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Τρίτη, 2 Ιουλίου 2019

Air Quality, Atmosphere & Health

Whether to wear a pollution filter


Development of air quality forecasting system in Macedonia, based on WRF-Chem model

Abstract

Urban air quality is composed of a complex interaction of factors associated with anthropogenic emissions, atmospheric circulation, and geographic factors; also, most of the urban pollution presents aerosols and trace gases toxic to human health and responsible for damaged flora, fauna, and materials. The air quality system based on the state-of-the-art Weather Research and Forecasting model coupled with chemistry (WRF-Chem) has been configured and designed for Macedonia. An extensive set of experiments have been performed with different model settings to forecast simultaneously the weather and air pollution over Macedonia. For the present work, a numerical simulation of extreme pollution episode over the urban area in Skopje has been simulated using 1-km WRF-Chem model and a newly developed set of urban mobile emissions. The modeled results implied that the model is very sensitive to the initial meteorological conditions, grid spacing, and mobile emissions. The results are validated against available observations for meteorological fields and pollutant concentrations. While the model forecasts with coarser horizontal grid resolution well fit with the hourly values of some air quality monitoring stations, these experiments tend to underpredict the peak level of about 1250 μg/m3 evidenced at the air quality station "Karpos." A WRF-Chem 5-km simulation shows increased PM10 concentrations with a peak value of about 1325 μg/m3 a few hours before the evidenced extreme concentration while 2.5-km grid run indicates the initial accumulation of air pollution with relatively high concentration with peak PM10 on 5 February 2017 at 0100 UTC. The 1-km model configuration well captures the PM10distribution over Skopje valley and the location and timing of the maximum measured air pollution. The verification analysis indicates that the best performance in the sense of the correlation coefficient is achieved with the 5-km WRF-Chem v.3.91 forecast. Numerical simulations with coarser grid resolution show less confidence and lower CC. The results suggest that model initialization and initial data using a mobile source emission provide a better quantitative assessment of extreme air pollution in urban areas. Overall, the present case study shows that the WRF-Chem model has an acceptable performance for meteorological variables as well as PM10concentration over Skopje. This study provides a general overview of WRF-Chem simulations and can serve as a reference for future air quality modeling studies.



Air quality impacts of open-plan cooking in tiny substandard homes in Hong Kong

Abstract

This study investigated the air quality impacts of open-plan cooking in subdivided units (SDUs), which is a type of substandard housing in Hong Kong. About 210,000 persons (2.9% of the population) currently live in such tiny and poorly ventilated dwellings. With a median floor area of merely 9.3 m2 (100 ft2), most SDUs do not have space for a partitioned kitchen to contain the air pollutants generated by cooking, posing a serious indoor air quality issue that affects all members living in the SDU. The CO, CO2, PM10, PM2.5 and VOC concentrations in seven SDUs were monitored for 72 h to capture the emissions from their routine cooking activities. All SDUs used induction or electric cookers and 32 cooking events were recorded. Under natural ventilation, the mean PM10 and PM2.5 concentrations during cooking were 36 and 20 μg/m3, which were 136% and 82% higher than the pre-cooking levels respectively. Their mean maximum concentrations reached 1644 and 749 μg/m3 respectively. The mean PM10 concentration exceeded the local guideline (excellent class) by 1.82 times. However, cooking activities did not contribute to substantial changes in CO, CO2 and VOC concentrations. When the air conditioner was turned on to relieve the heat from cooking, it took 90 min for air pollution to return to pre-cooking levels after a cooking event because of poor ventilation, which significantly increased the occupants' exposure to the cloistered air pollutants. Lacking a partitioned kitchen and effective ventilation in SDUs may pose chronic health threats to their occupants, particularly children.



Climatological evaluation in a Central Anatolian city and indirect effects of climatological variation on air quality

Abstract

Climate is defined as the statistics of weather over a long period of time. Climate has a dynamic structure, and climate change is caused either by natural or anthropogenic effects. Meteorological parameters are routinely recorded by national weather stations. In this study, climate variability was analyzed in a mid-populated city in the middle of the Anatolian Peninsula. Humidity, temperature, precipitation, open surface evaporation, and solar radiation records over 57-year period from 1960 to 2016 were considered. The increase in temperature and solar radiation was obvious. The increase rates were 0.05 °C and 0.62 W/m2 for temperature and solar radiation, respectively. Relative humidity showed a declining trend from 64 to 53%. This study also aimed to evaluate the climate change of planetary boundary layer development, which influences air quality level. AERMET, which is the AERMOD meteorological preprocessor was exploited in order to simulate the planetary boundary layer height, and twice daily upper air soundings, wind speed, wind direction, ambient temperature, and cloud cover have been used as minimum required parameters. The complete meteorological data available were between 2006 and 2016; for that reason, the boundary layer was calculated for 11 years. The determined average boundary layer height was 1018 m in 2006 and was reduced to 889 m in 2016.



