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1.
Chemosphere ; 282: 131052, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470149

RESUMO

The "Land of pyres", namely "La Terra dei Fuochi", is an area of Campania region (South-Italy), highly inhabited and comprises between the Provinces of Naples and Caserta, sadly known worldwide for the criminal activities related to the illegal waste disposal and burning. These fires, concomitantly with traffic emissions, might be the source of potential toxic element (PTE) dangerous for the human health and causing pathologies. In the framework of Correlation Health-Environment project, funded by the Campania region, eight municipalities (of area "Land of pyres") and three remote sites have been bio-monitored using the olive (Olea europaea L.) plants as biomonitors. Leaves of olive plants were collected in each assayed municipality and the concentration of 11 metal(loid)s was evaluated by means of ICP-OES. Our findings revealed that the air of these municipalities was limitedly contaminated by PTE; in fact, only Sb, Al and Mn were detected in the olive leaves collected in some of the assayed municipalities and showed a high enrichment factors (EC) manly due, probably, to the vehicular traffic emissions. Furthermore, the concentrations of the other assayed PTEs were lower than those of Sb, Al and Mn. For these reasons we suppose that their emissions in the troposphere have been and are limited, and they mainly have a crustal origin. Even if our data are very comforting for those urban area, regarded by many as one of the most contaminated one in Italy, a great environment care, in any case, is always needed.


Assuntos
Poluição do Ar , Olea , Eliminação de Resíduos , Monitoramento Biológico , Monitoramento Ambiental , Humanos , Emissões de Veículos
2.
Environ Monit Assess ; 193(9): 619, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34476626

RESUMO

Motor vehicle emissions especially occur at signalized intersections during idling, acceleration, and deceleration phases. The reduction of exhaust emissions from motor vehicles is on the focus of environmental studies. The main targets of this paper are the modeling of motor vehicle particulate matter (PM10) emissions by American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) and California Line Source for Queuing and Hot Spot Calculations (CAL3QHCR) models and investigating the effectiveness of a hypothetical green wave scenario as a pollution reduction strategy. The portion of D010 State Road in Zonguldak (Turkey) is selected. Vehicle counting is applied for determining the traffic volume. Then, the PM10 emission inventory is prepared. After that, PM10 pollution distribution maps at signalized intersections are created by running air quality models. Next, the CAL3QHCR model is run again for the green wave scenario which assumes free flow at signalized intersections. The maximum PM10 concentrations predicted by AERMOD and CAL3QHCR models are 16.8 µg/m3 and 14.9 µg/m3, respectively. Although these values are below the threshold value, it can be said that air quality may pose a threat to public health in the existence of other sources. With the implementation of signal optimization, the PM10 pollution is reduced by 10-50% at intersections. Cumulative model validation is employed including other PM10 sources in the study area. PM10 contribution of other sources at Zonguldak air quality monitoring station is determined by the AERMOD model. Finally, the sum of model outputs is validated against measured concentrations. According to the validation, both models are found as satisfactory and AERMOD performed better than CAL3QHCR.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental , Veículos Automotores , Material Particulado/análise , Emissões de Veículos/análise
3.
Ann R Coll Surg Engl ; 103(8): 599-603, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34464571

RESUMO

INTRODUCTION: The COVID-19 pandemic has demanded radical changes in service delivery. Our centre adopted the use of outpatient telemedicine to reduce close-contact interactions between patients and staff. We hypothesised that incidental gains may be associated with this. We evaluated financial, practical and environmental implications of substituting virtual clinics (VCs) for in-person urology outpatient appointments. METHODS: VCs were studied over a 3-month period. Based on patient-reported 'usual mode of transport' to the hospital, travel distance, time, petrol and parking costs, and the carbon emissions avoided by virtue of remote consultations were calculated. The underlying symptom/diagnosis and the 'effectiveness' of the VC were evaluated. RESULTS: Of 1,016 scheduled consultations, 736 (72.44%) were conducted by VCs over the study period. VCs resulted in an agreed treatment plan in 98.4% of a representative patient sample. The use of VCs was associated with an overall travel distance saving for patients of 31,038 miles (49,951km) over 3 months, with an average round-trip journey of 93.8 miles (151km) avoided for each rural-dwelling patient and an average financial saving of £25.91 (€28.70) per rural-dwelling car traveller. An estimated 1,257.8 hours of patient time were saved by avoidance of travel and clinic waiting times. Based on car-travelling patients alone, a 6.07-tonne reduction in carbon emissions was achieved with the use of VCs. CONCLUSIONS: In appropriate clinical circumstances, VCs appear to provide efficiency across a number of domains. Future healthcare may involve offering outpatients the option of telemedicine as an alternative to physical attendance.


