Roadside Locations Research Articles

Characterization of persistent organic contaminants in the atmosphere of Gadani's ship breaking yards and its surrounding: Implications for sustainable ship recycling practices

Gadani is internationally renowned for its extensive ship-breaking operations, positioning it as one of the globe's primary ship-breaking hubs. A comprehensive study was conducted to evaluate the presence of organic contaminants in the air within Gadani, encompassing the areas surrounding ship-breaking facilities, proximate residential settlements, and adjacent roadways. Passive air samplers were employed to collect a total of 30 air samples. The analytical results unveiled a notably elevated concentration of specific organic compounds, with a pronounced prevalence of polycyclic aromatic hydrocarbons (PAHs), short-chain chlorinated paraffins (SCCPs), and polychlorinated biphenyls (PCBs) at the ship-breaking yard. Notably, dichlorodiphenyltrichloroethanes (DDTs) and DDE were detected at substantially lower levels. In particular, sites in close proximity to ship-breaking activities exhibited elevated concentrations of PCBs (Σ7PCB 0.065429 to 7.345714 ng/sample), PAHs (Σ8PAH 2.44 to 134.23 ng/sample), and SCCPs (0.18 to 25.6 ng/sample). Conversely, DDTs and DDE demonstrated higher concentrations near residential settlements. The evaluation of Molecular Diagnostic Ratios for PAHs revealed anthracene/anthracene + phenanthrene ratios of 0.88, 0.69, and 0.5 for ship-breaking areas, roadside locations, and community surroundings, respectively. Furthermore, the benz[a]anthracene/benz-[a]anthracene + chrysene molecular ratios were measured at 0.77 (ship-breaking sites), 0.82 (roadside), and 0.83 (community), respectively. The molecular ratio of fluoranthene/fluoranthene + pyrene at ship-breaking sites was 0.23, while roadside and community ratios were 0.36 and 0.89, respectively. These findings underscore the significant contribution of ship-recycling activities to the atmospheric release of SCCPs, PCBs, and PAHs, emphasizing the global imperative for responsible ship recycling practices.

The impact of vegetative and solid roadway barriers on particulate matter concentration in urban settings.

A potentially important approach for reducing exposure to traffic-related air pollution (TRAP) is the use of roadside barriers to reduce dispersion from highway sources to adjacent populated areas. The Trees Reducing Environmental Exposures (TREE) study investigated the effect of vegetative and solid barriers along major controlled-access highways in Atlanta, Georgia, USA by simultaneously sampling TRAP concentration at roadside locations in front of barriers and at comparison locations down-range. We measured black carbon (BC) mass concentration, particle number concentration (PNC), and the size distribution of ultrafine aerosols. Our sample sites encompassed the range of roadway barrier options in the Atlanta area: simple chain-link fences, solid barriers, and vegetative barriers. We used Generalized Linear Mixed Models (GLMMs) to estimate the effect of barrier type on the ratio of particle concentrations at the comparison site relative to the roadside site while controlling for covariates including wind direction, temperature, relative humidity, traffic volume, and distance to the roadway. Vegetative barriers exhibited the greatest TRAP reduction in terms of BC mass concentration (37% lower behind a vegetative barrier) as well as PNC (6.7% lower), and sensitivity analysis was consistent with this effect being more pronounced when the barrier was downwind of the highway. The ultrafine size distribution was comprised of modestly smaller particles on the highway side of the barrier. Non-highway particle sources were present at all sample sites, most commonly motor vehicle emissions from nearby arterials or secondary streets, which may have obscured the effect of roadside barriers.

Robinia pseudoacacia L. (Black Locust) Leaflets as Biomonitors of Airborne Microplastics.

