Air Particulate Samples Research Articles

Analysis of 78 trace liquid crystal monomers in air by gas chromatography coupled with triple quadrupole mass spectrometry

Liquid crystal monomers (LCMs) comprise a class of organic pollutants that have garnered considerable attention because of their dioxin-like toxicity (i.e., modulation of genes) and presence in various environments. However, limited information about the identities, occurrence, and distribution of LCMs has highlighted an urgent need for a high-throughput and sensitive analytical method. In this study, we developed and validated a rapid, simple, sensitive method that involves minimal solvent consumption. The method was applied for the simultaneous detection and identification of 78 LCMs in atmospheric total suspended particulate samples (dae < 100 μm) using gas chromatography coupled with triple quadrupole mass spectrometry. The results showed high degrees of linearity with correlation coefficients >0.995 in the concentration range of 5.0–500 ng/mL. The instrumental detection limits ranged from 0.7 to 5.3 pg, and the method detection limits ranged from 0.1 to 0.9 pg/m3. The accuracy of the method was between 70 % and 130 % for most analytes, and the relative standard deviations of six replicates were <15 % at three levels of spiking (10, 50, and 200 ng/mL). The developed analytical method was applied to analyze real air particulate samples from Beijing, China. Overall, 45 LCMs ranged from 65.5 to 145.7 pg/m3, with a mean concentration of 92.5 pg/m3. Among them, (trans,trans)-4-propyl-4′-ethenyl-1,1′-bicyclohexane (PVB) was the most abundant, with an average concentration of 33.6 pg/m3. The total estimated daily intakes of LCMs for adults and children were 15.6 and 46.6 pg/kg bw/day, respectively. Accordingly, the method described herein is suitable for quantifying LCMs in atmospheric particulate samples. This study will be valuable for investigating LCM environmental occurrence, behaviors, and risk assessments.

130 Exposures to Airborne Human-Respirable Microplastic Particles

Abstract Plastics and their breakdown products, specifically microplastics, are ubiquitously present in the environment from a variety of sources. Analysis of air samples has also revealed the presence of fragmented, spherical, and fibrous plastic particles in a wide range of sizes from the submicrometer scale up to tens of micrometers in length and diameter. However, few studies have addressed the health consequences associated with exposures to airborne microplastics, specifically whether they can enter the respiratory tract, where they will deposit, and how polymer chemistry and morphology are linked to adverse health outcomes. Whether microplastics have unique toxicological properties in comparison to other particle types is also unknown. Our work has sought to address critical questions about the inhalability and respirability of microplastics in indoor and outdoor air via particle size-restricted sampling coupled with morphological assessment and estimation of plastic burdens via Nile red staining. We found Nile red-positive (putative plastic) particles in air samples from indoor environments (office, campus/household laundry rooms, 3-D printing/engineering laboratory), most of which appeared to have a fragment-like morphology. These particles represented ~1% of the total collected sample in terms of number. Importantly, these particles were also found when sampling was restricted to the human-respirable fraction (&amp;lt;4 micrometers in aerodynamic diameter), suggesting that they can reach the gas exchange region. Ongoing work is focused on identifying the polymeric species in these air samples, their distribution across particle size classes, and whether indoor and outdoor microplastic particles are similar in terms of morphology, size, and chemistry.

Optimization of the energy dispersive x‐ray fluorescence spectrometer for determination of elemental composition of air particulate matter samples

AbstractElemental composition of air particulate matter samples was determined by energy dispersive x‐ray fluorescence technique utilizing in‐house constructed secondary target excitation system. The system, based on 3 kW Mo‐anode x‐ray tube with Ni and Mo secondary targets, was operated in air at atmospheric pressure. The sensitivities of the measurement system were determined for a number of elements in the atomic number range from Z = 13 to Z = 39 (K‐series characteristic radiation) and from Z = 44 to Z = 82 (L‐series characteristic radiation). The results of measurement of reference material samples confirmed that the in‐house constructed system is well suited for analysis of air particulate matter deposits on filter substrate with application of the thin‐layer sample model, with sufficiently good detection limits also for low‐Z elements such as Al, Si, P, S, and Cl.

