Total Particulate Matter Concentrations Research Articles

Retrieval of particulate organic carbon concentration in Erhai Lake using sentinel-3 remote sensing data

ABSTRACT Particulate organic carbon (POC) plays a crucial role in the carbon cycle of inland lake ecosystems. The utilization of remote sensing satellite data provides an effective approach for monitoring the temporal and spatial variations in POC concentration within inland water. However, Erhai Lake, situated in the unique natural environment of the Yunnan-Kweichow Plateau, poses distinct challenges due to the complex and diverse origin of its water quality elements. Existing methods face difficulties in accurately detecting POC concentration in Erhai Lake. In this study, 112 water samples and 574 in-situ remote sensing reflectance curves were collected from Erhai Lake during April, May, and June 2023. The analysis of the optical characteristics of the water in Erhai Lake revealed the closest relationship between the concentration of total particulate matter and POC. Consequently, a POC concentration inversion algorithm was developed, utilizing bands 8, 12, and 16 of Sentinel-3 Ocean and Land Colour Instrument (OLCI). Various POC concentration inversion algorithms were evaluated utilizing a separate dataset. The results indicate that the three-band method offers superior accuracy in POC concentration inversion for Erhai Lake, with a root mean square error (RMSE) of 0.13 mg/L and a mean absolute percentage error (MAPE) of 28.80%. The three-band method was effectively applied to OLCI images from April, May, and June 2023, enabling the analysis of the spatiotemporal distribution of POC in Erhai Lake.

Elevated Exposure to Air Pollutants Accelerates Primary Glomerular Disease Progression

IntroductionEnvironmental contributors to kidney disease progression remain elusive. We explored how residential air pollution impacts disease progression in patients with primary glomerulopathies. MethodsNephrotic Syndrome Study Network (NEPTUNE) and CureGlomerulonephropathy (CureGN) participants with residential census tract data and ≥2 years of follow-up were included. Using Cox proportional hazards models, the associations per doubling in annual average baseline concentrations of total particulate matter with diameter ≤ 2.5 μm (PM2.5) and its components, black carbon, and sulfate, with time to ≥40% decline in estimated glomerular filtration rate (eGFR) or kidney failure were estimated. Serum tumor necrosis factor levels and kidney tissue transcriptomic inflammatory pathway activation scores were used as molecular markers of disease progression. ResultsPM2.5, black carbon, and sulfate exposures were comparable in NEPTUNE (n=228) and CureGN (n=697). In both cohorts, participants from areas with higher levels of pollutants had lower eGFR, were older and more likely self-reported racial and ethnic minorities. In a fully adjusted model combining both cohorts, kidney disease progression was associated with PM2.5 (adjusted HR 1.55 [95% CI:1.00, 2.38], p=0.0489) and black carbon (adjusted HR 1.43 [95% CI:0.98, 2.07], p=0.0608) exposure. Sulfate and PM2.5 exposure were positively correlated with serum tumor necrosis factor (TNF) (p=0.003) and interleukin-1β levels (p=0.03), respectively. Sulfate exposure was also directly associated with transcriptional activation of the TNF and JAK-STAT signaling pathways in kidneys (r=0.55-0.67, p-value <0.01). ConclusionElevated exposure to select air pollutants is associated with increased risk of disease progression and systemic inflammation in patients with primary glomerulopathies (word count: 248).

Particle emissions from heated tobacco products.