Here we investigate the suitability of Robinia pseudoacacia L. (black locust) leaflets as a novel biomonitor of airborne microplastics (MPs) including tyre wear particles (TWPs). Leaflets were collected from rural roadside locations (ROs, n = 5) and urban parks (UPs, n = 5) in Siena, Italy. MPs were removed by washing, identified by stereomicroscope, and analysed for polymer type by Fourier transform infrared spectroscopy. Daily MP deposition was estimated from leaf area. The mass magnetic susceptibility and the bioaccumulation of traffic-related potentially toxic elements (PTEs) were also analysed. The total number of MPs at ROs was significantly higher at 2962, dominated by TWPs, compared with 193 in UPs, where TWPs were not found. In contrast, total microfibres were significantly higher in UPs compared with ROs (185 vs. 86). Daily MP deposition was estimated to range from 4.2 to 5.1 MPs/m2/d across UPs and 29.9-457.6 MPs/m2/d across ROs. The polymer types at ROs were dominated by rubber (80%) from TWPs, followed by 15% polyamide (PA) and 5% polysulfone (PES), while in UPs the proportion of PES (44%) was higher than PA (22%) and polyacrylonitrile (11%). The mean mass magnetic susceptibility, a proxy of the bioaccumulation of traffic-related metallic particles, was higher at ROs (0.62 ± 0.01 10-8 m3/kg) than at UPs (-0.50 ± 0.03 10-8 m3/kg). The content of PTEs was similar across sites, except for significantly higher concentrations of Sb, a tracer of vehicle brake wear, at ROs (0.308 ± 0.008 µg/g) compared with UPs (0.054 ± 0.006 µg/g). Our results suggest that the waxy leaflets and easy determination of surface area make Robinia an effective biomonitor for airborne MPs including TWPs.

Roadside air pollution and secondary organic aerosol seasonal trends from an oxidation flow reactor in Seoul

The aim of this study was to determine the seasonal trends in secondary aerosols (SAs) and urban pollutants formed in an oxidation flow reactor (OFR) at a key roadside location in Seoul, South Korea. Spring 2019 saw high primary concentrations overall, and all seasons saw high levels of NOx, SO2, and equivalent black carbon (eBC) trends in the early morning (6:00–7:00). This exhibited similarities to the trend in diesel vehicle traffic volume. During the campaign, the modified hydroxyl radical (OH) exposure in the OFR was ∼1.1 × 1012 molecules cm−3 s (∼8.5 days), and the potential organic aerosol enhancement (OAPE) was 0.4–57.7 μg m−3 (winter 0.4−1.6, spring 28.4−52.3, summer 40.5−57.7, fall 18.1−31.1). The highest OAPE/ΔCO value was 89.5–414.7 μg m−3 for 0.1−4 OH·day in summer, and the lowest level was 1.1–8 μg m−3 for 0.5−8.5 in OH·day winter (including holidays). OAPE in seasons without winter under ∼4.5 OH· day had a ∼5.5 times higher value compared to that of organic on the roadside, accounting for 50.9−70.2% of the total sum (organic + eBC + OAPE). This had a high contribution to secondary organic aerosol (SOA) formation and, for winter, a value of only ∼5.5%. The predicted SOA formation from intermediate volatile organic compounds (IVOCs) calculated based on literature was 11–47% during mornings (9:30–11:30), excluding the winter season. This value was higher than the SOA formation from anthropogenic VOCs (benzene, toluene, ethylbenzene, and m,p,o-xylene) and biogenic VOCs (isoprene, monoterpenes, and sesquiterpenes), indicating the need for additional research into the domestic status of IVOCs. The marked seasonal change in South Korea's climate made applying research findings from other countries difficult. Therefore, further studies must be conducted based on realistic applicability, considering various environmental conditions, chemical speciation, and the classification of emission inventory components.

The Relationship between Roadside PM Concentration and Traffic Characterization: A Case Study in Macao

Road transportation is a common mode of transport in Macao and is also known to be a significant source of the emission of PM10 and PM2.5 on a local and regional scale. There are six air quality monitoring stations (AQMS) evenly distributed throughout Macao, but some densely populated areas are currently not covered by the monitoring network. Therefore, a monitoring campaign was conducted at four roadside locations in Macao’s most densely populated areas. This work aims to study the concentrations of PM10 and PM2.5 in several roadside locations in Macao. The monitoring campaign was conducted for 24 non-consecutive periods, with a total of 192 monitoring hours. The sampling sites were chosen based on Macao’s most densely populated areas and the most traffic-congested locations. In addition, traffic characterization was performed alongside the monitoring campaign to provide a clearer perspective on the pollution sources. Based on the collected data, a correlation analysis was performed between the number of vehicles and the levels of PM10 and PM2.5 concentration. The results showed a weak relationship between the hourly traffic flow and the level of PM10 and PM2.5 concentrations, with a correlation of determination (R2) of 0.001 to 0.122. In addition, the results showed a weak relationship between the vehicle types and the level of PM10 and PM2.5 concentrations, with an R2 of 0.000 to 0.043. As shown, there is little to no relationship between local traffic volume and roadside PM concentration in the monitored locations of Macao, leading us to conclude that PM concentration is more likely tied to regional sources and meteorological conditions. Nevertheless, the complex geographical setting of Macao is also likely an influential factor in this study.

