Evaluating temporal sand drift potential trends in the Sistan region, Southeast Iran

The Sistan region in Southeastern Iran is one of the world's most sensitive areas when it comes to sandstorms and wind erosion. One of the most influential factors in interpreting sandstorms is sand drift potential (DP), which is directly related to wind speed. Accurately, monitoring this phenomenon is still being determined, considering various temporal scales. Therefore, the main aim of this research is to analyze the trend of DP on monthly and annual scales. Our results showed that monthly variations of DP reached the highest and lowest values in July (609 VU) and January (47 VU), respectively. Blowing sand predominantly moved southeast, and the directional index fluctuated from 0.88 to 0.94. The annual DP was measured equal to 2700 VU, signifying a relatively high value when compared to other arid regions worldwide. The trend analysis results obtained from the Mann-Kendall test revealed both positive trends during the period 1987-2001 and negative ones from 2002 to 2016). However, the positive trend was found statistically insignificant. Furthermore, Sen's slope test results demonstrated that a negative trend could be observed with a steeper slope during July, September, and August, while a positive trend could be observed with a steeper pitch during November, December, and June. We recommend that land managers and stakeholders involved in controlling blowing sand using biological and physical methods should consider these trends in the Sistan region. Implementing nature-based solutions or control strategies should focus on these temporal sequences.

Impact of COVID-19 restrictions on hourly levels of PM10, PM2.5 and black carbon at an industrial suburban site in northern Spain

Due to the COVID-19 pandemic, lockdown restrictions were established around the world. Many studies have assessed whether these restrictions affected atmospheric pollution. Comparison between them is difficult as the periods of time considered are generally not the same and thus, different conclusions may be reached. Besides, most of them consider mean daily pollutant concentration, despite differences being observed according to the time of day. In this study, the hourly levels of PM10, PM2.5 and black carbon (BC) in an industrial suburban area in the north of Spain were analysed from May 2019 to June 2020 and compared with those from the literature, using the same period in each case. In general, the highest concentrations were reached when the wind direction came from the southwest (where a steelworks, a coal-fired power plant and other industries are located) and during the night-time, both before and during the lockdown. The highest concentrations of PM10, PM2.5 and BC were observed from December to February (on average: 45, 17 and 1.3 μg m^-3, respectively). The decrease/increase in those pollutants levels during the lockdown were found to be highly dependent on the period considered. Indeed, PM10 can be found to decrease by up to 39% or increase by 12%; PM2.5 can decrease by 21% or increase by up to 36%; and BC, although it generally decreases (by up to 42%), can increase by 7.4%.

Evaluation of the ventilation and pollutant exposure risk level inside 3D street canyon with void deck under different wind directions

With continuous global warming, growing urban population density, and increasing compactness of urban buildings, VD (void deck) street design has become increasingly popular in city planning, especially in tropical countries. However, understanding on traffic pollutant dispersion inside the street canyons with VDs is still at early stage. This paper evaluates quantitatively the effects of VD location and wind direction on the ventilation and traffic pollutant exposure inside the street canyon with VDs. The results show that under seven wind directions (0°, 15°, 30°, 45°, 60°, 75°, and 90°), the VD provides higher ACH than that of the regular canyon, especially at high α (angle between the approaching wind and the canyon axis). Also, mean K (dimensionless pollutant concentration) values of the canyon wall and pedestrian respiration plane on one side where VD is located are significantly reduced compared to the regular canyon. Therefore, when VDs are at both buildings, both pedestrian respiration planes and walls have the lowest K values, thus providing the best living environment for pedestrians and near-road residents. In addition, as α increases, the K values on both respiration planes significantly decrease except for the leeward respiration plane of the canyon with the windward VD. These findings can help to design urban street canyons for mitigating traffic pollution risk and improving ventilation in tropical cities with frequently changing wind directions.

