Levels Of Suspended Particulate Matter Research Articles

Satellite observations of suspended particulate matter concentration in Lake Gaoyou in the past four decades

Suspended Particulate Matter (SPM) concentration stands as a pivotal determinant of water quality within lake ecosystems. However, comprehension of the enduring dynamics of SPM within lakes is severely hindered due to a shortage of long-term records. Our research has developed a robust remote sensing algorithm to retrieve the SPM concentration in Lake Gaoyou, situated in the lower reaches of the Huai River basin in China. The algorithm demonstrates commendable performance, with an uncertainty of 28.68 %. Leveraging Landsat series sensors imagery, our investigation yields high spatial resolution SPM concentration maps, which first provide a four-decades record of the SPM distribution within Lake Gaoyou. Our findings unveil a significant annual reduction of 1.35 mg L−1 in SPM concentration over the past four decades. This notable decline is probably attributable to a series of ecological initiatives to enhancing the management of the eco-friendly within the basin. Furthermore, our research delineated the influence of environmental factors on the intra-annual SPM dynamics across distinct spatial domains, encompassing the natural inlet region, semi-obstructed inlet region and outlet areas within the lake The SPM concentration in the natural inlet region exhibits a conspicuous correlation with precipitation. Increased precipitation induces runoff within the basin, facilitating the transport of suspended solids and sediment into the lake, consequently augmenting SPM levels. Conversely, the semi-obstructed inlet and outlet areas are predominantly influenced by the wind field, with variations in SPM attributed to sediment resuspension caused by water mixing driven by wind forcing. Our research can be considered an important reference to the evaluation of the management of the lake over long periods.

Airborne Suspended Particulate Matter and the Prevalence of Allergic Conjunctivitis in Japan.

Background This study aimed to examine the association of suspended particulate matter (SPM) with outpatient attendance for allergic conjunctivitis. Methodology The information on air pollution, encompassing total hydrocarbons, non-methane hydrocarbons, methane, carbon monoxide, nitrogen oxide, nitric oxide, oxidants, and SPM alongside data concerning daily weather conditions such as temperature, wind speed, and humidity, was gathered. Subsequently, the weekly mean values for outpatient visits, air pollution, and weather parameters were computed. Results The number of outpatient visits for allergic conjunctivitis was significantly associated with SPM levels (r = 0.70, p = 0.0037), oxidant levels (r = 0.70, p = 0.0038), wind speed (r = 0.48, p = 0.0472), and humidity (r = 0.77, p = 0.0009) from January to March, as well as SPM levels (r = 0.53, p = 0.0309) and carbon monoxide (r = 0.56, p = 0.0230) from April to June. Multivariate analysis showed that SPM (odds ratio = 1.37, p = 0.0161) and wind velocity (odds ratio = 1.52, p = 0.0038) were significant predictors of the number of outpatient visits from January to December. Conclusions SPM levels were the only independent predictor of outpatient visits for allergic conjunctivitis, suggesting that SPM contributes to the pathophysiology of this condition.

Impacts of varied industrial activities within southern Nigeria on air environment and human health

The contamination of air environment by industrial activities is a global problem mostly in the underdeveloped and developing Nations where environmental issues are handled with levity. This research investigated the impact of industrial activities on air environment at the following companies; Crude Oil processing (COPC), beer processing (BPC), asphalt processing (APC), metal processing (MPC), and construction Company machinery Yard (CCMY) in Southern Nigeria. Air Monitors were employed to quantify nitrogen (IV) oxide (NO2), sulphur (IV) oxide (SO2), hydrogen sulphide (H2S), cabon (II) Oxide CO, total volatile organic carbon (TVOC), and suspended particulate matter (SPM) at the studied locations. The mean values of NO2, SO2, H2S, and CO obtained at all the industrial locations were higher than their recommended limits by the Federal Environmental and protection Agency (FEPA) except at BPC. The mean levels of TVOC were higher than the limit at all the locations apart from BPC and CCMY. However, the mean levels of SPM at all locations were higher than the permissible limit. The general trend for the discharge of air pollutants indicated that, COPC and BPC were rated the highest and lowest, respectively. The air quality index (AQI) values obtained revealed that, all the air pollutants at all the locations except BPC were harmful to human health. Nevertheless, the mean AQI value of SPM at BPC was also in the hazardous class. The Principal component analysis (PCA) confirmed that, industrial activities at the studied locations were responsible for the accumulation of these toxic substances in the adjoining air environment. Hierarchical cluster analysis (HCA) for the air pollutants corroborated that most of the parameters were from a common source. HCA for the studied locations indicated similarities between BPC and CCMY, APC and MPC, while COPC was in a separate cluster. Thus, this study has shown the effects of untreated gases released from industries into the air on the environment and appropriate measures should be adopted to ameliorate the trend.

