The scheduling of tower crane operations is a complex process. Overlapping areas between tower cranes often lead to increased collision possibilities, resulting in additional tower crane operation ...complexity. Single objectives related to time or economic aspects were always considered in dealing with this issue, which neglected other objectives and the relationships between different objectives. Therefore, this article proposes a novel method for the schedule of prefabricated component lifting tasks on the construction site, integrating the multi-objective optimization model with the decision-making method with the aim of minimizing energy consumption costs and minimizing the amplitude of the costs among multiple tower cranes. A non-dominated sorting genetic algorithm-III (NSGA-III) written in Python is used as the multi-objective optimization algorithm—which considers the selection of tasks for each tower crane and the order of lifting for each tower crane and technique for order preference by similarity to an ideal solution (TOPSIS), and is applied as the decision-making method for ranking the Pareto front. Then, a green construction production and education integration training building construction project located in Jinan, China is used as the case study to verify that the method is practical and reasonable. The results show that conflicts can be effectively avoided, energy consumption costs reduced, and equipment utilization increased by rationally distributing lifting tasks among multiple overlapping tower cranes. And among the top 11 solutions, the lifting tasks and priorities for tower crane 1 are close to the same. In contrast, the task lifting for tower crane 2 was assigned based on the balance of the energy consumption costs of the two tower cranes. The discovery of this article is helpful to eliminate collisions, interference, and frequent start and stop of several tower cranes, so as to realize the safe, stable, and efficient operation of the construction site.
Ozone and its precursors were measured from 15 June 2006 to 14 June 2007 at an urban site in Shanghai and used to characterize photochemical oxidant production in this region. During the observation ...period, ozone displays a seasonal variation with a maximum in spring. Observed nitrogen oxides (NOx) and carbon monoxide (CO) reached a maximum in winter and a minimum in summer. NOx and CO has a similar double‐peak diurnal cycle, implying that they are largely of motor vehicle origin. Total nonmethane organic compounds (NMOC) concentrations averaged over the morning, and the 24‐hour periods have a large day‐to‐day variation with no apparent seasonal cycle. Aromatics play a dominant role in contributing to total NMOC reactivity and ozone‐forming potential. Anthropogenic NMOC of diverse sources are major components of total NMOC and consist mainly of moderate and low reactivity species. In contrast, relatively low levels of biogenic NMOC concentrations were observed in urban Shanghai. The early morning NMOC/NOx ratios are typically below 8:1 with an average of around 4:1, indicating that the sampling location is situated in a NMOC‐limited regime. Model simulations confirm that potential photochemical ozone production in Shanghai is NMOC‐sensitive. It is presently difficult to predict the impact of future human activities, such as the increase of automobiles and vegetation‐covered landscapes and the reduction of aerosol on ozone pollution in the fast developing megacities of China, and additional studies are needed to better understand the highly nonlinear ozone problem.
Several data sets were introduced to investigate the possible effects of climate-change-related variation of wind on aerosol concentration during winter in Shanghai, China. These data sets included ...the daily wind speed, wind direction, visibility, and precipitation from 1956 to 2010, hourly PM10 concentration from 2008 to 2010, and the NCEP/NCAR reanalysis data of global atmospheric circulation from 1956 to 2010. The trend of aerosol concentration and its correlations with wind speed and wind direction in winter were analyzed. Results indicated that there was an increase in the number of haze days in winter of 2.1 days/decade. Aerosol concentration, represented by PMl0 in this study, was highly correlated to both wind speed and direction in winter. The PMl0 concentration increased as wind speed decreased, reaching maximum values under static wind conditions. The PM10 concentration was relatively lower under easterly winds and higher under westerly winds. The analysis showed that weaker East Asia winter monsoons have resulted in a reduction of wind speed, increase in static wind frequency, and decline in the frequency of northerly winds since the 1980s. Moreover, the rapid expansion of urban construction in Shanghai has changed the underlying surface considerably, which has led to a reduction in wind speed. Finally, a wind factor was defined to estimate the combined effects of wind speed and wind direction on aerosol concentrations in Shanghai. The analysis of this factor indicated that changes in atmosphere circulation and urbanization have had important effects on the number of winter haze days in Shanghai.
