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Snow melting system using warm-water sprinklers in Japan ((a) http://pds.exblog.jp/pds/1/201103/09/58/b0092858_21205671.jpg, (b) http://hondakenchiku.com/wp-content/uploads/2008/02/080209kokudou.jpg).
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The objective of this research paper is to describe the system architecture for an urban roadside automatic mist-generating system. Its primary purpose is to mitigate particulate matter especially PM
2.5–10
. In this paper, four graphs are provided to exhibit the constituent elements of this system. This paper also discusses the functional extensio...
Citations
... Roadside sprinklers are used in several megacities in China to combat air pollution, and a significant reduction in PM 2.5 concentrations has been noted through field monitoring [99]. In another study, an automated roadside sprinkling system was developed to suppress dust suspension and mitigate ambient PM, and it achieved a 95-100% reduction efficiency [100]. A sprinkler can be used to achieve other objectives too. ...
... A sprinkler can be used to achieve other objectives too. For example, it was used to generate fresh or salty water mist for the inactivation of airborne influenza viruses in winter, as the survivability of the viruses decreased with absolute humidity [100]. It was also used to spray salty water in winter to de-ice and de-snow roads, and a mist in summer to cool down the air [101]. ...
Artificial rain, a technology primarily used for drought relief, has recently been used for combating regional air pollution. However, there are limited available measurement data to confirm the effectiveness of this control practice. In this study, we summarize control theories and indirect but relevant observations/findings, including air pollutant reduction after natural rain events and roadside sprinkling. A brief review of artificial rain basics is also provided. Our work shows that artificial rain appears to be a promising management strategy for air pollution control. However, field measurements are needed to further assess the cost-effectiveness of the practice, as well as the other benefits or challenges it may create.
... For example, Yu (2014) indicated that the PM2.5 concentration could be decreased significantly using water spray technology. Liu et al. (2014) suggested using a sprinkling system in order to mitigate the PM2.5 and PM10 along the roadsides as the primary source of PM2.5. ...
... The concentration of those elements began to decrease at around 10:00 am when the PBL change rate started to exceed those industrial emission rates. Moreover, during the night, the PBL fell to approximately 100 m due to the low temperatures (Liu et al. 2014;Li et al. 2017b). Consequently, a low PBL pressed the pollutants to the Earth's surface, triggering the high pollutant concentrations in the night periods (Li et al. 2017a). ...
Urban atmospheric metallic element in PM2.5 is affected by multiple factors across spatial and temporal scales. Yet the coupling of metallic elements with PM2.5 and the relationship between metallic element concentrations and influencing factors are still poorly understood, which hampers the adoption of appropriate policies and measures to mitigate emission. Therefore, an hourly resolved measurement campaign was performed from March 2017 to February 2018 to investigate the characteristics of 17 metallic elements (i.e., K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ag, Cd, Ba, Au, Hg, and Pb) in PM2.5 using a CES Xact 625 multi-metals monitor in Chengdu, Southwest China. The hourly concentrations of all 17 studied metallic elements ranged from the detection limits to 27,630 ng·m⁻³, while the hourly PM2.5 values varied from 1.95 to 282.7 μg·m⁻³, with an average value of 51.4 ± 25.4 μg·m⁻³. The change of anthropogenic emissions and meteorological parameters in Chengdu jointly resulted in the unimodal diurnal and distinct seasonal variations of most metallic elements concentrations. Furthermore, the value of total metallic mass (TMM) might be extremely high when the concentration of PM2.5 is relatively low, indicating that the health risks of exposure to low PM2.5 could be underestimated in previous studies, in which the health risk assessment of exposure to PM2.5 had been dependent on PM2.5 concentration. The removal efficiency of rainfall on metallic elements and PM2.5 might vary depending on the rainfall intensity. Moderate rainfall has the highest removal efficiency for PM2.5 and TMM.
... Although these particles are difficult to mitigate since they are not products of tailpipe emissions, there are different control mechanisms that could be used to effectively reduce the airborne dust emissions as well as the suspended dust on the paved/unpaved roadside [28][29][30][31][32][33][34]. Among all, one of the most effective, but expensive, methods to remove the non-tailpipe emissions from the vehicles in roadways is the automatic mist-generating systems (i.e., water sprinkling), in which spraying of water via pressurized nozzles prevents the formation of airborne dust particles [29,30]. ...