This study determines the particle emissions from five heated tobacco products (HTPs). An aethalometer is used for the determination of black carbon (BC) and an aerosol monitor for total particulate matter (PM) concentration and also PM fractions (1, 2.5, 4, and 10 μm) in the mainstream emissions of 5 HTPs: IQOS, LIL, PULZE, ILUMA, and GLO. Fifteen different flavors were used, five sticks per flavor, which were smoked using a peristaltic pump under both ISO and Canadian smoking regimes. The method repeatability was determined using 15 sticks of one flavor for each brand for each smoking regime. All HTPs emit particles, and more than 99.7% of the particles emitted are smaller than 1 μm. Both BC and PM emissions show quite low repeatability. Particle emissions increase in relation to the heating temperature and the intensity smoking regime, and are depending on the flavor used. BC corresponds to a small percentage of total PM. Although HTPs are promoted as products of reduced risk compared to conventional cigarettes, high particle concentrations are detected in their emissions, depending on the smoking regime, the flavor used, and the operation parameters. PM emissions vary significantly between different brands under the ISO smoking regime, probably due to the heating temperature. In contrast, PM emissions under the Canadian smoking regime do not vary significantly between different brands. This could probably be attributed to the fact that increased puff frequency does not allow the device to cool down between puffs, resulting in an increase in PM emissions for all the brands, but not dependent on the maximum heating temperature of the device. BC emissions only consist of a very small fraction of PM and do not vary significantly between different brands under both smoking regimes.

Traceable determination of metal composition of tyres using tandem ICP-MS and benchmarking of emissions inventories.

Non-exhaust emissions are becoming of increasing significance with respect to total particulate matter (PM) concentrations in ambient air. Of particular interest is the metal content of this PM since metallic compounds are well known to have toxic effects on human health and the environment. In this study, 'bottom-up' annual tyre wear emission rates were estimated and compared to top-down' emissions declared by the UK; it was calculated that between 14 and 25 tonnes of Zn entered the atmosphere in PM10 in 2020. The emission rates were estimated using a cost-effective, simple but robust validated method for analysis of the metals in tyres using tandem inductively coupled plasma mass spectrometry (ICP-MS/MS) for the first time, involving minimal offline sample preparation. This method was applied to five different tyre makes and brands, all available for sale in the UK, and the uncertainty of each measurement was determined. Traceability was ensured in all methods and novel validation techniques were applied due to lack of available reference materials. Zn was found to be the largest metal component in all tyres with a mass fraction of approximately 10 mg g-1. The mean mass fractions of metals in the tyres decreased in the order of Zn > Al > Fe > Mg > Ti > Pb > Cu > Ba > Ni. Significant differences in composition were found between the five tyres. The relative expanded uncertainties of the metals measurements ranged from 4 to 21%, with elements of higher mass fraction resulting in lower uncertainties. These findings will contribute to assessing current and future air quality challenges and will help to inform regulation surrounding non-exhaust emissions.

Impact of inhalation exposure to cigarette smoke on the pathogenesis of pulmonary hypertension primed by monocrotaline in rats.

Extensive, long-term exposure to cigarette smoke (CS) was recently suggested to be a risk factor for pulmonary hypertension, although further validation is required. The vascular effects of CS share similarities with the etiology of pulmonary hypertension, including vascular inflammation and remodeling. Thus, we examined the influence of CS exposure on the pathogenesis of monocrotaline (MCT)-induced pulmonary hypertension, hypothesizing that smoking might accelerate the development of primed pulmonary hypertension. CS was generated from 3R4F reference cigarettes, and rats were exposed to CS by inhalation at total particulate matter concentrations of 100-300 μg/L for 4h/day, 7days/week for 4weeks. Following 1 week of initial exposure, rats received 60 mg/kg MCT and were sacrificed and analyzed after an additional 3weeks of exposure. MCT induced hypertrophy in pulmonary arterioles and increased the Fulton index, a measure of right ventricular hypertrophy. Additional CS exposure exacerbated arteriolar hypertrophy but did not further elevate the Fulton index. No significant alterations were observed in levels of endothelin-1 and vascular endothelial growth factor, or in hematological and serum biochemical parameters. Short-term inhalation exposure to CS exacerbated arteriolar hypertrophy in the lung, although this effect did not directly aggravate the overworked heart under the current experimental conditions.

Effect of third-party components on emissions from a pod style electronic cigarette.

