机场周围区域飞机噪声监测方法对比研究

中国机场周围区域飞机噪声监测一直采用计权等效连续感觉噪声级L_(WECPN)为评价量,标准修订后拟采用昼夜等效声级L_(dn)为评价量,监测方法也相应更改。该文通过理论推导及宁波栎社机场噪声现场监测数据,系统比较了2种机场周围区域飞机噪声监测方法,并分析了监测结果的差异及影响因素。结果表明:L_(WECPN)与L_(dn)在相差10 dB的基础上,差值受到单次飞机噪声值和傍晚飞行次数2个因素影响。单次飞机噪声监测量L_(EPN)和L_(AE)在飞机匀速直线经过时差值约为3.75 dB,实际上受到飞行航迹、飞机运动状态、噪声传播环境、突发噪声干扰等因素影响,此次监测的187次飞机L_(EPN)和L_(AE)的差值范围为2.1～5.5 dB。傍晚飞行次数引起的监测结果差值范围为0～4.8 dB。     

Major factors of industrial noise-induced hearing loss in Hong Kong

A tripartite participation of government, trade unions and university was formed in 1988 to study the situation of industrial noise and hearing acuity of workers. Since 1982, the six industries identified by the Noise Control Office were construction, electronics, metals, plastics, shipbuilding and repairing, and textiles. Safety-subcommittees were formed. With the help of these subcommittees, 21 out of 32 medium-size factories responded to the study. A total of 922 sound measurements were made and 1062 out of 10724 workers were examined. More than one third (37.5%) of workers worked in locations with noise level in excess of L _eq (8h) 90 dBA. Among examined subjects, 39.8% were exposed to L _eq (8) 90 dBA and above and 18.6% were found to have industrial hearing loss. Multiple logistic regression analyses adjusted for sex and age showed that for hearing loss, the important risk factors were duration of occupational noise exposure, noise intensity, floor vibration and military experience. Current legislation and measures in hearing conservation were inadequate despite the implementation of inspection by the Noise Control Office. Recommendations were directed at amending relevant legislation, increasing supervision of use of personal ear protection, and strengthening health education and audiometric surveillance of exposed workers.     

应用GIS技术研究车流量与交通噪声相关性

对无锡建成区交通噪声等效声级(L_(eq))与车流量进行监测,应用GIS技术分析交通噪声与车流量的空间分布,为交通噪声污染防治工作提供科学参考。结果表明:噪声L_(eq)峰值及车流量峰值均集中在高速公路出入口必经路段,此区域为噪声污染防治重点区域。同时发现,噪声L_(eq)与车流量在空间分布上并非成正比关系,在时间趋势上车流量上升但噪声值下降,说明在机动车保有量不断攀升的背景下,采取多种防治措施可以有效缓解甚至改善交通噪声污染。     

铁路噪声影响特点与评价方法研究

针对山东省境内一主要铁路路段的铁路噪声,布设了不同类型的多个点位进行了测量.应用大量的实测数据,对铁路噪声的变化规律及影响特点进行了分析研究.铁路噪声的Lmax对铁路两侧环境的影响明显大于Leq.     

Evaluation of Traffic Noise Pollution in Amman, Jordan

The City of Amman, Jordan, has been subjected to persistent increase in road traffic due to overall increase in prosperity, fast development and expansion of economy, travel and tourism. This study investigates traffic noise pollution in Amman. Road traffic noise index L ₁₀(1 h) was measured at 28 locations that cover most of the City of Amman. Noise measurements were carried out at these 28 locations two times a day for a period of one hour during the early morning and early evening rush hours, in the presence and absence of a barrier. The Calculation of Road Traffic Noise (CRTN) prediction model was employed to predict noise levels at the locations chosen for the study. Data required for the model include traffic volume, speed, percentage of heavy vehicles, road surface, gradient, obstructions, distance, noise path, intervening ground, effect of shielding, and angle of view. The results of the investigation showed that the minimum and the maximum noise levels are 46 dB(A) and 81 dB(A) during day-time and 58 dB(A) and 71 dB(A) during night-time. The measured noise level exceeded the 62 dB(A) acceptable limit at most of the locations. The CTRN prediction model was successful in predicting noise levels at most of the locations chosen for this investigation, with more accurate predictions for night-time measurements.     

