This study was aimed at testing the applicability of modified Weber number scaling with Alaska North Slope (ANS) crude oil, and developing a Reynolds number scaling approach for oil droplet size prediction for high viscosity oils. Dispersant to oil ratio and empirical coefficients were also quantified. Finally, a two-step Rosin-Rammler scheme was introduced for the determination of droplet size distribution. This new approach appeared more advantageous in avoiding the inconsistency in interfacial tension measurements, and consequently delivered concise droplet size prediction. Calculated and observed data correlated well based on Reynolds number scaling. The relation indicated that chemical dispersant played an important role in reducing the droplet size of ANS under different seasonal conditions. The proposed Reynolds number scaling and two-step Rosin-Rammler approaches provide a concise, reliable way to predict droplet size distribution, supporting decision making in chemical dispersant application during an offshore oil spill.

Determining how coral ecosystems are structured within extreme environments may provide insights into how coral reefs are impacted by future climate change. Benthic community structure was examined within the Persian Gulf, and adjacent Musandam and northern Oman regions across a 3-year period (2008–2011) in which all regions were exposed to major disturbances. Although there was evidence of temporal switching in coral composition within regions, communities predominantly reflected local environmental conditions and the disturbance history of each region. Gulf reefs showed little change in coral composition, being dominated by stress-tolerant Faviidae and Poritidae across the 3years. In comparison, Musandam and Oman coral communities were comprised of stress-sensitive Acroporidae and Pocilloporidae; Oman communities showed substantial declines in such taxa and increased cover of stress-tolerant communities. Our results suggest that coral communities may persist within an increasingly disturbed future environment, albeit in a much more structurally simple configuration.

The inner 1/3 of Isahaya Bay which is a tributary of Ariake Sea in Japan was shut off from the sea by a dike for the reclamation and disaster prevention in 1997. On the other hand, several environmental and fisheries problems occurred in Ariake Sea after 1990s. Some fishermen insisted that the major reason for the decrease of fishing must be the influence of the dike construction and filed lawsuits. Now the court decision is fixed and Japanese government must open the gates to reintroduce sea water into the reservoir. We made numerical simulations of currents, hydrography and sediment transport to assess the influences of the gate opening. To choose the environmentally wise procedure of gate opening, it is needed to reduce the erosion and deposition of bottom sediments caused by the enhanced tidal current and to minimize the occurrence of hypoxia in the reservoir.

Plastics are the most common material of marine litter and have become a global pollution concern. They are persistent in the environment where they gradually degrade into increasingly smaller particles–microplastics (MP). Our study presents results of sea-surface monitoring for MP in the Slovenian part of the Trieste Bay in the Northern Adriatic Sea. In 17 trawls conducted over a 20-month period we found a high average concentration of 406×103MPparticles/km2. Over 80% of the particles were identified as polyethylene. The significant variability of MP concentrations obtained on different sampling dates is explained by use of surface current maps and a recently developed Markov chain marine litter distribution model for the Adriatic Sea.

Six hindered phenolic antioxidants (HPAs) from emissions of light-duty diesel and gasoline vehicles were determined. Vehicles were tested on a dynamometer that conducted a typical city-driving protocol and their exhaust samples were collected on filters. A high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of HPAs in the exhaust samples. Method detection limits reached low ng/m3 in exhaust after optimization of experimental conditions. Identification and quantification were proven to be reliable for these phenols in lightly-loaded and ambient filter samples. In heavily loaded samples, matrix interferences existed, which decreased recoveries of surrogate in both filter and disk. However, matrix spike samples showed good recoveries of target HPAs. In vehicle emission samples, the highest level of HPAs was 2,6-di-tert-butylphenol at 52.7 ng/m3 (28.9 pg/mm2 on filter) in emission of a 2009 Volkswagen Jetta with a diesel engine. Most HPAs were not detected or near detection limits. Therefore, the additives of phenol antioxidants in fuels were mostly oxidized during the combustion process. Further, the 2009 diesel Jetta produced about 7 times more of HPAs than the 2008 Pontiac G5 with a gasoline engine. In addition, it is discovered that engines operated at a colder ambient temperature (−7 °C) yielded more HPA emissions than at the warmer condition (25 °C), because the combustion efficiency of engines are normally reduced at a lower temperature.