Electronic nicotine delivery systems (ENDS) have been associated with a dramatic increase in youth becoming addicted to nicotine following decades-long decline in cigarette smoking uptake. The United States Food and Drug Administration, Center for Tobacco Products (FDA/CTP) is responsible for regulating devices and consumable materials associated with ENDS. State and federal regulations regarding flavoring compounds in ENDS liquids (e-liquids) may be circumvented when vendors market refillable reservoirs side-by-side with noncompliant e-liquids. This study investigated the effect of third-party refillable versus manufacturer-supplied single-use reservoirs on total particulate matter (TPM) and nicotine emissions. The maximum TPM yield per puff was 5.6 times higher for the third-party (Blankz) reservoir (12.4 mg/puff) in comparison with the manufacturer's (JUUL) reservoir (2.2 mg/puff), whereas the maximum TPM concentration was over 7 times higher for third party (0.200 mg/ml) versus manufacturer (0.028 mg/ml) pod. The third-party pod was tested with nicotine concentrations ranging from 0% to 4%. The mass ratio of nicotine present in the aerosol (mg Nic/mg TPM) was found to be approximately the same as the mass ratio of the e-liquid (mg Nic/mg e-liquid) for both pods and all 3 nicotine laden e-liquids tested. Toxicant exposure may increase when consumers use third-party pods with ENDS devices. Refillable reservoirs are a significant barrier to regulatory restrictions on potentially toxic additives to e-liquids. It is recommended FDA/CTP require emissions characterization of third-party reservoirs used with each ENDS they are compatible with and should be required to demonstrate no increased potential toxicant exposure in comparison with manufacturer-provided reservoirs.

An iterative optimization scheme to accommodate inequality constraints in air quality geostatistical estimation of multivariate PM

The kriging-based estimation of the different types of atmospheric particulate matter (PM) pollutions defined in the air quality regulation raises some operational problems because the (co)kriging equations are obtained by minimizing a linear combination of the estimation variances subject to unbiasedness constraints. As a consequence, the estimation process can result in total PM10 concentrations that are less than the PM2.5 concentrations which would be physically impossible. In a previous publication, it was shown that a convenient external drift modeling can reduce the number of spatial locations where the inequality constraint is not satisfied, without completely solving the problem. In this work, the formulation of the cokriging system is modified, inspired by previous works focusing on positive kriging. The introduction of additional constraints on the cokriging weights are presented, leading to a unique and optimal solution to the problem of cokriging under inequality constraints between two variables. Some computational and algorithmic details are introduced. An evaluation of the penalized cokriging is provided by using the European PM monitoring sites dataset: some maps and performance scores are given to assess the relevance of our iterative optimization scheme.

Occupant's health and energy use in an office building: A sensor-enabled life cycle assessment

Indoor air quality (IAQ) has an important impact on human health and productivity. For this reason, its integration into the life cycle assessment (LCA) framework contributes to sustainably manage the operation of a building and improve the living and working conditions in homes and offices. In this study, the damages on human health caused by IAQ are quantified starting from the air pollutants’ concentrations recorded by dedicated sensors placed in an office building located in Luxembourg. Data on concentrations of total volatile organic compounds, particulate matter and radon are combined with estimated occupancy and intake fractions to calculate the total human health impact expressed in Disability Adjusted Life Years (DALYs). The impacts of indoor air quality on human health prove to be relevant, representing one tenth of the score obtained in a conventional LCA on the operational phase of the building. It can be highlighted that radon, a substance usually overlooked in IAQ studies, had the highest impact, contributing to 46% of the impact caused by exposure to indoor pollutants. The heating loads and the influence of different air exchange rates are analyzed starting from a simplified energy model of the building fed with real energy use data. LCA has proven a useful tool to analyze this trade-off in the operation of the building, where it is found that doubling the ventilation rate would reduce the impact of indoor pollutants on human health by 34% while resulting in less than 1% increase in the total energy demand over the studied period.

