บทความ

ชื่อเรื่อง : Impact of PM2.5 in indoor urban environments: a review 

ชื่อผู้แต่ง : Nuno R. Martins and Guilherme Carrilho da Grac

แหล่งที่มา : Sustainable Cities and Society. 2018, 42, 259-275.

บทคัดย่อ : 

          Airborne fine particulate matter (PM2.5) is a pollutant that is found in all urban environments. PM2.5 is predominantly generated by traffic and domestic fuel combustion and has significant negative health impacts. The ever-growing urban population spends most of their time in indoor environments where it is exposed to PM2.5 that is brought in from the outdoor environment by ventilation airflow. Several studies show this inflow of outdoor PM2.5, combined with internal sources (e.g. indoor combustion, particle re-suspension) can lead to an I/O ratio above one: indoor air quality is lower than outdoors. The most common approach to limit ventilation inflow of PM2.5 is the use of mechanical ventilation systems with cloth filters that can significantly increase ventilation fan energy consumption. Decreasing exposure to PM2.5 is challenging, requiring a thorough understanding of PM2.5’s origin and the interaction between buildings and their surrounding environment. This review of the impact of PM2.5 in indoor urban environments summarizes existing research in this area, specifically, the main PM2.5 sources and sinks in outdoor and indoor urban environments, the PM2.5 exposure limits that are currently applicable throughout the world, the main socio-economic impacts of exposure to PM2.5 and the most promising solutions to minimize indoor exposure.

#PM2.5 #Air quality modeling #คุณภาพอากาศ #ฝุ่นละอองขนาดเล็กไม่เกิน 2.5 ไมครอน 

ชื่อเรื่อง : Prediction of daily PM2.5 concentration in China using partial differential equations

ชื่อผู้แต่ง : Yufang Wang, Haiyan Wang, Shuhua Chang and Adrian Avram

แหล่งที่มา : PLoS ONE. 2018, 13(6), 13p.

บทคัดย่อ : 

          Accurate reporting and forecasting of PM2.5 concentration are important for improving public health. In this paper, we propose a partial differential equation (PDE) model, specially, a linear diffusive equation, to describe the spatial-temporal characteristics of PM2.5 in order to make short-term prediction. We analyze the temporal and spatial patterns of a real dataset from China's National Environmental Monitoring and validate the PDE-based model in terms of predicting the PM2.5 concentration of the next day by the former days' history data. Our experiment results show that the PDE model is able to characterize and predict the process of PM2.5 transport. For example, for 300 continuous days of 2016, the average prediction accuracy of the PDE model over all city-regions is 93% or 83% based on different accuracy definitions. To our knowledge, this is the first attempt to use PDE-based model to study PM2.5 prediction in both temporal and spatial dimensions.

#PM2.5 #คุณภาพอากาศ #ฝุ่นละอองขนาดเล็กไม่เกิน 2.5 ไมครอน 

ชื่อเรื่อง : Two-stage electrostatic precipitators for the reduction of PM2.5 particle emission.

ชื่อผู้แต่ง : A.Jaworek, A.Marchewicz, A.T.Sobczyk,A.Krupa and T.Czech

แหล่งที่มา : Progress in Energy and Combustion Science. 2018, 67, 206-233.

บทคัดย่อ : 

        Electrostatic precipitator is the most efficient device used for the removal of fly ash particles from the flue gases produced by coal-fired boilers in power plants. However, the fractional collection efficiency of electrostatic precipitators steeply decreases for particles smaller than 1 mm, and particles in the size range of 200-500 nm are removed with lower collection efficiency than those outside this range. These particles are dangerous to humans and have detrimental environmental effects, so there isa need for novel more efficient technologies for their control. One of the answers to this challenge is the two-stage electrostatic precipitator, in which the electrostatic charging and precipitation processes have been separated. The PM2.5 particles (of a size < 2.5 mm) are electrically charged in a separate device (precharger) to a maximal possible electric charge, and then precipitated in a parallel plate collector, free of corona discharge. The electric field in the collection stage can be higher than in an electrostatic precipitator due to the lack of sharp discharge points. A higher electric field allows an increase of the collection efficiency or PM2.5 particles. Another solution is the agglomeration of submicron particles to form larger particles before their precipitation by aparallel-plate collector, conventional electrostatic precipitator or any other gas cleaning device. In some of there viewed devices, both of these processes were combined in a single device that allowed further increases in the collection efficiency for submicronparticles. Devices of this type have been tested in a lab-or semi-industrial scale for the removal of PM2.5 particles from flue gases or diesel engine exhausts. In this paper, various constructions of two stage electrostatic precipitators, comprising a precharger and/or agglomerator in the first stage, and an electrostatic collector in the second stage, have been reviewed. Some of these devices were able to increase the mass collection efficiency above 95% for PM2.5 particles.

#PM2.5 #Electrostatic precipitation #คุณภาพอากาศ #ฝุ่นละอองขนาดเล็กไม่เกิน 2.5 ไมครอน 

ชื่อเรื่อง : Ambient air pollution of particles and gas pollutants, and the predicted health risks from long-term exposure to PM2.5 in Zhejiang province, China 

ชื่อผู้แต่ง : Yuanchen Chen, Lu Zang, Wei Du, Da Xu, Guofeng Shen, Quan Zhang, Qiaoli Zou, Jinyuan Chen, Meirong Zhao & Defei Yao

แหล่งที่มา : Environmental science and pollution research  2018, 25(24), 23833-23844.

บทคัดย่อ : 

          In recent years, ambient air has been severely contaminated by particulate matters (PMs) and some gas pollutants (nitrogen dioxide (NO₂) and sulfur dioxide (SO₂)) in China, and many studies have demonstrated that exposure to these pollutants can induce great adverse impacts on human health. The concentrations of the pollutants were much higher in winter than those in summer, and the average concentrations in this studied area were lower than those in northern China. In the comparison between high-resolution emission inventory and spatial distribution of PM_2.5, significant positive linear correlation was found. Though the pollutants had similar trends, NO₂ and SO₂ delayed with 1 h to PM_2.5. Besides, PM_2.5 had a lag time of 1 h to temperature and relative humidity. Significant linear correlation was found among pollutants and meteorological conditions, suggesting the impact of meteorological conditions on ambient air pollution other than emission. For the 24-h trend, lowest concentrations of PM_2.5, NO₂, and SO₂ were found around 15:00–18:00. In 2015, the population attributable fractions (PAFs) for ischemic heart disease (IHD), cerebrovascular disease (stroke), chronic obstructive pulmonary disease (COPD), lung cancer (LC), and acute lower respiratory infection (ALRI) due to the exposure to PM_2.5 in Zhejiang province were 25.82, 38.94, 17.73, 22.32, and 31.14%, respectively. The population-weighted mortality due to PM_2.5 exposure in Zhejiang province was lower than the average level of the whole country—China.

#PM2.5 #Particulate matters #คุณภาพอากาศ #ฝุ่นละอองขนาดเล็กไม่เกิน 2.5 ไมครอน