Deployment and Evaluation of a Network of Open Low-Cost Air Quality Sensor Systems

Low-cost air quality sensors have the potential to complement the regulatory network of air quality monitoring stations, with respect to increased spatial density of observations, however, their data quality continues to be of concern. Here we report on our experience with a small network of open low-cost sensor systems for air quality, which was deployed in the region of Stavanger, Norway, under Nordic winter conditions. The network consisted of AirSensEUR sensor systems, equipped with sensors for, among others, nitrogen dioxide and fine particulate matter. The systems were co-located at an air quality monitoring station, for a period of approximately six weeks. A subset of the systems was subsequently deployed at various roadside locations for half a year, and finally co-located at the same air quality monitoring station again, for a post-deployment evaluation. For fine particulate matter, the co-location results indicate a good inter-unit consistency, but poor average out-of-the-box performance (R2 = 0.25, RMSE = 9.6 μg m−3). While Köhler correction did not significantly improve the accuracy in our study, filtering for high relative humidity conditions improved the results (R2 = 0.63, RMSE = 7.09 μg m−3). For nitrogen dioxide, the inter-unit consistency was found to be excellent, and calibration models were developed which showed good performance during the testing period (on average R2 = 0.98, RMSE = 5.73 μg m−3), however, due to the short training period, the calibration models are likely not able to capture the full annual variability in environmental conditions. A post-deployment co-location showed, respectively, a slight and significant decrease in inter-sensor consistency for fine particulate matter and nitrogen dioxide. We further demonstrate, how observations from even such a small network can be exploited by assimilation in a high-resolution air quality model, thus adding value to both the observations and the model, and ultimately providing a more comprehensive perspective of air quality than is possible from either of the two input datasets alone. Our study provides valuable insights on the operation and performance of an open sensor system for air quality, particularly under challenging Nordic environmental conditions.

Assessment of Traffic Induced Noise Pollution Indices and its Impact on Students’ Health at Bangladesh Agricultural University

The Bangladesh Agricultural University (BAU) is a prime campus of agricultural study on 488 hectares of scenic land on the western array of the old Brahmaputra River. This study aimed to measure the prevailing levels of traffic induced noise pollution at the core academic points and to assess the impacts of noise pollution on students’ health at BAU. The recorded Lave ranges from 55–85 dB. The Lave ranges from 79–85 dB throughout the whole day at FoA and FoAH. The Lave at these two core academic points are almost the double than the permissible limit of 45 dB. The Lmax pressure (96 dB) at Jobber moor during the noon is the maximum inside the whole BAU campus. The movement of traffic vehicles is responsible as the main sources of these noise. The noise level indices and their degree of fluctuation as given by Leq, Lnp, and NC are higher in roadside locations namely at FoA, FoAH, FoAERS. In terms of noise pollution, three of the sampled areas namely FoA, FoAH, and KR market show ‘moderate risk’ (Lave: 81 dB) during the morning whilst, the FoAH possessed the ‘high risk’ with the Lave of 85 dB. The results show that the FoA, FoAH, KR market, Jobber moor, and administration building can be labelled as the highest zone of noise level intensity. Due to excessive noise, university students are facing disorders like irritation, headache, nervousness, insomnia, anxiety, hearing problem, and hypertension. Controlling noise pollution is an absolute necessity for BAU to ensure noise-less academic culture whilst the dwellers of BAU is in the risk of serious noise-related health hazards. The results would be very useful for BAU authority to monitor and formulate a structural noise management policy, and to control excessive noise at our beloved BAU.

Assessment of Sources and Pollution Level of Airborne Toxic Metals through Foliar Dust in an Urban Roadside Environment

Concentrations of 19 elements (Al, Fe, Ca, K, Mg, Na, S, Ti, Ba, Sr, Zn, V, Cu, Mn, Cr, Pb, Ni, Co, and Cd) in foliar dust samples were determined from 6 different roadside locations of Bilaspur city (Chhattisgarh), India. Principal component analysis (PCA) indicated the significance of vehicular activities followed by sources such as firework events and other industrial/regional/transboundary sources in foliar dust in the area of study. Risk assessment of metal levels in foliar dust was performed using several indices based on the data collected from different sites. The geo-accumulation index (Igeo) analysis indicated foliar dust was moderately and extremely polluted with S and Cd, respectively, while practically unpolluted with most other elements (Al, Fe, Ca, K, Mg, Na, Ti, Ba, Sr, Zn, V, Cu, Mn, Cr, Pb, Ni, and Co). The values of pollution (IPOLL) index and contamination factor (CF) of Cd indicated a high pollution level. Comparable results were found for the ecological risk (Eri) of Cd (above 320) with a very high Eri at all sites. In addition, the overall Eri index (RI) of foliar dust at all sites was very high due to a greater Cd contribution.

