Ambient air pollution is one of the most significant environmental problems, and many individuals around the world die each year prematurely from diseases caused by this type of pollution. PM2.5 can transpire deep to the lungs and induce some dangerous health effects in humans. In this study, the health effects of long-term PM2.5 were estimated on expected life remaining (ELR) and years of life lost (YLL) indices in Ahvaz city during the years 2008–2017 using the AirQ+ software developed by WHO. Values obtained from the PM2.5 averaging, ELR, and YLL data were processed for the whole population in the age range of 0–64 and over 64. These values were entered into AirQ+ software. The mean annual concentration of PM2.5 was highly variable, with the highest concentration being 70.72 μg/m3 in 2010 and the lowest 41.97 μg/m3 in 2014. In all studied years, the concentration of PM2.5 with the variations between 4.2 to 7.07 times was higher than the WHO standard (10 μg/m3). Ahvaz city also did not experience any clean day during the 10-year period, and in 2010, there were 47 very unhealthy days and 27 dangerous days, i.e., the highest number of very unhealthy and dangerous days during the period. The results estimated that the highest and lowest YLL in the next 10 years for all ages groups would be 137,760.49 (2010) and 5035.52 (2014), respectively. Also, the ELR index was lower than the Iranian standard and EPA which was significantly correlated with the concentration of PM2.5.
To date, several methods have been proposed to explain the complex process of air pollution prediction. One of these methods uses neural networks. Artificial neural networks (ANN) are a branch of artificial intelligence, and because of their nonlinear mathematical structures and ability to provide acceptable forecasts, they have gained popularity among researchers. The goal of our study as documented in this article was to compare the abilities of two different ANNs, the multilayer perceptron (MLP) and radial basis function (RBF) neural networks, to predict carbon monoxide (CO) concentrations in the air of Pardis City, Iran. For the study, we used data collected hourly on temperature, wind speed, and humidity as inputs to train the networks. The MLP neural network had two hidden layers that contained 13 neurons in the first layer and 25 neurons in the second layer and reached a mean bias error (MBE) of 0.06. The coefficient of determination (R2), index of agreement (IA), and the Nash–Scutcliffe efficiency (E) between the observed and predicted data using the MLP neural network were 0.96, 0.9057, and 0.957, respectively. The RBF neural network with a hidden layer containing 130 neurons reached an MBE of 0.04. The R2, IA, and E between the observed and predicted data using the RBF neural network were 0.981, 0.954, and 0.979, respectively. The results provided by the RBF neural network had greater acceptable accuracy than was the case with the MLP neural network. Finally, the results of a sensitivity analysis using the MLP neural network indicated that temperature is the primary factor in the prediction of CO concentrations and that wind speed and humidity are factors of second and third importance when forecasting CO levels. 相似文献
The Haraz River is one of the most significant rivers in the southern Caspian Sea basin. Towards the estuary, the river receives discharges of industrial, agricultural, and urban wastes. In the present investigation, bulk concentrations of Cu, Zn, As, Cd, Pb, Fe, Ni, Cr, Co, and Sr in Haraz River (Iran) bed sediments were measured from several sample locations. In addition, association of studied metals with various sedimentary phases was assessed to determine the proportions of metals in different forms. The intensity of sediment contamination was evaluated using an enrichment factor (EF), geo-accumulation index (Igeo), and a newly developed pollution index (Ipoll). Both EF and Igeo formulae compare present concentrations of metals to their background levels in crust and shale, respectively. In a specific area with its own geological background like Haraz River water basin where naturally high concentrations of metals may be found, such a comparison may lead to biased conclusions regarding levels of anthropogenic contamination. Accordingly, chemical partitioning results are substituted for the mean crust and shale levels in the new index (Ipoll). The Pearson correlation coefficient between the anthropogenic portion of metallic pollution in Haraz river-bed sediments with Ipoll showed much more value in comparison with those of geochemical accumulation index and enrichment factor. The order of metals introduced by anthropogenic activities are as follows: Sr > Pb > Co > Cd > Zn > Cu > Ni > As > Cr > Fe. The results showed relatively higher concentrations of Cd, As, Sr, and Pb in comparison with those of shale. However, based on the chemical partitioning of metals, it is found that Sr, Pb, Co, and Cd are the most mobile metals. In spite of the high As concentrations in sediments, it is not likely that this element is a major hazard for the aquatic environment since it is found mainly in the residual fraction. Also, Fe, Cr, and Ni are present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments. 相似文献
Cadmium (Cd) and lead (Pb) were determined in three species of mollusks and associated sediment. Samples were collected from two locations along the intertidal zone of the Persian Gulf near Bandar Abbas. The study was conducted during the spring of 2011, 10 sediment samples and 15 mollusks from each of the following species: Saccostrea cucullata, Solen brevis, and Callista umbonella, were simultaneously collected. Soft tissue, shell, and sediment were tested for metals using an atomic absorption spectrophotometer. Geochemical fractions of the sediment were examined for metals using a sequential extraction technique. Our results indicate that over half of Cd and Pb in the sediment had natural origins. Independent sample t test showed statistically significant (p?<?0.05) inter-tissue differences in accumulation of Cd and Pb. Soft tissue of C. umbonella contained highest levels of Cd. Pb accumulation was highest in S. brevis shell. Significant correlations (p?<?0.05) were found between Cd in the soft tissue of C. umbonella and its levels in the geochemical fractions of the sediment. Lead levels in the resistant geochemical fractions of the sediment and S. brevis shell were significantly correlated. Our results suggest that soft tissue of C. umbonella and shell of S. brevis are reliable biomonitoring tools for Cd and Pb, respectively. 相似文献