Assuntos
Redução de Custos , Consulta Remota , Viagem , Emissões de Veículos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reino Unido , Urologia , Adulto Jovem
4.
Artigo em Inglês | MEDLINE | ID: mdl-34444129

RESUMO

The present study attempts to examine the research gap in terms of comparing the environmental impact of trolleybuses and diesel buses in the conditions of a country with an unfavourable energy mix. The analysed example concerns the trolleybus transport system in Gdynia, in northern Poland, which also partially serves the neighbouring city of Sopot. In the last few years, two bus lines have been electrified with trolleybuses in the In-Motion-Charging technology, which enables operation on sections without an overhead network. Using the actual operational data, a comparative analysis of the emissivity of diesel buses and trolleybuses used on the same lines in an identical operating regime was conducted. Moreover, an attempt was made to estimate the damage costs of the emission of air pollutants for the above-mentioned means of transport. Research has shown that trolleybuses significantly help to reduce emissions of nitrogen oxides, non-methane volatile organic compounds and particulate matter, while increasing sulphur dioxide emissions on the served lines. They also generate lower specific emissions of carbon dioxide compared to diesel buses. However, taking into account the differences in the number of seats in these vehicles, the length of routes resulting from a need to provide access to the necessary infrastructure and the total amount of kilometres covered on a given route, they may cause higher emissions per year and per the product life cycle than diesel buses. This is related to the unfavourable structure of energy production in Poland, which is dominated by coal sources. The research results clearly show that the use of trolleybuses in public transport contributes to a reduction of the damage costs of the emission of pollutants that amount to approximately EUR (€) 30,000-60,000 per year for the analysed lines.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , Poluentes Atmosféricos/análise , Veículos Automotores , Material Particulado/análise , Emissões de Veículos/análise
5.
Sci Total Environ ; 791: 148138, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34412410

RESUMO

Although pollutant sources are often assumed to be spatially uniform, traffic in real cities may vary significantly in space. Consequently the local air quality within a street may not be determined solely by the traffic volume of the street. Using building-resolving large-eddy simulation, the relationship between traffic volume and air quality is investigated in the context of two idealised problems: (i) the influence of pollutants emitted from a main road on the surrounding side streets and (ii) the pedestrianisation of a central thoroughfare. It is shown that the spatial variation of traffic volume is of crucial importance within a near-field region defined by a radius of homogenisation (RAD). Furthermore, the actual impact depends strongly on the wind direction. Hence the benefits of pedestrianisation may be limited: for example, after removing 100% of the traffic along a street in a central business district, the annual-averaged local concentration decreases by ~30% when the urban background is neglected. The impact may be significantly lower when the background concentration is considered. This work is relevant to the formulation of effective traffic control policy and the improved understanding of spatially inhomogeneous pollutant sources.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Cidades , Emissões de Veículos/análise , Vento
6.
J Environ Sci (China) ; 107: 138-149, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34412776

RESUMO

A rapid reaction occurs near the exhaust nozzle when vehicle emissions contact the air. Twenty diesel vehicles were studied using a new multipoint sampling system that is suitable for studying the exhaust plume near the exhaust nozzle. The variation characteristics of fine particle matter (PM2.5) and its components in diesel vehicle exhaust plumes were analyzed. The PM2.5 emissions gradually increased with increasing distance from the nozzle in the plume. Elemental carbon emissions remained basically unchanged, organic carbon and total carbon (TC) increased with increasing distance. The concentrations of SO42-, NO3- and NH4+ (SNA) directly emitted by the vehicles were very low but increased rapidly in the exhaust plume. The selective catalytic reduction (SCR) reduced 42.7% TC, 40% NO3- emissions, but increased 104% SO42- and 36% NH4+ emissions, respectively. In summary, the SCR reduced 29% primary PM2.5 emissions for the tested diesel vehicles. The NH4NO3 particle formation maybe more important in the plume, and there maybe other forms of formation of NH4+ (eg. NH4Cl). The generation of secondary organic carbon (SOC) plays a leading role in the generation of secondary PM2.5. The SCR enhanced the formation of SOC and SNA in the plume, but comprehensive analysis shows that the SCR more enhanced the SNA formation in the plume, which is mainly new particles formation process. The inconsistency between secondary organic aerosol (SOA) and primary organic aerosol definitions is one of the important reasons for the difference between SOA simulation and observation.