Modelling the European wind-blown dust emissions and their impact on particulate matter (PM) concentrations

Abstract. Wind-blown dust (WBD) emitted by the Earth’s surface due to sandblasting can potentially have important effects on both climate and human health via interaction with solar and thermal radiation, reducing air quality. Apart from the main dust “centres” around the world, like deserts, dust can be emitted from partly vegetated mid- and high-latitude areas like Europe if certain conditions are suitable (strong winds, bare soil, reduced soil moisture, etc.). Using a wind-blown dust model (WBDUST) along with a chemical transport model (Comprehensive Air-quality model with Extensions, CAMx) coupled to a regional climate model (Weather Research and Forecasting, WRF), this study is one of the first to provide a model-based estimate of such emissions over Europe as well as the long-term impact of WBD emissions on the total particulate matter (PM) concentrations for the 2007–2016 period. We estimated average WBD emissions of about 0.5 and 1.5 Mgyr-1km-2 in fine and coarse modes. Maximum emissions occur over Germany, where the average seasonal fine- and coarse-mode emission flux can reach 0.5 and 1 gs-1km-2, respectively. Large variability is seen in the averaged daily emissions with values of up to 2 gs-1km-2 for the coarse-mode aerosol on selected days. The WBD emissions increased the modelled winter PM2.5 and PM10 concentrations by up to 10 and 20 µg m−3, respectively, especially over Germany, where the highest emissions occur. The impact on other seasons is lower. Much higher impacts are modelled, however, on selected days when occasionally the urban PM2.5 and PM10 concentrations are increased by more than 50 and 100 µg m−3. The comparison with measurements revealed that if WBD is considered, the summer biases are reduced; however, the winter PM is overestimated even more greatly (so the bias increases). We identified a strong overestimation of the modelled wind speed (the maximum daily wind is almost 2 times higher in WRF than the measured ones) suggesting that WBD emissions are also overestimated – hence the enhanced winter PM biases. Moreover, we investigated the secondary impacts of the crustal composition of fine WBD particles on secondary inorganic aerosol (SIA): sulfates (PSO4), nitrates (PNO3) and ammonium (PNH4). Because the water pH value, and thus the uptake of the gaseous precursors of SIA, is perturbed and because the increased aerosol surface serves as an oxidation site, we modelled seasonal PSO4 and PNO3 concentrations increased by up to 0.1 µg m−3 and PNH4 ones decreased by up to −0.05 µg m−3, especially during winter. In terms of average daily impact, these numbers can, however, reach much larger values of up to 1–2 µg m−3 for sulfates and nitrates, while the decrease in ammonium due to WBD can reach −1 µg m−3 on selected days. The sensitivity test on the choice of the inorganic equilibrium model (ISORROPIA vs. EQuilibrium Simplified Aerosol Model V4, EQSAM) showed that if EQSAM is used, the impact on SIA is slightly stronger (by a few 10 %) due to larger number of cations considered for water pH in EQSAM. Our results have to be regarded as a first estimate of the long-term WBD emissions and the related effects on PM over Europe. Due to the strong positive wind bias and hence strong WBD emissions, we should consider these results as an upper bound. More sensitivity studies involving the impact of the driving meteorological fields, WBD model choice and the input data used to describe the land surface need to be carried out in future to better constrain these emissions.

Unequal airborne exposure to toxic metals associated with race, ethnicity, and segregation in the USA

Persons of color have been exposed to a disproportionate burden of air pollution across the United States for decades. Yet, the inequality in exposure to known toxic elements of air pollution is unclear. Here, we find that populations living in racially segregated communities are exposed to a form of fine particulate matter with over three times higher mass proportions of known toxic and carcinogenic metals. While concentrations of total fine particulate matter are two times higher in racially segregated communities, concentrations of metals from anthropogenic sources are nearly ten times higher. Populations living in racially segregated communities have been disproportionately exposed to these environmental stressors throughout the past decade. We find evidence, however, that these disproportionate exposures may be abated though targeted regulatory action. For example, recent regulations on marine fuel oil not only reduced vanadium concentrations in coastal cities, but also sharply lessened differences in vanadium exposure by segregation.

