Influence of springtime atmospheric circulation types on the distribution of air pollutants in the Arctic

The transport and distribution of short-lived climate forcers in the Arctic are influenced by the prevailing atmospheric circulation patterns. Understanding the coupling between pollutant distribution and dominant atmospheric circulation types is therefore important, not least to understand the processes governing the local processing of pollutants in the Arctic, but also to test the fidelity of chemistry transport models to simulate the transport from the southerly latitudes. Here, we use a combination of satellite-based and reanalysis datasets spanning over 12 years (2007–2018) and investigate the concentrations of NO2, O3, CO and aerosols and their co-variability during eight different atmospheric circulation types in the spring season (March, April and May) over the Arctic. We carried out a self-organizing map analysis of mean sea level pressure to derive these circulation types. Although almost all pollutants investigated here show statistically significant sensitivity to the circulation types, NO2 exhibits the strongest sensitivity among them. The circulation types with low-pressure systems located over the northeast Atlantic show a clear enhancement of NO2 and aerosol optical depths (AODs) in the European Arctic. The O3 concentrations are, however, decreased. The free tropospheric CO is increased over the Arctic during such events. The circulation types with atmospheric blocking over Greenland and northern Scandinavia show the opposite signal in which the NO2 concentrations are decreased and AODs are smaller than the climatological values. The O3 concentrations are, however, increased, and the free tropospheric CO is decreased during such events. The study provides the most comprehensive assessment so far of the sensitivity of springtime pollutant distribution to the atmospheric circulation types in the Arctic and also provides an observational basis for the evaluation of chemistry transport models.

Estimation of the spatial distribution of maximum PM10 and PM2.5 concentration in Bandung City and surrounding countries using WRF-Chem Model (case study in July and October 2018)

Bandung is one of big cities in Indonesia with high activities on industrial and transportation that will increase the air pollutant emission and causes adversely affect the public health. Based on that matter, monitoring of air pollutant concentration is urgently needed to predict the direction of pollutant dispersion and to analyze which locations are vulnerable to maximum exposure of the pollutant. Field monitoring of air pollutant concentration needs much time and high cost, but modeling could help for this. One of the models that can be used to predict the direction of pollutant distribution is the Weather Research Forecasting/Chemistry (WRF-Chem) model, which is a model that combines meteorological models with air quality models. The output of the WRF-Chem running model on July and October 2018, which has been analyzed visually, showed the dispersion pattern of PM10 and PM2.5 is spread mostly to the west, northwest, and north following the wind direction. According to the output of the WRF-Chem model, Bandung Kulon is the most polluted subdistrict by PM10 and PM2.5 with an exposure frequency of 22 hours (PM10), 24 hours (PM2.5) on July 2018 and 19 Hours (PM10), 14 hours (PM2.5) on October 2018. The correlation value for meteorological parameters is quite high in July 2018 (R = 0.9 for wind speed and R = 0.82 for air temperature). So based on the meteorological factor, WRF-Chem model can be used to predict the direction of pollutant distribution.

Three-Dimensional Numerical Modeling of Large-Scale Free Surface Flows with Heat and Contaminant Transfer in Reservoirs

The temperature distribution and pollutant distribution in large reservoirs have always been a hotspot in the field of hydraulics and environmentology, and the three-dimensional numerical modeling that can effectively simulate the interactions between the temperature fields, concentration fields, and flow fields needs to be proposed. The double-diffusive convection lattice Boltzmann method is coupled with a single-phase volume of fluid model for simulating heat and contaminant transfer in large-scale free surface flows. The coupling model is used to simulate the double-diffusive natural convection in a cubic cavity and the temperature distribution of a model reservoir. The mechanism of convection-diffusion, gravity sinking flow, and the complexity of the temperature and the pollutant redistribution process are analyzed. Good agreements between the simulated results and the reference data validate the accuracy and effectiveness of the proposed coupling model in studying free surface flows with heat and contaminant transfer. At last, the temporal and spatial variations of flow state, water temperature stratification, and pollutant transport in the up-reservoir of a pumped-storage power station are simulated and analyzed by the proposed model. The obtained variations of the flow field agree well with the observations in the physical model test and in practical engineering. In addition, the simulated temperature field and concentration field are also consistent with the general rules, which demonstrates the feasibility of the coupling model in simulating temperature and pollutant distribution problems in realistic reservoirs and shows its good prospects in engineering application.

Marine Gel Interactions with Hydrophilic and Hydrophobic Pollutants

Microgels play critical roles in a variety of processes in the ocean, including element cycling, particle interactions, microbial ecology, food web dynamics, air–sea exchange, and pollutant distribution and transport. Exopolymeric substances (EPS) from various marine microbes are one of the major sources for marine microgels. Due to their amphiphilic nature, many types of pollutants, especially hydrophobic ones, have been found to preferentially associate with marine microgels. The interactions between pollutants and microgels can significantly impact the transport, sedimentation, distribution, and the ultimate fate of these pollutants in the ocean. This review on marine gels focuses on the discussion of the interactions between gel-forming EPS and pollutants, such as oil and other hydrophobic pollutants, nanoparticles, and metal ions.