Characteristics of Suspended Road Dust According to Vehicle Driving Patterns in an Urban Area and PM10 Content in Silt

Characterizing the influence factors of exhaust gas based on the suspended road dust on paved roads, according to the number of vehicles and their distance with regard to driving pattern, is important in order to provide a coefficient for driving patterns to find a model equation. This has been a limitation of previous studies, in which this was difficult to carry out in a large area reflecting various driving patterns because some sections were selected according to empirical measurement results, and only one vehicle measurement was used to find the level of road dust. This study measured the concentration of suspended road dust that could occur, depending on the vehicle’s driving patterns, on an experimental road in Yongin, South Korea, from May to July 2023. The study was conducted to determine the degree of the effect of exhaust gas, according to the concentration of suspended road dust generated, by determining the separation distance based on real-time measurements. This study attempted to determine the changes in suspended road dust based on driving patterns in urban areas and factor in the concentration of suspended road dust with regard to emission characteristics in terms of exhaust gas and particulate matter with a diameter of 10 microns or less (PM10). This was in accordance with conditions evaluated using mobile laboratories, based on suspended-PM10-concentration-measuring equipment. This study mainly focused on the following main topics: (1) increasing the level of suspended particulate matter at less than 10 m intervals produced by exhaust gas; (2) decreasing the level of suspended road dust with an increase in the number of vehicles, with the area measured at a distance of three cars in front showing the lowest level of suspended road dust in the air and a low level for the rear vehicle; (3) demonstrating that PM10 is effective in measuring the generation of suspended road dust; and (4) evaluating suspended road dust levels by road section. Based on the results, this research is necessary to more appropriately set the focus of analyses that aim to characterize suspended road dust according to exhaust gas and PM10 content in silt.

Spatial variation of air pollutants by using GIS modelling

<p>Air pollution in Tamil Nadu has become a pressing issue, as various pollutants have surpassed the limits established by the pollution control board. The major air pollutants in the region, namely sulphur dioxide, nitrogen dioxide, and suspended particulate matter, have been identified. This study aims to monitor and analyse the levels of air pollution in Tamil Nadu, with a specific focus on key parameters such as SO2, NO2, PM2.5, PM10, and ozone. By examining the atmospheric levels of these pollutants and their correlation with temperature fluctuations, the impact on human health and respiratory problems can be evaluated. Moreover, the study will assess the contribution of traffic emissions and vehicular pollution to the concentration of PM10 in different areas. Additionally, GIS technology will be utilized to spatially and temporally investigate pollution concentrations and evaluate their effect on the air quality index. By comparing the pollution concentration from thermal power stations and vehicular pollution, the study will identify the sources of pollutants, with a particular emphasis on SO2 and NOx emissions from vehicles and higher levels of suspended particulate matter from thermal stations. The analysis of these pollutants and their sources will provide valuable insights for the implementation of effective pollution control measures and the management of environmental pollution in Tamil Nadu. Given the concerns regarding pollutants exceeding the prescribed limits set by the pollution control board, monitoring air pollution in Tamil Nadu is of utmost importance.</p>

Nutrient dynamics in the Yellow River -a case study of different reservoir regulation operations