Application of nanotechnology to ambient air quality and safety in niger delta, Nigeria

An assessment of the extent of pollutants present in the ambient air in the Niger Delta relative to permissible levels has been reviewed with respect to the National Ambient Air Quality Standards. Man’s activities such as deforestation, urbanization, industrialization, transportation, oil exploration and exploitation, gas flaring, unlimited usage of pesticides and herbicides, for sustenance in the region have led to the degradation of the ambient air quality drastically. Results of some ambient air quality assessments show that levels of concentrations of carbon oxides, nitrogen oxides, sulphur oxide and total particulate matter exceed existing Federal Environmental Protection Agency Standards. These pollutants are a threat to ambient air quality and safety of water, plants, animals and humans. These environmental pollutants are found as mixture in the air and are very difficult to remediate using existing conventional technologies. Overcoming this Promethean Paradigm requires latest technologies that control reactions at the nanoscale using engineered nanomaterials. Nanomaterials having relatively larger surface area per unit mass, utilizes their unique physical and chemical characteristics to combat environment air pollution through pollution prevention, remediation and sensing of pollutants. Therefore using nanotechnology facilitates green manufacturing resulting in cleaner, more efficient industrial processes, improved ability to detect and eliminate pollution thus improving ambient air quality in the Niger Delta. In any case, a comprehensive risk assessment of the safety on human health and environmental impact should be adequately evaluated at all stages of nanotechnology applications.

Filtration and biodeposition rates of Crassostrea oysters for southern Brazilian waters

Shellfish are considered to be one of the most sustainable sources of animal protein that also contribute substantial ecosystem services back into the environment in which they are grown. Although filtration and biodeposition services of bivalves have been explored in many parts of the world, less information is available about bivalve-environmental interactions in Southwest Atlantic. In this study, clearance, filtration and biodeposition rates for oysters Crassostrea gigas, Crassostrea gasar, and Crassostrea rhizophorae were evaluated in the bays of the island of Florianópolis, Brazil. The data were taken from the end of summer of 2019 until the middle of spring of 2019 in two sites. Temperature, salinity, chlorophyll, seston organic content (OCS), total particulate matter (TPM) and organic particulate material (POM) of seawater were determined and the clearance, filtration and biodeposition rates data were collected. C. rhizophorae showed greater average clearance (3.50 ± 0.21 L h−1 g−1), filtration (66.03 ± 6.82 mg h−1 g−1), and biodeposition rates (63.65 ± 6.62 mg h−1 g−1), indicating that this species processes the greatest amount of water and suspended particles than other species (2.15 ± 0.12, 29.85 ± 2.48, 27.28 ± 2.36 and 1.81 ± 0.12, 29.14 ± 2.36 and 27.58 ± 2.42, respectively for C. gigas and C. gasar). The clearance rate of each species was similar between sites and seasons of the year. However, total particulate matter concentrations were significantly different between sites, with average values of 20.65 ± 7.63 and 15.09 ± 11.97 mg L−1, respectively, for Baía Norte and Sul. Furthermore, clearance rate was correlated with animal weight, TPM and OCS while filtration and biodeposition rates were dependent on seston.

