Total Suspended Particulate Matter Concentrations Research Articles

Analysis of Suspended Particulate Matter in a Conventional Seed Spices Cleaning and Grading Industry: A Case Study of Unjha Vicinity in Gujarat, India

A large number of seed spices (Cumin, Fennel, Coriander, Fenugreek etc.) cleaning-grading units are situated in Gujarat and Rajasthan. In-plant study was performed in such a cleaning-grading industry located at Unjha (Gujarat) in collaboration with Centre for Research on Seed Spice (SDAU), Jagudan, Mehsana. Apprehension for wellbeing of workers of such dust/ suspended particulate matter (SPM) generating industries are growing with time. SPM samples were collected using standard High Volume Sampler and these samples were analyzed for their respirable suspended particulate matter (RSPM) and total SPM concentration (µg/m3). The highest concentration of RSPM (< 10 micron) inside the plant was found to be 20 x103 µg/m3, while the highest SPM concentration level was 168x103 µg/m3. The average particle size of SPM was 1.96 µ to 9.43 µ while that of RSPM was 1.7 µ. The Ambient air quality norms prescribed by Central Pollution Control Board (CPCB) for industrial areas limit these values to 100 µg/m3 (SPM) and 60 µg/m3 (RSPM). Such highly polluted in-plant atmosphere of seed spices cleaning-grading industry may cause severe health problems, leading to respiratory diseases among the workers. In order to protect the health of workers engaged in these industries, it is suggested to install the electrostatic precipitator (ESP) device and retrofitting of existing equipment (such that dust levels are within permissible limits) may be considered.

Ambient particulate matter levels and health profile in residents of Choba and Mgbuoba areas of Rivers State: A cross-sectional study

ABSTRACT The study investigated the health profile of individuals exposed to particulate matter (Black) soot in Choba and Mgbuoba localities of Port Harcourt. The analysis was executed with the aid of 100 respondents (50 from Choba and 50 from Mgbuoba). A structured questionnaire with the outlined elements was utilized during data collection for the study: manner of living, type of occupation, environmental exposure, known health issues, fitness and cleanliness, and Key Informant Interviews (KII) were exploited to gain pertinent data from health professionals. A hand-held Kestrel weather tracker was employed to ascertain the wind speed, temperature, and relative humidity of the study areas while A Met One Instrument, Inc. Aerosol Mass Monitor Model GT–531 was utilized to estimate total suspended particulates. Biochemical parameters such as lipid profile, renal markers, and liver markers activities were analyzed from blood samples obtained from the subjects using spectrophotometric methods. The air quality profile of Mgbuoba showed significant (p < .05) increment in total suspended particulate matter, total suspended particulate matter (TSPM), particulate matter that is 10 microns in diameter or less (PM10), and particulate matter that is 2.5 microns in diameter or less (PM2.5) from 6 a.m. to 8 a.m. compared with Choba. The increment in Total suspended particulate matter, PM10, and PM2.5 levels were beyond the 24-hour PM10 and PM2.5 recommended level by the World Health Organization (WHO). The alanine transaminase (ALT) and low density lipoproptein (LDL) levels of Choba and Mgbuoba residents were beyond the reference limits set by the Medical Council of Canada. The study showed that residents in Mgbuoba in Port Harcourt may be more at risk and have higher vulnerability to the undesirable outcomes associated with exposures to these air contaminants. A rising and worrisome trend in respiratory and related conditions among less mobile residents call for emergency response to emission of black soot in the area. Implications: The study investigated the health profile of individuals exposed to particulate matter (Black) soot in Choba and Mgbuoba localities of Port Harcourt. This outcome clearly shows that these air pollutants are higher in concentrations early in the morning and their concentrations decreased as the day went by. Therefore, by implication, the residents in these areas may be at high risk of exposure to these air pollutants from 6 a.m. to 8 a.m. The present study has demonstrated that these air pollutants are more prominent very early in the mornings and variations in meteorological conditions at a particular time, and anthropogenic activities might have contributed to the elevations in the concentration of TSPM, PM10, and PM2.5 in Choba and Mgbuoba.

