Results 1 - 10 of 590
Results 1 - 10 of 590. Search took: 0.024 seconds
|Sort by: date | relevance|
[en] In September–October 2015, El Niño and positive Indian Ocean Dipole conditions set the stage for massive fires in Sumatra and Kalimantan (Indonesian Borneo), leading to persistently hazardous levels of smoke pollution across much of Equatorial Asia. Here we quantify the emission sources and health impacts of this haze episode and compare the sources and impacts to an event of similar magnitude occurring under similar meteorological conditions in September–October 2006. Using the adjoint of the GEOS-Chem chemical transport model, we first calculate the influence of potential fire emissions across the domain on smoke concentrations in three receptor areas downwind—Indonesia, Malaysia, and Singapore—during the 2006 event. This step maps the sensitivity of each receptor to fire emissions in each grid cell upwind. We then combine these sensitivities with 2006 and 2015 fire emission inventories from the Global Fire Assimilation System (GFAS) to estimate the resulting population-weighted smoke exposure. This method, which assumes similar smoke transport pathways in 2006 and 2015, allows near real-time assessment of smoke pollution exposure, and therefore the consequent morbidity and premature mortality, due to severe haze. Our approach also provides rapid assessment of the relative contribution of fire emissions generated in a specific province to smoke-related health impacts in the receptor areas. We estimate that haze in 2015 resulted in 100 300 excess deaths across Indonesia, Malaysia and Singapore, more than double those of the 2006 event, with much of the increase due to fires in Indonesia’s South Sumatra Province. The model framework we introduce in this study can rapidly identify those areas where land use management to reduce and/or avoid fires would yield the greatest benefit to human health, both nationally and regionally. (letter)
[en] Phytoplankton are key components of ecosystems. Their growth is deeply influenced by temperature. In a context of global change, it is important to precisely estimate the impact of temperature on these organisms at different spatial and temporal scales. Here, we review the existing deterministic models used to represent the effect of temperature on microbial growth that can be applied to phytoplankton. We first describe and provide a brief mathematical analysis of the models used in constant conditions to reproduce the thermal growth curve. We present the mechanistic assumptions concerning the effect of temperature on the cell growth and mortality, and discuss their limits. The coupling effect of temperature and other environmental factors such as light are then shown. Finally, we introduce the models taking into account the acclimation needed to thrive with temperature variations. The need for new thermal models, coupled with experimental validation, is argued.
[en] Years of life lost (YLL) is a more informative and accurate indicator than daily death counts for assessing air pollution related premature death. However, there is limited evidence available about the relationship of air pollution with YLL, especially in China. We conducted a ten-year (from January 1st, 2001 to December 31st, 2010) multi-district time-series study to estimate the effects of ambient particulate matter with an aerodynamic diameter of less than 10 μm in size (PM10) on daily non-accidental deaths and YLL in six districts of Tianjin, China. Meta-analysis was used to merge the results of the six districts. We found that the increase of PM10 was significantly associated with daily death and YLL in the six districts, except with the YLL in Heping district. 10 μg/m3 increases in PM10 were associated with the maximum increases in excess risk (ER) of death counts of 0.33% (95% confidence interval [CI]: 0.25%, 0.41%) at lag01 and in YLL of 0.80 (95%CI: 0.47, 1.13) person year at lag01 for the combined effects of six districts, respectively. Moreover, the associations of PM10 on daily death counts and YLL were stronger in the elder people (≥65 years) than those in the younger ones (<65 years). These findings may help to shed light on the policy-making of PM-control in China and provide useful information for the protection of susceptible population. - Highlights: • A more informative indicator (YLL) was used to assess PM10-related health effects. • A ten-year multi-county time-series study was conducted to assess effects of PM10. • PM10 was significantly associated with daily non-accidental death and YLL. • The associations were stronger in the elderly than that in the younger ones. • This study provides more convincing evidence for the policy-making of PM-control. - This ten-year time-series study showed that PM10 was significantly associated with daily non-accidental death and YLL.