Global airborne bacterial community—interactions with Earth’s microbiomes and anthropogenic activities

Airborne bacteria are an influential component of the Earth's microbiomes, but their community structure and biogeographic distribution patterns have yet to be understood. We analyzed the bacterial communities of 370 air particulate samples collected from 63 sites around the world and constructed an airborne bacterial reference catalog with more than 27 million nonredundant 16S ribosomal RNA (rRNA) gene sequences. We present their biogeographic pattern and decipher the interlacing of the microbiome co-occurrence network with surface environments of the Earth. While the total abundance of global airborne bacteria in the troposphere (1.72 × 1024 cells) is 1 to 3 orders of magnitude lower than that of other habitats, the number of bacterial taxa (i.e., richness) in the atmosphere (4.71 × 108 to 3.08 × 109) is comparable to that in the hydrosphere, and its maximum occurs in midlatitude regions, as is also observed in other ecosystems. The airborne bacterial community harbors a unique set of dominant taxa (24 species); however, its structure appears to be more easily perturbed, due to the more prominent role of stochastic processes in shaping community assembly. This is corroborated by the major contribution of surface microbiomes to airborne bacteria (averaging 46.3%), while atmospheric conditions such as meteorological factors and air quality also play a role. Particularly in urban areas, human impacts weaken the relative importance of plant sources of airborne bacteria and elevate the occurrence of potential pathogens from anthropogenic sources. These findings serve as a key reference for predicting planetary microbiome responses and the health impacts of inhalable microbiomes with future changes in the environment.

Application of a handheld X-ray fluorescence analyzer for the quantification of air particulate matter on Teflon filters

Elemental characterization of air particulate matter samples through the application of X-ray fluorescence (XRF) spectrometry is a widespread analytical technique. This work presents the optimization and calibration methodology of a handheld XRF spectrometer and its subsequent application in elemental quantification of unknown particulate matter samples. The optimization of the handheld spectrometer was conducted through investigation of the elemental sensitivities and Limits of Detection (LoD) at variable excitation conditions (voltage, filter). Accordingly, five optimum operating conditions were obtained each one targeted in different elemental range: 1) Z = 11–12, 2) 12 < Z < 17, 3) 16 < Z < 23, 4) 22 < Z < 31 and 5) 30 < Z < 92. Subsequently, a number of reference (5 multi-element and 42 compound/single-element) materials were used to obtain calibration curves for 24 elements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Pb). Weighted least-square regression analysis was implemented to best fit the experimentally measured intensities with mass loadings resulting for most of the elements to high correlations (Pearson r > 0.98) and low statistical error. In addition, intercomparison of the elemental concentrations from 28 unknown particulate matter samples between the handheld and a benchtop XRF spectrometer showed good agreement.

Winter and spring variation in sources, chemical components and toxicological responses of urban air particulate matter samples in Guangzhou, China

The sources and chemical components of urban air particles exhibit seasonal variations that may affect their hazardousness to human health. Our aims were to investigate winter and spring variation in particulate matter (PM) sources, components and toxicological responses of different PM size fractions from samples collected in Guangzhou, China. Four size-segregated PM samples (PM10–2.5, PM2.5–1, PM1–0.2, and PM0.2) were collected separately during winter (December 2017 and January 2018) and spring (March 2018). All PM samples were analyzed for chemical components and characterized by source. RAW 264.7 macrophages were exposed to four doses of PM samples for 24 h. Cytotoxicity, oxidation, cell cycle, genotoxicity and inflammatory parameters were tested. PM concentrations were higher in the winter samples and caused more severe cytotoxicity and oxidative damage than to PM in the spring samples. PM in winter and spring led to increases in cell cycle and genotoxicity. The trends of size-segregated PM components were consistent in winter and spring samples. Metallic elements and PAHs were found in the largest concentrations in winter PM, but ions were found in the largest concentrations in spring PM. metallic elements, PAHs and ions in size-segregated PM samples were associated with most toxicological endpoints. Soil dust and biomass burning were the main sources of PM in winter, whereas traffic exhaust and biomass burning was the main source with of spring PM. Our results suggest that the composition of PM samples from Guangzhou differed during winter and spring, which led to strong variations in toxicological responses. The results demonstrate the importance of examining a different particle sizes, compositions and sources across different seasons, for human risk assessment.