Assessment of Air Quality Around Gbaran – Ubie Gas Processing Plant, yenagoa, Bayelsa State, Southern Nigeria

This study determined the air quality status around Gbaran and its environs as a result of gas processing taking place in the area. The study characterized and quantified air pollutants emitted into the surrounding at two different seasons and also determined the seasonal variations in the concentration levels of gases in the air sample with a view to evaluating the air quality implication of the gas processing plant. Digital hand - held gas Analyzers were used to monitor air pollutants including; Total Suspended Particulate Matter (TSPM), Sulphur dioxide (SO 2 ), carbon monoxide (CO) and Volatile Organic Compounds (VOCs), while Kestrel Model NO. 4500 pocket weather tracker was used to monitor the meteorological parameters such as: ambient temperature, relative humidity, wind speed. The direction of wind was also detected using wind vane. The results of the study showed dominant wind direction during the wet season within the SE and the NE direction while during the dry season it was NW and NE. The maximum wind speed during the wet and dry seasons was 3.75m/s and 2.80m/s respectively. The Relative humidity values in wet season ranged between 82.40% - 98.80% while in the dry were between 37.15% - 74.95%. Temperature in the wet season ranged between 24.80 o C – 30.40 o C while during the dry season it was between 31.05 o C– 43.20 o C. The mean concentration of TSPM during the wet season ranged between 16.00µg/m 3 –2,423.50µg/m 3 while in the dry, it was between 508.00 µg/m 3 – 3,800.00 µg/m 3 . That of SO 2 during the wet season ranged between 0 ppm – 1 ppm while in the dry season it was between 0.50 ppm – 1.50 ppm. CO was emitted in the range of 0 .50ppm – 6.00 ppm in the wet season and 0.87 ppm – 2.00 ppm in the dry season. For VOCs, its mean concentration during the wet season ranged between 0.65 ppm – 3.25 ppm and 3.15 ppm – 10.00 ppm during the dry season. The study observed that the mean concentrations of gaseous pollutants in the dry season were higher than the wet season and were also found to exceed the limits recommended by Federal Ministry of Environment, except CO that was lower and below the set limit. The study therefore concluded that the Gbaran - Ubie gas processing plant is a source of air pollution in the area. Keywords: Assessment, Air quality, Gas processing plant, Gbaran – Ubie, Obunagha, Yenagoa DOI : 10.7176/JEES/9-7-03 Publication date :July 31 st 2019

Simulation of Sedimentation in Lake Taihu with Geostationary Satellite Ocean Color Data

In this study, the goal is to estimate the sedimentation on the bottom bed of Lake Taihu using numerical simulation combined with geostationary satellite ocean color data. A two-dimensional (2D) model that couples the dynamics of shallow water and sediment transport is presented. The shallow water equations are solved using a semi-implicit finite difference method with an Alternating Direction Implicit (ADI) method. Suspended sediment transport is simulated by solving the general convection-diffusion equation with resuspension and deposition terms using a second-order explicit central difference method in space and two-step Adams–Bashforth method in time. Moreover, the total suspended particulate matter (TSM) is retrieved by the world’s first geostationary satellite ocean color sensor Geostationary Ocean Color Imager (GOCI) using atmospheric correction algorithm for turbid waters using ultraviolet wavelengths (UV-AC) and regional empirical TSM algorithm. The 2D model and GOCI-retrieved TSM are applied to study the sediment transport and sedimentation in Lake Taihu. Validation results show rationale TSM concentration retrieved by GOCI, and the simulated TSM concentrations are consistent with GOCI observations. In addition, simulated sedimentation results reveal the dangerous locations that must be observed and desilted.

Particulate matter and particulate-bound mercury in a heavily polluted site related to ancient mining and metallurgy: a proposal for dry deposition modeling based on micrometeorological conditions.