Anthropogenic aerosols have significant impacts on the environment and human health in the Yangtze River Delta region, one of the most densely populated regions in the world. A biomass-buming plume ...swept across this area （Shanghai） in May 2009, leading to changes in the physical and optical properties of aerosols, which were investigated using ground-based remote sensing and in situ measurements via comparisons with dust pollution and background conditions. Experiments show that the biomass-burning plume led to an increase in the average aerosol optical depth （AOD） at 500 nm from 0.73 to 1.00 （37% higher）, an absorption Angstrom exponent （AAE） of 1.48, and an increase in the Angstrom exponent （ce） up to 1.53. Furthermore, local dust aerosols derived from road dust andor construction dust also led to higher values of AOD （2.68） and AAE （2.16）, and a daily average value of a of 1.05. For the biomass-burning plume, the aerosol particles exhibited significant variations in short-wavelength spectra. The single scattering albedo at 670 nm decreased remarkably under the influence of the biomass-burning plume, indicating the significant absorptive ability of the biomass-burning pollution and higher ratio of absorption aerosols within the plume. Under the effects of the biomass-burning, the volume concentration of fine-mode aerosols increased significantly and the PM-fineIPM-coarse volume concentration ratio reached 12.33. This relatively large change in fine-mode particles indicates that biomass-burning has a greater impact on fine-mode aerosols than on coarse-mode aerosols.
Eight-year measurements at urban (Xujiahui, XJH) and remote (Dongtan, DT) sites during time period 2010–2017 are employed to examine the surface ozone (O3)-temperature relationship in Shanghai, ...China. O3 pollution was getting worse in Shanghai, with daily maximum O3 concentrations increasing at a rate of 2.47 ppb yr−1 in urban site. The climate penalty (mO3-T), defined as the slope of O3 change with increasing temperature, exhibited largest values in summer. Summertime O3 increased faster as temperature increased, with mean rates of 6.65 and 13.68 ppb °C−1, respectively in XJH and DT above 30 °C. Sensitivity experiments indicate that the temperature dependence of biogenic volatile organic compounds (VOCs) emissions could be the main chemical driver of the high-temperature O3 response in summer, since the simulated mO3-T are most sensitive to changes of biogenic isoprene emissions. NOx emission reductions strengthened the high-temperature O3 response, with summer mean mO3-T values increasing from 1.52 ppb°C−1 during 2010–2012 to 2.97 ppb °C−1 during 2013–2017. As NOx emissions continue to decrease, the O3 production in urban Shanghai tend to become transitional and the dependence of mO3-T on the biogenic VOC emissions might be weakened. Model results suggest that anthropogenic VOC emission reductions would effectively relieve O3 pollution and reduce the sensitivity of O3 to increasing temperatures in urban Shanghai. Tailored emission reductions as well as scientific city planning strategies should be formulated to balance VOC/NOx ratios, so as to wrestle with the challenges for future O3 pollution under a warming climate.
•Surface O3 in Shanghai increased during 2010–2017, with decreased NOx level in urban city.•The high-temperature O3 response is stronger in low NOx emission area.•Biogenic VOCs dominate the high-temperature O3 response in urban Shanghai.•NOx reductions increase the sensitivity of O3 to increases in temperature.
In recent years, ozone (O3) is often the major pollutant during summertime in China. In order to better understand this problem, a long-term measurement of ozone (from 2006 to 2015) and its ...precursors (NOx and VOCs) as well as the photochemical parameter (UV radiation) in a mega city of China (Shanghai) is analyzed. The focus of this study is to investigate the trend of O3 and the causes of the O3 trend in large cities in China. In order to understand the relationship between the O3 precursors and O3 formation, two distinguished different sites of measurements are selected in the study, including an urbanization site (XJH-Xujiahui) and a remote site (DT-Dongtan). At the XJH site, there are high local emissions of ozone precursors (such as VOCs and NOx), which is suitable to study the effect of O3 precursors on O3 formation. In contrast, at the DT site, where there are low local emissions, the measured result can be used to analyze the background conditions nearby the city of Shanghai. The analysis shows that there were long-term trends of O3 and NOx concentrations at the urban site (XJH) from 2006 to 2015 (O3 increasing 67% and NOx decreasing 38%), while there were very small trends of O3 and NOx concentrations at the background site (DT). The analysis for causing the O3 trend suggests that (1) the large O3 increase at the urban area (XJH) was not due to the regional transport of O3; (2) the measurement of solar radiation had not significant trend during the period, and was not the major cause for the long-term O3 trend; (3) the measurement of VOCs had small change during the same period, suggesting that the trend in NOx concentrations at the urban site (XJH) was a major factor for causing the long-term change of O3 at the urban area of Shanghai. As a result, the O3 and NOx concentrations from 2006 to 2015 at the urban area of Shanghai were strongly anti-correlated, suggesting that the extremely high NOx concentration in the urban area depressed the O3 concentrations. It is interesting to note that the anti-correlation between O3 and NOx was in an un-linearly relationship. Under high O3 concentration condition, the ratio of ΔO3/ΔNOx was as large as −1.5. In contrast, under low O3 concentrations, the ratio of ΔO3/ΔNOx was only −0.2. This result suggested that when O3 concentration was high, it was more sensitive to NOx concentration, while when O3 concentration was low, it was less sensitive to NOx concentration. This study provides useful insights for better understanding the causes of the long-term-trend of regional O3 pollution nearby Shanghai, and has important implication for air pollution control in large cities in China. Due to the fact that NOx and VOCs are not only precursors for O3, but also are important precursors for particular matter (PM). If reduction of NOx leads to decrease in PM, but increase in O3, the NOx emission control become a very complicated issue and need to carefully design a comprehensive control method.