Concordance of SARS-CoV-2 RNA in Aerosols From a Nurses Station and in Nurses and Patients During a Hospital Ward Outbreak

Aerosol-borne SARS-CoV-2 has not been linked specifically to nosocomial outbreaks. To explore the genomic concordance of SARS-CoV-2 from aerosol particles of various sizes and infected nurses and patients during a nosocomial outbreak of COVID-19. This cohort study included patients and nursing staff in a US Department of Veterans Affairs inpatient hospital unit and long-term-care facility during a COVID-19 outbreak between December 27, 2020, and January 8, 2021. Outbreak contact tracing was conducted using exposure histories and screening with reverse transcriptase-polymerase chain reaction (RT-PCR) for SARS-CoV-2. Size-selective particle samplers were deployed in diverse clinical areas of a multicampus health care system from November 2020 to March 2021. Viral genomic sequences from infected nurses and patients were sequenced and compared with ward nurses station aerosol samples. SARS-CoV-2. The primary outcome was positive RT-PCR results and genomic similarity between SARS-CoV-2 RNA in aerosols and human samples. Air samplers were used to detect SARS-CoV-2 RNA in aerosols on hospital units where health care personnel were or were not under routine surveillance for SARS-CoV-2 infection. A total of 510 size-fractionated air particle samples were collected. Samples representing 3 size fractions (>10 μm, 2.5-10 μm, and <2.5 μm) obtained at the nurses station were positive for SARS-CoV-2 during the outbreak (3 of 30 samples [10%]) and negative during 9 other collection periods. SARS-CoV-2 partial genome sequences for the smallest particle fraction were 100% identical with all 3 human samples; the remaining size fractions shared >99.9% sequence identity with the human samples. Fragments of SARS-CoV-2 RNA were detected by RT-PCR in 24 of 300 samples (8.0%) in units where health care personnel were not under surveillance and 7 of 210 samples (3.3%; P = .03) where they were under surveillance. In this cohort study, the finding of genetically identical SARS-CoV-2 RNA fragments in aerosols obtained from a nurses station and in human samples during a nosocomial outbreak suggests that aerosols may have contributed to hospital transmission. Surveillance, along with ventilation, masking, and distancing, may reduce the introduction of community-acquired SARS-CoV-2 into aerosols on hospital wards, thereby reducing the risk of hospital transmission.

A Snapshot of Antibiotic Resistances in Air Particulate of a Provincial Capital City, Indonesia

Bacteria may become resistant to antibiotics due to gene mutation or adopting resistance genes from other bacteria via horizontal gene transfer. The existence of toxic substances to bacteria, such as antibiotics, biocides, and heavy metals, may influence the pathway into the genome. This study aimed to detect the presence of antibiotic-resistance bacteria in air particulates in Makassar - a provincial capital located in Indonesia with a low to moderate air quality index (AQI). We determined the correlations between antibiotic resistance (resistance rate, RR) and the heavy-metal concentrations in the air particulates. Air particulate samples were taken from seven locations in the summer (Dry Season: July - August 2019). We analyzed the concentration of As, Cu, and Zn of the air particulates and determined RR from presumptive Escherichia coli (E. coli) isolated from the air particulates. We estimated the RR towards five antibiotics with different mechanisms of action: amoxicillin-clavulanate, chloramphenicol, amikacin, norfloxacin, and trimethoprim. The concentrations of the heavy metals were relatively low, ranging from (µg/Nm3) 0.001 – 0.009 for As, 0.001 – 0.003 for Cu, and 0.007 to 0.783 for Zn. We observed different antibiotic resistance at various locations, ranging from 25% to 100% RR. While there were indications of possible antibiotic resistance patterns in the different areas sampled, the power of this perspective snapshot was insufficient to make statistically valid generalizations.