Short-term effects of exposure to particulate matter concentrations originating from desert dust on mortality in Athens, Greece

Background &amp;#x26; Aim: Evidence on the independent associations of source-specific particulate matter (PM) exposures with health outcomes is limited. Our aim was to investigate the effects of short-term exposure to PM&amp;#x2264; 10&amp;#x3bc;m (PM10) concentrations originating from windblown desert dust and local sources on mortality. Methods: We investigated the effect of exposure to total PM10 concentrations, as well as estimated concentrations originating from desert dust and other sources on total mortality, between the years 2010-2019. We used Poisson regression models to estimate the association between PM10 from different sources, also controlling for possible confounding by season, meteorology, day of the week and holiday effect. Results: During the 10-year study period, 35% of days were affected by desert dust (desert dust PM10&amp;#x3e; 0&amp;#x3bc;g/m3). An increment of 10&amp;#x3bc;g/m3 in total PM10 concentrations was associated with a 0.52% (lag 0–1, 95% confidence interval (CI): 0.21, 0.83%) increase in natural mortality. When mutually adjusting non-desert and desert dust PM10 concentrations, a 10&amp;#x3bc;g/m3 increase in non-desert was associated with a 0.45% (95% CI: 0.07% to 0.84%) increase in natural mortality. On the other hand, the effect of desert PM10 (lag 0-1 days) concentrations was non-significant (0.59%; 95% CI: -0.53% to 1.72%). Conclusions: Our findings support the hypothesis that daily exposure to traffic-related particles have more toxic effects, compared to ones originating from windblown desert dust, in Athens, Greece leading to increased mortality.

The characterization and quantification of viable and dead airborne biological particles using flow cytometry and double fluorescent staining

Primary biological aerosol particles (PBAPs) are important air pollutants because they are ubiquitous in the atmosphere; influence human health, air quality, atmospheric chemistry and physics; and play important roles in regulating atmospheric processes. In investigations of the effects of PBAPs in ambient environments, it is necessary to distinguish them from other particles. In this study, flow cytometry (FCM) was utilized in combination with permeant (SYBR Green dyes) and impermeant (Propidium Iodide, PI) nucleic acid fluorescent stains, to characterize and quantify the viable and dead airborne PBAPs in ambient aerosol in Beijing, China. The number concentrations of viable and dead PBAPs showed a consistent trend and correlated well with one another (R2 = 0.72, p < 0.01). However, no relationship was found between the number concentration of PBAPs and non-biological particles. The mean number concentrations of total particulate matter, dead PBAPs and viable PBAPs were 5.78 × 106 m−3, 1.11 × 106 m−3 and 7.09 × 105 m−3, respectively. The median PBAPs number concentrations (the sum of dead and viable) exhibited a seasonal cycle, i.e., highest in summer and autumn, lowest during winter and spring. Despite a lower median PBAPs number concentration during winter compared with other seasons, the viability peaked during winter, coinciding with the winter flu season. Stable synoptic conditions, polluted southwesterly air mass and long-range transported dust from the northwest desert region all contributed to the occurrence of explosive fluorescent PBAP episodes in Beijing, China.

Inventory of Commercial Cooking Activities and Emissions in a Typical Urban Area in Greece

The pollutants emitted during meal preparation in restaurants deteriorate the air quality. Thus, it is an environmental issue that needs to be addressed, especially in areas where these activities are densely located. The purpose of this study is to examine the impact on air quality from commercial cooking activities by performing a qualitative and quantitative analysis of the related parameters. The area of interest is located in the southeastern Mediterranean (Greater Athens area in Greece). Due to the lack of the necessary activity information, a survey was conducted. Emissions from the fuel burnt during the cooking procedures were calculated and it was found that, overall, 940.1 tonnes are attributed to commercial cooking activities annually (generated by classical pollutants, heavy metals, particulates and polycyclic aromatic hydrocarbon emissions). Comparing the contribution of different sources to the pollutants emitted, it was found that commercial cooking is responsible for about 0.6%, 0.8% and 1.0% of the total CO, NOx and PM10 values. Cooking organic aerosol (COA) and volatile organic compound (VOC) emissions from grilled meat were also calculated, accounting for 724.9 tonnes and 37.1 tonnes, respectively. Monthly, daily and hourly profiles of the cooking activities were developed and emissions were spatially disaggregated, indicating the city center as the area with higher values. Numerical simulations were performed with the WRF/CAMx modeling system and the results revealed a contribution of about 6% to the total PM10 concentrations in the urban center, where the majority of restaurants are located.