Confidence intervals of Leq in the case of stationary random noise measurements

A common practice in random noise measurements is to assume that the noise samples are normally distributed. Since the sound pressure level (L _p) is related with the sound energy by a non linear equation, the distribution of the two variables will be different. If one assumes that the probability density function (pdf) of L _p is normal, the pdf of noise energy is not and vice versa. A simple criterion based on statistical properties of sampled noise can be used for the determination of the kind of distribution of the measured noise. The case in which the noise energy emitted by the source, and the case in which the measured noise level is normally distributed are examined. For each case confidence intervals of the calculated equivalent level are calculated.     

Noise surveys of hand-held pneumatic rock drills in Hong Kong

A study of the noise generated by hand-held pneumatic rock drills at 15 road works locations in Hong Kong was conducted in 1989. The locations of road construction works were identified over one week period. Sound pressure levels (SPL) and band frequency analysis were measured with the integrated sound level meter at the level of the operator's ears. The sound levels for all 15 operators exceeded the local statutory limit of 90 dBA. The average sound level was 107.4 dBA and the corresponding continuous equivalent level adjusted to 8 hours or L _eq (8h) was 104.8 dBA. The sound levels for the octave frequencies from 125 Hertz to 8000 Hertz were all in excess of 90 dBA. Estimates of the risk of developing hearing impairment for conversation speech among the operators were 18% and 42% after 5 and 10 years of exposure, respectively. Although there is adequate statutory control to restrict and reduce the hazards caused by noise at road construction works to the workers and to the public at large, no noise control measures were noted at the work sites and none of the operators used hearing protection. This situation was compounded by the short-term nature of road works and the high mobility of the operators.     

Urban daytime traffic noise prediction models

An evaluation was made of the acoustic environment generated by an urban highway using in situ measurements. Based on the data collected, a mathematical model was designed for the main sound levels (L _eq, L ₁₀, L ₅₀, and L ₉₀) as a function of the correlation between sound levels and between the equivalent sound pressure level and traffic variables. Four valid groups of mathematical models were generated to calculate daytime sound levels, which were statistically validated. It was found that the new models can be considered as accurate as other models presented in the literature to assess and predict daytime traffic noise, and that they stand out and differ from the existing models described in the literature thanks to two characteristics, namely, their linearity and the application of class intervals.     

Assessment of noise level in sundry processing and manufacturing industries in Ilorin metropolis, Nigeria

In this work, noise level in five selected processing and manufacturing industries in Ilorin are evaluated and compared. Emphasis is given to noise emitted by individual industrial machinery from the selected industries. Event L _Aeq and L _N cycles were studied to identify the noisy machines and to generate baseline data. Findings show that hammer mill machine from mineral-bearing rock-crushing mills produced the highest average noise [98.4 dB(A)], an electric generator 1 [95.6 dB(A)] from the soft drink bottling industry, an electric generator [97.7 dB(A)] from the beer brewing and bottling industry, a vacuum pump [93.1 dB(A)] from the tobacco making industry, and an electric generator 2 [94.1 dB(A)] from the mattress-making industry. The highest and lowest average noise exposure levels are recorded in mineral-bearing rock-crushing mills [93.16 dB(A)] and the mattress making industry [84.69 dB(A)], respectively. The study shows that, at 95% confidence level, there is significant difference (P < 0.05) in noise levels in the industries surveyed. The percentages of machines that emit noise above Federal Environmental Protection Agency and Occupational Safety and Health Administration recommendations [90 dB(A)] are from the soft drink bottling industry (83.3%), the beer brewing and bottling industry (42.9%), the tobacco making industry (71.4%), the mattress making industry (11.1%), and minerals crushing mills (87.5%). In the past 20 years, the noise levels in the soft drink bottling industry were reduced by 0.58 dB(A), and those of the beer brewing and bottling industry were reduced by 9.66 dB(A). However, that of the mattress making industry increased by 2.69 dB(A). On average, the noise level in these industries has been reduced by 2.52 dB(A). The results of this study show that the noise control measures put in place have significant impacts on the noise exposure level in the industries surveyed.     