Molecular and elemental marker-based source apportionment of fine particulate matter at six sites in Hong Kong, China

Source apportionment of PM2.5 was performed using positive matrix factorization (PMF) based on chemical speciation data from 24-h filters collected throughout 2015 at six sampling sites of varying urban influences in Hong Kong. The input data include major inorganic ions, organic and elemental carbon, elements, and organic tracers. Nine factors were resolved, including (1) secondary sulfate formation process, (2) secondary nitrate formation process, (3) industrial emissions, (4) biomass burning, (5) primary biogenic emissions, (6) vehicle emissions, (7) residual oil combustion, (8) dust, and (9) aged sea salt. The PMF-resolved factor contributions in conjunction with air mass back trajectories showed that the two major sources for PM2.5 mass, secondary sulfate (annual: 41%) and secondary nitrate (annual: 9.9%), were dominantly associated with regional and super-regional pollutant transport. Vehicular emissions are the most important local source, and its contributions exhibit a clear spatial variation pattern, with the highest (6.9 μg/m3, 24% of PM2.5) at a downtown roadside location and the lowest (0.4 μg/m3, 2.0% PM2.5) at two background sites away from city centers. The ability of producing a more reliable source separation and identifying new sources (e.g. primary biogenic source in this study) was a direct advantageous result of including organic tracers in the PMF analysis. PMF analysis conducted on the same dataset in this study but without including the organic tracers failed to separate the biomass burning emissions and industrial/coal combustion emissions. PMF analysis without the organic tracers would also over-apportion the contribution of vehicular emissions to PM2.5, which would bias the evaluation of the effectiveness of vehicle-related control measures. This work demonstrates the importance of organic markers in achieving more comprehensive and less biased source apportionment results.

Volatile Organic Compound Composition of Urban Air in Nairobi, Kenya and Lagos, Nigeria

Sub-Saharan Africa is seeing rapid urbanization, with the population of cities such as Lagos and Nairobi growing at a rate of 3–4% a year. The region is extremely under-sampled for all air pollutants, particularly VOCs, which are useful markers for source apportionment as well as toxic in their own right. There are many contributors to air pollution in the region, and studies examining fine particulate pollution implicate traffic as the primary source in urban areas. In this pilot study, VOCs were analysed at a selection of roadside and urban background locations in Nairobi and Lagos, and 74 VOCs were quantified. GC×GC–MS/FID analysis revealed all locations were dominated by hydrocarbons typical of vehicle emissions, with the aromatic hydrocarbons benzene and toluene among the most abundant VOCs. Typical personal exposure scenarios for citizens of the cities were calculated to far exceed those of a resident in a city in Europe/US. Finally, the calculated ozone forming potential of the VOCs measured was found to be similarly high to other large cities studied with similar air pollution problems. Further study is therefore essential to determine the full extent of VOC pollution in the region and its impact on tropospheric chemistry.

1005. DROSERA ALLANTOSTIGMA: Droseraceae

SummaryDrosera allantostigma (N.G.Marchant & Lowrie) Lowrie & Conran is illustrated and described. The species is a tiny herbaceous carnivorous plant native to a single roadside location in Western Australia, from which it has not been observed in almost a decade. Weed encroachment, agricultural runoff and altered hydrology continue to affect the location. We discuss the conservation status and threats facing the species, and suggest that D. allantostigma may be the first Australian carnivorous plant to have become extinct in the wild.