Assuntos
Material Particulado , Emissões de Veículos , Aerossóis/análise , Carbono , Simulação por Computador , Emissões de Veículos/análise
7.
Huan Jing Ke Xue ; 42(9): 4158-4167, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414714

RESUMO

This study examined high-resolution online monitoring data from January to February 2020 to study the extinction characteristics and sources of heavy pollution episodes during winter in Tianjin. Heavy pollution episodes occurred during this period from January 16 to 18 (episode Ⅰ), from January 24 to 26 (episode Ⅱ), and from February 9 to 10 (episode Ⅲ). The results showed that the concentrations of PM2.5 during the three heavy pollution episodes were (229±52), (219±48), and (161±25) µg·m-3, respectively, with NO3-, SO42-, NH4+, OC, EC, Cl-, and K+ comprising the main species. The values of the scattering coefficient(Bsp550) during the three heavy pollution episodes were (1055.65±250.17), (1054.26±263.22), and (704.44±109.89) Mm-1, respectively, while the absorption coefficient(Bap550) showed much lower values of (52.96±13.15), (39.72±8.21), and (34.50±8.53) Mm-1, respectively. PM2.5 played a major role in atmospheric extinction during heavy pollution episodes. Specifically, nitrate (38.9%-48.8%), sulfate (31.1%-40.7%), and OM (9.9%-21.8%) were the most important extinction components. The contribution of PM2.5 chemical components to the extinction coefficient varied significantly between the three episodes; the percentage of nitrate was higher in episode Ⅰ than in the other two episodes; in episode Ⅱ, the percentage of OM was highest, significantly affected by the discharge of fireworks; in episode Ⅲ, as traffic decreased but coal combustion emissions remained constant, the contribution of nitrate to the extinction coefficient decreased, while that of sulfate increased. Source apportionment of extinction coefficients was performed using PMF model combined with IMPROVE. Various pollution sources contributed to the extinction coefficient, namely: secondary sources (37.1%-42.0%), industrial and coal combustion (22.9%-24.2%), vehicle exhaust (23.9%-27.2%), crustal dust (5.0%-6.4%), and fireworks and biomass burning (3.9%-6.2%). Compared with episode Ⅰ, the contribution of fireworks and biomass burning increased significantly during episode Ⅱ, while the contribution of vehicle exhaust decreased significantly during episode Ⅲ. The contribution of industrial and coal combustion was similar during all three heavy pollution episodes. According to backward analysis, the small-scale and short-distance transmissions from Hebei provinces, as well as the medium and short-distance transmissions from central Inner Mongolia, were the major sources during heavy pollution episodes in the winter in Tianjin City.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Emissões de Veículos/análise
8.
Huan Jing Ke Xue ; 42(9): 4191-4201, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414717

RESUMO

As an important precursor of ozone, volatile organic compounds (VOCs) have attracted much attention. This study analyzed the temporal variation and composition of atmospheric VOCs in the coastal background of the Pearl River Delta, using real-time online monitoring data of VOCs obtained at the Yangmeikeng Ecological Environment Monitoring Station from August 2019 to July 2020. The major sources of VOCs were identified using a receptor model based on the PMF (positive matrix factorization) and HYSPLIT (hybrid single particle Lagrangian integrated trajectory) models. The results showed that the annual mean concentration of anthropogenic VOCs in the coastal background area of the Pearl River Delta was 9.30×10-9(volume fraction). There was obvious seasonal variation of VOCs in this area, with higher values in autumn and winter and lower values in summer. The coastal background area of the Pearl River Delta exhibited a different diurnal variation pattern to that of cities and other backgrounds. While the peak of VOCs concentration mainly occurred in the morning, from 10:00 to 11:00, concentration remained at a low level during the early morning and after 15:00. Ethylene, propylene, toluene, isopentane, isoprene, m/p-xylene, n-butane, and acetylene were the key species that affected the chemical composition of VOCs. The air masses affecting the coastal background area of the Pearl River Delta were mainly short-distance air masses from elsewhere in the province (25%), ocean air masses (27%), coastal air masses (31%), and inland air masses outside the province (17%). Among them, the average concentration of VOCs was lowest under the influence of ocean air masses, which is mainly affected by the mixed source of ship emissions and aging VOCs, gasoline volatilization, and vehicle emissions. In comparison, the concentration level of VOCs increased by 70.1% to 148.8% under the influence of other air masses. The transmission effects of industrial sources, LNG and LPG volatiles, and petrochemical sources were more prominent. Generally, the atmosphere of coastal background areas was severely affected by anthropogenic pollution, especially by air pollution masses transported from the land, while the impact of pollution by ships near shore and tourist traffic cannot be ignored.