[en] Internal exposure from inhalation of radon and its progeny is one of the most significant sources of natural radiation exposure of the population. Radon levels and radon equilibrium factor were measured in the dwellings of Al-Kharj, Saudi Arabia using passive technique. Calibrated CR-39 diffusion type radon detectors were used for radon measurements and the method of can and bare is adapted for the measurement of radon equilibrium factor. Passive measurements enable the accumulation of the result over a long period and cover a wide area. The probability of cancer induction and then the expected mortality was calculated based on different approaches. The results show that the overall weighted mean of annual effective dose for Al-Kharj resident is equal to 1.51 ± 0.8 mSv and The average expected mortality for residents in dwellings of Al-Kharj city is ranged from 0.596 ± 0.25 to 0.369 ± 0.15 death per 10,000 persons of ages from 40 to 70 years respectively. Also, the lifetime excess absolute risk (LEAR) of the residents of the Al-Kharj city is equal to (2.06 ± 0.8) 104 . The effect of dwelling types, ventilation and construction materials on the expected mortality is discussed
[en] Marine debris is one of the most significant problems facing the marine environment, endangering wildlife, polluting oceans and is an issue which holds global significance. Plastics constitute a large proportion of marine debris, and their persistence can cause a number of negative consequences for biota and the environment, including entanglement and ingestion, which can lead to mortality. Most plastics never biodegrade and instead break down into smaller pieces which are more difficult to monitor and eventually become so small (micro and nanoplastics), that they are challenging to observe or intercept in the ocean. Marine-based Research Infrastructures (RIs) monitor several environmental parameters and are situated around the globe; however, none of these are routinely monitoring marine debris or plastics. Currently, the only infrastructures in place with regard to marine debris are ‘physical debris interception infrastructure’ in the form of barriers constructed to prevent marine debris from entering the ocean. Several knowledge gaps and restraints exist within current in situ infrastructure including technological immaturity, diverse methodologies and lack of data harmonisation. Nevertheless, marine RIs could monitor microplastics within the water column on a long-term basis and initial steps towards developing technology are promising. (letter)
[en] Highlights: • Plastic debris collar wrappings (PDCW) are involved in the frequent entanglement of several groups of marine animals. • We present records for four species afflicted by plastic debris collars. • PDCW reduced fish swimming performances, feeding and antipredator behavior. • Given the importance of these performances on survival, reduction in fitness is expected. - Abstract: Plastic debris collar wrappings (PDCW) are involved in the frequent entanglement of several groups of marine animals. In fishes, however aside from ‘ghost fishing’, PDCW events are rarely documented, and no record of this occurrence exists in tropical reef fishes. Here, we present records for four species afflicted by plastic debris collars. Observations occurred during snorkeling, and included the silver mojarra Eucinostomus argenteus, Atlantic thread herring Ophistonema oglinum, tomtate grunt Haemulon aurolineatum and gray parrotfish Sparisoma axillare. While PDCW may not create an instantaneous source of mortality, our observations suggest that debilitating stress, created by reduced swimming performances, feeding and/or antipredator behavior are likely consequences for afflicted individuals. Given the importance of these performances on survival, reduction in fitness is expected. This note aims to report cases of PDCW and underscore that such interactions between fishes and plastic pollution may be more prevalent than previously expected in coastal reef habitats.
[en] Gammarus spp. (G. daiberi and G. tigrinus) experienced no increased latent mortalities for periods up to 10 days after being exposed to an 8.3C ΔT above an ambient temperature of 25.5C for periods up to 60 minutes. An 11.1C ΔT above an ambient temperature of 26.5 C resulted in significant reductions in survival in groups of Gammarus spp. exposed for 30 and 60 minutes. No significant mortalities were observed, however, following a 5-minute exposure to the 11.1 C ΔT. At an ambient temperature of 11.7 C, Gammarus spp. exposed to 16.7 C ΔT's for periods up to 180 minutes displayed no increased mortalities 10 days after exposure. A sustained 17-day exposure of Gammarus spp. to a 15.6 C ΔT at ambient temperatures of 11.2 to 7.1 C resulted in no increased mortalities and stimulated reproductive behavior. Subsequent reproductive activities were not affected by up to 60-minute exposures of mature Gammarus spp. to an 8.3C ΔT at an ambient temperature of 26.0 C. The same exposure also did not affect the release of young by ovigerous female Gammarus spp. An 11.0 C ΔT for 30 minutes resulted, however, in almost no release of young from ovigerous females