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•There are insignificant trends of O3 and NOx from 2006 to 2015 in a mega city (Shanghai).•The trends between O3 and NOx are strongly anti-correlated, indicating that the O3 is strongly depressed by high NOx.•The study suggests that the reduction of NOx can reduce PM2.5, while causes O3 to increase.•The NOx emission control becomes a very complicated issue and needs to carefully design a comprehensive control method.
In recent years, ozone (O
) is often the major pollutant during summertime in China. In order to better understand this problem, a long-term measurement of ozone (from 2006 to 2015) and its ...precursors (NO
and VOCs) as well as the photochemical parameter (UV radiation) in a mega city of China (Shanghai) is analyzed. The focus of this study is to investigate the trend of O
and the causes of the O
trend in large cities in China. In order to understand the relationship between the O
precursors and O
formation, two distinguished different sites of measurements are selected in the study, including an urbanization site (XJH-Xujiahui) and a remote site (DT-Dongtan). At the XJH site, there are high local emissions of ozone precursors (such as VOCs and NO
), which is suitable to study the effect of O
precursors on O
formation. In contrast, at the DT site, where there are low local emissions, the measured result can be used to analyze the background conditions nearby the city of Shanghai. The analysis shows that there were long-term trends of O
and NO
concentrations at the urban site (XJH) from 2006 to 2015 (O
increasing 67% and NO
decreasing 38%), while there were very small trends of O
and NO
concentrations at the background site (DT). The analysis for causing the O
trend suggests that (1) the large O
increase at the urban area (XJH) was not due to the regional transport of O
; (2) the measurement of solar radiation had not significant trend during the period, and was not the major cause for the long-term O
trend; (3) the measurement of VOCs had small change during the same period, suggesting that the trend in NO
concentrations at the urban site (XJH) was a major factor for causing the long-term change of O
at the urban area of Shanghai. As a result, the O
and NO
concentrations from 2006 to 2015 at the urban area of Shanghai were strongly anti-correlated, suggesting that the extremely high NO
concentration in the urban area depressed the O
concentrations. It is interesting to note that the anti-correlation between O
and NO
was in an un-linearly relationship. Under high O
concentration condition, the ratio of ΔO
/ΔNO
was as large as -1.5. In contrast, under low O
concentrations, the ratio of ΔO
/ΔNO
was only -0.2. This result suggested that when O
concentration was high, it was more sensitive to NO
concentration, while when O
concentration was low, it was less sensitive to NO
concentration. This study provides useful insights for better understanding the causes of the long-term-trend of regional O
pollution nearby Shanghai, and has important implication for air pollution control in large cities in China. Due to the fact that NO
and VOCs are not only precursors for O
, but also are important precursors for particular matter (PM). If reduction of NO
leads to decrease in PM, but increase in O
, the NO
emission control become a very complicated issue and need to carefully design a comprehensive control method.
A real-time numerical source apportionment system was established based on the operational regional atmospheric environmental modelling system (RAEMS) for eastern China in order to calculate the ...contribution of emissions from different provincial regions over the Yangtze River Delta (YRD) region to the PM2.5 concentration. The 2019 modelling results showed good and reliable performance of the RAEMS in modelling PM2.5 concentrations over 55 cities in the YRD region. Herein, the analysis results indicated the importance of local emissions on PM2.5 concentration at both provincial and city scales, with contribution rates of 54%–65% and 62.3%−70.7%, respectively. The contribution of mutual inner-regional transport among provinces was clear, contributing varied proportions (1%–22%) among themselves and similar proportions (23%–29%) to the provincial city PM2.5 concentration. The cross-regional transport contributed from regions outside the YRD provided relatively weaker contributions of 3.3%–10.6%. However, this contribution doubled during cold air events. Note that the temporal trend of PM2.5 over Shanghai is largely dominated by the contributions from Zhejiang and Jiangsu, whereas the other provinces are highly self-dominated. In addition to controlling local emissions to decrease the PM2.5 pollution rate, varied effects were found by reducing inner-regional transport. The cross-regional transport contribution found herein was relatively lower throughout the year than that in previous pollution episode studies. The results of this research provide support for both the real-time emergency PM2.5 pollution prevention and joint strategy policy making for anthropogenic emission regulation and control in the YRD region.
•A real-time modelling system was established for source apportionment of PM2.5 over the YRD region•Contributions to PM2.5 concentration over provincial regions and cities in 2019 were investigated in detail•PM2.5 over YRD are dominated by local emissions and inner-regional transport and influenced by cross-regional transport at yearly scale•Temporal trend of PM2.5 over Shanghai is dominated by the contributions from Zhejiang and Jiangsu, whereas the others are self-dominated
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