Influence of wind direction on the ventilation and pollutant dispersion in different 3D street canyon configurations: numerical simulation and wind-tunnel experiment

Configuration of street canyon and the wind environment have a great influence on the self-ventilation capacity of the canyon, but the couple-effect of these two factors could not be considered in the previous study. The purpose of this study is to clarify the couple effect of street canyon configuration and wind environment on the ventilation and pollutant dispersion inside the street canyon. For this purpose, five wind directions of α = 90°, 60°, 45°, 30°, and 0° (α is the angle between the approaching wind and street canyon) and three canyon configurations (flat, step-up, and step-down canyons) were considered with numerical simulation and wind-tunnel experiment. Meanwhile, ACH (air exchange rate) and NEV (net escape velocity) were used to evaluate the ventilation capacity of the canyon. The results reveal that the wind direction has a vital influence on the ventilation in the different canyon configurations. Under the parallel wind direction (α = 0°), the airflow and ventilation capacity inside the three canyons are similar. Relative difference of ACH, named as RDA ((ACH_asymmetric-ACH_symmetric)/ACH_symmetric [Formula: see text] 100%), is 1.82%. However, under the oblique (α = 30°, 45°, and 60°) and perpendicular wind direction (α = 90°), the airflow of the step-down canyon is very different from the step-up and flat canyons. In step-down canyons, reverse flow occurs under the oblique and perpendicular wind direction, and the strength of the reverse flow increases as α increases. Due to this reverse flow, the ventilation capacity of the step-down canyon is lower than that of the step-up and flat canyons. As for the ventilation capacity in the pedestrian respiration domain, the ventilation capacity of the leeward pedestrian domain (leeward NEV) is higher in the step-down canyon than in the step-up canyon and the flat canyon (when α = 90°, leeward NEV of step-down canyon is 2.47 times the flat canyon). Conversely, the ventilation capacity of the windward pedestrian domain is lower in step-down canyons than in step-up or flat canyon (when α = 90°, windward NEV of step-down canyon is 0.1 times that of step-up canyon). The aforementioned findings are helpful to understand the effects of canyon configurations together with wind directions on the airflow as well as pollutant concentration inside the canyon. Although further researches are still required to provide practical guidelines, this study present effective methodologies to quantify the influences of street configurations and wind directions on street canyon ventilation for urban design purpose.

Dispersion of airborne mercury species emitted from the cement plant

The cement industry is the second largest source of anthropogenic mercury (Hg) emissions in Europe, accounting for 11% of global anthropogenic Hg emissions. The main objective of this study was to examine the influence of Hg emissions from the Salonit Anhovo cement plant on Hg levels measured in the ambient air at Vodarna, 1 km downwind from the flue gas chimney. The findings reveal that the plant raw mill operational status plays an important role in Hg concentrations in the flue gas emitted from the plant. Emitted total gaseous mercury was, on average, higher (49.4 μg/m³) when raw mills were in the direct mode (both raw mills-off) and lower (23.4 μg/m³) in the combined mode (both raw mills-on). The average Hg concentrations in Vodarna were 3.14 ng/m³ for gaseous elemental mercury, 53.7 pg/m³ for gaseous oxidised mercury, and 41.9 pg/m³ for particulate bound mercury for the whole measurement period. Atmospheric Hg speciation in Vodarna, coupled with plant emissions and wind data, has revealed that the total gaseous mercury emitted from the cement plant is clearly related to all Hg species measured in Vodarna. Wind blowing from the northeastern quadrant (mostly NE, ENE) is responsible for the elevated Hg levels in Vodarna, where gaseous oxidised mercury levels are highly linked to the cement plant emissions. However, elevated levels of Hg species in the absence of northeastern winds indicate potential inputs from other unknown local sources as well as inputs from regional and global transport mechanisms.

Variation of centennial precipitation patterns in Kuwait and their relation to climate change

The impact of climate change could be inferred by observing long-term climate variables like temperature, precipitation, and evapotranspiration. A local study on the climatic factors such as temperature, precipitation, CO₂ emissions, and population was carried out. The temperature records of the study period reflected an increase of 1.3 °C, higher than the global average. The relationship between the climatic factors from statistical analysis inferred that local factors did not influence the precipitation in Kuwait but showed an interrelationship among temperature, CO₂ emissions, and, population. Therefore, Kuwait's precipitation concerning regional atmospheric processes like sea surface temperature, volcanic eruption, wind direction, and El Nino and La Nina events were studied. The pragmatic change in wind direction in Kuwait from northwest to north after 2005 has enforced to study the effect of the volcanic eruption of Mount Etna on the precipitation in Kuwait. A marked correlation between the precipitation trends and post-eruptive periods of Mount Etna was observed. Similarly, El Nino and La Nina events were correlated, especially with the monthly temperature and total rainfall. Thus, the increase in sea surface temperature and volcanic events influenced the Hadley cell circulation and the shift of the Intertropical Convergence Zone, affecting the rain events in Kuwait.