Global dam construction and reservoir artificial regulations change the biogeochemical processes of nutrients along river networks. Herein, nutrients and hydrologic parameters were analyzed to ascertain their spatiotemporal heterogeneity in the Yellow River and assess the retention effect of nutrients in the Xiaolangdi Reservoir (XLDR). Nutrients increased upstream of reservoirs (the Sanmenxia Reservoir and XLDR) due to the inflow of tributaries (Wei River and Fen River). The XLDR maintained a balanced effect on most nutrient levels from upstream of reservoirs to downstream by the disparities in biogeochemical processes during various periods, including biotic assimilation consumption in the upper layer and regeneration and release in the lower layer during the Drainage period; limited water residence time of the XLDR and constrained biotic assimilation processes in the Flood control period; vertical water mixing in the Impoundment period. The disparities of most nutrient levels upstream of reservoirs played a crucial role in nutrient characteristics in the Yellow River during various periods. The higher DSi levels derived from enhanced physical erosion and chemical weathering of rock/soil responded to the higher water discharge and suspended particulate matter levels upstream and in the Yellow River during the Flood control and Impoundment periods; however, the lower DIN (dissolved inorganic nitrogen) and TDP (total dissolved phosphorus) resulted from the point pollution source and amplified water dilution effect. We demonstrated that the XLDR acted as a nutrient source for DIN, DIP and DSi based on the mass balance model in a hydrological year (June 2017-May 2018), with retention efficiency (RETf) of −1.4 %, −11% and −7%, respectively. The decreased RETf of DIP primarily stemmed from the pronounced reservoir source effect in the Drainage period. Consequently, the XLDR could relieve the P limitation downstream and estuary by changing the nutrient stoichiometry ratios of outflow.

Particulate Metal Contamination Assessment in Surabaya Coast, East Java, Indonesia

Surabaya’s coasts, situated in an active metropolitan region, threatened by metal contamination, which can be found in particulate matter. However, data of suspended particulate matter (SPM) and particulate metals on the Surabaya Coast are scarce. This study aims to systematically evaluate the impact of trace metals on the environment through particulate metal analysis. Water sample was taken in May 2017 at 17 sites, and analyzed using the acid digestion procedure and measured by ICP-MS. The results show that SPM levels range from 10.80 – 51.80 mg/L, while the concentrations of particulate metals range from 0 – 2.78 mg/kg, 1.14 – 130.77 mg/kg, 3.43 – 60.19 mg/kg and 0.87 – 7.00 mg/kg dry weight for Cd, Cu, Pb, and As, respectively. The location of Surabaya coast might affects salinity and temperature where eastern part is more affected by Madura Strait, but metal concentration are all affected by riverine input. Based on the Geo-accumulation Index and Pollution Load Index, several sites on the Surabaya’s coasts are polluted. However, they have low-level toxicity and insignificant mortality, indicating the Surabaya Coast environments is still safe for living habitat. Meanwhile, particulate metal concentrations are relatively high in several locations, possibly caused by the port, marine tourism, and other anthropogenic activities.

How environmental factors determine mussel metal concentrations? A comparative study between areas facing different pressures

This study examines mussel accumulation capacity in relation to metal concentrations in the marine environment as well as mussel food availability in the coastal marine environment. Field data obtained from mussel-farms facing different natural and/or human derived pressures (Thermaikos gulf receiving river discharges and Elefsis bay receiving industrial effluents). Cd, Cr, Cu, Fe, Mn, Ni and Zn concentration in mussels and seawater (particulate phase) chlorophyll α, particulate organic carbon and suspended particulate matter (SPM), seawater temperature and salinity were measured. Median mussel metal concentrations measured as μg g−1 dw were 0.62 for Cd, 5.6 for Cu, 2.8 for Cr, 5.0 for Ni, 129 for Zn, 311 for Fe and 12.4 for Mn. The corresponding concentrations in SPM expressed as μg L−1 were 0.004 for Cd, 0.33 for Cu, 1.14 for Cr, 0.31 for Ni, 3.60 for Zn, 46.0 for Fe and 1.63 for Mn. Mussel metal concentrations were higher at the industrial site. Metals in the seawater particulate phase were higher in the estuary front, which was attributed to higher SPM levels from river discharges. Due to the limited nutritional value of the SPM in the industrial area, mussels were exposed to elevated metal load by both the anthropogenic activities and the slower and more effective digestion of their potential food in order to optimize available organic matter exploitation from restricted and low nutrition value food.

Air Pollution Trends in Metropolitan Cities of India: Tales of the future generation.

Air pollution, a rising concern, is a major contributor to respiratory disease, and action is needed to control the same. In this paper, we tried to analyze this problem of Air Pollution trends by quantitative changes in the levels of SO2 (Sulphur Dioxide), NO2 (Nitrogen Dioxide), SPM (Suspended Particulate Matter), and RSPM (Respirable Suspended Particulate Matter) in Annual Pollution Report among major metropolitan cities.