Association between road traffic noise and prevalence of coronary heart disease

There is an established evidence that exposure to high levels of road traffic noise is associated with elevated risk of coronary heart disease (CHD). The results however have been heterogeneous and mostly inconclusive. The present investigation aimed to examine this association in adult subjects, with a secondary aim of identifying potentially vulnerable sub-populations. Similar studies have never been reported from Indian population. For exposure assessment, the time-weighted road traffic noise indicator, L _den, was used as a continuous and categorical predictor. A cross-sectional study was designed, and sociodemographic and lifestyle- and health-related characteristics were recorded for 909 (533 females and 376 males) subjects aged 18–80 years. The respondents living in areas with L _den?<?60 dB(A) were designated as the reference group. Odds for self-reported CHD in relation to traffic noise exposure were estimated by univariate and multifactorial logistic regression with adjustments for potential confounders and effect modifiers. The adjusted odds ratio (OR) for self-reported CHD was 1.72 (95 % CI 1.36–2.19) per 5 dB(A) increase of L _den (range 55–80 dB(A)). A gender-related risk difference was observed among male (OR 1.47 (1.07–2.02)) and female (OR 1.83 (1.27–2.65)) respondents. A stronger effect for subjects in the age group 55–64 years old was found, with age, residence period, body mass index, and self-reported stress being significant confounders. This study suggests epidemiological evidence that exposure to road traffic noise of L _den?>?65 dB(A) may be associated with occurrence of CHD in adult subjects. A trend was observed indicating increasing risk with higher exposure levels. The study results are also suggestive of higher risk of outcome among those with other chronic ailments (diabetes, pulmonary, or renal issues) and residing in the same location in excess of 15 years. Orientation of bedroom windows was identified as a significant effect modifier.     

Magnetic properties of the road dusts from two parks in Wuhan city, China: implications for mapping urban environment

Magnetic parameters and heavy metal concentrations of road dusts collected from two parks with distance about 16 km in Wuhan city, China, were measured. The Guishan Park is circled by main roads with heavy traffic, and the Moshan Park is located on the downwind hills of steelworks and a power plant. Mean values of magnetic susceptibility (??) and saturation magnetization (M _s) of the dusts from the Moshan Park are 1.31 and 1.57 times those from the Guishan Park, respectively. Their magnetic mineralogy is dominated by pseudo-single domain magnetite; however, minor hematite was also identified in those from the Guishan Park. The dominant sources of non-natural magnetic particles and heavy metals were inferred as windblown emissions from the steelworks and the power plant for the Moshan Park, and road/railway traffics for the Guishan Park, respectively. Spatial variation in magnetic properties of road dust in the two parks and their different magnetic behavior propose that the magnetic measurements are sensitive to the different pollutant origins, as well as the urban environment, and that magnetic techniques have a high efficiency in mapping urban environment. Correlation between magnetic parameters and heavy metal concentrations is strongly site-specific: strong correlations were observed in the Moshan Park with correlation coefficients generally higher than 0.800, whereas correlations are poor in the Guishan Park. Therefore, it is strongly recommended that these relationships should be examined thoroughly before magnetic mapping.     