In present research work the effect of climate change over the humidex in Iran is analyzed. From this research, we can conclude that the PDIAQ index showed a special sensibility to changes in temperature and relative humidity, hence, it can be an interesting tool, may be even better than the humidex to show the expected effect of climate change in perception of air quality. Thus, it was found that the humidex expected in the future will be more elevated than that in the preceding period and, on the other hand, the PDWRC has clearly reached a lower value than in the preceding period. The same effects, other than those using the earlier indexes in a more detailed manner, were observed with the PDIAQ. This index showed a higher sensitivity to variations in temperature and relative humidity, than the humidex. Finally, the main results obtained must be considered at the time of design and during construction of future buildings, since buildings that are being constructed today will be occupied in the future years of the 2100s. 相似文献
The objective of the project was to identify all hazardous waste sites in Burlington County, New Jersey that could be detected on existing, medium-scale aerial photographs of the county. The complete set of over 1000 black- and-white stereopairs at a scale of 1:12,000 was carefully examined for initial identification of possible sites. All suspicious sites were examined again on color transparencies of the county at the same 1:12,000 scale. Out of the 1094 black- and-white photos, 250 required further checking on color transparencies using a zoom stereoscope. This examination resulted in a final identification of 67 sites, the locations of which were delineated on 1:24,000 USGS maps. The use of air photo interpretation techniques provided an effective procedure for identifying waste sites quickly as well as providing a useful demonstration program for county and state officials. 相似文献
Antimony (Sb) accumulates in the liver which is one of the target organs for metal-mediated toxicity. Although toxicity of Sb was previously investigated, the precise mechanism of Sb-induced hepatotoxicity remains to be determined. The aim of this study was to examine the role of oxidative stress, and mitochondria in the induction of cell death by Sb. Our results showed that liver cell lysis induced by Sb is mediated by reactive oxygen species (ROS) formation, lipid peroxidation and decline of mitochondrial membrane potential (MMP). Antimony-induced ROS formation, lipid peroxidation and reduction of MMP were significantly diminished by antioxidants and ROS scavengers such as dimethyl sulfoxide and mannitol; mitochondrial permeability transition (MPT) pore sealing agents such as carnitine and trifluoperazine; and adenosine triphosphate (ATP) generator, L-glutamine. Antimony-induced ROS formation, lipid peroxidation and fall in MMP were potentiated by glutathione (GSH) depletion via n-bromoheptane. MPT pore sealing agents and ATP generator inhibited hepatotoxicity, indicating Sb-activated cell death via mitochondrial pathway. Pretreatment of hepatocytes with antioxidants and ROS scavengers also blocked cell death induced by Sb, whereas GSH depletion enhances Sb-induced cell death, suggesting that oxidative stress may be directly involved in the reduction of MMP. These findings contribute to a better understanding of the mechanisms that mediate Sb-induced cell death in isolated rat hepatocytes. 相似文献
Background The management of its available water resources has become a key issue for Iran. During the last few decades, the water quality
of Siahroud River in the coastal plain of the Caspian Sea in Gilan Province in Northern Iran has significantly degraded. The
scarcity of water has been compounded by rapid population growth and increasing pollution from fertilizers, pesticides, and
municipal and industrial wastes. One of the sources of this degradation is the movement of heavy metals from the river's watershed
into the various water systems supported by the river, including the water system for Rasht City.
Methods To study the magnitude of heavy metal pollution in the Siahroud River, seven heavy metals including Zn, Cu, Pb, Cd, Mn, Fe,
and Ni were measured in duplicate from replicated water samples collected over five consecutive seasons and analyzed by Atomic
Absorption Spectrometry. In situ measurements of pH were taken with the samples and total organic carbon (TOC) was analyzed
by IR gas measurement.
Results The results demonstrated that four of the seven heavy metals including Pb, Fe, Cd, and Mn exceeded permissible safe levels
as established by the United States Environmental Protection Agency. Multivariate factor analysis suggested that industrial
land-use was the main contributing factor for the high levels of Fe and Mn in the Siahroud River, whereas, Cd was principly
from agricultural activities in the watershed. The data also suggested that pH and TOC had an important role in the behaviour
of Pb and Mn, and that the elevated levels of these two heavy metals in Siahroud River was the consequence of other anthropogenic
sources. Only negligible levels of Zn, Cu and Ni were detected. Finally, all the sampling stations were subjected to cluster
analysis. The results indicated that three different zones could be distinguished according to the levels of pollution. In
addition, it was shown that the urban areas did not have a significant impact on the heavy metal pollution in the river. This
observation stems from the fact that the data from the sampling stations before and after Rasht City were not significantly
different.
Recommendation . Preventive measures need to be undertaken in the land-use systems and watersheds of the Siahroud River to reduce the pollution
levels of Pb, Cd, Mn and Fe. 相似文献