Investigation of dust pollutants and the impact of suspended particulate matter on the performance of photovoltaic systems

The purpose of this study is to investigate the potential of airborne particulate matter (PM10 and PM2.5) and its impact on the performance of the photovoltaic (PV) system installed in the Sargodha region, being affected by the crushing activities in the hills. More than 100 stone crushers are operating in this region. Four stations within this region are selected for taking samples during the summer and winter seasons. Glass–fiber papers are used as a collection medium for particulate matter (PM) in a high-volume sampler. The concentration of PM is found above the permissible limit at all selected sites. The chemical composition, concentration, and the formation of particulate matter (PM10 and PM2.5) layers on the surface of the photovoltaic module varies significantly depending on the site’s location and time. The accumulation of PM layers on the PV module surface is one of the operating environmental factors that cause significant reduction in PV system performance. Consequently, it leads to power loss, reduction of service life, and increase in module temperature. For the PV system’s performance analysis, two PV systems are installed at the site, having higher PM concentration. One system is cleaned regularly, while the other remains dusty. The data of both PV systems are measured and compared for 4 months (2 months for the summer season and 2 months for the winter season). It is found that when the level of suspended particulate matter (PM10 and PM2.5) increases, the energy generation of the dusty PV system (compared to the cleaned one) is reduced by 7.48% in May, 7.342% in June, 10.68% in December, and 8.03% in January. Based on the obtained results, it is recommended that the negative impact of PM on the performance of the PV system should be considered carefully during the decision-making process of setting solar energy generation targets in the regions with a high level of particulate matter.

Comparison of Ambient Air Quality among Industrial and Residential Areas of a Typical South Asian City

The rapid increase in population growth due to industrialization and urbanization has resulted in air quality deterioration in Pakistan. Consequently, a considerable increase has been seen in the types of sources of air pollutants. However, the air quality of the country has deteriorated in the absence of management capabilities against air quality. Evidence from numerous governmental organizations and international bodies has specified that the environment, health, and quality of life are at high risk due to air pollution. Although the government of Pakistan established the Pakistan Clean Air Program, along with continuous monitoring stations to manage the quality of ambient air, air quality values have not yet been achieved. The present investigations were made in the city of Faisalabad in selected locations. Sampling of a 24 h average was done for selected sites. The air quality parameters such as NO2, SO2, COx, O2, noise level, and suspended particulate matter (SPM) were measured at two locations, i.e., Khurrianwala and Liaqatabad in the Faisalabad District. The measured values of air quality parameters were compared with national environmental quality standards (NEQS). Air pollutants such as SPM, SO2, and noise levels were found to be significantly higher than the 24-h standards of NEQS, which poses harmful effects on the quality of air and health, whereas the O2 concentration was found to be lower than the normal values, and NO2 and COx values were normal. The SO2, CO2, noise level, SPM, and O2 values ranged from 418–652 and 423–661 µg/m3, 3.03–3.44 and 3.08–3.51 mg/m3, 68–73 and 69–75 dB, 555–667 and 581–682 µg/m3, and 19.5–20 and 19.5–20.3 % for summer and winter season, respectively, as compared to standard values (150 µg/m3, 10 mg/m3, 65 dB, 550 µg/m3 and 21%). After the complete analysis of the selected locations, it was concluded that the ambient air quality of this area is severely degraded due to industrial as well as other commercial activities. These significant variations in air quality parameters suggest that there is a need to check the air quality regularly to take appropriate measures for reducing ambient air pollutants, especially in industrial areas as well as commercial areas.

Effect of COVID-19 Movement Control Order Policy on Water Quality Changes in Sungai Langat, Malaysia Within Distinct Land Use Areas

For the first time in the 21st century, many nations have been forced to conduct a lockdown that restricts their industrial, transportation, and social activities to avoid the extensive COVID-19 spread. Therefore, our study aimed to analyze the status of water quality that was measured by suspended particulate matter (SPM) in Sungai Langat, Selangor, Malaysia using the remote sensing technique. The study was concerned with rivers located in distinct land-use areas such as high-density urban, low-density urban, and agricultural areas. The study period included before and after movement control order (MCO) periods that occurred in February 2020 and February 2021, respectively. The SPM levels in each period were calculated using the remote sensing technique through Landsat-8 OLI images then they were analyzed using statistical analysis. The results of the remote sensing technique showed the highest decrease of SPM levels during the MCO period was observed in Sungai Langat within a high-density urban area (34.1%). Then, the SPM levels in all Sungai Langat raised significantly after the MCO period with the highest change at 31.6%. Rainfall and erosion factors had a significant impact on the SPM level through natural processes but the COVID-19 restriction had a direct impact on the SPM level due to the restriction of industrial and social activities. The suspended activities have made the lower emission compared with before the COVID-19 period in 2019.