In this study, a hypothesis based on observations is offered to explain levels of ambient ozone in Quito, a busy urban center located at high altitude along the equatorial Andes. Supporting data includes first-time measurements of boundary layer depths in addition to ozone, NO (nitric oxide), and oxidized nitrogen observations. Mixing layer measurements were taken in June and July 2014 and in April 2015. The air quality data set is presented for the months of July through September 2014. From a total of four midday soundings launched under sunny conditions, a deep mixing layer up to 2200 magl (meters above ground level) was found only once when surface temperature was unusually high. In the other three cases, layered structures were found with the top of the mixing layer at 687 magl on average. These measurements were obtained when surface temperatures were within the usual range. Furthermore, the morning boundary layer depth was measured twice between 07:00 and 08:00. On average, a depth of 185 magl was determined. Air quality measurements for the study period show that ozone stayed below 55 ppbv while NO levels were routinely higher than 100 ppbv in the morning rush hour, and oxidized nitrogen stayed high during daytime. Observations of a generally shallow boundary layer indicate that the environment at this Andean location has the potential to accumulate pollutants. Thus, vertical dilution alone is unable to explain the observed low levels of ambient ozone. When ozone reached the highest values in the second half of September 2014, it was found that it increases with decreasing NO levels during daylight hours between 11:00 and 16:00. Therefore, air quality observations along with findings of shallow mixing layers suggest that inhibition of ozone production potentially occurs due to a NOx-saturated chemical regime.

Dispersion modeling is an important decision tool for estimating the impact of human activities on the environment and its populations. However, it was proved by researchers that AERMOD and CALPUFF, the current regulatory models, do not account for the effect of averaging time. In consequence, these models do not have the ability to predict short-term time peak concentrations. This inability arises from the errors in the lateral and vertical dispersion estimates, which are reliable only to predict 10 min or longer average concentrations. In this paper, a novel evaluation based on Irwin (1983) was conducted to investigate the effect of averaging time on the lateral dispersion and maximum concentration estimates. The Pasquill-Gifford, Högström, Draxler (embedded in CALPUFF) and AERMOD lateral dispersion schemes were tested using the Round Hill II experiment, developed to investigate the effects of averaging time on atmospheric transport and diffusion. The observed lateral dispersion was derived from the lateral concentration profiles along 3 sampling arcs (50, 100 and 200 m), measured on 3 different averaging times (0.5; 3 and 10 min). The observed lateral dispersion was compared to those estimates. The results of the comparison show that AERMOD and Draxler correlate better with measured data than the PG and Högström methods. However, their estimates are biased and the magnitude of systematic errors tends to grow as the averaging time decreases. Moreover, AERMOD and Draxler, with Peak-to-Mean (P-M) adjustment, tend to overestimate the lateral dispersion farther from the source and underestimate at downwind distances less than 200 m. The analysis also highlights some concerns on the P-M ratio application due its subjectivity. The present investigation on the effect of short-term averaging times on atmospheric transport and diffusion may help to understand some issues related to the use of dispersion models in the case of flammability, malodor nuisance and toxicity

We examined the associations between the daily variations of air pollutants and mortality in the population of İstanbul, Turkey, using generalized linear models while controlling for time trends and meteorological factors over a 6-year period (2007–2012) at different time lags (0–10 days). Effects of the pollutants (Relative Risk (RR) on current-day (lag 0) mortality to the first ten days (lag 10) were determined. Data on daily mortality, daily mean concentrations of air pollutants of PM10, SO2 and NO2 and daily mean concentrations of temperature and humidity for İstanbul were used in the study. We found significant associations between air pollution and daily mortality from cardiovascular disease, respiratory diseases, and total non-accidental causes in İstanbul. An increase of 10 μg/m3 in concentrations of PM10, SO2 and NO2 over 10 days of lag corresponds to RR = 1.0222 (95% Confidence Interval (CI) = 0.9957–1.0494), RR = 1.1639 (95% CI = 1.0279–1.3177) and RR = 1.0327 (95% CI = 1.0105–1.0554) increase of cardiovascular mortality, respectively. The associations for total non-accidental and respiratory mortality were also positive. Among the three air pollutants, SO2 was associated with the largest RR for deaths from cardiovascular disease, respiratory disease and total mortality. In conclusion, our study showed that short-term exposure to air pollution was associated with increased cardiovascular, respiratory and total non-accidental mortality in the city during 2007–2012. These findings may have implications for local environmental and social policies.

Tokyo Bay, Ise Bay, and the Seto Inland Sea are the total pollutant load control target areas in Japan. A significant correlation between the incidence of red tides and water quality has been observed in the Seto Inland Sea (Honjo, 1991). However, while red tides also occur in Ise Bay and Tokyo Bay, similar correlations have not been observed. Hence, it is necessary to understand what factors cause red tides to effectively manage these semi-closed systems. This study aims to investigate the relationship between the dynamics of the Red Tide Index and nitrogen regulation as well as phosphorus regulation, even in Ise Bay where, unlike Tokyo Bay, there are few observation items, by selecting a suitable objective variable. The introduction of a new technique that uses the Red Tide Index has revealed a possibility that the total pollution load control has influenced the dynamics of red tide blooms in Ise Bay.