Air quality at two stations (Gdynia and Rumia) located in the region of Gulf of Gdansk during periods of intensive smog in Poland

Abstract

The study was conducted to establish whether an extremely high concentration of aerosols occurred in the region of the Gulf of Gdansk at the very end of 2016, and if so which factors determined it. This period was notable in terms of intensity of smog episodes across the rest of Poland. The main goal was to consider pollution sources affecting two nearby stations in the area, which is usually characterised by better air quality than other parts of the country. To achieve this, concentrations of PM1 and PM2.5 were studied in Gdynia and PM10 concentration was measured in Rumia from 22 December 2016 to 22 January 2017. Concentrations of OC, EC, PAHs and major ions were also examined in order to indicate the origin of pollutants. The average daily concentration ranged 6.0–50.0 μg·m−3 for PM1 and 8.3–61.9 μg·m−3 for PM2.5 in Gdynia, and 8.6–71.9 μg·m−3 for PM10 in Rumia. High concentrations of PM1 and PM2.5, classified as values higher than 25 μg·m−3, were noted 4 times. The 24-h limit value of PM10 was exceeded 3 times. Even though the highest aerosol concentration obtained in our results exceeded the limit value by 150%, it was nevertheless lower than in other Polish regions at the same time. This was due to dissimilar meteorological conditions, heavy snowfall and the landfall of Hurricane Barbara. However, high PAH concentrations in aerosols measured in Gdynia and Rumia indicate poor air conditions despite there being a relatively low average concentration of PM at the same time.



Passive sampling as a feasible tool for mapping and model evaluation of the spatial distribution of nitrogen oxides in the city of Curitiba, Brazil

Abstract

Nitrogen oxides (NOx) are important pollutants that affect air quality in urban areas and are associated with harmful effects in human health. These compounds are emitted by combustion process especially vehicles. The main aim of this paper is to assess the concentrations of NOx in the atmosphere of Curitiba by using Ogawa samplers and dispersion models. The determination of compounds in 11 places was performed by using a simple colorimetric reaction and spectrophotometry. A comparison between the Ogawa samplers and the reference chemiluminescence analyzer showed good agreement and repeatability of the method used. Two-week sampling campaigns were performed at 11 stations from July 29 to August 12, and from August 15 to 29, 2016. The results showed the highest concentrations in places with high traffic vehicular and at street level (121 μg m−3 for NOx, 47.9 μg m−3 for NO2, and 48 μg m−3 for NO) as compared to the roof level that can be attributed to the impact of local traffic passing the street canyon. The similarity of monitored and modeled NOx concentrations (17 out of 26 pointwise comparisons within ± 25%) gives confidence in the emission inventory and the model simulations, allowing a conclusion of the source contributions.



Air quality assessment of the Tobacco Heating System 2.2 under simulated residential conditions

Abstract

Despite the growing popularity of new alternatives to traditional tobacco products, there is still limited evidence on their indoor effect in particular in residential spaces as specific environments where enforcement of air quality standards is difficult. Hence, the impact of the Tobacco Heating System 2.2 (THS, marketed as IQOS®) on indoor air quality was assessed under controlled experimental conditions using ventilation representative of residential buildings with natural ventilation. Smoking of cigarettes (Marlboro Gold®) at the same ventilation conditions and consumption rates was used as positive control. Before each THS 2.2 or Marlboro Gold session, a background session with the same volunteers as for the product-use session was held. In the high-load simulated residential environment, out of the 24 measured airborne constituents, only the increase of the indoor concentrations of nicotine, acetaldehyde, and glycerin above the background was attributable to the use of THS 2.2. The quantified concentrations of these three airborne compounds were significantly below the harmful levels defined in the air quality guidelines. Smoking Marlboro Gold resulted in much greater increases in the concentrations of all measured indoor air constituents, except for glycerin, and the indoor concentrations of several constituents exceeded the exposure levels set forth by cognizant authorities. Based on these data, it is reasonable to conclude that the use of THS 2.2 in environments where norms for indoor exposure in terms of adequate ventilation are respected does not adversely affect the overall indoor air quality.