This manuscript reported data for total suspended particulate matter (TSPM), particle-bound mercury (PBM), and total gaseous mercury (TGM) in Almadenejos, a rural zone of ancient Hg mining and metallurgical works. Concentrations of TSPM characterize the study site as being a rural area, with levels below 40μgm-3 during most of the year and sporadic events involving dust intrusions from Africa. Mercury speciation of PM and nearby soils, which contain both cinnabar and organic Hg, confirms that the PM comes from local soil emissions involving the soils polluted by ancient metallurgical works. Conversely, PBM and TGM levels (average 1.8ngm-3 and 88ngm-3, respectively) define Almadenejos as a contaminated site similar to urban areas. A multiple linear regression analysis showed that evapotranspiration is the micrometeorological parameter that best explains the TSPM and PBM data, with the creation of a diurnal mixing layer being the main process involved in Hg emissions in the solid and gaseous states. Based on these findings, a micrometeorological-based model has been developed to acquire a complete set of daily PBM data and these were used to obtain dry deposition rates (317μgm-2year-1), which were seasonally distributed as 40% in summer, 33% in autumn, 16% in spring, and 11% in winter. In addition, an estimation of PBM emissions showed that 335gyear-1 can be suspended in the Almadenejos environment. A large proportion of this PBM should be removed from the atmosphere through dry deposition in a continuous Hg exchange at the soil-atmosphere interface. Mercury fractionation (cinnabar and organic Hg) can increase the risk to the human population and nearby ecosystems of Almadenejos.

Forms of phosphorus in suspended particulate matter in agriculture-dominated lowland catchments: Iron as phosphorus carrier

The fate and environmental effects of phosphorus (P) in natural waters depend on its chemical forms. The particulate P (PP) concentration is dominant over the dissolved P concentration in agriculture-dominated headwaters in the Netherlands. Routine water quality monitoring programmes do not include the chemical fractionation of PP. To quantify the chemical forms of PP under various conditions in six agriculture-dominated lowland catchments in the Netherlands, a sequential chemical extraction method was applied to suspended particulate matter (SPM) samples collected by centrifugation or filtration. Centrifuge samples had lower values for the sum of the PP fractions compared with the filtration samples due to lower contents from PP fractions other than the Fe-P pool. With an average value of 8.8mgg−1, internationally high P contents of the SPM were found. Ferric iron-bound P was the most important PP fraction in SPM samples (38–95%; median 74%), followed by organic P (2–38%; median 15%). Exchangeable P ranged from 0.2 to 27%, with a median of 4.4%, Ca-P ranged from 0.1 to 11% with a median of 3.9% and detrital P was present in only a small fraction (0–6%; median 1.1%). Ferric iron-bound P was the dominant PP pool throughout the entire range of watercourses (from headwater ditches to catchment outlets) and in samples taken during winter months as well as those taken during summer months. Furthermore, the PP fraction distribution did not change markedly when flow conditions were altered from low to high discharge. The dominance of the Fe-P pool denotes the presence of Fe(III) precipitates in SPM that originate from exfiltration of anoxic Fe-bearing groundwater. These Fe(III) precipitates are a major fraction of the total SPM concentration (4 to 67% as Fe(OH)3; median 18%). Although not measured directly, our results suggest that formation of authigenic Fe(III) precipitates causes a rapid transformation of dissolved P in groundwater to PP in surface water. We advise including sequential chemical extraction of SPM monitoring programmes because the composition of particles is critical for P bioavailability, which is a key driving factor for eutrophication.

Risk of a false decision on conformity of an environmental compartment due to measurement uncertainty of concentrations of two or more pollutants

Risks of false decisions in conformity assessment of an environmental compartment due to measurement uncertainty of concentrations of two or more pollutants are discussed. Even if the assessment of conformity for each pollutant in the compartment is successful, the total probability of a false decision concerning the compartment as a whole might still be significant. A model of the total probability of a false decision, formulated on the base of the law of total probability, is used, for example, for a study of test results of total suspended particulate matter (TSPM) concentration in ambient air near to three independent stone quarries located in Israel, as the sources of the air pollution. Total probabilities of underestimation of TSPM concentration (total risk of the inhabitants) and overestimation (total risk of the stone producers) are evaluated as a combination of the particular risks of air conformity assessment concerning TSPM concentration for each quarry. These probabilities characterize conformity of the TSPM concentration in the region of the quarries as a whole. Core code developed in R programming environment for the calculations is provided.