... Although these particles are difficult to mitigate since they are not products of tailpipe emissions, there are different control mechanisms that could be used to effectively reduce the airborne dust emissions as well as the suspended dust on the paved/unpaved roadside [28][29][30][31][32][33][34]. Among all, one of the most effective, but expensive, methods to remove the non-tailpipe emissions from the vehicles in roadways is the automatic mist-generating systems (i.e., water sprinkling), in which spraying of water via pressurized nozzles prevents the formation of airborne dust particles [29,30]. In addition, there are mechanical and chemical methods to remove the suspended dust from roadside, including the use of dust suppressants, water flushing, and street sweeping, which are mostly used by municipalities [28]. ...
In this study, we used the positive matrix factorization (PMF) model to evaluate the sources of ambient coarse particulate matter (PM) and their temporal variations in two sampling sites, i.e., a school dormitory and a retirement home, located in central Tehran. 24-h ambient PM samples were collected using low-volume air samplers from May 2012 to June 2013. The collected filters were analyzed for their chemical components, including water-soluble ions, metals, and trace elements, which were used as the input to the PMF model. Our results indicated annual averages of 45.7 ± 3.8 µg/m3 and 36.2. ± 4.0 µg/m3 for coarse PM at the School dormitory and Tohid retirement home, respectively. Moreover, higher ambient coarse PM mass concentrations were observed in the warm season (53.3 ± 5.8 µg/m3 for school dormitory and 43.1 ± 6.1 µg/m3 for Tohid retirement home) as opposed to the cold season (41.4 ± 4.7 µg/m3 for school dormitory and 28.7 ± 4.6 µg/m3 for Tohid retirement home). Our PMF analysis also identified road dust, soil, and industry, and atmospherically processed coarse PM as the three sources of ambient coarse PM in central Tehran. Road dust, soil, and industry were the major sources of ambient coarse PM, contributing respectively to 74 ± 9% and 19 ± 2% of the total coarse PM mass concentration, while atmospherically aged aerosols had a rather minimal contribution of 7 ± 1% to total coarse PM mass concentration. The temporal trends of the resolved factors also revealed higher contributions of road dust to total ambient coarse PM during warm season as opposed to cold season, due to the increased resuspension rate from road surfaces as a result of higher wind speeds, and temperatures, combined with lower relative humidity. Similarly, higher resuspension rate of mechanically originated particulates resulted in higher warm-season time contributions of the soil factor. Results of this study clearly revealed the key role of road dust and non-tail pipe emissions on ambient coarse PM mass concentrations in crowded areas of central Tehran, and have important implications on the potential health impacts that can be caused by these difficult to mitigate sources of coarse PM.
... Theoretically, precipitation could enhance the wet scavenging of airborne pollutants and reduce their ability to suspend, as the increased moisture might capture the particles (Kuhns et al., 2003;Karanasiou et al., 2011). Water spray (from sprinkler on road or atop a tall building) to simulate natural types of precipitation has been proposed as an important abatement strategy to facilitate the reduction of ambient PM concentrations (including trace elements) in urban China (Liu et al., 2014;Yu, 2014). However, several field measurements revealed that water spray activities did not influence the PM mass levels (e.g., Karanasiou et al., 2012;Karanasiou, 2014). ...