Impact of COVID-19 restrictions on the dry deposition fraction of settleable particulate matter at three industrial urban/suburban locations in northern Spain

Ninety 24-h samples of the dry deposition fraction of settleable particulate matter (DSPM) were collected at one suburban industrial site ('EMA') and two urban industrial sites ('Lauredal' and 'Laboratory') in the western area of Gijón (North of Spain) from December 2019 to June 2020. The levels registered point to an environmental issue that should receive close attention from environmental authorities. Before lockdown restrictions due to COVID-19 were established, all samples collected at the EMA site exceeded 300 mg·m^-2·d^-1 (the Spanish limit value until 2002). Large amounts of DSPM were also registered at the Lauredal and Laboratory sites, maximum levels reaching 1039.2 and 672.7 mg·m^-2·d^-1, respectively. Seven metals were analysed in DSPM samples: Al, Ca, Fe, K, Mg, Mn and Na. Fe reached the highest values: 2473.4, 463.4 and 293.3 mg·m^-2·d^-1 (EMA, Lauredal and Laboratory sites, respectively). This study quantifies the reductions in the DSPM levels registered (on average, 97.2, 73.5 and 90.5% at the EMA, Lauredal and Laboratory sites, respectively) during the lockdown, which involved the restriction of population mobility and industrial activity. The influence of wind speed and its direction were also assessed to better understand the role of these restrictions in the observed reductions. The concentrations of all the metals in the DSPM were reduced by more than 75%, on average, except for K at the Laboratory and Lauredal sites. These decreases were much higher than those found by other authors for smaller fractions of the atmospheric particulate matter (PM10, PM2.5). The findings of the present study highlight the importance of DSPM in highly industrialized urban/suburban locations and indicate the direction that legal measures might take, given the influence of anthropogenic emissions.

SOLETE, a 15-month long holistic dataset including: Meteorology, co-located wind and solar PV power from

The aim of the SOLETE dataset is to support researchers in the meteorological, solar and wind power forecasting fields. Particularly, co-located wind and solar installations have gained relevance due to the rise of hybrid power plants and systems. The dataset has been recorded in SYSLAB, a laboratory for distributed energy resources located in Denmark. A meteorological station, an 11 kW wind turbine and a 10 kW PV array have been used to record measurements, transferred to a central server. The dataset includes 15 months of measurements from the 1st June 2018 to 1st September 2019 covering: Timestamp, air temperature, relative humidity, pressure, wind speed, wind direction, global horizontal irradiance, plane of array irradiance, and active power recorded from both the wind turbine and the PV inverter. The data was recorded at 1 Hz sampling rate and averaged over 5 min and hourly intervals. In addition, there are three Python source code files accompanying the data file. RunMe.py is a code example for importing the data. MLForecasting.py is a self-contained example on how to use the data to build physics-informed machine learning models for solar PV power forecasting. Functions.py contains utility functions used by the other two.

Microplastics in a tropical Andean Glacier: A transportation process across the Amazon basin?

Microplastic (MPs) contamination is ubiquitous in most terrestrial and aquatic ecosystems. Recently MPs have been reported at high altitudes which indicates that air masses can transport and deposit MPs in the surface snow of high mountain ecosystems, however, whether MPs typification and abundance can be influenced by direction and origin of air masses still remains an open question. Here we present the first report of MPs above 5000 m a.s.l from surface snow of a glacier in the tropical Andes. We collected surface snow along an elevational gradient, from 5000 to 5400 m a.s.l., in the Antisana Glacier, in the northern Andes cordillera of Ecuador to analyze MPs abundance and polymeric identification with the Fourier Transform Infrared (FTIR) and also to hypothesized the possible MPs sources in this remote area by comparing the oxygen and hydrogen stable isotopic ratio composition of the snow samples and by analyzing the wind direction. We observed an average of 131 ± 24 MPs L^-1 in our samples. Fibers corresponded to 70% of all MP shapes; FTIR results showed that MPs composition mainly included polyurethane, polyethylene, polyamide, polyester, and high-density polyethylene in surface snow. There were no statistically significant differences of MPs abundance among sampled elevations, and the isotopic ratio composition did not differ among locations. Our results suggest that MP that accumulated in the glacier may be transported from the east, across the Amazonia, by the prevalent eastward air flow. The absence of industrial cities at least 2000 km further east from Antisana, indicates that the remote Andean glaciers could constitute important depositional zones for long-distance transported contaminants.