Spatial and Seasonal Variations in Chlorophyll-Nutrient Relationships in The Shallow Hypertrophic Lake Manyas, Turkey

Regression and correlation analyses were used to predict responses of phytoplankton biomass (chlorophyll) (μg L⁻¹) to nitrate (NO₃) (mg L⁻¹), phosphate (PO₄) (mg L⁻¹) and ammonium (NH₄) (mg L⁻¹) dynamics in the shallow hypertrophic Lake Manyas, Turkey. Nutrient concentrations showed a descending gradient with distance, while chlorophyll concentrations showed an ascending gradient with the distance from the Sığırcı Inlet to the Karadere Outlet. Higher nutrient concentrations did always not coincide with higher chlorophyll concentrations. The results showed that regression models developed using seasonal data were more accurate in predicting chlorophyll concentrations than those developed using the pooled data from whole year (based on R ² and the difference between the measured and predicted values). The findings also revealed that within a single large shallow lake, chlorophyll-nutrient relationships might show significant variations spatially. The objective of this study was to determine the seasonal and spatial variations in the relationships between chlorophyll, nitrate, phosphate and ammonium in the shallow hypertrophic Lake Manyas, Turkey.     

A comparative study of noise pollution levels in some selected areas in Ilorin Metropolis, Nigeria

The noise pollution is a major problem for the quality of life in urban areas. This study was conducted to compare the noise pollution levels at busy roads/road junctions, passengers loading parks, commercial, industrial and residential areas in Ilorin metropolis. A total number of 47-locations were selected within the metropolis. Statistical analysis shows significant difference (P < 0.05) in noise pollution levels between industrial areas and low density residential areas, industrial areas and high density areas, industrial areas and passengers loading parks, industrial areas and commercial areas, busy roads/road junctions and low density areas, passengers loading parks and commercial areas and commercial areas and low density areas. There is no significant difference (P > 0.05) in noise pollution levels between industrial areas and busy roads/road junctions, busy roads/road junctions and high density areas, busy roads/road junctions and passengers loading parks, busy roads/road junctions and commercial areas, passengers loading parks and high density areas, passengers loading parks and commercial areas and commercial areas and high density areas. The results show that Industrial areas have the highest noise pollution levels (110.2 dB(A)) followed by busy roads/Road junctions (91.5 dB(A)), Passengers loading parks (87.8 dB(A)) and Commercial areas (84.4 dB(A)). The noise pollution levels in Ilorin metropolis exceeded the recommended level by WHO at 34 of 47 measuring points. It can be concluded that the city is environmentally noise polluted and road traffic and industrial machineries are the major sources of it. Noting the noise emission standards, technical control measures, planning and promoting the citizens awareness about the high noise risk may help to relieve the noise problem in the metropolis.     

A modified toxicity testing method using tropical marine microalgae

Toxicity testing of four heavy metals(Cd, Cu, Mn and As) using four species of tropicalmarine phytoplankton, Chaetoceros calcitrans, Isochrysis galbana, Tetraselmis tetrahele and Tetraselmis sp., was carried out in multiwellplates with test volumes of 2 mL and the resultscompared to those of standard, large volume,shake-flasks. IC₅₀ values (concentrations of metalsestimated to inhibit 50% growth relative to thecontrol) were determined after 96 hours based onautomated O.D. readings measured in Elisa microplatesby a Multiskan spectrophotometer. Good agreement wasachieved between O.D. readings and cell countsindicating that this new method is a simple,economical, practical and rapid technique for toxicitytesting, and provides good reproducibility of IC₅₀ values. Results of the toxicity testsindicate that Cu was the most toxic metal (averageIC₅₀ values ranging from 0.04 to 0.37 mg L^-1), followed by Cd (0.06–5.7 mg L^-1), Mn (7.2–21.4 mg L^-1) and As (33.9–319.3 mg L^-1).Test species had different degrees of sensitivity tothe metals tested, with I.galbana and C. calcitrans the mostsensitive to Cu, Cd and Mn. Based on these findingsit is recommended that the existing Malaysian InterimStandards for Marine Water Quality for Cd and Cu be reviewed.     