Pollution levels and health risk assessment of particulate phthalic acid esters in arid urban areas

The pollution levels and health risks of phthalic acid esters (PAEs) in atmospheric particulates in a typical arid urban area of China were studied and discussed in this paper. Gas chromatography-mass spectrometry (GC–MS) was used to analyze the PAE concentrations at seven sites in Changji City during all four seasons. The results indicated that total PAE in atmospheric particulates ranged from 40 to 388 ng m−3 in 2014. The PAE concentrations also showed significant seasonal variation with relatively higher values in summer and autumn (191 and 319 ng m−3) than in spring and winter (70 and 55 ng m−3). Dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) were found as predominant compounds in PAEs accounting for ca. 90% of the total. Evidence confirms that factors including anthropogenic activities and total suspended particulate matter concentration (TSP) influenced the spatial distribution of phthalates in the atmosphere. The non-cancer and cancer risks assessment of PAEs using U.S. EPA method showed that the respective values were <1 for the former, and <10−6 for the latter; therefore, both of them were within the acceptable level and met the international guidelines. The study here establishes a baseline for future monitoring and management of these contaminants in arid area.

Traffic signatures in suspended dust at pedestrian levels in semiarid zones: Implications for human exposure

Deeper knowledge on dust suspension processes along semiarid zones is critical for understanding potential impacts on human health. Hermosillo city, located in the heart of the Sonoran Desert was chosen to evaluate such impacts. A one-year survey of Total Suspended Particulate Matter (TSPM) was conducted at two different heights (pedestrian and rooftop level). The minimum values of TSPM were reported during monsoon season and winter. Maximum values showed a bimodal distribution, with major peaks associated with increase and decrease of temperature, as well as decreasing humidity. Concentrations of TSPM were significantly exceeded at pedestrian level (∼44% of analyzed days) when compared to roof level (∼18% of analyzed days). Metal concentrations of As, Pb, Cu, Sb, Be, Mg, Ni, and Co were higher at pedestrian level than at roof level. Pixel counting and interpretations based on scanning electron microscopy of dust filters showed a higher percentage of fine particulate fractions at pedestrian level. These fractions occur mainly as metal-enriched agglomerates resembling coarser particles. According to worldwide guidelines, particulate matter sampling should be conducted by monitoring particle sizes equal and inferior to PM10. However, this work suggests that such procedures may compromise risk assessment in semiarid environments, where coarse particles act as main carriers for emergent contaminants related to traffic. This effect is especially concerning at pedestrian level, leading to an underestimation of potential impacts of human exposure. This study brings forward novel aspects that are of relevance for those concerned with dust suspension processes across semiarid regions and related impact on human health.

Application of the Geostationary Ocean Color Imager to Mapping the Diurnal and Seasonal Variability of Surface Suspended Matter in a Macro-Tidal Estuary

Total suspended particulate matter (TSM) in estuarine and coastal regions usually exhibits significant natural variations. The understanding of such variations is of great significance in coastal waters. The aim of this study is to investigate and assess the diurnal and seasonal variations of surface TSM distribution and its mechanisms in coastal waters based on Geostationary Ocean Color Imager (GOCI) data. As a case study, dynamic variations of TSM in the macro-tidal Yalu River estuary (YRE) of China were analysed. With regard to diurnal variability, there were usually two peaks of TSM in a tidal cycle corresponding to the maximum flood and ebb current. Tidal action appears to play a vital role in diurnal variations of TSM. Both the processes of tidal re-suspension and advection could be identified; however, the diurnal variation of TSM was mainly affected by a re-suspension process. In addition, spring-neap tides can affect the magnitude of TSM diurnal variations in the YRE. The GOCI-retrieved TSM results clearly showed the seasonal variability of surface TSM in this area, with the highest level occurring in winter and the lowest in summer. Moreover, although river discharge to the YRE was much greater in the wet season than the dry season, TSM concentrations were significantly higher in the dry season. Wind waves were considered to be the main factor affecting TSM seasonal variation in the YRE.