A numerical study of local traffic volume and air quality within urban street canyons

Although pollutant sources are often assumed to be spatially uniform, traffic in real cities may vary significantly in space. Consequently the local air quality within a street may not be determined solely by the traffic volume of the street. Using building-resolving large-eddy simulation, the relationship between traffic volume and air quality is investigated in the context of two idealised problems: (i) the influence of pollutants emitted from a main road on the surrounding side streets and (ii) the pedestrianisation of a central thoroughfare. It is shown that the spatial variation of traffic volume is of crucial importance within a near-field region defined by a radius of homogenisation (RAD). Furthermore, the actual impact depends strongly on the wind direction. Hence the benefits of pedestrianisation may be limited: for example, after removing 100% of the traffic along a street in a central business district, the annual-averaged local concentration decreases by ~30% when the urban background is neglected. The impact may be significantly lower when the background concentration is considered. This work is relevant to the formulation of effective traffic control policy and the improved understanding of spatially inhomogeneous pollutant sources.

Directionally and spatially varying relationship between land surface temperature and land-use pattern considering wind direction: a case study in central China

The spatially varying relationship between land surface temperature (LST) and land-use factors at a large scale has been widely studied by geographically weighted regression (GWR) models. However, the directionally varying relationship caused by wind directions has not yet been considered. In this study, the wind directions in the summer and the winter of Wuhan in 2017 were extracted to build a geographically-directionally weighted regression (GDWR) to identify the spatially and directionally varying relationships between them. The results indicated that both the R2 and the significance have been improved by the GDWR model in the summer and the winter. Specially, the GDWR performed best in the winter of 2017, increasing R2 from 0.0688 to 0.6635 provided by ordinary least squares (OLS)-based multiple linear regression (MLR) and GWR, to 0.7839 by the GDWR, with P-value lower than 0.05 all across the study area. Furthermore, the residual has been dramatically reduced in the north and southeast part of Wuhan by GDWR in the winter. It's probably due to the fact that in the winter, wind was flowed from south to north. But the GDWR did not reduce the residual in central Wuhan. It suggests that the wind would cause an obviously directionally varying relationship in the suburbs; while it would not make a significant impact on the relationship between LST and its driving factors in the central city where complex land uses existed.

Using Kriging incorporated with wind direction to investigate ground-level PM2.5 concentration

Conventional interpolation methods, such as spatial averaging, nearest neighbor, inverse distance weight and ordinary Kriging (OK); for estimating the spatial distribution of ground-level particulate matter (PM) data, do not account for the wind direction for estimating the spatial distribution of PM_2.5. In this work, an interpolation algorithm, Win-OK accounting for the wind direction, is developed. In contrast to ordinary Kriging where all locations (irrespective of the wind direction) in the vicinity of a site is considered, the new algorithm (Win-OK) predicts the value at a certain location based on the measured values at locations upwind as determined by the wind direction. This new methodology, Win-OK is validated by applying it to analyze the hourly spatial distribution of ground-level PM_2.5 concentrations during Chinese New Year and Chinese National Day in 2017 in Xinxiang city, China. The performance of OK and Win-OK are compared by using them to build PM_2.5 concentration heat-maps. A "leave-one-out" cross validation methodology is used to calculate the root-mean-square error (RMSE) and standard deviation for evaluating both algorithms. The results show that OK sometimes gives an extremely high RMSE value using a Gaussian semi-variance model, and the standard deviation significantly deviates from the measured values. Win-OK was found to more accurately predict the PM_2.5 spatial distribution in a specific sector. The performance of Win-OK is more stable than OK as established by comparing the calculated RMSE and standard deviation from predictions of both algorithms. Win-OK with a spherical semi-variance model is the most accurate method investigated here for deriving the spatial distribution of ground-level PM_2.5. The new algorithm developed here could improve the prediction accuracy of PM_2.5 spatial distribution by considering the effect of wind direction.