Impact of Diwali celebrations on urban air and noise quality in Delhi City,India

A study was conducted in the residential areas of Delhi, India, to assess the variation in ambient air quality and ambient noise levels during pre-Diwali month (DM), Diwali day (DD) and post-Diwali month during the period 2006 to 2008. The use of fireworks during DD showed 1.3 to 4.0 times increase in concentration of respirable particulate matter (PM₁₀) and 1.6 to 2.5 times increase in concentration of total suspended particulate matter (TSP) than the concentration during DM. There was a significant increase in sulfur dioxide (SO₂) concentration but the concentration of nitrogen dioxide (NO₂) did not show any considerable variation. Ambient noise level were 1.2 to 1.3 times higher than normal day. The study also showed a strong correlation between PM₁₀ and TSP (R ² ≥ 0.9) and SO₂ and NO₂ (R ² ≥ 0.9) on DD. The correlation between noise level and gaseous pollutant were moderate (R ² ≥ 0.5). The average concentration of the pollutants during DD was found higher in 2007 which could be due to adverse meteorological conditions. The statistical interpretation of data indicated that the celebration of Diwali festival affects the ambient air and noise quality. The study would provide public awareness about the health risks associated with the celebrations of Diwali festival so as to take proper precautions.     

Indices of Benthic Community Tolerance in Contaminated Great Lakes Sediments: Relations with Sediment Contaminant Concentrations, Sediment Toxicity, and the Sediment Quality Triad

We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (T _L and T _H , respectively); toxic units accounted for 42% T _L and 53% T _H of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of T _L and T _H indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.     

高速公路交通噪声预测模型探讨

针对我国当前广泛使用的2种高速公路噪声预测模型《06规范》预测模型与《09导则》预测模型在预测时比较研究,重点利用环境现状监测数据分别对2种模型验证与对比分析.结果表明,2种模型预测值与实测值相差3dB ～5dB,车流量＞ 300辆/h,《09导则》更接近实测值;在夜间车流量＜300辆/h,《06规范》更接近实测值,2种模型结合采用《06规范》计算的车速,距离衰减考虑车流量的大小,在此基础上应用《09导则》,预测结果与实测值更为接近.     

Analysing and mapping spatial and temporal dynamics of urban traffic noise pollution: a case study in Kahramanmaraş, Turkey

This study aimed at quantifying noise pollution from urban traffic in the city of Kahramanmara?, Turkey. A total of 114 measurements for the equivalent noise level (L _Aeq) were made at 38 urban locations classified as “residential areas”, “residential and commercial areas” and “industrial areas” according to the national regulations, during morning, mid-day and evening hours. Our findings tabulated and mapped revealed that mean noise level in “residential and commercial areas” was highest relative to the other land-use types. Minimum and maximum values of noise pollution were recorded during the mid-day and evening hours, regardless of the land-use types. Noise limit values were exceeded at two locations only out of 38 based on the national regulation criteria and at over half of the locations based on the international criteria.     

Adsorption and degradation of sulfosulfuron in soils

Adsorption of sulfosulfuron was studied in two soils (topsoil from Alfisol and Inceptisol). The adsorption of sulfosulfuron was greater in topsoil collected from Alfisol than in Inceptisol. The soil sorption coefficient K and the soil organic carbon sorption coefficient K _oc are the basic parameters used for describing the environmental fate of the herbicides. In topsoil the calculated K values from Alfisol was 4.43 and in topsoil from Inceptisol was 2.00. K _c values were 6.06 in topsoil from Alfisol and 3.33 in topsoil from Inceptisol. The K _oc values were 886.36 in topsoil from Alfisol and 770.26 in topsoil from Inceptisol. Field experimental plots with no previous history of sulfosulfuron were selected and studied the degradation of sulfosulfuron in the topsoil collected from Alfisol and Inceptisol. The half-life of sulfosulfuron in topsoil from Alfisol: T ₁− 3.97 days and T ₂− 4.54 days; topsoil from Inceptisol: T ₁ − 4.68 days and T ₂ − 5.52 days. The degradation of sulfosulfuron followed first-order kinetics. The persistence of sulfosulfuron was found relatively longer in the Inceptisol than in Alfisol. The combination of degradation data (t _1/2 – soil) and organic carbon based sorption (K _oc) data of herbicides have been used to assess the pesticide environmental impact in soils through Gustafson Ubiquity Score (GUS). The GUS values were found to be 0.69 in topsoil from Alfisol and 0.83 in Inceptisol.