The effectiveness of decommissioning roadside mineral licks on reducing moose (Alces alces) activity near highways: implications for moose–vehicle collisions

Roadside mineral licks form when road salt used to de-ice highways in winter runs off road surfaces and accumulates in roadside ditches. Some ungulates are attracted to these roadside licks as they seek to satisfy their mineral requirements. Within the distribution of moose (Alces alces (Linnaeus, 1758)) in North America, motorists often encounter moose visiting roadside licks in mid-summer, with many jurisdictions reporting summer peaks in moose–vehicle collisions (MVCs) at these locations. We used camera traps to monitor the moose visitation of 22 roadside locations (including roadside licks, roadside ponds, and dry roadsides) in central British Columbia, Canada, from December 2009 to July 2020. We tested the efficacy of treatment (decommissioning) methods used to reduce moose visitation to roadside licks and roughly estimated decommissioning costs. Moose visitation to roadside licks was greatest from May to July. As we hypothesized, untreated licks were visited more often by moose than decommissioned licks, roadside ponds (absence of road salt), and dry roadsides. Decommissioning roadside licks by replacing or mixing lick waters and soils with materials, such as riprap, cedar mulch, pine logs, or dog (Canis lupus familiaris Linnaeus, 1758) fur and human (Homo sapiens Linnaeus, 1758) hair, is an effective and inexpensive means of reducing moose visitations to roadside areas and should increase motorist safety where roadside licks are visited by moose.

Morphological properties, chemical composition, cancer risks and toxicological potential of airborne particles from traffic and urban background sites

From a sampling campaign from December 2018 to June 2019, at a traffic and an urban background site in Coimbra, Portugal, two particulate matter (PM10) samples from each month were selected to characterise the morphology by scanning electron microscopy, to determine the organic and inorganic chemical composition by multiple analytical techniques and to assess the ecotoxicity by the Vibrio fischeri bioluminescence inhibition assay. PM10 concentrations in winter were approximately twice as high as those recorded in the spring. Biomass burning was the greatest contributor to air pollution in winter at both sites. The contribution of vehicle emissions to the PM10 at the roadside was, on average, 7 times higher than at the background location. Distinct particle morphologies were observed. Higher abundances of aggregates enriched in Fe, Ti, Ba, Cr, Co, Cu, Zr, Mn and soot particles were registered in samples from the roadside. Bivariate plots suggested common sources of PAHs, mostly traffic and biomass burning, across the city. Benzo[a]pyrene equivalent concentrations were within the values documented for other European cities. Cancer risks resulting from exposure to PAHs by inhalation were estimated to be low (10−6 ≤ to <10−4) for both sites. The noncarcinogenic risks from particulate trace elements were always higher than the target value of 1. Cancer risks for Cr were found to be higher than the acceptable level (10−6). The calculation of toxic units indicated that 64% of the samples from the roadside location were toxic and 14% very toxic, while the corresponding shares for the urban background site were 50% and 7%, respectively. Many PM10-bound constituents, especially markers of biomass burning (e.g. anhydrosugars) and traffic emissions (e.g. Fe, Cu, Zn), showed significant statistical correlations with toxicity.

Air quality assessment in three East African cities using calibrated low-cost sensors with a focus on road-based hotspots

Poor air quality is a development challenge. Urbanization and industrial development along with increased populations have brought clear socio-economic benefits to Low-and Middle-Income Countries (LMICs) but can also bring disadvantages such as decreasing air quality. A lack of reliable air quality data in East African cities makes it difficult to understand air pollution exposure and to predict future air quality trends. This work documents urban air quality and air pollution exposure in the capital cities of Kampala (Uganda), Addis Ababa (Ethiopia) and Nairobi (Kenya). We build a situational awareness of air pollution through repeated static and dynamic mobile monitoring in a range of urban locations, including urban background, roadside (pavement and building), rural background, and bus station sites, alongside vehicle-based measurements including buses and motorcycle taxis. Data suggest that the measured particulate matter mass concentrations (PM2.5, PM10) in all studied cities was at high concentrations, and often hazardous to human health, as defined by WHO air quality guidelines. Overall, the poorest air quality was observed in Kampala, where mean daily PM2.5 and PM10 concentrations were significantly above the WHO limits at urban background locations by 122% and 69% and at roadside locations by 193% and 215%, respectively. Traffic is clearly a major contributor to East African urban air pollution; monitoring in Kampala and Addis Ababa, on motorcycle taxis, in buses and at bus stations indicated that drivers and commuters were exposed to poor air quality throughout their commute. Road-related air pollution can also impact indoor locations near roads. Using one exemplar building located within Nairobi’s Central Business District, it is shown that measured outdoor PM concentrations significantly correlate with the indoor air quality (r = 0.84). This link between roadside emissions and indoor air pollution within buildings located close to the road should be explored more fully. This study, through a series of case studies, provides clear evidence that roads and traffic need to be a focus for mitigation strategies to reduce air pollution exposure in East African cities.