Physico-chemical characterization of total suspended particulate matter over two coastal stations of Antarctica and adjoining ocean

Physical and chemical characteristics of the total suspended particulate matter (TSPM) measured during 11 January–21 March, 2009 and 09 December 2009–09 January, 2010 over two stations of Antarctica (Larsemann Hills and Maitri) and adjoining ocean are investigated. It is found that the concentration of TSPM is low over all the observational locations. Day-to-day variation in the concentration of TSPM is mainly controlled by variation in the weather systems and associated meteorological parameters. Average concentration of TSPM over Larsemann Hills is 7.6 μg/m3 during Jan–Mar 2009 and 2.4 μg/m3 during Dec. 2009–Jan 2010. It is 9.0 μg/m3 over Maitri during Jan–Mar 2009. On excluding the TSPM data of the disturbed weather days during Jan–Mar 2009, the concentration of TSPM is found to be 4.2 μg/m3 over Larsemann Hills and 4.3 μg/m3 over Maitri. The TSPM at all the observational locations is acidic in nature with a maximum pH value of 5.56 at Larsemann Hills. The pH value of TSPM over Maitri is found to be 5.28. The acidic nature of TSPM indicates the absence of sufficient neutralizing alkaline minerals. Among the measured chemical anions Cl− dominates at all the locations except at Maitri where SO42− ion shows maximum concentration. The dominant cation is Na+ at all the observational stations. Sizeable fraction of SO42− is found at all the observational locations. Abundance of SO42− in the atmosphere of Antarctica and its surrounding region is mainly due to emission of dimethylsulfide (DMS) phytoplankton and its oxidation finally to SO42− particles by gas-to-particle conversion. The highest concentration of SO42− over Maitri is attributed to the contribution from anthropogenic activity at Maitri, in addition to the biogenic SO42−. NH4+ plays dominant role in neutralizing the acidic components of the aerosols.

Fluctuations of satellite-derived chlorophyll concentrations and optical indices at the Southern Yellow Sea

Time series of chlorophyll-a concentration (chl a), backscattering coefficient at 490 nm (bbp(490)) and spectral slope of bbp (γ) derived from satellite imagery of ocean color were used to study the aquatic ecosystem of the Southern Yellow Sea during the time period of 1997–2007. Our study indicated that chl a increased in offshore waters by 0.02 mg m−3 y −1 (p &amp;lt; 0.05), in contrast to a decline observed in the middle and low-latitude global waters. bbp(490), a proxy of total suspended particulate matter concentration did not have any significant trend, while γ, a proxy of the relative proportion of small-sized and larger particles in the surface ocean, decreased significantly. Annual spring phytoplankton blooms occurred in nearshore and offshore waters of the central Southern Yellow Sea; while autumn blooms only occurred in nearshore waters.

Sediment mobility in response to tidal and wind-driven flows along the Belgian inner shelf, southern North Sea

The effect of hydro-meteorological forcings (tidal and wind-induced flows) on the transport of suspended particulate matter (SPM), on the formation of high-concentrated mud suspensions and on the occurrence of sand–mud suspensions has been studied using long-term multi-parametric observations. Data have been collected in a coastal turbidity maximum area (southern North Sea) where a mixture of sandy and muddy sediments prevails. Data have been classified according to variations in subtidal alongshore currents, with the direction of subtidal flow depending on wind direction. This influences the position of the turbidity maximum; as such also the origin of SPM. Winds blowing from the NE will increase SPM concentration, whilst SW winds will induce a decrease. The latter is related to advection of less turbid English Channel water, inducing a shift of the turbidity maximum towards the NE and the Westerschelde estuary. Under these conditions, marine mud will be imported and buffered in the estuary. Under persistent NE winds, high-concentrated mud suspensions are formed and remain present during several tidal cycles. Data show that SPM consists of a mixture of flocs and locally eroded sand grains during high currents. This has implications towards used instrumentation: SPM concentration estimates from optical backscatter sensors will only be reliable when SPM consists of cohesive sediments only; with mixtures of cohesive and non-cohesive sediments, a combination of both optical and acoustic sensors are needed to get an accurate estimate of the total SPM concentration.