Evaluation of Secondary Organic Aerosol (SOA) Simulations for Seoul, Korea

AbstractOrganic aerosols (OA) represent a significant fraction of total submicron particulate matter (PM1) concentrations globally, including densely populated megacities such as Seoul. However, scientific understanding of the atmospheric formation and removal processes of OA, especially for secondary organic aerosols (SOA), is still highly uncertain. In this study, we examine the characteristics of SOA formation in Seoul during spring‐summer 2016 and fall‐winter 2017/2018, using airborne and ground observations along with a 3‐D global chemical transport model, GEOS‐Chem. We use four different SOA schemes in the model, including simplified and complex volatility‐based frameworks, and evaluate them by comparing the simulations with the observations to examine how our scientific understanding embedded in each SOA scheme affects the observed biases. Our analysis of the model performance of each scheme also provides the most suitable approach in simulating SOA in a typical urban environment. Comparisons of the simulated versus observed OA concentrations show that model biases range from −72% to +118%, with considerable variability among different schemes and seasons. We find that the inclusion of semi/intermediate volatile precursors, in addition to the traditional precursors, and chemical aging (functionalization) are important factors to simulate surface SOA concentrations in Seoul. However, a comparison of observed and simulated SOA/∆CO enhancement ratios suggests that most schemes underpredict SOA aging in upper levels in the boundary layer. We also find that the simplified SOA scheme can reproduce observed OA but often shows overestimation in surface air, indicating that uncertainties exist in bottom‐up emissions and precursor parameterization in Seoul.

Indoor air quality in wards of dental school clinic: Variations of VOCs, CO2 and airborne particle levels

Introduction: The indoor environment of dental clinics may endanger dental patients and personnel and due to a great variety of air pollutants throughout the usual dental operation. The purpose of the present cross-sectional study was the evaluation of Indoor Air Quality (IAQ) and factors affecting it in a dentistry faculty of Arak University of Medical Sciences.&#x0D; Material and methods: The IAQ of five dental active wards and the patient waiting room was evaluated. The concentrations of Total Volatile Organic Compounds (TVOC), CO2, particulate matter, and bioaerosols were measured.&#x0D; Results: The TVOCs concentration in sampling locations ranged between 817 to 3670 μg/m3 during dental work and exceeded the Leadership in Energy and Environmental Design (LEED) guideline in all sampling locations. The highest values of Particulate Matter (PM) for PM10, PM2.5, and PM1 were observed in the periodontics ward, while the lowest values were observed in the endodontics ward. The PM2.5 concentrations exceeded the WHO limit in periodontics and pediatric wards. TVOC levels had a significant positive correlation with temperature (r=0.374, p&lt;0.01) and RH (r=0.265, p&lt;0.05). The predominant bacterial genus of the patient waiting area was Bacillus (36%), while the dominant bacterial genus of the other sampling site was Micrococcus spp. Penicillium (35.5%) and Cladosporium (28%) were the predominant fungi detected.&#x0D; Conclusion: Controlling of airborne particles is to be standardized by the infection control actions of dental clinics and improved ventilation capacity in the air conditioning system was suggested for reducing VOCs and PM concentrations.

Temporal variations in the chemical composition of aerosols over the coastal Bay of Bengal