Noise exposure of the residential areas close to urban expressways in a high-rise mountainous city

Urban expressways can generate excessive noise in the surrounding urban areas, and it tends to be more complex in mountainous cities, due to the undulating terrain, dense population and compact urban structures. This article aims to investigate the objective acoustic environment and road traffic noise exposure, including the noisy evaluation, annoyance and effect of roadside apartments in residential areas close to urban expressways in the high-density, high-rise, mountainous city of Chongqing. Three housing estates were selected for a series of field measurements, questionnaire surveys and noise mapping. There was a significant negative correlation between night-time noise levels and the distances to the urban expressway ( p &lt; 0.01). Moreover, the differences between the daytime and night-time noise levels were generally insignificant (0.7 to 3.6 dBA) at the roadside locations. Differences in reaction to noise exposure in a variety of both person-related and housing condition variables were found, especially between roadside and non-roadside locations or residents. In addition, 75.0% of roadside residents identified the traffic noise as ‘very’ or ‘extremely’ annoying, and 66.7% of them regarded the acoustic environment as the priority environmental factor that needs to be improved. Difference in the ‘bedroom-window orientation’ had a significant effect on subjective noise evaluation. Rectangular-shaped apartments along the roadside obtain better noise reduction capacities than tower-blocks through the simulation. The acoustic performance of road cuttings, as an appropriately designed earth embankment, is improved along with deeper vertical alignment, and slope angles of 30° and 75° should be avoided.

Review of land use specific source contributions in PM2.5 concentration in urban areas in India

Source apportionment studies are expected to provide relative contribution of different sources responsible for deteriorated air quality in an urban area, so that the agency responsible for urban air quality management can adopt prioritized source-specific control measures. Robust assessment of source contributions in a typical urban land-use pattern is the prime step for development of effective emission control strategies. This necessitates a critical review of the PM2.5 source apportionment studies conducted in different urban land uses and delineation of the dominant sources along with its contribution to reveal the diversifications among the peculiar land use classifications even within the same city. The present study reviewed the source apportionment studies carried out at 37 locations from seven Indian cities and categorized the sources contribution on seasonal (winters and summers) average basis for residential, commercial, industrial, kerbside, and mixed locations. The findings of the review studies inferred considerable variations in the source’s contribution to air pollution with land use change. For example, during winter, domestic/biomass emission was reported as a significant source in residential (34%), commercial (26%), mixed (46%), industrial (31%), and road side (27%) locations in Delhi city in North India. However, vehicle (57%) was found to be the dominant source in residential area whose contribution increased up to 76% at road side location in Bangalore City in South India. It is also observed that source contributions vary in different seasons depending upon the activity levels. More or less similar observation was found in other cities selected for this study. The variations in source apportionment findings for a particular city might be attributed to heterogeneity of sources/major activity areas, nonuniform adoption of methodology. The study emphasizes on the need for the development of urban air quality management plan based on the land use specific source apportionment studies.

Water Retention Performance at Low-Impact Development (LID) Field Sites in Taipei, Taiwan

Low-impact development (LID) aims to retain stormwater at source sites rather than achieve water drainage. The infiltration and storage of rainwater on site is the most commonly applied LID design concept, turning impervious pavements into pervious pavements. In this study, three field sites in Taipei city, Taiwan, were monitored. Two of the sites were located on campuses, and one site was a roadside location. They were constructed at different times and had distinct purposes, but the common design aspect was the infiltration function of the ground surface. We monitored the water retention performance at the above three sites and applied a verified stormwater management model (SWMM) to characterize the performance at these case sites. The observed data show that if the accumulative rainfall was lower than 20 mm, the water retention rate at each of the three case sites reached almost 50%; at 60 mm rainfall, the rate was 40%. With increased rainfall amount, the water retention rate decreased because the storage capacity was limited. Because water retention is typically controlled by the infiltration capacity, the rainfall intensity dominated the performance. At the three field sites, the water retention rate was 40% on average at a rainfall intensity below 20 mm/h. Above this rainfall intensity, the infiltration performance of the pervious pavement decreased. The verified model was applied to assess the performance at the three sites under the Taipei city drainage system design standard, i.e., the five-year recurrent period storm level, at 78.8 mm/h. The results demonstrate that the water retention rates were 9.1%, 14.2%, and 61.0% at the three sites, indicating that the pervious pavement could reduce the loading of the current stormwater drainage system. Dispersed sites should be considered in urban stormwater management to mitigate flooding risk in urban areas.