Development and performance evaluation of statistical models correlating air pollutants and meteorological variables at Pantnagar, India

Ambient air quality in respect of SO2, NO2 and total suspended particulate matter (TSPM) was monitored at Pantnagar, India from May, 2008 to April, 2009 and statistically analyzed with meteorological variables such as relative humidity (RH), wind speed (WS), precipitation (P) and mean air temperature (T). TSPM was found to be the major air pollutant causing significant deterioration of air quality with annual mean concentrations of 280μg/m3. Further, weekly mean air pollutant concentrations were statistically analyzed through stepwise multiple linear regression analysis in respect of independent meteorological variables to develop suitable statistical models. Both NO2 and TSPM concentrations were found to have been influenced by meteorological variables with coefficient of determination (R2) of 82.21 and 92.84%, respectively. However, atmospheric SO2 revealed only 22.87% of dependencies on meteorological variables. Partial correlation coefficients revealed that wind speed has the maximum influence (77.80 and 31.50%) on proposed equations for NO2 and SO2, closely followed by weekly mean temperature (73.60 and 24.30%). However, in case of TSPM, individual contribution of ambient temperature (94.40%) was found maximum, followed by relative humidity (86.50%). Model performances were evaluated through both quantitative data analysis techniques and statistical methods. Nearly 98 and 95% of potential error has been explained by the model developed for TSPM and NO2, while in case of SO2, it is found as only 61%. Therefore, performances of models (for TSPM and NO2) to predict ambient weekly mean concentrations based on forecasted weather parameters were found to be excellent, however, performance of model developed for SO2 was found only satisfactory.

Winter-time size distribution and source apportionment of total suspended particulate matter and associated metals in Delhi

A study of the winter time size distribution and source apportionment of total suspended particulate matter (TSPM) and associated heavy metal concentrations have been carried out for the city of Delhi. This study is important from the point of view of implementation of compressed natural gas (CNG) as alternate of diesel fuel in the public transport system in 2001 to reduce the pollution level. TSPM were collected using a five-stage cascade impactor at six sites in the winters of 2005–06. The results of size distribution indicate that a major portion (~ 40%) of TSPM concentration is in the form of PM0.7 (< 0.7 μm). Similar trends were observed with most of the heavy metals associated with various size fractions of TSPM. A very good correlation between coarse and fine size fraction of TSPM was observed. It was also observed that the metals associated with coarse particles have more chances of correlation with other metals; rather they are associated with fine particles. Source apportionment was carried out separately in coarse and fine size modes of TSPM by Chemical Mass Balance Receptor Model (CMB8) as well as by Principle Component Analysis (PCA) of SPSS. Source apportionment by PCA reveals that there are two major sources (possibly vehicular and crustal re-suspension) in both coarse and fine size fractions. Results obtained by CMB8 show the dominance of vehicular pollutants and crustal dust in fine and coarse size mode respectively. Noticeably the dominance of vehicular pollutants are now confined to fine size only whilst during pre CNG era it dominated both coarse and fine size mode. An increase of 42.5, 44.4, 48.2, 38.6 and 38.9% in the concentrations of TSPM, PM10.9, coarse particles, fine particles and lead respectively was observed during pre (2001) to post CNG (2005-06) period.