Impact of Wind Speed and Direction and Key Meteorological Parameters on Potential Pesticide Drift Mass Loadings from Sequential Aerial Applications

Pesticide spray drift is potentially a significant source of exposure to off-target, adjacent aquatic habitats. To estimate the magnitude of pesticide drift from aerial or ground applications, regulatory agencies in North America, Europe, and elsewhere rely on spray drift models to predict spray drift deposition for risk assessments. Refined assessments should ultimately depend on best-available data for exposure modeling. However, when developing lower tier "screening" assessments designed to indicate whether further refinement is needed, regulators often make conservative assumptions with a resulting increased level of uncertainty in estimating environmental exposure or risk. In the United States, it is generally accepted that, to ensure conservative regulatory assessments, it is reasonable to assume that the wind speed might be 4.47 m/s (10 miles per hour [mph]), the relative humidity and temperature are highly conducive to drift, and the wind is blowing directly toward a receiving water for any given single spray event in a season. However, what is the probability these conditions will all co-occur for each of 4 sequential spray events spaced a week apart (common practice for insecticides)? The refined approach in the present study investigates this question using hourly meteorological data sets for 5 United States Environmental Protection Agency (USEPA) standard crop scenarios to understand how real-world data can reduce unnecessary uncertainty for sequential applications. The impact of wind speeds, temperatures, relative humidity, and wind direction at different times of day on annual drift loadings has been examined using a stepwise process for comparison with corresponding regulatory default loading estimates. The impacts on drift estimates were significant; interestingly, the time of day of the applications impacted variability more than did the selected crop scenario. When all these real-world factors were considered, estimated 30-y total drift loads ranged from 2% to 5% greater than the default estimate (2 of 30 cases due to high afternoon wind speeds) to 51% to 86% reductions (25 of 30 cases) with an overall average reduction of 63%. Integr Environ Assess Manag 2020;16:197-210. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Data set on wind speed, wind direction and wind probability distributions in Puerto Bolivar - Colombia

This paper presents wind speed and direction data measured with a weather station located in Puerto Bolivar, department of La Guajira, situated in the extreme north of Colombia, whose geographic coordinates are 12°11′N 71°55′W. A wind speed and direction sensor, a barometric pressure sensor, and a temperature sensor were used to obtain the presented data. These data were taken at the height of 10 m, which is the highest point of the weather station. The data taken by the meteorological station correspond to a period of 20 years (1993–2013), with hourly frequency. For the missing data, a mathematical model to estimate the Julian averages was developed, allowing to calculate the frequency histograms and four types of probability distributions for these data. Also, the representative wind roses were generated, taking into account the averages in each of the 12 months of the year.

A large volume wind data for renewable energy applications

The objective of the collection of dataset is to calculate the wind energy potential in the selected location using large volume of wind dataset. The wind energy potential data were collected at 100 m height from MSL (Mean Sea Level) from 2014 to 2016. The wind speed and direction were used to analyse wind energy characteristics and suitable site for wind turbine installation. The maximum wind power density was observed at monitoring sites S1, S2, S3 and S4. The altitude of the monitoring station and geomorphology of the site significantly controls the wind power density.

The study to environmental factors using microclimate survey of traditional wooden Silsang Temple in Korea

Weathering of wooden temples is attributable to temperature and humidity. Here, we explore the microclimatic characteristics of a traditional Korean temple; we measured temperature, relative humidity, wind velocity, and wind direction at one internal and five external points in/near Silsang Temple. Both the temperature and humidity varied by season. The internal and external daily temperature ranges were most similar in autumn, followed by spring, winter, and summer. The relative humidity inside was 40% greater (compared to outside) in spring and winter, but not in summer and autumn. Wind velocity variations within the temple were significant in certain seasons. Neither the outside temperature nor internal relative humidity was greatly affected by location. Correlations were evident between the outside temperature and relative humidity.

A land use regression model for explaining spatial variation in air pollution levels using a wind sector based approach

Estimating pollutant concentrations at a local and regional scale is essential in environmental and health policy decision making. Here we present a novel land use regression (LUR) modelling methodology that exploits the high temporal resolution of fixed-site monitoring (FSM) to produce a national-scale air quality model for the key pollutant NO₂. The methodology partitions concentration time series from a national FSM network into wind-dependent sectors or "wedges". A LUR model is derived using predictor variables calculated within the directional wind sectors, and compared against the long-term average concentrations within each sector. Validation results, based on 15 FSM training sites, show that the model captured 78% of the spatial variability in NO₂ across the Republic of Ireland. This compares favourably to traditional LUR models based on purpose-designed monitoring campaigns despite using approximately half the number of monitoring points. Results also demonstrate the value of incorporating the relative position of emission source and receptor into the empirical LUR model structure. We applied the model at a high-resolution across the Republic of Ireland to enable applications such as the study of environmental exposure and human health, assessing representativeness of air quality monitoring networks and informing environmental management and policy makers. While the study focuses on Ireland, the methodology also has potential applicability for other criteria pollutants where appropriate FSM and meteorological networks exist.