Complex analysis focused on influence of biodiesel and its mixture on regulated and unregulated emissions of motor vehicles with the aim to protect air quality and environment

Abstract

The main task of this study is to perform a complex analysis dealing with influence of biodiesel and its mixture on regulated and unregulated gaseous emissions of diesel engine, which is installed in a motorcar as a driving unit determined for standard road traffic. As a real technical platform intended for realisation of the required experiments, a motor vehicle equipped with the TDI engine was chosen because just this kind of engine was directly affected by the affair "dieselgate". This type of piston combustion engine is widely used in the traffic, together with negative impacts on the air quality. Various diesel fuel mixtures, which represented the applied experimental fuels, were created by mixing of the ultra-low sulphur diesel fuel (ULSDF) with the biodiesel, using different mixture ratios. The individual experiments were performed during a 13-mode test cycle especially developed for the diesel engine in such a way, so that it was possible to identify influence of the engine loading and engine speed on the regulated and unregulated gaseous emissions of the given TDI diesel engine. It is possible to say according to the obtained results that a higher portion of the biodiesel in the fuel mixture reduces the amount of the hydrocarbons (HC), carbon monoxide (CO) and particulate matters (PM) in the gaseous emissions, but it increases volume of the nitrogen oxides (NOX). A higher portion of the biodiesel causes a growth of the formaldehyde emissions and acetaldehyde emissions in the case of unregulated diesel engine emissions. The same trend is also typical for the 1,3-butadiene, propene and ethene. The biodiesel additive increases emissions of benzene; however, it reduces emissions of the toluene and xylene within the aromatic substance emissions. The obtained results confirm a fact that all the gaseous emissions are influenced by the engine operational regimes, especially by the engine loading status.



Assessment of particulate matter, metals of toxicological concentration, and health risk around a mining area, Odisha, India

Abstract

In this study, trace element concentrations in PM10 and suspended particulate matter (SPM) have been investigated for their distribution, enrichment factor, and health impacts in Ganjam, Odisha. We investigated the presence of metals in air particulates to appraise the levels of the metals in the workplace of mine. The spatial variation of metals of toxicological around mining and residential areas were also studied. PM10 levels in mining and residential area were found to be in the range of 30–59 and 12–54 μg m−3, respectively, with an average value of 45 ± 12 and 32 ± 12 μg m−3, respectively, throughout the year and well within the prescribed NAAQS. SPM and PM10 concentrations were observed minimum in the rainy season because of precipitation and maximum in the winter season. The annual average concentration of Pb is higher in the SPM as compared to PM10in the residential area and within 10% of the national ambient air quality standard of 500 ng m−3. Human health risk in the mining areas is 1.1 times higher than the risk for the nearby residential areas. Carcinogenic risk assessment illustrated that there is no potential danger to the populace in the investigation studied.



A hybrid framework for forecasting PM2.5 concentrations using multi-step deterministic and probabilistic strategy

Abstract

PM2.5 concentration forecasting can provide powerful assistance to avoid health and economy loss. Recent research studies have proven that the PM2.5 concentration series is significantly non-stationary and does not obey standard distribution. In this study, a hybrid framework is proposed to solve the above difficulties. The proposed hybrid model consists of five algorithms: wavelet packet decomposition (WPD), gradient boost regression tree (GBRT), linear programming boosting (LPBoost), multi-layer perceptron (MLP), and Dirichlet process mixture model (DPMM). A hybrid preprocessing method WPD-GBRT is firstly applied to extract multi-resolution exogenous features, the LPBoost algorithm can assemble MLPs to achieve better forecasting performance, and the DPMM algorithm is finally built to model complex distribution of PM2.5 concentrations adaptively. Four pollutant data with different time intervals collected from Tangshan are utilized for data simulation. The results indicate the proposed model has excellent forecasting performance. In 1-h interval data, the index of agreement (IA) of the proposed model is 0.9490 and the coverage width-based criterion (CWC) with 99% confidence level is 0.3370.



Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
6948891480

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