Temporal trends of phosphorus in urban atmospheric aerosols

Air particulate samples collected from a Canadian urban area station showed the seasonal trend of the phosphorus with peak levels observed for April–June periods and levels not significantly changed between 2007 and 2015. The phosphorus measured as total phosphorus (TP) in digested aqueous extracts showed an exponential increase with daily temperature (R2 = 0.544, N = 474), with the best correlation observed for the 2010 subset (R2 = 0.727, N = 55). The temperature correlation was not observed with the total suspended particles (TSP). Longer dry periods during spring to summer months favored a higher P level on aerosols. The temperature and precipitation pattern dependence indicate a possible climate change influence on the aerosol P levels. The unchanged yearly aerosol TP content does not directly reflect the dropping trend observed in surface water after 1990s from the same area during spring to summer period.

Winter and Spring Variation in Sources, Chemical Components and Toxicological Responses of Urban Air Particulate Matter Samples in Guangzhou, China

Winter and Spring Variation in Sources, Chemical Components and Toxicological Responses of Urban Air Particulate Matter Samples in Guangzhou, China

X-ray fluorescence analysis of air particulate matter generated at a welding site

The air particulate matter generated during welding operations is a major health concern for the welders as they trigger respiratory diseases. The information on elemental composition of the air particulate matter is required to know the toxicity as it depends on the constituent elements. We report the rapid analysis of air particulate matter at welding site, collected on whatman-41 filter paper. Internal standard method was used for the quantification of the elements both in energy dispersive X-ray fluorescence (EDXRF) and total reflection X-ray fluorescence (TXRF) spectrometry. In EDXRF, the sample was found to be thin for the elements Z > 29 and intermediate thickness for the elements 28 ≤ Z ≤ 19 and thick for elements of Z ≤ 17. About 17 elements were detected in air particulate matter and out of which Al, Si, Ca and Fe share the highest contribution. The composition of particulate matter is modulated by the composition of the welding material and the adjacent construction activities. The combined uncertainty in XRF was evaluated by identifying all the uncertainty sources. The study showed fast, non-destructive analysis capability of EDXRF and TXRF as an excellent micro-analytical technique for the air particulate samples.

Detecting the relations between meteorological elements and alpha and beta activity concentration at Al-Tuwaitha site, Baghdad

In this study, 50 samples of air particulates collected from different places in- and outside the Al-Tuwaitha nuclear site, south of Baghdad were used to measure daily gross alpha and beta activity concentrations (AAC and BAC) for the period from 28 January 2015 to 13 April 2017. At the same time, several meteorological factors such as air temperature, wind speed, wind direction, air pressure, relative humidity, and solar radiation, were also measured. Air stability classes were also derived from wind speed and solar radiation. AAC/BAC variations in the surface air layer were discussed in relation to these factors. The results show that there are inverse relations between AAC/BAC and wind speed and temperature, linear relations between AAC/ABC and air pressure and weak relations between AAC/BAC and relative humidity and solar radiation. Lastly, AAC/BAC measurements in unstable air are as large as in neutral air.

Positive no-touch surfaces and undetectable SARS-CoV-2 aerosols in long-term care facilities: An attempt to understand the contributing factors and the importance of timing in air sampling campaigns

BackgroundLong-term care facilities (LTCF) are environments particularly favorable to coronavirus disease (SARS-CoV-2) pandemic outbreaks, due to the at-risk population they welcome and the close proximity of residents. Yet, the transmission dynamics of the disease in these establishments remain unclear.MethodsAir and no-touch surfaces of 31 rooms from 7 LTCFs were sampled and SARS-CoV-2 was quantified by real-time reverse transcription polymerase chain reaction (RT-qPCR).ResultsAir samples were negative but viral genomes were recovered from 20 of 62 surface samples at concentrations ranging from 13 to 36,612 genomes/surface. Virus isolation (culture) from surface samples (n = 7) was negative.ConclusionsThe presence of viral RNA on no-touch surfaces is evidence of viral dissemination through air, but the lack of airborne viral particles in air samples suggests that they were not aerosolized in a significant manner during air sampling sessions. The air samples were collected 8 to 30 days after the residents’ symptom onset, which could indicate that viruses are aerosolized early in the infection process. Additional research is needed to evaluate viral viability conservation and the potential role of direct contact and aerosols in SARS-CoV-2 transmission in these institutions.