Locust displacing winds in eastern Australia reassessed with observations from an insect monitoring radar

Based on previous investigations, adult Australian plague locusts are believed to migrate on warm nights (with evening temperatures >25 °C), provided daytime flight is suppressed by surface winds greater than the locusts' flight speed, which has been shown to be 3.1 m s^-1. Moreover, adult locusts are believed to undertake briefer 'dispersal' flights on nights with evening temperature >20 °C. To reassess the utility of these conditions for forecasting locust flight, contingency tests were conducted comparing the nights selected on these bases (predicted nights) for the months of November, January, and March and the nights when locust migration were detected with an insect monitoring radar (actual nights) over a 7-year period. In addition, the wind direction distributions and mean wind directions on all predicted nights and actual nights were compared. Observations at around 395 m above ground level (AGL), the height at which radar observations have shown that the greatest number of locusts fly, were used to determine the actual nights. Tests and comparisons were also made for a second height, 990 m AGL, as this was used in the previous investigation. Our analysis shows that the proposed criteria are successful from predicting migratory flight only in March, when the surface temperature is effective as a predicting factor. Surface wind speed has no predicting power. It is suggested that a strong daytime surface wind speed requirement should not be considered and other meteorological variables need to be added to the requirement of a warm surface temperature around dusk for the predictions to have much utility.

Effects of natural factors on the spatial distribution of heavy metals in soils surrounding mining regions

Various studies have shown that soils surrounding mining areas are seriously polluted with heavy metals. Determining the effects of natural factors on spatial distribution of heavy metals is important for determining the distribution characteristics of heavy metals in soils. In this study, an 8km buffer zone surrounding a typical non-ferrous metal mine in Suxian District of Hunan Province, China, was selected as the study area, and statistical, spatial autocorrelation and spatial interpolation analyses were used to obtain descriptive statistics and spatial autocorrelation characteristics of As, Pb, Cu, and Zn in soil. Additionally, the distributions of soil heavy metals under the influences of natural factors, including terrain (elevation and slope), wind direction and distance from a river, were determined. Layout of sampling sites, spatial changes of heavy metal contents at high elevations and concentration differences between upwind and downwind directions were then evaluated. The following results were obtained: (1) At low elevations, heavy metal concentrations decreased slightly, then increased considerably with increasing elevation. At high elevations, heavy metal concentrations first decreased, then increased, then decreased with increasing elevation. As the slope increased, heavy metal contents increased then decreased. (2) Heavy metal contents changed consistently in the upwind and downwind directions. Heavy metal contents were highest in 1km buffer zone and decreased with increasing distance from the mining area. The largest decrease in heavy metal concentrations was in 2km buffer zone. Perennial wind promotes the transport of heavy metals in downwind direction. (3) The spatial extent of the influence of the river on Pb, Zn and Cu in the soil was 800m. (4) The influence of the terrain on the heavy metal concentrations was greater than that of the wind. These results provide a scientific basis for preventing and mitigating heavy metal soil pollution in areas surrounding mines.

Estimation of daily PM2.5 concentration and its relationship with meteorological conditions in Beijing

When investigating the impact of air pollution on health, particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5) is considered more harmful than particulates of other sizes. Therefore, studies of PM_2.5 have attracted more attention. Beijing, the capital of China, is notorious for its serious air pollution problem, an issue which has been of great concern to the residents, government, and related institutes for decades. However, in China, significantly less time has been devoted to observing PM_2.5 than for PM₁₀. Especially before 2013, the density of the PM_2.5 ground observation network was relatively low, and the distribution of observation stations was uneven. One solution is to estimate PM_2.5 concentrations from the existing data on PM₁₀. In the present study, by analyzing the relationship between the concentrations of PM_2.5 and PM₁₀, and the meteorological conditions for each season in Beijing from 2008 to 2014, a U-shaped relationship was found between the daily maximum wind speed and the daily PM concentration, including both PM_2.5 and PM₁₀. That is, the relationship between wind speed and PM concentration is not a simple positive or negative correlation in these wind directions; their relationship has a complex effect, with higher PM at low and high wind than for moderate winds. Additionally, in contrast to previous studies, we found that the PM_2.5/PM₁₀ ratio is proportional to the mean relative humidity (MRH). According to this relationship, for each season we established a multiple nonlinear regression (MNLR) model to estimate the PM_2.5 concentrations of the missing periods.