Spatiotemporal variability and sources of aerosol water-soluble organic nitrogen (WSON), in the Eastern Mediterranean

This study aims to characterize the variability and sources of water-soluble organic nitrogen (WSON) in aerosol over Cyprus in the Eastern Mediterranean. Measurements of PM10 particles were conducted during the calendar year of 2011 at two sites, located at a roadside location in Nicosia (urban traffic) and in the rural area of Agia Marina Xyliatou (regional background). Filter samples were analyzed for water-soluble total nitrogen (WSTN), nitrate and ammonium, to determine WSON. Additional analyses were performed, for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), major ions and trace metals. Annual mean WSON concentrations of 0.20 and 0.16 μgN m−3 were determined at the urban traffic and regional background sites, respectively. The organic fraction of WSTN was about 20%, with limited inter-site and seasonal variability. Distinct seasonal patterns were observed at the two sites, with warm-period concentrations being significantly higher at the regional background site, while the enhanced local emissions during winter at the traffic site smoothed out the observed variability. Mean WSON/WSOC ratios of 0.09–0.12 were calculated at the two sites, with the two parameters being weakly correlated. A roadside WSON enhancement was verified, although moderate on an annual basis (9%). However, concentrations in Nicosia were more than one time higher than the background during winter. The observed temporal and inter-site variability highlighted the necessity of source apportionment, which was performed using Positive Matrix Factorization (PMF) modeling, utilizing the analytical datasets at the two sites. In this way, the estimated contribution of regional transport of processed aerosols was found to be more pronounced at the regional background site (59% vs. 38%), while a sizeable input (35%) was linked to vehicular emissions at the traffic site. An additional anthropogenic impact, probably related to biomass burning, was estimated at both sites (16%), while contributions of natural sources like mineral dust (4–8%) and marine aerosol (2–3%) were smaller.

Location Patterns of Small Sacral Architecture in Rural Landscapes – Case Studies from Eastern Slovakia

Specific locations of small objects of sacral architecture in the landscape represent both tangible and intangible values, which are the result of long-lasting ties between man – society and the landscape. The objects of small sacral architecture, small chapels, statues of saints, crucifixes, small belfries or other typological forms of small sacral objects, are located at specific places, important sites linked to the life of local inhabitants, on places with good visibility and accessibility, for example along roads, at crossroads, at borders of settlements, field boundaries, or elevated locations, determining compositional linkages in space. We have examined the location patterns of objects of small sacral architecture in rural landscapes of Eastern Slovakia, in selected cadastral areas of village settlements in the district Vranov nad Topľou, in the Prešov region. The results of the research show that most of the locations in the open landscape outside of the built-up area of settlements are the road-side locations along currently used roads or along the field roads and abandoned former roads which in the past connected the villages. Only a few are found on sites near springs of mineral water, or on elevated top-hill position. Within the built-up areas of settlements, the most of objects of small sacral architecture are located in the private fenced spaces of front gardens; only a few are located in public space. Many objects of small sacral architecture are abandoned, vanish from the rural landscape, deteriorate and fall into decay. The reinvention of their values and their valorization will help to preserve the character and traditional local identity of rural cultural landscapes.

Impact of a truck Driver's strike on air pollution levels in São Paulo

From May 21st to 31st, 2018, a truck driver strike greatly decreased all vehicle activity in Brazil. We evaluated the concentrations of criteria pollutants in seven different microenvironments during this period in the São Paulo Megacity. Results were evaluated by violin plots, the Kruskal-Wallis test and diurnal cycles, comparing the year 2018 to an average of 4 previous years. Primary pollutants (CO and NO) decreased by 50% in 2018, predominantly in roadside (RDS) locations. NO2, PM10, and PM2.5 did not decrease as much, suggesting the relevance of secondary reactions and other sources (ex: fires). Ozone increased significantly (about 30–50%), possibly due to favourable atmospheric conditions (solar radiation) and changes in the NOx/VOCs ratio caused by the decrease in NO. Our findings help to better assess the role of vehicular emissions and provide insights on the impacts of interruption of activities (ex: during lockdowns) over air quality in metropolitan environments.