Exposure to mercury vapor (Hg0) causes serious health problem in human body. In this study, a novel and applied method based on solid gas phase extraction (SGPE) with silver nanoparticles (AgNPs) coating on micro glassy balls (MGB) was used for Hg0 removal from artificial air. In bench scale set up, the mercury vapor in air composition was produced by mercury vapor generation system (HgGS) and restored in polyethylene air bag (5 Li). In optimized conditions, the mercury vapor in air bag, passed through AgNPs-MGB and absorbed on it. Then, the mercury was completely desorbed from AgNPs by increasing temperature up to 245 °C and online determined by cold vapor atomic absorption spectrometry (CV-AAS). By proposed procedure, the method recovery and capacity of AgNPs were obtained 98% and 91.8 mg g−1, respectively. A simple, fast and low cost synthesis of AgNPs causes, the SGPE introduce as a cost-effective method for mercury vapor removal from air. Validation of methodology was confirmed using ultra trace mercury analyzer (MC3000).

Vegetation acts as a momentum and thermal sink, affecting the mixing of species and temperature-dependent constants of reaction rates. Numerical simulations were performed to investigate the effects of vegetation on the dispersion of reactive pollutants using a computational fluid dynamic (CFD) model coupled with NO-NO2-O3 photochemistry. Moreover, characteristics of temperature and flow fields were analyzed for different aspect ratios and leaf area densities. The results showed that flow is reversed in the presence of trees, and it enhances as leaf area density (LAD) increases; additionally, vegetation creates downward and vortex flows. The results also revealed that the dispersion of nitrogen oxides is influenced by the flow patterns; nevertheless, chemical reactions are significant for the dispersion of ozone. In addition, the vegetation is observed to weaken ventilation efficiency of NO and NO2; however, ventilation efficiency of O3 improves in LAD = 0.5 and 1.0. Aspect ratios and leaf area densities are also found to interact with each other; consequently, the optimum LAD is different for each aspect ratio. The larger regions with maximum concentrations of nitrogen oxides at the height of 2 m for aspect ratios of 0.5, 1.0, and 2.0 correspond to LAD = 2.0, 1.5, and 1.0, respectively. Furthermore, vegetation as compared to tree-free environment, mostly leads to a better chemical equilibrium.

This study assessed the concentrations of specific volatile organic compounds (VOCs) inside vehicle cabins under different practical vehicle driving conditions in China. The mean concentrations of the VOCs, including benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, acetone, and acrolein, were 16.73 μg/m3, 66.02 μg/m3, 14.20 μg/m3, 6.78 μg/m3, 28.09 μg/m3, 16.43 μg/m3, 12.47 μg/m3, and 20.65 μg/m3 (the sum of acetone and acrolein), respectively. All the specified VOCs inside vehicle cabins were not exceeded the limits of the national standard. The in-cabin VOCs concentrations were investigated for 16 private vehicles under three ventilation conditions: (i) fan off and recirculation (RC) off, (ii) fan on and RC off, and (iii) fan on and RC on. The VOCs concentrations increased 50.46% (mean of the measured VOCs) when the ventilation condition changed from (ii) to (i), and increased 51.38% (mean of the measured VOCs) when ventilation condition changed from (ii) to (iii). Two vehicle models (vehicle model A and vehicle model B) were tested in the study to investigate the influence on in-cabin VOCs concentrations of two typical interior trims (leather, fabric). The VOCs concentrations inside B vehicles (leather interiors) were averagely 1.42 times larger than the concentrations in A vehicles (fabric interiors). For new vehicles, the concentrations of benzene, toluene, xylene, ethylbenzene, formaldehyde, acetaldehyde, acetone and acrolein were larger than the concentrations inside old vehicles by 12.89%, 103.54%, 123.14%, 104.20%, 6.26%, 6.31%, and 10.67%, respectively. The VOCs concentrations significantly increased as the raise of ambient temperature. Toluene, styrene, ethylbenzene, and xylene were the most sensitive VOCs to temperature, which increased 513.6%, 544.8%, 767.0%, and 597.7% as the temperature increased from 11 °C to 25 °C.

The production rate of secondary pollutants was highly non-linear with the emission intensity of their precursors. In this study, the air quality modeling system RAMS-CMAQ with zero-out sensitivity test was applied to conduct source sensitivity approaches of PM2.5 for four source categories (industry, power plants, transport, and residential) over the North China Plain (NCP) in January and July of 2013. The results show that the residential and industry emission sector were the greatest contributors to domain-wide PM2.5 in January and July, respectively. The largest variation could exceed 200 μg m−3 attributed to the residential sector in January when a heavy pollution period appeared, and could reach 40–60 μg m−3 attributed to the industry sector in July in the heavy pollution area, respectively. The nonlinear relationship between the secondary pollutant formation and its precursors was reflected by this source sensitivity approaches, as the summation of the secondary pollutant variations attributed to the four sources was obviously different from the simulated baseline concentration and the mass burden of nitrate would increase upon removal of the power plants or transport emission sector in the heavy pollution regions in January. Further analysis indicated that the improvement of atmospheric oxidation capacity due to emission sector removal coupled with the sufficient precursor nitrogen oxide under severe pollution background should be the main reason of the negative variation of nitrate appeared in the sensitivity test. This feature indicates that the atmospheric oxidation capacity is an important impact factor in determining the production rate of nitrate formation, and could further influence the variation feature of PM2.5 mass burden during the pollution episode. Thus, it is suggested that the comprehensive pollution control strategies should be implemented based on the specific pollution condition. Additionally, the nonlinearity of secondary pollutants formation should be reasonably considered for developing effective emission control strategies.

