The Impact of COVID-19 on the Directors’ Life and Management of Daycare Centers in Metropolitan Area

2021 ◽  
Vol 28 (4) ◽  
pp. 227-251
Author(s):  
Kim Youngshim
2016 ◽  
Vol 16 (2) ◽  
pp. 777-797 ◽  
Author(s):  
A Vara-Vela ◽  
M. F. Andrade ◽  
P. Kumar ◽  
R. Y. Ynoue ◽  
A. G. Muñoz

Abstract. The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the ultraviolet radiation and induced a decrease in ozone formation. The ground-level O3 concentration decreased by about 2 % when the aerosol-radiation feedback is taken into account.


Urban Studies ◽  
2017 ◽  
Vol 56 (6) ◽  
pp. 1113-1128 ◽  
Author(s):  
Masatomo Suzuki ◽  
Yasushi Asami

With a simple model of land use and market arbitrage, this paper investigates the impact of population decline – when existing homeowners compete to attract a small number of new residents – on homeownership and land use. We show that, if a strictly positive cost is required for ownership abandonment, selling used houses is impossible in the periphery, while leasing is possible. We also show that only long-life-quality houses, which require a larger initial investment and sustain greater utility for longer than conventional ones, attract new residents to the periphery. Social welfare may decrease, because the government has to maintain the slowly shrinking, less densely inhabited urban area.


2018 ◽  
Author(s):  
Daun Jeong ◽  
Roger Seco ◽  
Dasa Gu ◽  
Youngro Lee ◽  
Benjamin A. Nault ◽  
...  

Abstract. Nitryl chloride (ClNO2) is a radical reservoir species that releases chlorine radicals upon photolysis. An integrated analysis of the impact of ClNO2 on regional photochemistry in the Seoul Metropolitan Area (SMA) during the Korean-United States-Air Quality (KORUS-AQ) 2016 field campaign is presented. Comprehensive multiplatform observations were conducted aboard the NASA DC-8 and at two ground sites (Olympic Park, OP; Taehwa Research Forest, TRF), representing an urbanized area and a forested region downwind, respectively. The overall diurnal variations of ClNO2 in both sites appeared similar but the night time variation were systematically different. For about half of the observation days at the OP site the level of ClNO2 increased at sunset but rapidly decreased at around midnight. On the other hand, high levels were sustained throughout the night at the TRF site. Significant levels of ClNO2 were sustained at both sites for 4–5 hours after sunrise. Airborne observations, box model calculations, and back trajectory analysis consistently show that this high levels of ClNO2 in the morning is likely due to the transport of air masses within the boundary layer. Box model results show that chlorine radical initiated chemistry can impact the regional photochemistry by elevating net ozone production rate up to ~ 25 % in the morning.


Atmosphere ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Changhan Bae ◽  
Byeong-Uk Kim ◽  
Hyun Cheol Kim ◽  
Chul Yoo ◽  
Soontae Kim

This study identified the key chemical components based on an analysis of the seasonal variations of ground level PM2.5 concentrations and its major chemical constituents (sulfate, nitrate, ammonium, organic carbon, and elemental carbon) in the Seoul Metropolitan Area (SMA), over a period of five years, ranging from 2012 to 2016. It was found that the mean PM2.5 concentration in the SMA was 33.7 μg/m3, while inorganic ions accounted for 53% of the total mass concentration. The component ratio of inorganic ions increased by up to 61%–63% as the daily mean PM2.5 concentration increased. In spring, nitrate was the dominant component of PM2.5, accounting for 17%–32% of the monthly mean PM2.5 concentrations. In order to quantify the impact of long-range transport on the SMA PM2.5, a set of sensitivity simulations with the community multiscale air-quality model was performed. Results show that the annual averaged impact of Chinese emissions on SMA PM2.5 concentrations ranged from 41% to 44% during the five years. Chinese emissions’ impact on SMA nitrate ranged from 50% (winter) to 67% (spring). This result exhibits that reductions in SO2 and NOX emissions are crucial to alleviate the PM2.5 concentration. It is expected that NOX emission reduction efforts in China will help decrease PM2.5 concentrations in the SMA.


Author(s):  
Nipher M Malika ◽  
Guisella Barbagelatta ◽  
Mary Penny ◽  
Kelly A Reynolds ◽  
Ryan Sinclair

Abstract Background The metropolitan area of Lima, Peru has a third of the nation’s population living in slum dwellings that are hypothesized to contribute to inefficient household hygienic practices. The purpose of this study was to quantitatively assess which living conditions have the greatest impact on handwashing practices. Methods A cross-sectional epidemiological design of participants ≥16 y of age from San Juan de Miraflores, a slum on the outskirts of Lima, Peru, was used. Poisson regression was applied to assess the impact of living conditions on handwashing practices. Results We could not demonstrate a relationship between living conditions (home structure, overcrowding, water, grey water disposal) and reported handwashing. The reported lack of handwashing is associated with the number of children in the home (those with children <5 y of age were more likely not to report washing their hands) and length of stay in the slum in years. Conclusions Living conditions play an important role in one’s health, therefore improved study designs are needed to determine which strategies are likely to be the most effective in improving outcomes for slum dwellers.


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