Effect of air pollution on age at menarche in polish females, born 1993\u20131998

The aim of the study was to analyse the association between the degree of air pollution (suspended particulate matter, sulphur dioxide, benzopyrene levels) in the location of residence during childhood and adolescence and the age at menarche. The research was carried out in the period from 2015 to 2018 in Poland. Anthropometric measurements were performed, and questionnaire data were collected from 1,257 women, aged 19–25 years. The average levels of subjects’ exposure to analysed air pollutants, i.e., particulate matter, sulphur dioxide, nitric oxide and benzene during childhood-adolescence was assessed from the data acquired by the Polish Chief Inspectorate for Environmental Protection. Negative relationships between age at menarche and suspended particulate matter as well as nitrogen levels were found. A similar trend was observed in an analysis of the relationship between age at menarche and the complex air pollution index. The tendency for age at menarche to decrease together with worsening air quality was also visible after adjusted for socioeconomic status. Girls exposed to high suspended particulate matter levels were characterised by higher risk of early age at menarche. High levels of air pollution are related to younger age at menarche and the risk of the menstruation onset below 11 years.

Human health risk associated to particulate matter and polycyclic aromatic hydrocarbon levels and their relation with preponderant sources in Gran La Plata, Argentina.

Levels of suspended particulate matter (PM) of both fractions PM10 and PM2.5 in ambient air were monitored in three areas of Gran La Plata: industrial, urban, and residential (2017-2019). Associated polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) to PM were also determined and possible emission sources were identified. Assessment of health risk to PM exposure and associated compounds was realized. Results showed a decrease in levels of PM10 in each area along the period studied, especially in the industrial area. Decreases in PM2.5 levels were also observed in urban and residential areas over the years, although the trend is not as marked as with PM10 levels. Then, PM2.5 levels in the industrial area have remained practically constant. The 89% of both PM10 and PM2.5 annual mean exceeds the WHO reference values. The presence of most of the 16 US EPA priority PAHs studied was found with a detection frequency greater than 60% and it was possible to identify the importance of the contributions of vehicular emissions as predominant sources of PAH emission. From the calculations of the risk of contracting cancer throughout life (LCR), in the case of adults, the US EPA limits were not complied in the industrial and urban areas and in both fractions of PM. From the evaluation of the burden of disease (EBD), the calculated relative risks of mortality were very similar for the studied districts, being the relative risk in La Plata slightly lower, about 3-5%, than those in Berisso and Ensenada.

Potential Chemical Stressors Emitted During the Operation of Machines in the Digital Printing Process

ABSTRACT The digital printing process contributes to the quality of indoor air through the emission of chemical stressors such as total volatile organic compounds (TVOCs) and suspended particulate matter (SPM). The concentration levels of SPM and TVOCs were determined using the gravimetric and gas chromatography method, respectively. The results show that the digital printing machines and the cutting machine do not produce PM2.5 particles. The significant cumulative mass concentrations of PM10 suspended particles of 9.91 μg/m3 for a single-colour digital printing machine, 4.45 μg/m3 for a four-colour digital printing machine, and 2.02 μg/m3 for a cutting machine, were detected. By comparing the cumulative values of TVOC concentration levels measured, it can be concluded that the values have been 4 to 12 times higher for the four-colour digital printing machine than for the single-colour digital printing machine. Namely, the TVOC concentration levels measured for the four-colour digital printing machine ranged from 28.69 to 57.30 mg/m3, while the values for the single-colour digital printing machine ranged from 2.31 to 13.51 mg/m3. Considering the fact that there are no standards of quality of indoor air in printing offices defined in the Republic of Serbia, the results obtained could represent a valid basis and a worthy guideline for the definition of values necessary for the indoor air quality assessment.

