromatography (GC-FID). A TAG internal standard (tripentadecanoin) is added prior to the analytical procedure to correct for losses during extraction and incomplete transesterification.

A method for the determination of fatty acid content and composition in microalgae based on mechanical cell disruption, solvent based lipid extraction, transesterification, and quantification and identification of fatty acids using gas chromatography is described. A tripentadecanoin internal standard is used to compensate for the possible losses during extraction and incomplete transesterification.

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of ...

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water&#8217;s surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males.

Use of Chironomidae Diptera Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrates are often used to monitor and assess water quality. An efficient protocol involves collections of Chironomidae surface-floating pupal exuviae (SFPE). Here, techniques for field collection, laboratory processing, slide mounting, and identification of Chironomidae SFPE are described.

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. ...

Protocols for Robust Herbicide Resistance Testing in Different Weed Species

Robust protocols to test putative herbicide resistant weed populations at whole plant level are essential to confirm the resistance status. The presented protocols, based on whole-plant bioassays performed in a greenhouse, can be readily adapted to a wide range of weed species and herbicides through appropriate variants. Seed samples from plants that survived a field herbicide treatment are collected and stored dry at low temperature until used. Germination methods differ according to weed species and seed dormancy type. Seedlings at similar growth stage are transplanted and maintained in the greenhouse under appropriate conditions until plants have reached the right growth stage for herbicide treatment. Accuracy is required to prepare the herbicide solution to avoid unverifiable mistakes. Other critical steps such as the application volume and spray speed are also evaluated. The advantages of this protocol, compared to others based on whole plant bioassays using one herbicide dose, are related to the higher reliability and the possibility of inferring the resistance level. Quicker and less expensive in vivo or in vitro diagnostic screening tests have been proposed (Petri dish bioassays, spectrophotometric tests), but they provide only qualitative information and their widespread use is hindered by the laborious set-up that some species may require. For routine resistance testing, the proposed whole plant bioassay can be applied at only one herbicide dose, so reducing the costs.

A robust and flexible approach to confirm herbicide resistance in weed populations is presented. This protocol allows the herbicide resistance levels to be inferred and applied to a wide range of weed species and herbicides with minor adaptations.

Robust protocols to test putative herbicide resistant weed populations at whole plant level are essential to confirm the resistance status. The presented ...

Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions

We demonstrate a method for sectioning sediment cores and extracting pore waters while maintaining oxygen-free conditions. A simple, inexpensive system is built and can be transported to a temporary work space close to field sampling site(s) to facilitate rapid analysis. Cores are extruded into a portable glove bag, where they are sectioned and each 1-3 cm thick section (depending on core diameter) is sealed into 50 ml centrifuge tubes. Pore waters are separated with centrifugation outside of the glove bag and then returned to the glove bag for separation from the sediment. These extracted pore water samples can be analyzed immediately. Immediate analyses of redox sensitive species, such as sulfide, iron speciation, and arsenic speciation indicate that oxidation of pore waters is minimal; some samples show approximately 100% of the reduced species, e.g. 100% Fe(II) with no detectable Fe(III). Both sediment and pore water samples can be preserved to maintain chemical species for further analysis upon return to the laboratory.

A protocol for sectioning sediment cores and extracting pore waters under anoxic conditions in order to permit analysis of redox sensitive species in both solids and fluids is presented.

We demonstrate a method for sectioning sediment cores and extracting pore waters while maintaining oxygen-free conditions. A simple, inexpensive system is ...

Reliable Method for Assessing Seed Germination, Dormancy, and Mortality under Field Conditions

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester fabric and glue can be folded and glued to construct a strip of compartments that house seeds and identifying information, while allowing contact with soil leachate, water, microorganisms, and ambient temperature. Strips may be constructed with a wide range of compartment numbers and sizes and allow the researcher to house a variety of genotypes within a single species, different species, or seeds that have experienced different treatments. As opposed to individual seed packets, strips are more easily retrieved as a unit. While replicate packets can be included within a strip, different strips can act as blocks or can be retrieved at different times for observation of seed behavior over time. We used a high temperature glue gun to delineate compartments and sealed the strips once the seed and tags identifying block and removal times were inserted. The seed strips were then buried in the field at the desired depth, with the location marked for later removal. Burrowing animal predators were effectively excluded by use of a covering of metal mesh hardware cloth on the soil surface. After the selected time interval for burial, strips were dug up and seeds were assessed for germination, dormancy and mortality. While clearly dead seeds can often be distinguished from ungerminated living ones by eye, dormant seeds were conclusively identified using a standard Tetrazolium chloride colorimetric test for seed viability.

Here we present a protocol for assessing seed survivorship, germination and dormancy under field conditions using buried, labeled seed strips and tetrazolium chloride (TZ) viability testing.

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester ...

