Carcinogenic and human health risk assessment of children's and adults' exposure to toxic metal(oid)s from air PM10 in critical sites of the Republic of Serbia.

With global urbanization and industrialization, air pollution has become an inevitable problem. Among air pollutants, toxic metals bound to particulate matter (PM) have a high hazardous potential, contributing to the development of several diseases, including various types of cancer. Due to PM pollution, Serbia is considered to be among the most polluted countries in Europe. Therefore, the objective of the study was to assess and characterize the non-carcinogenic and carcinogenic risks of children's and adults' exposure to metal(oid)s (Pb, Cd, Ni, and As) bound to PM10 in five of the most polluted areas in the Republic of Serbia (Subotica, Smederevo, Bor, Valjevo, and Kraljevo). Non-carcinogenic (HQ and HI) and carcinogenic risk (CR) were calculated using USEPA methodology. Our results show that PM10 concentrations exceeded the annual limit of 40 µg/m3 at four out of five monitoring sites (ranging from 44.33 to 63.25 µg/m3). Results obtained from Bor monitoring station show that safe limits were exceeded for both children and adults, indicating an unacceptable risk (> 1) obtained for inhalation exposure to the As (HQ = 6.14) and Cd (HQ = 1.17), while total HI was 7.43, which characterized the risk as unacceptable. For the same station, the CR value was 1.44E-04 (> 1 × 10-4). In other sites, the risks were acceptable. The characterized risk from exposure to the toxic elements via PM10 in critical locations in Serbia contributes to improving air quality by requiring regulatory organs to take new actions and adopt new measures to reduce air pollution.

The PM2.5-bound polycyclic aromatic hydrocarbon behavior in indoor and outdoor environments, part II: Explainable prediction of benzo[a]pyrene levels.

Among the polycyclic aromatic hydrocarbons (PAH), benzo[a]pyrene (B[a]P) has been considered more relevant than other species when estimating the potential exposure-related health effects and has been recognized as a marker of carcinogenic potency of air pollutant mixture. The current understanding of the factors which govern non-linear behavior of B[a]P and associated pollutants and environmental processes is insufficient and further research has to rely on the advanced analytical approach which averts the assumptions and avoids simplifications required by linear modeling methods. For the purpose of this study, we employed eXtreme Gradient Boosting (XGBoost), SHapley Additive exPlanations (SHAP) attribution method, and SHAP value fuzzy clustering to investigate the concentrations of inorganic gaseous pollutants, radon, PM2.5 and particle constituents including trace metals, ions, 16 US EPA priority PM2.5-bound PAHs and 31 meteorological variables, as key factors which shape indoor and outdoor PM2.5-bound B[a]P distribution in a university building located in the urban area of Belgrade (Serbia). According to the results, the indoor and outdoor B[a]P levels were shown to be highly correlated and mostly influenced by the concentrations of Chry, B[b]F, CO, B[a]A, I[cd]P, B[k]F, Flt, D[ah]A, Pyr, B[ghi]P, Cr, As, and PM2.5 in both indoor and outdoor environments. Besides, high B[a]P concentration events were recorded during the periods of low ambient temperature (<12 °C), unstable weather conditions with precipitation and increased soil humidity.

The PM2.5-bound polycyclic aromatic hydrocarbon behavior in indoor and outdoor environments, part I: Emission sources.

The previous research, aimed at exploring the relationships between the indoor and outdoor air quality, has evidenced that outdoor PM2.5-bound polycyclic aromatic hydrocarbons (PAH) levels exhibit significant daily and seasonal variations which does not necessary corresponds with PAH indoor dynamics. For the purpose of this study, a three-month measurement campaign was performed simultaneously at indoor and outdoor sampling sites of a university building in an urban area of Belgrade (Serbia), during which the concentrations of O3, CO, SO2, NOx, radon, PM2.5 and particle constituents including trace metals (As, Cd, Cr, Mn, Ni and Pb), ions (Cl-, Na+, Mg2+, Ca2+, K+, NO3-, SO42- and NH4+) and 16 US EPA priority PAHs were determined. Additionally, the analysis included 31 meteorological parameters, out of which 24 were obtained from Global Data Assimilation System (GDAS1) database. The Unmix and PAH diagnostic ratios analysis resolved the source profiles for both indoor and outdoor environment, which are comparable in terms of their apportionments and pollutant shares, although it should be emphasized that ratio-implied solutions should be taken with caution since these values do not reflect emission sources only. The highest contributions to air quality were attributed to sources identified as coal combustion and related pyrogenic processes. Noticeable correlations were observed between 5- and 6-ring high molecular weight PAHs, but, except for CO, no significant linear dependencies with other investigated variables were identified. The PAH level predictions in the indoor and outdoor environment was performed by using machine learning XGBoost method.

Explainable extreme gradient boosting tree-based prediction of toluene, ethylbenzene and xylene wet deposition.

Current research suggests that, apart from photochemical reactions, toluene, ethylbenzene and xylene (TEX) removal from ambient air might be affected by atmospheric precipitation, depending on the concentrations and water solubility of the compounds, Henry's law, physico-chemical properties of the water, as well as the frequency and intensity of precipitation events. Nevertheless, existing knowledge of the role that wet deposition plays in biogeochemical cycles of volatile species remains insufficient, and this topic requires more scientific effort to be explored and understood. In this study, we employed the eXtreme Gradient Boosting tree ensemble for revealing TEX transfer from ambient air to rainwater, and applied a novel SHapley Additive exPlanations feature attribution framework to examine the relevance of the monitored parameters and identify key factors that govern wet deposition of TEX. According to the results, main impacts, including ambient air TEX concentrations, and rainwater and air temperatures, and occasional, but less important impacts, including wind speed, air pressure, turbidity, and total organic carbon, NO3-, Cl- and K+ rainwater concentration, shaped TEX partition between gaseous and aqueous phases during rain events.

