An optimized development of urban air quality monitoring network design based on particulate matters.

The design of an air quality monitoring network (AQMN) is the mandatory step to manage air pollution in megacities. Several studies are being done on the location selection of AQMNs based on topography, meteorology, and pollution density. Still, the critical research gap that needs to be addressed is the role of pollutants' importance and prioritization in AQMN. This study aims to utilize the sphere of influence (SOI) method to design an AQMN in a megacity based on particulate matter (PM) as the most serious urban pollutant. Model evaluation was done by employing annual emission inventory data of PM in Tabriz, an industrial and crowded megacity with high exposure to salt particulates, considering 3549 square blocks with a size of 500 m * 500 m. Then, the SOI methodology utilizing the utility function (UF) approach is applied using MATLAB software calculations to determine optimal air quality monitoring network configurations. A range of numbers of utility functions was yielded for every spot on the map. It resulted in grid city maps with final spots for PM10, PM2.5, and intersecting spots. As a result, ten sites are selected as the best possible locations for the AQMN of a 2 million population city. These results could play a precise and significant role in urban air quality decision-making and management.

Real-world and bottom-up methodology for emission inventory development and scenario design in medium-sized cities.

Efficient management of air quality requires a comprehensive emission inventory to support decision-making on air quality improvement. This article presents a comprehensive framework for detailed emission inventory development in cities with low-quality basic data, which examines the emission of primary criteria pollutants (CO, NOx, SO2, PM2.5, PM10, and VOC) from mobile sources, residential, commercial, and public services, fuel stations, transport terminals, energy conversion sections, and industries. This research was applied to Tabriz in Northwest Iran, one of the polluted medium-sized cities with a population of 1.77 million. Results show the city daily emission per capita is 569.8 g of CO, 68.6 g of NOx, 38.6 g of VOC, 17.6 g of SOx, and 3.7 g of PM. Vehicular emissions accounted for 98% of CO, 91% of VOCs, 61% of NOx, and 56% of PM; meaning alternative policy strategies in vehicles would reduce emissions rapidly. Fifteen applicable and effective scenarios in transport and one concerning stationary sources were proposed and reduction potential of them was evaluated. Effectiveness of the public transport improvement and replacement of old passenger cars were founded the key scenarios. These two alternatives decrease 14 and 2 tons of SO2 and 6797 and 2394 tons of NOx annually with the cost of $99.5 MM and $366.5 MM, respectively. The findings of this study provides the choice of travel method by each citizen is a function of cost, speed, comfort and safety of travel; therefore, all the requirements of any scenarios must be fully considered in the implementation step.

An analysis of emission reduction strategy for light and heavy-duty vehicles pollutions in high spatial-temporal resolution and emission.

Traffic as the main source of urban air pollution created severe problems for human health and sustainability. To propose a bottom-up method in emissions reduction, accurate emission inventories of vehicles in a medium-sized city are developed. Traffic emission factors were obtained using traffic flow data, traffic control cameras, and International Vehicle Emission (IVE) model to calculate CO, VOCs, NOx, SOx, and PM of passenger cars, taxis, and urban buses emission inventory. Annual overall emissions of CO, VOCs, NOx, SOx, and PM pollutants, respectively, are 346, 20.9, 25, 44.4, and 0.5 kt/year. VOC and CO emissions in the start-up phase are in the scale of the running phase, while NOx, SOx, and PM allocate much less than the running phase. The highest emission value of SOx and PM occurs in arterials while CO, VOC, and NOx in highways. Eight renovation scenarios have been designed to evaluate their environmental and economic efficiency. Two scenarios entitled "renovation of carbureted, Euro 1 and Euro 2 LDV" and "renovation of high mileage Euro 1 and Euro 2 standard urban buses" showed the highest decrease in pollution emission and pollution social costs. For these two important scenarios, implementation costs were calculated at 477 and 46 M$, while social costs decrease are calculated to be 172.6 and 77.5 M$, respectively. Renovation of vehicles could benefit both the government and society by reducing fuel consumption and pollutant emission. The emission mitigation scenarios considering mobile sources could be a guide for adopting policies in developing countries. Governmental and social cost-share and governmental and social repayment because of fuel-saving costs have also been calculated.

Molecular insights into water desalination performance of pristine graphdiyne nanosheet membrane.

Desalination is an exciting technology to solve the global water problem. In recent years, the graphyne-based membranes have been paid much attention to water purification, because of their high resistance and efficiency, as well as low production cost. Herein, the molecular simulations were done to investigate the salt rejection from aqueous solution through the pristine graphdiyne (graphyne-2) nanosheet. For this purpose, a simulation cell including an aqueous solution of sodium and chloride ions and a graphdiyne membrane has been considered. For ion rejection from aqueous solution, a range of hydrostatic pressures was applied to the box. The water density, radial distribution function, and water density map analysis were studied to investigate the structure of water molecules in different parts of the simulation box including the feed side and the pure water side. The results demonstrated that the graphdiyne membrane has 100% salt rejection at pressures <400 MPa, and its permeability is higher than conventional polymeric membranes.