Atmospheric deposition in the Athabasca Oil Sands Region decreased exponentially with distance from the industrial center. Throughfall deposition (kg ha−1 yr−1) of NH4–N (.8–14.7) was double that of NO3–N (.3–6.7), while SO4–S ranged from 2.5 to 23.7. Gaseous pollutants (NO2, HNO3, NH3, SO2) are important drivers of atmospheric deposition but weak correlations between gaseous pollutants and deposition suggest that particulate deposition is also important. The deposition (eq ha−1) of base cations (Ca + Mg + Na) across the sampling network was highly similar to N + S deposition, suggesting that acidic deposition is neutralized by base cation deposition and that eutrophication impacts from excess N may be of greater concern than acidification. Emissions from a large forest fire in summer 2011 were most prominently reflected in increased concentrations of HNO3 and throughfall deposition of SO4–S at some sites. Deposition of NO3–N also increased as did NH4–N deposition to a lesser degree.

Anaerobic digestion (AD) of putrescible urban waste for energy recovery has seen rapid growth over recent years. In order to ascertain its systems scale sustainability, however, determination of the environmental fate of the large volume of digestate generated during the process is indispensable. This paper evaluates the environmental burdens to air associated with land applied food-based digestate in terms of primary pollutants (ammonia, nitrogen dioxide) and greenhouse gases (methane and nitrous oxide). The assessments have been made in two stages – first, the emissions from surface application of food-based digestate are quantified for the business as usual (BAU). In the next step, environmental burden minimisation potentials for the following three mitigation measures are estimated – mixed waste digestate (MWD), soil-incorporated digestate (SID), and post-methanated digestate (PMD). Overall, the mitigation scenarios demonstrated considerable NH3, CH4 and N2O burden minimisation potentials, with positive implications for both climate change and urban pollution.

Unionised ammonia (NH3) is highly toxic to freshwater organisms. Yet, most of the available toxicity data on NH3 were predominantly generated from temperate regions, while toxicity data on NH3 derived from tropical species were limited. To address this issue, we first conducted standard acute toxicity tests on NH3 using ten tropical freshwater species. Subsequently, we constructed a tropical species sensitivity distribution (SSD) using these newly generated toxicity data and available tropical toxicity data of NH3, which was then compared with the corresponding temperate SSD constructed from documented temperate acute toxicity data. Our results showed that tropical species were generally more sensitive to NH3 than their temperate counterparts. Based on the ratio between temperate and tropical hazardous concentration 10% values, we recommend an extrapolation factor of four to be applied when surrogate temperate toxicity data or temperate water quality guidelines of NH3 are used for protecting tropical freshwater ecosystems.

Nitrogen (N) doped TiO2 supported vanadium phosphorus oxide (VPO) catalysts were prepared and tested for catalytic oxidation of NO. The experimental results showed that 0.1V(5)PO/TiN(1) was the optimal catalyst for NO oxidation and the NO conversion could reach 61% at temperature of 350°C. The physico–chemical properties of 0.1V(5)PO/TiN(1) catalyst were characterized by Brunauer–Emmett–Teller measurements (BET), Photoluminescence (PL), X–ray photoelectron spectroscopy (XPS), Infrared spectroscopy measurements of NH3 adsorbed on catalysts (NH3–IR), and Infrared Fourier transform spectroscopy (FTIR). The PL and XPS spectra revealed that the oxygen storage capacity and catalytic activity of VPO/Ti catalyst can be improved by nitrogen doping. The H2–TPR profile also indicated that V(5)PO/TiN(1) catalyst had a superior redox property. Activity test results and FTIR spectra showed that 0.1V(5)PO/TiN(1) catalysts had a superior resistivity to SO2 and the NO oxidation rate is above 50% at temperature of 350°C when SO2 concentration is 200ppm to 800ppm.

Use of nitrogen- and phosphorus-based synthetic fertilizers shows an increasing trend, but this has led to large-scale influx of reactive nitrogen in the environment, with serious implications on human health and the environment. On the other hand, phosphorus, a non-renewable resource, faces a serious risk of depletion. Therefore, recovery and reuse of nitrogen and phosphorus is highly desirable. For nitrogen recovery, an ion exchange/adsorption-based process provides concentrated streams of reactive nitrogen. Bioelectrochemical systems efficiently and effectively recover nitrogen as NH₃ (g) or (NH₄)₂SO₄. Air stripping of ammonia from anaerobic digestate has been reported to recover 70–92 % of nitrogen. Membrane separation provides recovery in the order of 99–100 % with no secondary pollutant in the permeate.With regard to phosphorus (P) removal, physical filtration and membrane processes have the potential to reduce suspended P to trace amounts but provide minimal dissolved P removal. Chemical precipitation can remove 80–99 % P in wastewater streams and recover it in the form of fertilizer (struvite). Acid hydrolysis can convert recovered P into usable phosphoric acid and phosphate fertilizers. Physical-chemical adsorption and ion exchange media can reduce P to trace or non-detect concentrations, with minimal waste production and high reusability. Biological assimilation through constructed wetlands removes both N (83–87 %) and P (70–85 %) from wastewaters, with recovery in the form of fish/animal feeds and biofuel. The paper discusses methods and important results on recovery of nitrogen and phosphorus from wastewater.