Particulate Matter-Based Air Quality Index Estimate for Abuja, Nigeria: Implications for Health

In recent years, urban air quality in developing countries such as Nigeria has continued to degenerate and this has constituted a major environmental risk to human health. It has been shown that an increase in ambient particulate matter (PM10) load of 10 μg/m3 reduces life expectancy by 0.64 years. Air Quality Index (AQI) as demonstrated in this study shows how relatively clean or polluted the boundary layer environment of any location can be. The study was designed to measure the level of suspended particulate matter (PM2.5 and PM10) for dry and wet seasons, compute the prevalent air quality index of selected locations in Abuja with possible health implications. Suspended particulate matter (PM2.5 and PM10) was assessed using handheld aerosol particulate sampler. The US Oak Ridge National AQI was adopted for the eleven (11) locations sampled and monitored. The study results showed that the air quality of the selected areas in Abuja were generally good and healthy. Dry season, assessments, showed 15 - 95 μg/m3 and 12 - 80 μg/m3 for PM2.5 and PM10, respectively. While in wet season, 09 - 75 μg/m3 and 07 - 65 μg/m3 were recorded for PM2.5 and PM10. However at Jebi Central Motor Park, there was light air contamination with AQI of 42 for dry season and 31 for wet season. Other locations had clean air with AQI ≤ 11. It is revealed that clean air exists generally during the wet season. Comparing study outcome to other cities in Nigeria, residents of Abuja are likely not to be affected with health hazards of particulate matter pollution. Nonetheless, the high range of PM2.5 and PM10 (fine and coarse particles) ratio evaluated i.e., 1.06 - 1.79 was higher than the WHO recommended standard of 0.5 - 0.8. This ratio remains a health concerns for sensitive inhabitants like pregnant women and their foetus as well as infants below age five whose respiratory airways are noted to have high surface areas and absorption capacity for fine particulate matter. Vegetation known to absorb suspended particulate matter should be planted across Abuja metropolitan areas and air quality monitoring stations installed at strategic locations for continuous monitoring and evaluations.

Assessment of the physical impact of a short-term dredging operation on a semi-enclosed environment: South Euboean Gulf, Greece.

The potential influence of short-period (May-June 2012) dredging activities (for the installation of a submarine gas pipeline) on physical properties of the marine environment of two shallow-water sites in the Aliveri and Varnavas areas of South Euboean Gulf (Greece) has been evaluated. During the dredging operation in Varnavas, the induced dredge plume traveled up to ~ 750m from the shoreline, featured by light attenuation coefficient (cp) maxima of 4.01-4.61m-1 and suspended particulate matter (SPM) concentrations up to 6.01mgL-1. After dredging the previous parameters reduced to the ambient seawater condition, ~ 0.45m-1 and < 2.8mgL-1 on average, respectively. Likewise in Aliveri, the dredging-associated sediment plume drifted offshore up to ~ 400m from the shoreline, characterized by cp maxima of 2.11-4.86m-1 and SPM concentrations up to 13.07mgL-1. After the completion of the excavation and trenching activities, the cp and SPM values were restored to the pre-disturbance condition, ~ 0.6m-1 and < 2.2mgL-1 on average, respectively. The migration of the dredge plume in both dredging sites was accomplished through the formation of intermediate and benthic nepheloid layers, whose development and evolution were governed by seawater stratification and flow regime. The dredging-derived SPM levels appeared to increase within a distance of no more than 300m from the shoreline (near-field zone). Based on data from the literature, this SPM enhancement together with the deposition of a post-dredging residual mud veneer in the near-field zone could deteriorate local marine biota, but in a reversible way.