Assuntos
Poluentes Atmosféricos , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Rios , Emissões de Veículos/análise , Compostos Orgânicos Voláteis/análise
9.
Environ Monit Assess ; 193(9): 575, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34392406

RESUMO

Motor vehicles operating on the road are a significant source of Particulate Matter (PM) emissions depending on the fuels used in the vehicles. Gasoline and Diesel vehicles are directly responsible for the tailpipe PM emissions (specifically PM2.5: particles ≤ 2.5 µm), known as primary PM2.5 emissions. The other major direct emissions from the vehicles, which include volatile organic compounds (VOCs), and nitrogen oxides (NOx) contribute to the formation of secondary organic PM, also known as secondary organic aerosols (SOA), through some inter-related chemical reactions. The SOAs are highly toxic and contribute to a portion of total PM emissions. In this research, emission scenarios of both primary PM2.5 and SOA for a car-dependent expanding Australian city (Adelaide) were analyzed. The variability of traffic characteristics on road was considered and conducted a probabilistic emissions inventory for tailpipe primary PM2.5 and precursors, while statistical analysis of the probable chemical conversion ratios was considered for the SOA inventory. It was found that the tailpipe emissions from the vehicles were higher than the air quality standard, while the SOA contribution from the vehicles was not significantly high but contributed to the increase of total PM concentration. The analysis of the chemical transformation of SOA precursors justified the importance of conducting more detailed emissions modelling for sustainable urban air quality planning.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , Austrália , Monitoramento Ambiental , Gasolina/análise , Material Particulado/análise , Emissões de Veículos/análise
10.
Sci Total Environ ; 793: 148602, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34351295

RESUMO

Vehicle emissions have a significantly negative impact on climate change, air quality and human health. Drivers of vehicles are the last major and often overlooked factor that determines vehicle performance. Eco-driving is a relatively low-cost and immediate measure to reduce fuel consumption and emissions significantly. This paper reports investigation of the effects of an on-board green-safety device on fuel consumption and emissions for both experienced and inexperienced drivers. A portable emissions measurement system (PEMS) was installed on a diesel light goods vehicle (LGV) to measure real-driving emissions (RDE), including total hydrocarbons (THC), CO CO2, NO, NO2 and particulate matter (PM). In addition, driving parameters (e.g. vehicle speed and acceleration) and environmental parameters (e.g. ambient temperature, humidity and pressure) were recorded in the experiments. The experimental results were evaluated using the Vehicle Specific Power (VSP) methodology to understand the effects of driving behavior on fuel consumption and emissions. The results indicated that driving behavior was improved for both experienced and inexperienced drivers after activation of the on-board green-safety device. In addition, the average time spent was shifted from higher to lower VSP modes by avoiding excessive speed, and aggressive accelerations and decelerations. For experienced drivers, the average fuel consumption and NO, NO2 and soot emissions were reduced by 5%, 56%, 39% and 35%, respectively, with the on-board green-safety device. For inexperienced drivers, the average reductions were 6%, 65%, 50% and 19%, respectively. Moreover, the long-term formed habits of experienced drivers are harder to be changed to accept the assistance of the green-safety device, whereas inexperienced drivers are likely to be more receptive to change and improve their driving behaviors.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Gasolina , Humanos , Material Particulado/análise , Equipamentos de Proteção , Emissões de Veículos/análise
11.
Environ Pollut ; 286: 117576, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34438497