Concentrations, particle-size distributions, and dry deposition fluxes of aerosol trace elements over the Antarctic Peninsula in austral summer

Abstract. Size-segregated particulate air samples were collected during the austral summer of 2016–2017 at Palmer Station on Anvers Island, western Antarctic Peninsula, to characterize trace elements in aerosols. Trace elements in aerosol samples – including Al, P, Ca, Ti, V, Mn, Ni, Cu, Zn, Ce, and Pb – were determined by total digestion and a sector field inductively coupled plasma mass spectrometer (SF-ICP-MS). The crustal enrichment factors (EFcrust) and k-means clustering results of particle-size distributions show that these elements are derived primarily from three sources: (1) regional crustal emissions, including possible resuspension of soils containing biogenic P, (2) long-range transport, and (3) sea salt. Elements derived from crustal sources (Al, P, Ti, V, Mn, Ce) with EFcrust&lt;10 were dominated by the coarse-mode particles (&gt;1.8 µm) and peaked around 4.4 µm in diameter, reflecting the regional contributions. Non-crustal elements (Ca, Ni, Cu, Zn, Pb) showed EFcrust&gt;10. Aerosol Pb was primarily dominated by fine-mode particles, peaking at 0.14–0.25 µm, and likely was impacted by air masses from southern South America based on air mass back trajectories. However, Ni, Cu, and Zn were not detectable in most size fractions and did not present clear size patterns. Sea-salt elements (Ca, Na+, K+) showed a single-mode distribution and peaked at 2.5–4.4 µm. The estimated dry deposition fluxes of mineral dust for the austral summer, based on the particle-size distributions of Al measured at Palmer Station, ranged from 0.65 to 28 mg m−2 yr−1 with a mean of 5.5±5.0 mg m−2 yr−1. The estimated dry deposition fluxes of the target trace elements in this study were lower than most fluxes reported previously for coastal Antarctica and suggest that atmospheric input of trace elements through dry deposition processes may play a minor role in determining trace element concentrations in surface seawater over the continental shelf of the western Antarctic Peninsula.

Sensitivity Calibrations of K- and L-shell X-ray Lines for Elemental Analysis of Air Particulate Samples Using a Handheld XRF Spectrometer

The portability, ease of use, relative lower cost of procurement and simple maintenance of a handheld X-ray fluorescence analyzer makes it a potential alternative for air particulate analysis especially in highly polluted and economically disadvantaged regions of the world. Thus, this study assessed the performance of such analyzer in characterizing aerosol laden filters. Spectra of Certified Reference Materials (NIST 2783 CRM for aerosol filters) measured with a handheld X-ray fluorescence analyzer were calibrated and fitted using iterative nonlinear least-square fitting procedure provided by the International Atomic Energy Agency-Quantitative X-ray Analysis System. Elemental sensitivity calibration curves, method detection limits, uncertainty estimates of K- and L- X-ray lines in the elemental range 18 < Z < 39 and 47 < Z < 83 respectively were determined for four excitation conditions [High (Hi), Main (Ma), Light (Li) and Low (Lo)]. Signal counts for $$K_{\alpha {\text{and}} \beta }$$ (Ni, Zn, Se) and $$L_{\alpha {\text{and}} \beta }$$ (Pt, Te, Au) lines of the CRM’s were used to validate the analytical method. Concentrations values were evaluated for trueness and precision. Hi excitation condition has the least sensitivity (5 times less than Ma, 30–40 times less than Lo and more than 100 times lower than Li) within varying range of atomic number. However, Hi (R2 = 0.99) and Ma (R2 = 0.96) condition had the best overall trueness and precision score within an acceptable relative standard deviation ≤ 6% for the six CRM’s evaluated.

Plasticizer contamination in the urine and hair of preschool children, airborne particles in kindergartens, and drinking water in Hong Kong.