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence the oxidizing capacity of the atmosphere through interactions with ozone and hydroxyl radicals. The main sink of NOx is the formation and deposition of nitric acid, a component of acid rain and a bioavailable nutrient. NOx is emitted from a mixture of natural and anthropogenic sources, which vary in space and time. The collocation of multiple sources and the short lifetime of NOx make it challenging to quantitatively constrain the influence of different emission sources and their impacts on the environment. Nitrogen isotopes of NOx have been suggested to vary amongst different sources, representing a potentially powerful tool to understand the sources and transport of NOx. However, previous methods of collecting atmospheric NOx integrate over long (week to month) time spans and are not validated for the efficient collection of NOx in relevant, diverse field conditions. We report on a new, highly efficient field-based system that collects atmospheric NOx for isotope analysis at a time resolution between 30 min and 2 hr. This method collects gaseous NOx in solution as nitrate with 100% efficiency under a variety of conditions. Protocols are presented for collecting air in urban settings under both stationary and mobile conditions. We detail the advantages and limitations of the method and demonstrate its application in the field. Data from several deployments are shown to 1) evaluate field-based collection efficiency by comparisons with in situ NOx concentration measurements, 2) test the stability of stored solutions before processing, 3) quantify in situ reproducibility in a variety of urban settings, and 4) demonstrate the range of N isotopes of NOx detected in ambient urban air and on heavily traveled roadways.

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx

Previous work suggests that the nitrogen isotopic composition of atmospheric nitrogen oxides might distinguish the influence of different sources in the environment. We report on an automated, mobile, field-based method for the high collection efficiency of atmospheric NOx for N isotopic analysis at an hourly time resolution.

Nitrogen oxides (NOx = NO + NO2) are a family of atmospheric trace gases that have great impact on the environment. NOx concentrations directly influence ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and stability of the suspension. In this study, a systematic step-wise approach is carried out to identify optimal sonication conditions in order to achieve a stable dispersion. This approach has been adopted and shown to be suitable for several nanomaterials (cerium oxide, zinc oxide, and carbon nanotubes) dispersed in deionized (DI) water. However, with any change in either the nanomaterial type or dispersing medium, there needs to be optimization of the basic protocol by adjusting various factors such as sonication time, power, and sonicator type as well as temperature rise during the process. The approach records the dispersion process in detail. This is necessary to identify the time points as well as other above-mentioned conditions during the sonication process in which there may be undesirable changes, such as damage to the particle surface thus affecting surface properties. Our goal is to offer a harmonized approach that can control the quality of the final, produced dispersion. Such a guideline is instrumental in ensuring dispersion quality repeatability in the nanoscience community, particularly in the field of nanotoxicology.

Here, we present a step-wise protocol for the dispersion of nanomaterials in aqueous media with real-time characterization to identify the optimal sonication conditions, intensity, and duration for improved stability and uniformity of nanoparticle dispersions without impacting the sample integrity.

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and ...

Composition and Properties of Aquafaba: Water Recovered from Commercially Canned Chickpeas

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce stable foams and emulsions, and can act as a thickener. Recently interest in this product has been enhanced through the internet where it is proposed that this solution, now called aquafaba by a growing community, can be used a replacement for egg and milk protein. As aquafaba is both new and being developed by an internet based community little is known of its composition or properties. Aquafaba was recovered from 10 commercial canned chickpea products and correlations among aquafaba composition, density, viscosity and foaming properties were investigated. Proton NMR was used to characterize aquafaba composition before and after ultrafiltration through membranes with different molecular weight cut offs (MWCOs of 3, 10, or 50 kDa). A protocol for electrophoresis, and peptide mass fingerprinting is also presented. Those methods provided valuable information regarding components responsible for aquafaba functional properties. This information will allow the development of practices to produce standard commercial aquafaba products and may help consumers select products of superior or consistent utility.

Aquafaba is a viscous juice from canned chickpea that, when stirred vigorously, produces a relatively stable white froth or foam. The primary research goal is to identify the components of aquafaba that contribute viscosifying/thickening properties using nuclear magnetic resonance (NMR), ultrafiltration, electrophoresis, and peptide mass fingerprinting.

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce ...

Stress Distribution During Cold Compression of Rocks and Mineral Aggregates Using Synchrotron-based X-Ray Diffraction

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) coupled with synchrotron X-radiation. A cube-shaped sample assembly is prepared and compressed, at room temperature, by a set of four X-ray transparent sintered diamond anvils and two tungsten carbide anvils, in the lateral and the vertical planes, respectively. All six anvils are housed within a 250-ton hydraulic press and driven inward simultaneously by two wedged guide blocks. A horizontal energy dispersive X-ray beam is projected through and diffracted by the sample assembly. The beam is commonly in the mode of either white or monochromatic X-ray. In the case of white X-ray, the diffracted X-rays are detected by a solid-state detector array that collects the resulting energy dispersive diffraction pattern. In the case of monochromatic X-ray, the diffracted pattern is recorded using a two-dimensional (2-D) detector, such as an imaging plate or a charge-coupled device (CCD) detector. The 2-D diffraction patterns are analyzed to derive lattice spacings. The elastic strains of the sample are derived from the atomic lattice spacing within grains. The stress is then calculated using the predetermined elastic modulus and the elastic strain. Furthermore, the stress distribution in two-dimensions allow for understanding how stress is distributed in different orientations. In addition, a scintillator in the X-ray path yields a visible light image of the sample environment, which allows for the precise measurement of sample length changes during the experiment, yielding a direct measurement of volume strain on the sample. This type of experiment can quantify the stress distribution within geomaterials, which can ultimately shed light on the mechanism responsible for compaction. Such knowledge has the potential to significantly improve our understanding of key processes in rock mechanics, geotechnical engineering, mineral physics, and material science applications where compactive processes are important.

We report detailed procedures for compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus coupled with synchrotron X-radiation. Such experiments allow quantification of the stress distribution within samples, that ultimately sheds light on compaction processes in geomaterials.

We report detailed procedures for performing compression experiments on rocks and mineral aggregates within a multi-anvil deformation apparatus (D-DIA) ...