RESUMO

Conventional factor analyses can present problems in cases with changing numbers of sources and/or time-dependent source compositions. There is also lack of a reliable method to estimate uncertainties in the source contributions derived by positive matrix factorization (PMF). Applying a moving window evolving PMF to hourly PM2.5 composition dataset from a field campaign in Tianjin China that included the Spring and Lantern Festivals and the start of COVID-19 pandemic has substantially improved the apportionment compared to a conventional analysis using the entire data. Festival-related sources (e.g., fireworks and residential burning here) have been clearly identified and estimated during both the Spring and Lantern Festivals. During this period, the sources changed because the time period overlaps with the outbreak of COVID-19 and related reductions in activity during the lockdown that began on Lunar New Year. Multiple PMF runs providing source contribution estimates made it possible to estimate the uncertainties in these values. Our results show that winds-dependent sources like dust and distant point sources have larger uncertainties than the other sources. Compared with conventional PMF analyses, the current method may better reflect the actual emissions as well as being able to estimate uncertainties. Thus, this approach appears to be an improvement if the appropriate data are available.


Assuntos
Poluentes Atmosféricos , COVID-19 , Poluentes Atmosféricos/análise , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Pandemias , Material Particulado/análise , SARS-CoV-2 , Emissões de Veículos/análise
12.
Environ Pollut ; 286: 117577, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34438498

RESUMO

Revealing the changes in chemical compositions and sources of PM2.5 is important for understanding aerosol chemistry and emission control strategies. High time-resolved characterization of water-soluble inorganic ions, elements, organic carbon (OC), and elemental carbon (EC) in PM2.5 was conducted in a coastal city of southeast China during the COVID-19 pandemic. The results showed that the average concentration of PM2.5 during the city lockdown (CLD) decreased from 46.2 µg m-3 to 24.4 µg m-3, lower than the same period in 2019 (PM2.5: 37.1 µg m-3). Concentrations of other air pollutants, such as SO2, NO2, PM10, OC, EC, and BC, were also decreased by 27.3%-67.8% during the CLD, whereas O3 increased by 28.1%. Although SO2 decreased from 4.94 µg m-3to 1.59 µg m-3 during the CLD, the concentration of SO42- (6.63 µg m-3) was comparable to that (5.47 µg m-3) during the non-lockdown period, which were attributed to the increase (16.0%) of sulfate oxidation rate (SOR). Ox (O3+NO2) was positively correlated with SO42-, suggesting the impacts of photochemical oxidation. A good correlation (R2 = 0.557) of SO42- and Fe and Mn was found, indicating the transition-metal ion catalyzed oxidation. Based on positive matrix factorization (PMF) analysis, the contribution of secondary formation to PM2.5 increased during the epidemic period, consisting with the increase of secondary organic carbon (SOC), while other primary sources including traffic, dust, and industry significantly decreased by 9%, 8.5%, and 8%, respectively. This study highlighted the comprehensive and nonlinear response of chemical compositions and formation mechanisms of PM2.5 to anthropogenic emissions control under relatively clean conditions.


Assuntos
Poluentes Atmosféricos , COVID-19 , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Pandemias , Material Particulado/análise , SARS-CoV-2 , Estações do Ano , Sulfatos , Emissões de Veículos/análise
13.
Environ Monit Assess ; 193(9): 560, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34379192

RESUMO

Mining activities in Canada's pristine Arctic (e.g., driving on unpacked roads, blasts, rock grinding, diesel combustion, and garbage incineration) could add local sources of airborne fine particulate matter with a diameter of < 2.5 µm (PM2.5) to their surrounding area. The increase in PM2.5 above the background level around a mine represents a potential disturbance to caribou. To quantify the spatial distribution of the elevated PM2.5, we investigated three different sampling schemes to measure PM2.5 concentration using a portable monitor. We found that the best sampling scheme was to use the regional background PM2.5 as the reference and analyze the anomaly of PM2.5 measured at sites around the mine complex from the background level. The regional background PM2.5 values were measured at the Daring Lake Tundra Research Station during 2018 and 2019. Our results indicated that the background PM2.5 was not a low and constant value but varied with rain events, wind direction, and the impacts of forest fire smoke. After excluding periods affected by forest fires smokes, we found the background PM2.5 was close to 0 µg m-3 for the first few hours after rain, and then increased logistically with the time after rain (tar) to the maximum of 5 (or 10) µg m-3 when the wind came from the north (or south) of the NW-SE axis. The NW-SE axis in western Canada divides the tundra north with few anthropogenic PM2.5 sources from the forested south with many PM2.5 sources from forest fire smokes and human activities. Analyses of PM2.5 anomaly from the background (i.e., PM2.5 measured at a site around the mining complex-the background level at the corresponding tar and wind direction) revealed that the zone of elevated PM2.5 around the mine (Zepm) expanded with tar. In the first few hours after rain, PM2.5 was close to 0 everywhere except within meters of a source (e.g., a truck exhaust) in the downwind direction. During tar = 6 to 96 h, Zepm expanded to 6.3 km in the downwind direction when the wind came from south of the NW-SE axis. A similar result was found in the downwind direction when the wind came from north of the NW-SE axis, with Zepm = 4.4 km. In the upwind direction, the value of Zepm was much smaller, being 0.7 km (or 1.0 km) when the wind came from the north (or south) of the NW-SE axis. For the period of tar between 96 and 192 hours, Zepm further expanded to 21.2 km when the wind from the south of the NW-SE axis. The results from this study indicated that this reference paradigm that uses the regional background PM2.5 as the reference in combination with a portable PM2.5 monitor worked well for quantifying the tempo-spatial patterns of PM2.5 at locations in remote and mostly pristine Arctic. However, their effectiveness for other regions needs further investigation.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Humanos , Veículos Automotores , Material Particulado/análise , Emissões de Veículos/análise
14.
Sci Total Environ ; 790: 148220, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380245