Ammonia (NH₃) contributes to widespread adverse health impacts, affects the climate forcing of ambient aerosols, and is a significant component of reactive nitrogen, deposition of which threatens many sensitive ecosystems. Historically, the scarcity of in situ measurements and the complexity of gas-to-aerosol NH₃ partitioning have contributed to large uncertainties in our knowledge of its sources and distributions. However, recent progress in measurements and modeling has afforded new opportunities for improving our understanding of NH₃ and the role it plays in these important environmental issues. In the past few years, passive measurements of NH₃ have been added to monitoring networks throughout the USA, now in place at more than 60 stations, while mobile measurements aboard aircrafts and vehicles have provide detailed observations during several recent field campaigns. In addition, new remote sensing observations from multiple satellite instruments have begun to provide vast amounts of NH₃ observations throughout the globe. These sources of information have collectively driven new air quality modeling capabilities, by revealing deficiencies in current air quality models and spurring development of mechanistic enhancements to models’ physical representation of the diurnal variability and bidirectional nature of NH₃ fluxes. In turn, these advanced models require further observational constraints, as existing NH₃ measurements are still limited in spatiotemporal coverage. We thus evaluate the potential value of a new geostationary remote sensing instrument (GCIRI) for providing constraints on NH₃ fluxes through multiple Observing System Simulation Experiments (OSSEs).

The formation and distribution of oxygen-deficient water mass (ODW) in Jinhae Bay exhibited seasonal patterns similar to those of the summer thermocline, indicating a close mutual relationship, and the influence of ODW formation conditions appeared prominently in the bottom water. The principal factors analysis indicate that dissolved oxygen and NO2 in the bottom water during the time of ODW formation were highly correlated with NH3 and dissolved inorganic phosphorus. The findings clearly illustrate the effects on ODW of seasonal physical and chemical changes. ODW that formed in the bottom water of Jinhae Bay during summer produced high concentrations of nutrients in the bottom water; since the growth of phytoplankton was limited by the strong stratification and low concentrations of dissolved oxygen (<3mg/L) in the bottom layer, these nutrients (especially NH3 and DIP) were retained and accumulated, serving as a major source of nutrients during the dry winter.

The whole-sediment Toxicity Identification Evaluation (TIE) approach is a useful technique that allows for the identification of the contaminants responsible for the toxicity of complex sediment samples. This study aimed to compare the effectiveness of this technique in identifying the causes of toxicity when the test organism used in the toxicity test is capable of ingesting sediment particles. Two forms of exposure were compared: whole-sediment (WS), which integrates dermic and dietary exposures; and sediment–water interface (SWI), which involves dermic exposure only. The combined analysis of the TIE experiments revealed that metals, ammonia and, at one station, organic compounds, were responsible for sediment toxicity. The integrated use of WS and SWI TIE manipulations provided a more complete overview of the causes of toxicity, and thus enabled a better comprehension of complex contamination situations and, consequently, a better ecological assessment.

Liaohe River has received significant attention in the northeast region and even in the entire country. As part of a recently completed water quality assessment, a series of water column and sediment toxicity tests was performed throughout the watershed. In the current study, we subjected sediments from the Liaohe River to toxicity identification evaluation manipulations and tests for chronic toxicity with midge (Chironomus riparius), with survival as the end point. In Phase I, the sediments were treated with zeolite, cation-exchange resin, and powdered coconut charcoal. Results confirmed that ammonia compounds were the major contaminants in terms of toxicity, although toxic effects from metals were also a concern in at least three sites. In Phase II identification, chemical analysis provided a strong evidence that the metals As and Cd are the probable causes of toxicity in the sediments, without the influence of ammonia. Temporally, ammonia is responsible for the toxicity of the selected sediments.

Air pollutant emissions are a fundamental input for accurate air quality simulations. Therefore, a detailed estimation of current emissions should be performed, mainly for the activity sectors that have higher contributions to emission totals. In order to estimate air quality under climate change at regional scale, it is extremely important to provide the most accurate emission inventories based on the emission scenarios used as input for the global climate models. The Representative Concentration Pathways (RCPs) are the most recent developed emission scenarios. Emission inventories used in air quality simulations at regional scale for future periods should be based on these recent developments. In this sense, an Emission Projections under RCP scenarios (EmiPro–RCP) model was developed to assist the estimation of future emission inventories for GHG and common air pollutants. This paper describes the methodology developed under EmiPro–RCP model and presents the estimation of current and projected emissions for Portugal for CO, PM2.5, PM10, SOx, NOx, NMVOC and NH3, which will be used as input in air quality modeling systems. A comparison between the inventories was performed and the results indicated that all the RCPs scenarios predict a decrease in most of the air pollutant emissions until 2100, with the exception of NH3 that increases. The main decreases are found in the coastal zone of Portugal, mainly in Porto and Lisbon urban areas, while the NH3 increases are located not only in the coastal zone but also in the southern inland of Portugal.