Atmospheric trace elements, especially metal species, are an emerging environmental and health concern with insufficient understanding of their levels and sources in Shanghai, the most important industrial megacity in China. Here we continuously performed a 1 year (from March 2016 to February 2017) and hourly resolved measurement of 18 elements in fine particles (PM2.5) at the Shanghai urban center with an Xact multi-metals monitor and several collocated instruments. Mass concentrations (mean ± 1σ; ng m-3) determined by Xact ranged from detection limits (nominally 0.1 to 20 ng m-3) to 15 µg m-3. Element-related oxidized species comprised an appreciable fraction of PM2.5 during all seasons, accounting for 8.3 % on average. As a comparison, the atmospheric elements concentration level in Shanghai was comparable with that in other industrialized cities in East Asia but 1 or 2 orders of magnitude higher than at sites in North America and Europe. Positive matrix factorization (PMF) was applied to identify and apportion the sources of the elements in the PM2.5 mass. Five different factors were resolved (notable elements and relative contribution in parentheses): traffic-related (Ca, Fe, Ba, Si; 46 %), shipping (V, Ni; 6 %), nonferrous metal smelting (Ag, Cd, Au; 15 %), coal combustion (As, Se, Hg, Pb; 18 %) and ferrous metal smelting (Cr, Mn, Zn; 15 %). The contribution from the exhaust and non-exhaust vehicle emissions, i.e., the traffic-related factor shows a strong bimodal diurnal profile with average concentration over 2 times higher during the rush hour than during nighttime. The shipping factor was firmly identified because V and Ni, two recognized tracers of shipping emissions, are almost exclusively transported from the East China Sea and their ratio (around 3.2) falls within the variation range of V / Ni ratios in particles emitted from heavy oil combustion. Interestingly, nearly half of the K was derived from coal combustion with high mineral affinity (elements associated with aluminosilicates, carbonates and other minerals in coal ash). The contributions of nonferrous metal smelting to the trace elements are consistent with a newly developed emission inventory. Although the precipitation scavenging effect on the mass concentration of the trace elements varied among different species and sources, precipitation could effectively lower the concentration of the traffic- and coal combustion-related trace elements. Therefore, water spray to simulate natural types of precipitation could be one of the abatement strategies to facilitate the reduction of ambient PM2.5 trace elements in the urban atmosphere. Collectively, our findings in this study provide baseline levels and sources of trace elements with high detail, which are needed for developing effective control strategies to reduce the high risk of acute exposure to atmospheric trace elements in China's megacities.
Despite regulations and policies to improve city-level air quality in the long run, there lack precise control measures to protect critical urban spots from heavy air pollution. In this work, we propose iSpray, the first-of-its-kind data analytics engine for fine-grained PM2.5 and PM10 control at key urban areas via cost-effective water spraying. iSpray combines domain knowledge with machine learning to profile and model how water spraying affects PM25 and PM10 concentrations in time and space. It also utilizes predictions of pollution propagation paths to schedule a minimal number of sprayers to keep the pollution concentrations at key spots under control. In-field evaluations show that compared with scheduling based on real-time pollution concentrations, iSpray reduces the total sprayer switch-on time by 32%, equivalent to 1, 782 m3 water and 18, 262 kWh electricity in our deployment, while decreasing the days of poor air quality at key spots by up to 16%.
Clean air is a fundamental requirement for the existence of life on earth. However, with the rapid rate of economic development, globalization, and increasing energy demand, large amount of emissions and waste are generated, leading to severe air pollution. This paper surveys the literature to provide an overview of the impact of air pollution on various aspects of human life. The impact is categorized broadly into health and socio-economic aspects and further subcategorized into multiple dimensions of health and socio-economic consequences. The survey reveals that the impact of air pollution is comprehensive, ranging from chronic to life-threatening diseases, and from malfunctioning of specific organ systems to subjective well-being. Additionally, evidence of the impact of air pollution on unexpected dimensions such as housing prices, larger economy, academic outcomes, and more is uncovered, leaving no doubt on the need to address this problem with the attention of the highest order. This evidence can be used to trigger more research and give policy-makers a starting point for clean-air campaigns. Merely highlighting the seriousness of the issue is not enough, and hence the paper also surveys the broader literature to identify interventions for clean air developed by public and private stakeholders across the world. While none of them may be ripe for blind duplication, this paper aims to provide decision-makers and researchers a bouquet of solutions to choose from while developing clean air programs and research agenda.
Natural language is a complex adaptive system with multiple levels. The hierarchical structure may have much to do with the complexity of language. Dependency Distance has been invoked to explain various linguistic patterns regarding syntactic complexity. However, little attention has been paid to how the structural properties of language to minimize dependency distance. This article computationally simulates several chunked artificial languages, and shows, through comparison with Mandarin Chinese, that chunking may significantly reduce mean dependency distance of linear sequences. These results suggest that language may have evolved the mechanism of dynamic chunking to reduce the complexity for the sake of efficient communication. © 2016 Wiley Periodicals, Inc. Complexity, 2016