RESUMO

With changing numbers, compositions, emission standards and fuel quality of on-road vehicles, it is imperative to accordingly characterize and update vehicular emissions of carbonaceous aerosols for better understanding their health and climatic effects. In this study, a 7-day field campaign was conducted in 2019 in a busy urban tunnel (>30,000 vehicles day-1) in south China with filter-based aerosol samples collected every 2 h at both the inlet and the outlet for measuring carbonaceous aerosols and their light absorbing properties. Observed fleet average emission factor (EF) of total carbon (TC) was 13.4 ± 8.3 mg veh-1 km-1, and 17.4 ± 11.3 mg veh-1 km-1 if electric and LPG-driven vehicles were excluded; and fleet average EF of organic carbon (OC) and elemental carbon (EC) was 8.5 ± 6.6 and 4.9 ± 2.6 mg veh-1 km-1 (11.0 ± 8.8 and 6.3 ± 3.6 mg veh-1 km-1 if excluding electric and LPG vehicles), respectively. Regression analysis revealed an average TC-EF of 319.8 mg veh-1 km-1 for diesel vehicles and 2.1 mg veh-1 km-1 for gasoline vehicles, and although diesel vehicles only shared ~4% in the fleet compositions, they still dominate on-road vehicular carbonaceous aerosol emissions due to their over 150 times higher average TC-EF than gasoline vehicles. Filter-based light absorption measurement demonstrated that on average brown carbon (BrC) could account for 19.1% of the total carbonaceous light absorption at 405 nm, and the average mass absorption efficiency of EC at 635 nm and that of OC at 405 nm were 5.2 m2 g-1 C and 1.0 m2 g-1 C, respectively.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono/análise , China , Monitoramento Ambiental , Material Particulado/análise , Emissões de Veículos/análise
15.
Sci Total Environ ; 790: 148149, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380266

RESUMO

Volatile organic compounds (VOCs) from anthropogenic sources are deleterious to air quality, climate, human health and vegetation. However, research on VOCs source profiles of the non-solvent use in some industries and the emission characteristics of motor vehicles under actual road conditions is limited in China. In this research, VOCs source profiles of industries (wood-based panel manufacturing and pharmacy) based on all product processes were constructed, and those of light and medium duty vehicles exhaust based on actual road conditions at different speeds were acquired in Chengdu, a megacity in southwest China. The results show that VOCs groups of various sources were dominated by oxygenated VOCs (OVOCs), which accounted for 27-84% of the total VOCs emission. Due to the great contribution of OVOCs to industrial source reactivity (SR), attention should be paid to the control over the emissions of the species with high reactivity, such as aromatics and alkenes, but also to the production processes with relatively large proportions of OVOCs species emission. VOCs emissions from gasoline and diesel vehicles running at a speed ranging from 0 to 40 km/h have approximately the same ozone formation potential (OFP), while the contribution of VOCs emission from diesel vehicles to the formation of urban ozone pollution deserves further attention. It is found that VOCs emission characteristics of some industries in China have changed as the upgrading of production processes in automobile manufacturing and other industries, such as the extensive use of water-based coatings instead of outdated solvent-based coatings, which increased the uncertainty of judgment parameters (B/T ratio, etc.) in source apportionment research. The ranges of B/T ratio of industrial process sources, solvent use sources and motor vehicles are 0.00-0.23, 0.01-0.75 and 0.35-0.92, respectively. Therefore, updating existing source profiles and further understanding the emission constitutions of characteristic species in these source profiles (such as BTEX ratio) will be conducive to further research on emission inventory, source apportionment for O3 pollution control effectively.