Single and combined effects of air pollutants on circulatory and respiratory system-related mortality in Belgrade, Serbia.

The aim of this study was to investigate the association between short- and long-term exposure to particulate matter (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), and soot and mortality attributed to circulatory and respiratory diseases in Belgrade area (Serbia). The analyzed data set comprised results of regular pollutant monitoring and corresponding administrative records on frequency of daily mortality in the period 2009-2014. Nonlinear exposure-response dependencies and delayed effects of temperature were examined by means of distributed lag nonlinear models. The air pollutant loadings and circulatory system-related death rates in Belgrade area are among the highest in Europe. Data demonstrated that excess risk of death with short-term exposure to elevated concentrations of PM10, SO2, and soot was not significant, whereas marked effect size estimates for exposure over 90 d preceding mortality were found. The influence of chronic exposure was shown to be greater for respiratory than circulatory system-related mortality. When stratified by age and gender, higher risk was noted for male individuals below the age of 65 years.

Assessment of PM10 pollution level and required source emission reduction in Belgrade area.

The aim of this study was to assess PM10 pollution level and estimate required source emission reduction in Belgrade area, the second largest urban center in the Balkans. Daily mass concentrations and trace metal content (As, Cd, Cr, Mn, Ni, Pb) of PM10 were evaluated for three air quality monitoring sites of different types: urban-traffic (Slavija), suburban (Lazarevac) and rural (Grabovac) under the industrial influence, during the period of 2012-13. Noncompliance with current Air Quality Standards (AQS) was noticeable: annual means were higher than AQS at Slavija and Lazarevac, and daily frequency threshold was exceeded at all three locations. Annual means of As at Lazarevac were about four times higher than the target concentration, which could be attributed to the proximity of coal-fired power plants, and dust resuspension from coal basin and nearby ash landfills. Additionally, levels of Ni and Cr were significantly higher than in other European cities. Carcinogenic health risk of inhabitants' exposure to trace metals was assessed as well. Cumulative cancer risk exceeded the upper limit of acceptable US EPA range at two sites, with Cr and As as the major contributors. To estimate source emission reduction, required to meet AQS, lognormal, Weibull and Pearson 5 probability distribution, functions (PDF) were used to fit daily PM10 concentrations. Based on the rollback equation and best fitting PDF, estimated reduction was within the range of 28-98%. Finally, the required reduction obtained using two-parameter exponential distribution suggested that risks associated to accidental releases of pollutants should be of greater concern.

Forecasting of VOC emissions from traffic and industry using classification and regression multivariate methods.

In this study, advanced multivariate methods were applied for VOC source apportionment and subsequent short-term forecast of industrial- and vehicle exhaust-related contributions in Belgrade urban area (Serbia). The VOC concentrations were measured using PTR-MS, together with inorganic gaseous pollutants (NOx, NO, NO2, SO2, and CO), PM10, and meteorological parameters. US EPA Positive Matrix Factorization and Unmix receptor models were applied to the obtained dataset both resolving six source profiles. For the purpose of forecasting industrial- and vehicle exhaust-related source contributions, different multivariate methods were employed in two separate cases, relying on meteorological data, and on meteorological data and concentrations of inorganic gaseous pollutants, respectively. The results indicate that Boosted Decision Trees and Multi-Layer Perceptrons were the best performing methods. According to the results, forecasting accuracy was high (lowest relative error of only 6%), in particular when the forecast was based on both meteorological parameters and concentrations of inorganic gaseous pollutants.

Functional magnetic stimulation for mixed urinary incontinence.

PURPOSE: In this study we determined the efficacy of functional magnetic stimulation (FMS) compared to placebo for treating women with mixed urinary incontinence (MUI). MATERIALS AND METHODS: A total of 39 women with MUI were randomly assigned to the FMS group (23 patients) or to the placebo group (16 patients). FMS was applied continuously at 18.5 Hz day and night for 2 months. Conventional urodynamic studies were performed before and after stimulation. Outcome measures assessed were clinical (daytime frequency, nocturia, pad use, pad weight) and urodynamic variables (first sensation of bladder filling, maximum cystometric capacity, maximum urethral closure pressure), and patient subjective assessment (visual analogue scale). RESULTS: After 2 months of FMS significant decreases in voiding frequency (from 9.0 to 6.7, p = 0.0002), nocturia (from 2.6 to 1.4, p = 0.0007) and pad use (from 3.9 to 2.2, p = 0.007) were observed only in the FMS group. First sensation of bladder filling and maximum cystometric capacity increased significantly after stimulation compared with prestimulation levels only in the FMS group, p = 0.003 (from 118 to 174 ml) and p = 0.00004 (from 267 to 396 ml), respectively. A total of 18 women (78.3%) reported an improvement in symptoms after FMS with an average success rate of 41.9%. The success rate was significantly lower in the placebo group (p = 0.021) at 22.9%. CONCLUSIONS: Functional magnetic stimulation was useful and safe for treating women with MUI.