High-risk mesothelioma relation to meteorological and geological condition and distance from naturally occurring asbestos

OBJECTIVES

Very few studies have investigated the incidence and risk of malignant mesothelioma (MM) associated with distinct sources of asbestos exposure, especially exposure to naturally occurring asbestos (NOA).

METHODS

Subjects were MM, lung, and breast cancer patients who were diagnosed and followed in Diyarbakir Province between 2008 and 2013. The birthplaces of patients were displayed on a geologic map. Geological and meteorological effects on MM were analyzed by logistic regression.

RESULTS

A total of 180 MM, 368 breast, and 406 lung cancer patients were included. The median distance from birthplace to ophiolites was 6.26 km for MM, 31.06 km for lung, and 34.31 km for breast cancer (p < 0.001). The majority of MM cases were seen within 20 km from NOA areas. The MM incidence inside of NOA was 1059/100.000, and out of NOA was 397/100.000; this difference was significant (p = 0.014). The largest concentration of MM residential areas was within ± 30° (34 residential areas 36.6%) of the dominant wind direction. Most MM patients were found in or near the dominant wind direction, especially in the acute angle defined by the dominant wind direction. MM incidence was directly proportional to {[area of NOA (km(2))] * [cosine α of wind direction angle]} and was inversely proportional to the square of the distance (R = 0.291, p = 0.023).

CONCLUSIONS

MM was higher near NOA and in the downwind direction. MM incidence and risk were affected by geological and meteorological factors.

Physical controls of hypoxia in waters adjacent to the Yangtze Estuary: A numerical modeling study

A three-dimensional circulation model (the Environmental Fluid Dynamic Code) was used to examine the role that physical forcing (river discharge, wind speed and direction) plays in controlling hypoxia in waters adjacent to the Yangtze Estuary. The model assumes that the biological consumption of oxygen is constant in both time and space, which allows the role of physical forcing in modulating the oxygen dynamics to be isolated. Despite of the simplicity of this model, the simulation results showed that it can reproduce the observed variability of dissolved oxygen in waters adjacent to the Yangtze Estuary, thereby highlighting the important role of changes in physical forcing in the variation of hypoxia. The scenarios tested revealed appreciable changes in the areal extent of hypoxia as a function of wind speed and wind direction. Interestingly, well-developed hypoxia was insensitive to river discharge.

Sandhopper orientation under natural conditions: comparing individual tracks

The analysis of animal movements may help to understand orientation strategies. While there have been many studies on sandhoppers' orientation mechanisms through the analysis of their orientation angles, no attempts have been made to analyze individual tracks under (varying) natural conditions. The species Talitrus saltator (Montagu, 1808) has the ability to recover the optimal zone of the beach at or below the drift-line and burrow into moist sand when released in the upper beach during the day. On dry sand sandhoppers typically jump and leave tracks; we measured the tracks in relation to the starting point. For each track we calculated: the mean angle of direction, distance covered from the starting point, number of jumps, number of effective turnings, rectilinearity and efficiency (how well the track was directed to the goal). We proposed a classification of the tracks based on both rectilinearity and efficiency. Freshly collected adult individuals from the population of San Rossore beach (Pisa, Italy) were compared to laboratory-born ones so as to highlight eventual differences related to experience. Most of the wild individuals made tracks with high rectilinearity and efficiency. This good orientation suggests that these individuals had developed experience of their beach rapidly recovering the optimal zone. Laboratory-born individuals showed a higher scatter in orientation and winding tracks. The factors that influenced the individuals during their movements could also be inferred by the track course. In addition to the sun azimuth (sun compass), wind direction appeared to be a major factor influencing orientation. The individuals released with onshore winds were more efficiently oriented seawards than those released with winds from other directions.

Effects of oblique air flow on burning rates of square ethanol pool fires

The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results.

Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure

High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R² = 0.46, p = 0.014).