Assuntos
Poluentes Atmosféricos , Ozônio , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Humanos , Ozônio/análise , Emissões de Veículos/análise , Compostos Orgânicos Voláteis/análise
16.
Sci Total Environ ; 796: 148963, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34265616

RESUMO

The occurrence of environmental persistent free radicals (EPFRs) in the environment has attracted a great deal of research attention. Although the major sources of EPFRs in the environment is diesel engine exhaust, the study on the emission characteristics of EPFRs at different working conditions is still very limited. An integrated engine system was adopted to simulate different working conditions of various altitudes and engine speeds, and to examine the emission process of a diesel engine. The results suggested that low engine speed and high altitude are generally associated with high PM10 emission with more stable and ordered structures. Based on the analysis of PAHs on solid and gas phases, PM10 generated from diesel engine at altitude higher than 2000 m may contain substantial amounts of PAHs embedded inside particles, but not adsorbed on the surface. EPFRs signal up to 1.66 × 1020 spins/g were detected in PM10 of the diesel exhaust. Higher engine speed and lower altitude were associated with stronger EPR signals on PM10. However, the accumulated EPR signal intensities after consuming 1 L of diesel were higher at lower engine speed and higher altitude, suggesting higher overall risks. A positive correlation between R value (signal strength ratio of D and G peaks on the Raman spectra) and EPFRs intensity indicated that the EPR signals were associated with the defects of carbon structure. EPFRs intensity in particles showed no significant change in dark, and over 70% of the EPR signals survived under UV light in a one-month aging simulation. The strong persistence of these EPFRs suggested their potential long lasting and widespread risks, which should be investigated extensively.


Assuntos
Material Particulado , Emissões de Veículos , Altitude , Carbono , Radicais Livres , Gasolina/análise , Material Particulado/análise , Emissões de Veículos/análise
17.
Sci Total Environ ; 795: 148809, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34328915

RESUMO

Chassis dynamometer experiments were conducted to investigate the effect of vehicle speed and usage of ethanol-blended gasoline (E10) on formation and evolution of gasoline vehicular secondary organic aerosol (SOA) using a Gothenburg Potential Aerosol Mass (Go: PAM) reactor. The SOA forms rapidly, and its concentration exceeds that of primary organic aerosol (POA) at an equivalent photochemical age (EPA) of ~1 day. The particle effective densities grow from 0.62 ± 0.02 g cm-3 to 1.43 ± 0.07 g cm-3 with increased hydroxyl radical (OH) exposure. The maximum SOA production under idling conditions (4259-7394 mg kg-fuel-1) is ~20 times greater than under cruising conditions. There was no statistical difference between SOA formation from pure gasoline and its formation from E10. The slopes in Van Krevelen diagram indicate that the formation pathways of bulk SOA includes the addition of both alcohol/peroxide functional groups and carboxylic acid formation from fragmentation. A closure estimation of SOA based on bottom-up and top-down methods shows that only 16%-38% of the measured SOA can be explained by the oxidation of measured volatile organic compounds (VOCs), suggesting the existence of missing precursors, e.g. unmeasured VOCs and probably semivolatile or intermediate volatile organic compounds (S/IVOCs). Our results suggest that applying parameters obtained from unified driving cycles to model SOA concentrations may lead to large discrepancies between modeled and ambient vehicular SOA. No reduction in vehicular `SOA production is realized by replacing normal gasoline with E10.