Variations in source, ionic composition and carbonaceous components of aerosols are expected in the atmosphere due to reversing the direction of winds from winter to summer over the coastal Bay of Bengal (BoB). To examine this monthly, samples were collected at the weekly interval between March 2016 and February 2017 in the coastal BoB. The air mass back trajectories suggested that the study region received aerosols from Indo-Gangetic Plain from October to February whereas from central India during June to September and south or southwest during March to May. A higher concentration of total suspended particulate matter (TSP) was observed from November to February (winter) compared to other months. The concentration of sulphate contributed more than half of water-soluble inorganic species followed by sodium, ammonium and nitrate. The dominant contribution of anthropogenic SO42− (>90%) to total SO42− was observed. The ambient elemental carbon loadings and organic carbon to EC ratios indicate the dominant contribution of biomass burning emissions in the study region. The significant contribution of non-sea salt sulphate and nss-K+ indicates a dominant contribution from the continental sources throughout the year. The mass ratio of NO3−/anthropogenic SO42− suggests stationary sources (i.e., coal burning in power plants) contribute significantly over vehicular emissions during the entire study period. The mass balance of ionic composition suggests the acidic nature of aerosols. The estimated secondary aerosols accounted for ∼50% of organic carbon and 7% of TSP in the study region. This study has implications for understanding the source, composition and nature of aerosols and possible impacts on coastal water upon its deposition.

Seasonal variation and size distribution of inorganic and carbonaceous components, source identification of size-fractioned urban air particles in Kuala Lumpur, Malaysia

This study aims to determine the inorganic and carbonaceous components depending on the seasonal variation and size distribution of urban air particles in Kuala Lumpur. Different fractions of particulate matter (PM) were measured using a Nanosampler from 17 February 2017 until 27 November 2017. The water-soluble inorganic ions (WSIIs) and carbonaceous components in all samples were analysed using ion chromatography and carbon analyser thermal/optical reflectance, respectively. Total PM concentration reached its peak during the southwest (SW) season (70.99 ± 6.04 μg/m3), and the greatest accumulation were observed at PM0.5–1.0 (22%–30%, 9.55 ± 1.03 μg/m3) and PM2.5–10 (22%–25%, 10.34 ± 0.81 μg/m3). SO42−, NO3− and NH4+ were major contributors of WSIIs, and their formation was favoured mainly during SW season (80.5% of total ions). PM0.5–1.0 and PM2.5–10 exhibited the highest percentage of WSII size distribution, accounted for 28.4% and 13.5% of the total mass, respectively. The average contribution of carbonaceous species (OC + EC) to total carbonaceous concentrations were higher in PM0.5–1.0 (35.2%) and PM2.5–10 (26.6%). Ultrafine particles (PM<0.1) consistently indicated that the sources were from vehicle emission while the SW season was constantly dominated by biomass burning sources. Using the positive matrix factorization (PMF) model, secondary inorganic aerosol and biomass burning (30.3%) was known as a significant source of overall PM. As a conclusion, ratio and source apportionment indicate the mixture of biomass burning, secondary inorganic aerosols and motor vehicle contributed to the size-segregated PM and seasonal variation of inorganic and carbonaceous components of urban air particles.

Probabilistic total PM2.5 emissions from vehicular sources in Australian perspective.

Motor vehicles operating on the road are a significant source of Particulate Matter (PM) emissions depending on the fuels used in the vehicles. Gasoline and Diesel vehicles are directly responsible for the tailpipe PM emissions (specifically PM2.5: particles ≤ 2.5µm), known as primary PM2.5 emissions. The other major direct emissions from the vehicles, which include volatile organic compounds (VOCs), and nitrogen oxides (NOx) contribute to the formation of secondary organic PM, also known as secondary organic aerosols (SOA), through some inter-related chemical reactions. The SOAs are highly toxic and contribute to a portion of total PM emissions. In this research, emission scenarios of both primary PM2.5 and SOA for a car-dependent expanding Australian city (Adelaide) were analyzed. The variability of traffic characteristics on road was considered and conducted a probabilistic emissions inventory for tailpipe primary PM2.5 and precursors, while statistical analysis of the probable chemical conversion ratios was considered for the SOA inventory. It was found that the tailpipe emissions from the vehicles were higher than the air quality standard, while the SOA contribution from the vehicles was not significantly high but contributed to the increase of total PM concentration. The analysis of the chemical transformation of SOA precursors justified the importance of conducting more detailed emissions modelling for sustainable urban air quality planning.