Influence of springtime atmospheric circulation types on the distribution of air pollutants in the Arctic

The transport and distribution of short-lived climate forcers in the Arctic is influenced by the prevailing atmospheric circulation patterns. Understanding the coupling between pollutant distribution and dominant atmospheric circulation types is therefore important, not least to understand the processes governing the local processing of pollutants in the Arctic, but also to test the fidelity of chemistry transport models to simulate the transport from the southerly latitudes. Here, we use a combination of satellite based and reanalysis datasets spanning over 12 years (2007–2018) and investigate the concentrations of NO2, O3, CO and aerosols and their co-variability during 20 different atmospheric circulation types in the spring season (March, April and May) over the Arctic. We carried out a Self-Organizing Maps analysis of MSLP to derive these circulation types. Although almost all pollutants investigated here show statistically significant sensitivity to the circulation types, NO2 exhibits the strongest sensitivity among them. The circulation types with low-pressure systems located over the northeast Atlantic show a clear enhancement of NO2 and AOD in the European Arctic. The O3 concentrations are, however, decreased. The free tropospheric CO is increased over the Arctic during such events. The circulation types with atmospheric blocking over Greenland and northern Scandinavia show the opposite signal in which the NO2 concentrations are decreased and AODs are smaller than the climatological values. The O3 concentrations are, however, increased and the free tropospheric CO decreased during such events. The study provides the most comprehensive assessment so far of the sensitivity of springtime pollutant distribution to the atmospheric circulation types in the Arctic and also provides an observational basis for the evaluation of chemistry transport models.

Suitable geochemical markers to determine tsunami impact - an approach on coastal areas in Northern Japan

<p>The 2011 Tohoku-oki tsunami had a destructive effect and impact on the coast of Japan. Coinciding with the inundation of vast coastal areas, the catastrophic event released many pollutants from damaged facilities but also remobilized sediment-bound residues. These environmental and depositional variations left a distinct signature in the sediment, both sedimentologically and geochemically.</p><p>A wide variety of organic geochemical substances were detected in the sampled sediment profiles in Northern Japan (Misawa harbor, Futakawame and Oirase). Some compounds reflect the 2011 tsunami’s impact and may serve as possible indicators for further investigation of the inundation and backwash, sediment and pollutant distribution, and the preservation. For comparability, the tsunami samples and the respective over- and underlying layers (topsoil & soil) were analyzed.</p><p>The selected compound groups differentiated the tsunami layer from the non-affected layers. Natural compounds, relocated by the tsunami, revealed an enrichment of short-chained <em>n</em>-alkanes as expressed by the terrigenous/aquatic ratio (TAR) and locally accumulated <em>n</em>-aldehydes pointing to an intensive mixing of marine and terrestrial material. Petrogenic pollutants, for instance hopanes, steranes, and polycyclic aromatic hydrocarbons (PAHs), illustrate a higher load in tsunami sediments as the result of damage of harbor facilities. Sewage-related compounds, such as linear alkylbenzene (LABs) and diisopropylnaphthalene (DIPN), were also enriched in the tsunami samples in contrast to the surrounding sites. Another compound group enriched in the tsunami deposits, are chlorinated pollution burdens by the backwash, such as DDX and polychlorinated biphenyls (PCBs), remobilized by erosion dominantly.</p><p>The different environmental- and pollution-related compounds illustrate the suitability of geochemical markers as indicators to assess tsunami impact in 2011 Tohoku-oki tsunami affected sediments of Misawa harbor, Futakawame and Oirase in Northern Japan.</p>

Modelling indoor pollutant distribution via passive scalar and virtual box approach

The distribution of PM2.5 around a thermal manikin with realistic female body shape in a naturally ventilated room has been modelled. The health risk (HR) due to inhalation of the PM2.5 has been quantified by integrating the pollutants mass flux over the boundaries of a virtual box around the mannequin’s head (the breathing zone). By the same approach HR is evaluated over the boundaries of another virtual box that surrounds the manikins body and defines the occupied zone. The paper focuses on the peculiarities of creating and meshing a virtual geometry, as well as on the application of user-defined functions (UDF) for defining a pollutant source within the room using Ansys Fluent modelling package.

Mapping the Finer-Scale Carcinogenic Risk of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Soil—A Case Study of Shenzhen City, China

The high-precision mapping of urban health risk is a difficult problem due to the high heterogeneity of the urban environment. In this paper, the spatial distribution characteristics of the Polycyclic Aromatic Hydrocarbon (PAH) content in the urban soil of Shenzhen City were analyzed through a field investigation. We propose an approach for improving the accuracy and spatial resolution of PAH carcinogenic risk assessment by integrating the pollutant distribution and Location Based Service (LBS) data. The results showed that the concentration of PAHs in the high-density urban area was 271.67 ng g−1, which was 27.2% higher than that in the green area. Although the average carcinogenic risk of PAHs in the surface soil of Shenzhen city was less than 10−6, the maximum carcinogenic risk at some sample sites exceeded 10−6, which indicates a potential health risk. The LBS data were effective for high-precision mapping of the population distribution. According to the combination relationship between the risk threshold of pollutants and the population density, four types of risk zones were proposed. Among them, 6.9% of the areas had a high-risk and high population density and 15.8% of the areas were high-risk with a low population density. These two kinds of zones were the critical areas for controlling risk. The fine-scale risk mapping approach for determining the carcinogenic risk of soil PAHs integrating pollutant distribution and location based service data was demonstrated to be a useful tool for explicit spatial risk management. This tool could provide spatial insights and decision support for urban health-risk management and pollution prevention.