Chronic low-frequency anthropogenic sound, such as shipping noise, may be negatively affecting marine life. The EU's Marine Strategy Framework Directive (MSFD) includes a specific indicator focused on this noise. This indicator is the yearly average sound level in third-octave bands with centre frequencies at 63Hz and 125Hz. These levels are described for Falmouth Bay, UK, an active port at the entrance to the English Channel. Underwater sound was recorded for 30min h−1 over the period June 2012 to November 2013 for a total of 435days. Mean third-octave levels were louder in the 125-Hz band (annual mean level of 96.0dB re 1μPa) than in the 63-Hz band (92.6dB re 1 μPa). These levels and variations are assessed as a function of seasons, shipping activity and wave height, providing comparison points for future monitoring activities, including the MSFD and emerging international regulation.

Kuril Islands of the Sea of Okhotsk and the western part of the Bering Sea are an area of natural feeding of Pacific salmon, and the catch area of ones for food market. Food safety of products is an important task of aquaculture. Сoncentrations of HCHs (α-, β-, γ-) and DDT and its metabolites (DDD and DDE) were determined in organs of the pink (Oncorhynchus gorbuscha), chum (O. keta), chinook (O. tshawytscha), and sockeye (O. nerka), which caught from the natural aquaculture region of Russia (near the Kuril Islands (the northern-western part of the Pacific Ocean), the Sea of Okhotsk and the Bering Sea). The average total concentration of OCPs in organs of salmon from Western Pacific is lower than that in salmon from the North Pacific American coast and the Atlantic Ocean. The region can be used to grow smolts, which will be later released into the ocean.

High spatial variability in polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, such as DDTs, and polybrominated diphenylethers was observed in plastic pellets collected randomly from 41 beaches (15 cities) in 2010 from the coast of state of São Paulo, southeastern Brazil. The highest concentrations ranged, in ng g−1, from 192 to 13,708, 3.41 to 7554 and <0.11 to 840 for PAHs, PCBs and DDTs, respectively. Similar distribution pattern was presented, with lower concentrations on the relatively less urbanized and industrialized southern coast, and the highest values in the central portion of the coastline, which is affected by both waste disposal and large port and industrial complex. Additional samples were collected in this central area and PCB concentrations, in ngg−1, were much higher in 2012 (1569 to 10,504) than in 2009/2010 (173 to 309) and 2014 (411), which is likely related to leakages of the PCB commercial mixture.

Nutrient pollution causes environmental damages on aquatic ecosystems worldwide. Eutrophication produces impacts in coastal ecosystems, affecting biota and ecosystem services. The Urias coastal lagoon (SE Gulf of California) is a sub-tropical estuary under several environmental pressures such as nutrient inputs from shrimp farm effluents and dredging related to port operations, which can release substances accumulated in sediments. We assessed the water quality impacts caused by these activities and results showed that i) nitrogen was the limiting nutrient, ii) shrimp farm effluents increased particulate organic matter and chlorophyll a in the receiving stations, and iii) dredging activities increased nitrite and reduced dissolved oxygen concentrations. The co-occurrence of the shrimp farm releases and dredging activities was likely the cause of a negative synergistic effect on water quality which mainly decreases dissolved oxygen and increases nitrite concentrations. Coastal zone management should avoid the co-occurrence of these, and likely others, stressors in coastal ecosystems.

In this study, basic sediment properties, nutrient flux, and nitrogen cycle (including denitrification, anaerobic ammonium oxidation [anammox], nitrification, and dissimilatory nitrate reduction to ammonium [DNRA]) were investigated at two sampling sites with different tree ages in the mangrove region of the Jiulong River Estuary, China. The results show that sediments at mangrove flat area have relatively strong capability to reduce NO3−, in which the DNRA rate is relatively high (204.53±48.32μmolNm−2h−1), which is approximately 75.7–85.9% of the total NO3− reduction, while the denitrification and anammox rates are relatively low – only approximately 5.6–9.5% and 8.5–14.8% of the total NO3− reduction, respectively. Thus, in the nitrogen-enriched subtropical mangrove system, DNRA is the main pathway to reduce NO3−, and most of the input nitrogen is conserved as NH4+ in the system, which assures high productivity of the mangrove system.