Uncertainties in selected river water quality data

Abstract. Monitoring of surface waters is primarily done to detect the status and trends in water quality and to identify whether observed trends arise from natural or anthropogenic causes. Empirical quality of river water quality data is rarely certain and knowledge of their uncertainties is essential to assess the reliability of water quality models and their predictions. The objective of this paper is to assess the uncertainties in selected river water quality data, i.e. suspended sediment, nitrogen fraction, phosphorus fraction, heavy metals and biological compounds. The methodology used to structure the uncertainty is based on the empirical quality of data and the sources of uncertainty in data (van Loon et al., 2005). A literature review was carried out including additional experimental data of the Elbe river. All data of compounds associated with suspended particulate matter have considerable higher sampling uncertainties than soluble concentrations. This is due to high variability within the cross section of a given river. This variability is positively correlated with total suspended particulate matter concentrations. Sampling location has also considerable effect on the representativeness of a water sample. These sampling uncertainties are highly site specific. The estimation of uncertainty in sampling can only be achieved by taking at least a proportion of samples in duplicates. Compared to sampling uncertainties, measurement and analytical uncertainties are much lower. Instrument quality can be stated well suited for field and laboratory situations for all considered constituents. Analytical errors can contribute considerably to the overall uncertainty of river water quality data. Temporal autocorrelation of river water quality data is present but literature on general behaviour of water quality compounds is rare. For meso scale river catchments (500–3000 km2) reasonable yearly dissolved load calculations can be achieved using biweekly sample frequencies. For suspended sediments none of the methods investigated produced very reliable load estimates when weekly concentrations data were used. Uncertainties associated with loads estimates based on infrequent samples will decrease with increasing size of rivers.

Size distribution and source identification of total suspended particulate matter and associated heavy metals in the urban atmosphere of Delhi

A study of the atmospheric particulate size distribution of total suspended particulate matter (TSPM) and associated heavy metal concentrations has been carried out for the city of Delhi. Urban particles were collected using a five-stage impactor at six sites in three different seasons, viz. winter, summer and monsoon in the year 2001. Five samples from each site in each season were collected. Each sample (filter paper) was extracted with a mixture of nitric acid, hydrochloric acid and hydrofluoric acid. The acid solutions of the samples were analysed in five-particle fractions by atomic absorption spectrometry (AAS). The impactor stage fractionation of particles shows that a major portion of TSPM concentration is in the form of PM0.7 (i.e. <0.7microm). Similarly, the most of the metal mass viz. Mn, Cr, Cd, Pb, Ni, and Fe are also concentrated in the PM0.7 mode. The only exceptions are size distributions pertaining to Cu and Ca. Though, Cu is more in PM0.7 mode, its presence in size intervals 5.4-1.6microm and 1.6-0.7microm is also significant, whilst in case of Ca there is no definite pattern in its distribution with size of particles. The average PM10.9 (i.e. <10.9microm) concentrations are approximately 90.2%+/-4.5%, 81.4%+/-1.4% and 86.4%+/-9.6% of TSPM for winter, summer and monsoon seasons, respectively. Source apportionment reveals that there are two sources of TSPM and PM10.9, while three and four sources were observed for PM1.6 (i.e. <1.6microm) and PM0.7, respectively. Results of regression analyses show definite correlations between PM10.9 and other fine size fractions, suggesting PM10.9 may adequately act as a surrogate for both PM1.6 and PM0.7, while PM1.6 may adequately act as a surrogate for PM0.7.

Assessment of Ambient Air Quality in Urban Centres of Haryana (India) in Relation to Different Anthropogenic Activities and Health Risks