Assuntos
Poluentes Atmosféricos , Gasolina , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Gasolina/análise , Emissões de Veículos/análise
18.
Artigo em Inglês | MEDLINE | ID: mdl-34203568

RESUMO

Although cancer is traditionally considered a genetic disease, the epigenetic abnormalities, including DNA hypermethylation, histone deacetylation, and/or microRNA dysregulation, have been demonstrated as a hallmark of cancer. Compared with gene mutations, aberrant epigenetic changes occur more frequently, and cellular epigenome is more susceptible to change by environmental factors. Excess cancer risks are positively associated with exposure to occupational and environmental chemical carcinogens, including those from gasoline combustion exhausted in vehicles. Of note, previous studies proposed particulate matter index (PMI) as a measure for gasoline sooting tendency, and showed that, compared with the other molecules in gasoline, 1,2,4-Trimethylbenzene, 2-methylnaphthalene and toluene significantly contribute to PMI of the gasoline blends. Mechanistically, both epigenome and genome are important in carcinogenicity, and the genotoxicity of chemical agents has been thoroughly studied. However, less effort has been put into studying the epigenotoxicity. Moreover, as the blending of ethanol into gasoline substitutes for carcinogens, like benzene, toluene, xylene, butadiene, and polycyclic aromatic hydrocarbons, etc., a reduction of secondary aromatics has been achieved in the atmosphere. This may lead to diminished cancer initiation and progression through altered cellular epigenetic landscape. The present review summarizes the most important findings in the literature on the association between exposures to carcinogens from gasoline combustion, cancer epigenetics and the potential epigenetic impacts of biofuels.


Assuntos
Poluentes Atmosféricos , Neoplasias , Poluentes Atmosféricos/análise , Etanol/toxicidade , Gasolina/análise , Gasolina/toxicidade , Neoplasias/induzido quimicamente , Neoplasias/epidemiologia , Material Particulado/análise , Tolueno , Emissões de Veículos/análise
19.
Artigo em Inglês | MEDLINE | ID: mdl-34204413

RESUMO

Excessive traffic pollutant emissions in high-density cities result in thermal discomfort and are associated with devastating health impacts. In this study, an improved data analytic framework that combines geo-processing techniques, social habits of local citizens like traffic patterns and working schedule and district-wise building morphologies was established to retrieve street-level traffic NOx and PM2.5 emissions in all 18 districts of Hong Kong. The identification of possible human activity regions further visualizes the intersection between emission sources and human mobility. The updated spatial distribution of traffic emission could serve as good indicators for better air quality management, as well as the planning of social infrastructures in the neighborhood environment. Further, geo-processed traffic emission figures can systematically be distributed to respective districts via mathematical means, while the correlations of NOx and mortality within different case studies range from 0.371 to 0.783, while varying from 0.509 to 0.754 for PM2.5, with some assumptions imposed in our study. Outlying districts and good practices of maintaining an environmentally friendly transportation network were also identified and analyzed via statistical means. This newly developed data-driven framework of allocating and quantifying traffic emission could possibly be extended to other dense and heavily polluted cities, with the aim of enhancing health monitoring campaigns and relevant policy implementations.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Ambientais , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Cidades , Ciência de Dados , Monitoramento Ambiental , Hong Kong/epidemiologia , Humanos , Material Particulado/análise , Emissões de Veículos/análise
20.
Environ Sci Pollut Res Int ; 28(33): 44598-44621, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34212326

RESUMO

Pyrolysis is an encouraging solution considering the facts of energy demand and waste plastic management as it produces liquid fuel for compression ignition engine application. This study provides critical insights into the effects of waste plastic oil on the emission and performance characteristics of compression ignition engines. Though most of the studies have shown a negative influence, promising outcomes have been noticed in a few specific cases. A maximum of 71%, 80%, 76%, 71%, 21%, and 13% decrease in nitrogen oxide emission, carbon monoxide emission, unburnt hydrocarbon emission, smoke emission, exhaust gas temperature, and brake-specific fuel consumption, respectively, have been noticed with waste plastic oil or its blends at certain operating conditions. Nevertheless, the presence of long carbon chains, higher aromatic content, and non-homogeneous air-fuel mixture owing to the wide product distribution in plastic oil are the few reasons which affected the emission and performance characteristics of the engines. More rigorous investigations are needed to improve the quality of the fuel and to establish correlations between the fuel properties and pyrolysis parameters. In addition, the effects of incorporating exhaust gas recirculation, emulsification process, and use of additives with waste plastic oil need to be explored more for reducing the emissions with satisfactory engine performance, and in this regard, the use of bio-additives with waste plastic oil can provide a new direction to this research field. Further, studies on the economic feasibility and the impact of waste plastic oil on engine materials are also required.


Assuntos
Gasolina , Pirólise , Biocombustíveis , Monóxido de Carbono/análise , Plásticos , Emissões de Veículos
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