Common plasticizers and their alternatives are environmentally ubiquitous and have become a global problem. In this study, common plasticizers (phthalates and metabolites) and new alternatives [bisphenol analogs, t-butylphenyl diphenyl phosphate (BPDP), and bisphenol A bis(diphenyl phosphate) (BDP)] were quantified in urine and hair samples from children in Hong Kong, drinking water (tap water/bottled water) samples, and airborne particle samples from 17 kindergartens in Hong Kong. The results suggested that locally, children were exposed to various plasticizers and their alternatives. High concentrations of BPDP and BDP were present in urine, hair, tap water, bottled water, and air particulate samples. The geometric mean (GM) concentrations of phthalate metabolites in urine samples (126-2140ng/L, detection frequencies<81%) were lower than those detected in Japanese and German children in previous studies. However, a comparison of the estimated daily intake values for phthalates in tap water [median: 10.7-115ng/kg body weight bw/day] and air particles (median: 1.23-7.39ng/kgbw/day) with the corresponding reference doses indicated no risk. Bisphenol analogs were detected in 15-64% of urine samples at GM concentrations of 5.26-98.1ng/L, in 7-74% of hair samples at GM concentrations of 57.5-2390pg/g, in 59-100% of kindergarten air samples at GM concentrations of 43.1-222pg/m3, and in 33-100% of tap water samples at GM concentrations of 0.90-3.70ng/L. A significant correlation was detected between the concentrations of bisphenol F in hair and urine samples (r=0.489, p<.05). The estimated daily urinary excretion values of bisphenol analogs suggest that exposure among children via tap water intake and airborne particle inhalation in kindergartens cannot be ignored in Hong Kong.

Occurrence and distribution of typical semi-volatile organic chemicals (SVOCs) in paired indoor and outdoor atmospheric fine particle samples from cities in southern China.

Interest in the potential human health of semi-volatile organic chemicals (SVOCs) in indoor and outdoor environments has made the exposure assessment and source appointment a priority. In this study, paired indoor and outdoor atmospheric fine particle (PM2.5) samples were collected from 15 homes representing five typical urban cities in southern China. Four typical SVOCs, including 16 congeners of polycyclic aromatic hydrocarbons (PAHs), 13 congeners of organophosphorus flame retardants (OPFRs) and 8 congeners of polybrominated diphenyl ethers (PBDEs), as well as tetrabromobisphenol A (TBBPA) and its three debrominated congeners were analyzed. The highest total concentrations were found for OPFRs, followed by PAHs, PBDEs, and TBBPA. The indoor concentrations of two alkyl-OPFR isomers, tributylphosphate (TBP) and tris (2-butoxyethyl) phosphate (TBEP), were 4.3 and 11 times higher, respectively, than those of outdoors (p<0.05). Additionally, the ratios of indoor to outdoor concentrations of alkyl-OPFR isomers varied greatly, suggesting that these compounds originated mainly from different household goods and products used in individual homes. The outdoor concentrations of PAHs and highly brominated PBDEs (BDE-209) typically exceeded the indoor concentrations. Significant correlations were also found between indoor and outdoor PM2.5 samples for PAHs and BDE-209, indicating that outdoor sources such as vehicle exhausts and industrial activities strongly influence their atmospheric occurrence. Additionally, the concentrations of debrominated TBBPA derivatives were higher than those of TBBPA in over 33% of both indoor and outdoor air particle samples. Nevertheless, our results indicated that inhalation exposure to typical SVOCs posed no non-carcinogenic risks to the human body. Although we observed notable differences in the sources, occurrences, and distributions of typical SVOC congeners, more studies using matched samples are still needed to unambiguously identify important indoor and outdoor sources in order to accurately assess the contributions of different sources and the associated human exposure risks.