Considering the mounting evidences of the effects of air pollution on health, the present study was undertaken to assess the ambient air quality status in the fast growing urban centres of Haryana state, India. The samples were collected for total suspended particulate matter (TSPM), respirable suspended particulate matter (PM(10)), sulfur dioxide (SO(2)), and oxides of nitrogen (NO(2)) during different seasons from 8 districts of Haryana during January, 1999 to September, 2000. The four types of sampling sites with different anthropogenic activities i.e. residential, sensitive, commercial and industrial were identified in each city. The ambient air concentration of TSPM and PM(10) observed was well above the prescribed standards at almost all the sites. The average ambient air concentrations of SO(2) and NO(2) were found below the permissible limits at all the centres. Comparatively higher concentration of SO(2) was observed during winter seasons, which seems to be related with the enhanced combustion of fuel for space heating and relatively stable atmospheric conditions. Air Quality Index (AQI) prepared for these cities shows that residential, sensitive and commercial areas were moderately to severely polluted which is a cause of concern for the residents of these cities. The high levels of TSPM and SO(2) especially in winter are of major health concern because of their synergistic action. The data from Hisar city reveals a significant increase in the total number of hospital visits/admissions of the patients with acute respiratory diseases during winter season when the level of air pollutants was high.

Satellite-derived parameters for biological modelling in coastal waters: Illustration over the eastern continental shelf of the Bay of Biscay

In biological modelling of the coastal phytoplankton dynamics, the light attenuation coefficient is often expressed as a function of the concentrations of chlorophyll and mineral suspended particulate matter (SPM). In order to estimate the relationship between these parameters over the continental shelf of the northern Bay of Biscay, a set of in situ data has been gathered for the period 1998–2003 when SeaWiFS imagery is available. These data comprise surface measurements of the concentrations of total SPM, chlorophyll, and irradiance profiles from which is derived the attenuation coefficient of the photosynthetically available radiation, KPAR. The performance of the IFREMER look-up table used to retrieve the chlorophyll concentration from the SeaWiFS radiance is evaluated on this new set of data. The quality of the estimated chlorophyll concentration is assessed from a comparison of the variograms of the in situ and satellite-derived chlorophyll concentrations. Once the chlorophyll concentration is determined, the non living SPM, which is defined as the SPM not related to the dead or alive endogenous phytoplankton, is estimated from the radiance at 555 nm by inverting a semi-analytic model. This method provides realistic estimations of concentrations of chlorophyll and SPM over the continental shelf all over the year. Finally, a relationship, based on non living SPM and chlorophyll, is proposed to estimate KPAR on the continental shelf of the Bay of Biscay. The same formula is applied to non living SPM and chlorophyll concentrations, observed in situ or derived from SeaWiFS radiance.

Significance of particle interaction to the modelling of cohesive sediment transport in rivers

AbstractAggregation processes of fine sediments have rarely been integrated in numerical simulations of cohesive sediment transport in riverine systems. These processes, however, can significantly alter the hydrodynamic characteristics of suspended particulate matter (SPM), modifying the particle settling velocity, which is one of the most important parameters in modelling suspended sediment dynamics. The present paper presents data from field measurements and an approach to integrate particle aggregation in a hydrodynamic sediment transport model. The aggregation term used represents the interaction of multiple sediment classes (fractions) with corresponding multiple deposition behaviour. The k–ε–turbulence model was used to calculate the coefficient of vertical turbulent mixing needed for the two‐dimensional vertical‐plane simulations. The model has been applied to transport and deposition of tracer particles and natural SPM in a lake‐outlet lowland river (Spree River, Germany). The results of simulations were evaluated by comparison with field data obtained for two levels of river discharge. Experimental data for both discharge levels showed that under the prevailing uniform hydraulic conditions along the river reach, the settling velocity distribution did not change significantly downstream, whereas the amount of SPM declined. It was also shown that higher flow velocities (higher fluid shear) resulted in higher proportions of fast settling SPM fractions. We conclude that in accordance with the respective prevailing turbulence structures, typical aggregation mechanisms occur that continuously generate similar distribution patterns, including particles that settle toward the river bed and thus mainly contribute to the observed decline in the total SPM concentration. In order to determine time‐scales of aggregation and related mass fluxes between the settling velocity fractions, results of model simulations were fitted to experimental data for total SPM concentration and of settling velocity frequency distributions. The comparison with simulations for the case of non‐interacting fractions clearly demonstrated the practical significance of particle interaction for a more realistic modelling of cohesive sediment and contaminant transport. Copyright © 2004 John Wiley &amp; Sons, Ltd.