Contribution of Asian Dust to suspended particulate matter and its association with daily mortality in Southern Japan

TPS 683: Short-term health effects of air pollutants 2, Exhibition Hall, Ground floor, August 28, 2019, 3:00 PM - 4:30 PM Previous studies investigating the health effects of Asian Dust (AD) have used different methods to identify dust events. No study has formally characterized the contribution of AD to particulate matter. We adapted the European reference method to quantify suspended particulate matter (SPM) by dust contribution to examine the short-term association with total mortality in Fukuoka, Japan. We identified AD events (April 2013 - December 2015) using multiple criteria – visibility indicator, Light Detection and Ranging (LIDAR) data, SPM concentration and its ratio with fine particles (PM2.5). To estimate net dust load on AD days, we first obtained background SPM level by applying monthly moving 40th percentile to the observed SPM in Fukuoka on days without AD, and then subtracted this amount from total SPM, providing the AD-related SPM. We estimated the associations of SPM by dust contribution (AD and non-AD) with daily mortality using time-stratified case-crossover study design (conditional Poisson model). Results were reported as relative risk (RR) per 10 μg/m3 increase in SPM. There were 28 days of AD event (2.8%) observed mainly in spring and summer. Approximately 60% of SPM was attributable to AD on these days. Mean estimated net AD load was 28.9 μg/m3 [standard deviation (SD) = 12.7] versus mean [SD] SPM of 22.4 [11.7] μg/m3 for the whole period. The estimated RR for AD-related SPM was 1.047 (95% confidence interval: 0.977, 1.018). For non-AD related SPM, the estimated RR during AD and non-AD days was 1.239 (1.021, 1.504) and 0.991 (0.977, 1.006), respectively. We found no evidence linking AD-related SPM to daily total mortality, but there was a positive association between non-AD-related SPM and mortality on AD days, suggesting a synergic effect of atmospheric pollutants and AD events. Nevertheless, findings and applicability of the reference method should be confirmed in further studies in East Asia.

Short- and medium-chain chlorinated paraffins in the Henan section of the Yellow River: Occurrences, fates, and fluxes

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in sediment and suspended particulate matter (SPM) from the middle and lower reaches of the Yellow River in the three seasons to elucidate their environmental behavior. The mean concentrations of ∑SCCPs and ∑MCCPs were 262 and 97.1 ng g−1 dw (dry weight) in sediment and 17,055 and 2573 ng g−1 dw in SPM, respectively, and higher SCCP levels did not clearly reflect a shift to more MCCPs in this section of the Yellow River. The predominant homologue groups were C10-CP and C11-CP for SCCPs and C14-CP for MCCPs. The CPs possibly mainly derived from the use of CP commercial mixtures, mainly included CP-42 and CP-52. The spatial distributions and principal component analysis indicated that industrial inputs, dams, and topography played important roles in influencing the environmental behavior of CPs in both sediment and SPM. In addition, decreasing fluxes of CPs were observed in SPM from Tongguan to Aishan stations, particularly in reservoirs, which implies that CPs may have accumulated in the Henan section of the Yellow River.

Oceanographic setting and short-timescale environmental variability at an Arctic seamount sponge ground

Mass occurrences of large sponges, or ‘sponge grounds’, are found globally in a range of oceanographic settings. Interest in these grounds is growing because of their ecological importance as hotspots of biodiversity, their role in biogeochemical cycling and bentho-pelagic coupling, the biotechnological potential of their constituent sponges, and their perceived vulnerability to physical disturbance and environmental change. Little is known about the environmental conditions required for sponges to persist and for grounds to form, and very few studies have explicitly characterised and interpreted the importance of oceanographic conditions. Here, results are presented of the first observational oceanographic campaign at a known sponge ground on the Schultz Massif Seamount (SMS; Arctic Mid-Ocean Ridge, Greenland / Norwegian Seas). The campaign consisted of water column profiling and short-term deployment of a benthic lander. It was supported by multibeam echosounder bathymetry and remotely operated vehicle video surveys. The seamount summit hosted several environmental factors potentially beneficial to sponges. It occurred within relatively nutrient-rich waters and was regularly flushed from above with slightly warmer, oxygen-enriched Norwegian Arctic Intermediate Water. It was exposed to elevated suspended particulate matter levels and oscillating currents (with diurnal tidal frequency) likely to enhance food supply and prevent smothering of the sponges by sedimentation. Elevated chlorophyll a concentration was observed in lenses above the summit, which may indicate particle retention by seamount-scale circulation patterns. High sponge density and diversity observed on the summit is likely explained by the combination of several beneficial factors, the coincidence of which at the summit arises from interaction between seamount geomorphology, hydrodynamic regime, and water column structure. Neighbouring seamounts along the mid-ocean ridge are likely to present similarly complex oceanographic settings and, as with the SMS, associated sponge ground ecosystems may therefore be sensitive to changes over a particularly broad range of abiotic factors.