Air pollution caused by phthalates and cyclic siloxanes in Hanoi, Vietnam: Levels, distribution characteristics, and implications for inhalation exposure

Contamination status and distribution characteristics of ten phthalic acid esters (PAEs) and three cyclic volatile methyl siloxanes (CSs) were determined in the air (gas and particle) samples collected from indoor and outdoor spaces of several chemistry laboratories, offices, and homes from urban area of Hanoi, the capital city of Vietnam. Air concentrations of Σ10PAEs (median 688; range 142–2390 ng m−3) and Σ3CSs (171; not detected–1100 ng m−3) in the indoor air samples were significantly higher than those measured in the outdoor ones (Σ10PAEs: 161; 34.1–515 ng m−3 and Σ3CSs: 43.2; not detected–258 ng m−3), partly suggesting the predominance of indoor emission sources of these substances. There were significant positive correlations in total air concentrations of phthalates and siloxanes between the indoor and outdoor air samples. The most predominant phthalates were diethyl-, di-n-butyl-, diisobutyl-, and di(2-ethylhexyl) phthalate. For siloxanes, D5 and D6 were more abundant than D4 in most samples. Except for di(2-ethylhexyl)- and di-n-octyl phthalate in some locations, almost all the compounds were likely associated with gas phase than particle phase. Daily intake doses of airborne phthalates and siloxanes, and non-cancer and cancer risks of selected phthalates were estimated for different exposure groups such as adults, children, and university subjects (e.g., laboratory staff and students), indicating relatively low levels of risk.

Polycyclic aromatic hydrocarbons volatilized from two polluted lagoons on Red Sea east coast: levels, sources, meteorological effects, and gas–particle partitioning

Polycyclic aromatic hydrocarbons (PAHs) in contaminated waterbodies can cause serious pollution to the adjacent atmosphere through volatilization. Gas–particle partitioning of PAHs controls the atmospheric concentrations of these pollutants. PAH levels in gaseous and particulate air samples were investigated near two polluted lagoons along the eastern coast of the Red Sea. Gas chromatography–mass spectrometry was used to analyze nine priority parent PAHs and nine methylated PAHs. Total gaseous and particulate PAHs ranged from 12.2 to 397.5 ng m−3, with an average of 125.6 ± 117.3 ng m−3, which was nearly 10-fold higher than that found in a previous study. Particulate PAHs (ranging from 0.04 to 16.32 ng m−3, with an average of 2.56 ± 1.71 ng m−3) contributed to less than 20% of the total atmospheric PAHs. Applied diagnostic indices showed that gasoline emissions were the main sources of PAHs in the lagoons’ atmosphere. Multiparameter statistical analyses indicated that wind speed strongly affected the distribution of atmospheric PAHs. The average PAH gas–particle partitioning coefficient was 0.49 m3 µg−1 (ranging from 2.1 × 10−8 to 51.23 m3 µg−1) and was significantly correlated with supercooled liquid vapor pressure. In addition to the effects of meteorological parameters and vehicle exhausts in the study area, the discharge of wastewater in the lagoons elevated PAH levels in the surrounding atmosphere.

Source analysis of heavy metal elements of PM2.5 in canteen in a university in winter

Indoor air particulate samples were collected in the first floor of the Xingyuan canteen of Nanjing University of Science and Technology (NJUST) in Nanjing during the winter season. Meanwhile, outdoor air particulate samples were collected on the roof of a building that is 28 m away from the canteen. The mean PM2.5 (fine particulate matter) concentrations of the indoor and outdoor samples were found to be 99.43 and 103.09 μg/m3, respectively. Through correlation analysis, it was found that more than half of the PM2.5 penetrates from the adjacent outdoor area into the canteen. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the concentration of heavy metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in the PM2.5, revealing that the concentration of As, Mn and Cd in the canteen exceeded health standards. Positive Matrix Factorization (PMF) was used to identify the pollution sources of the PM2.5-related heavy metals in the canteen, revealing the following sources in descending order: cooking (34.7%), fuel combustion (28.9%), canteen kitchenware (14.4%), transportation (9.6%), indoor building materials (8%) and the Earth's crust (4.4%). Enrichment factor analysis revealed the source of the excessive As in the canteen to be the outdoor air and the cooking of a large amount of meat in the canteen. The outdoor air contained excessive As and infiltrated the canteen. In addition, the Earth's crust was found to be the source of excessive Mn in the canteen, while transportation was the cause of excessive Cd.