Online Chemical Characterization and Sources of Submicron Aerosol in the Major Mediterranean Port City of Piraeus, Greece

Port cities are affected by a wide array of emissions, including those from the shipping, road transport, and residential sectors; therefore, the characterization and apportionment of such sources in a high temporal resolution is crucial. This study presents measurements of fine aerosol chemical composition in Piraeus, one of the largest European ports, during two monthly periods (winter vs. summer) in 2018–2019, using online instrumentation (Aerosol Chemical Speciation Monitor—ACSM, 7-λ aethalometer). PMF source apportionment was performed on the ACSM mass spectra to quantify organic aerosol (OA) components, while equivalent black carbon (BC) was decomposed to its fossil fuel combustion and biomass burning (BB) fractions. The combined traffic, shipping and, especially, residential emissions led to considerably elevated submicron aerosol levels (22.8 μg m−3) in winter, which frequently became episodic late at night under stagnant conditions. Carbonaceous compounds comprised the major portion of this submicron aerosol in winter, with mean OA and BC contributions of 61% (13.9 μg m−3) and 16% (3.7 μg m−3), respectively. The contribution of BB to BC concentrations was considerable and spatially uniform. OA related to BB emissions (fresh and processed) and hydrocarbon-like OA (from vehicular traffic and port-related fossil fuel emissions including shipping) accounted for 37% and 30% of OA, respectively. In summer, the average PM1 concentration was significantly lower (14.8 μg m−3) and less variable, especially for the components associated with secondary aerosols (such as OA and sulfate). The effect of the port sector was evident in summer and maintained BC concentrations at high levels (2.8 μg m−3), despite the absence of BB and improved atmospheric dispersion. Oxygenated components yielded over 70% of OA in summer, with the more oxidized secondary component of regional origin being dominant (41%) despite the intensity of local sources, in the Piraeus environment. In general, with respect to local sources that can be the target of mitigation policies, this work highlights the importance of port-related activities but also reveals the extensive wintertime impact of residential wood burning. While a separation of the BB source is feasible, more research is needed on how to disentangle the short-term effects of different fossil-fuel combustion sources.

Assessment of Greenhouse Gas Emissions in Soybean Cultivation Fertilized with Biochar from Various Utility Plants

Organic matter is an indispensable element of soil. Its quantity and quality affect its properties, e.g., structure, buffering, sorption capacity, air–water relations, and thermal properties. The purpose of the research was to assess greenhouse gas (GHG) emissions in soybean cultivation, fertilized with biochar from various crops. Two experimental factors were included: the dose of biochar and the type of biochar used as per raw material used in its production. The adopted functional unit was 1 ton of soybeans. To reach the adopted goal, a strict field experiment was carried out. The total amount of GHG emitted by the cultivation was calculated according to the ISO 14040 and ISO 14044 standards. The system boundaries included: GHG emissions from fertilizers and seeds used, GHG emissions related to biochar production, emissions related to fossil fuel combustion, and emissions related to the decomposition of crop residues and soil organic matter and the decomposition of biochar. The results of the research indicate a significant potential of biochar to reduce GHG emissions in agricultural production. From the environmental and production perspective, the addition of biochar at 60 Mg ha−1 is the most advantageous. A further increase in the addition of biochar was related to a decrease in plant yield and an increase in GHG emissions per functional unit of the product. The use of biochar in soybean cultivation resulted in a 25% reduction in GHG emissions compared to the object without the biochar addition. The amount of GHG emissions for soybeans ranged from 846.9 to 1260.1 kg of CO2/Mg. The use of biochar from forest biomass resulted in a higher yield, 12% on average, compared to sunflower husk biochar. The introduction of biochar to soils can be an effective improvement in the economic and environmental efficiency of plant production, as it increases the use of nutrients by the plant and intensifies carbon sequestration in soils.

The Role of Fossil Fuel Combustion Metals in PM2.5 Air Pollution Health Associations

In this review, we elucidate the central role played by fossil fuel combustion in the health-related effects that have been associated with inhalation of ambient fine particulate matter (PM2.5). We especially focus on individual properties and concentrations of metals commonly found in PM air pollution, as well as their sources and their adverse health effects, based on both epidemiologic and toxicological evidence. It is known that transition metals, such as Ni, V, Fe, and Cu, are highly capable of participating in redox reactions that produce oxidative stress. Therefore, particles that are enriched, per unit mass, in these metals, such as those from fossil fuel combustion, can have greater potential to produce health effects than other ambient particulate matter. Moreover, fossil fuel combustion particles also contain varying amounts of sulfur, and the acidic nature of the resulting sulfur compounds in particulate matter (e.g., as ammonium sulfate, ammonium bisulfate, or sulfuric acid) makes transition metals in particles more bioavailable, greatly enhancing the potential of fossil fuel combustion PM2.5 to cause oxidative stress and systemic health effects in the human body. In general, there is a need to further recognize particulate matter air pollution mass as a complex source-driven mixture, in order to more effectively quantify and regulate particle air pollution exposure health risks.

A method to dynamically constrain black carbon aerosol sources with online monitored potassium

The result of Aethalometer model to black carbon (BC) source apportionment is highly determined by the absorption Ångström exponent (α) of aerosols from fossil fuel combustion (αff) and wood burning (αwb). A method using hourly measured potassium to calculate the αff and αwb values was developed in this study. Results showed that the optimal αff and αwb were 1.09 and 1.79 for the whole dataset. The optimal α values in the diurnal resolution were also calculated with αff and αwb varied in 1.02 –1.19 and 1.71–1.90, respectively. Using the dynamic α values, the Pearson correlation coefficient between BC and potassium from wood burning substantially improved compared to the results derived from the fixed α values. The method developed in this study is expected to provide more reasonable BC source identification results, which are helpful for air quality, climate, and human health modeling studies.

Health Risk Assessment of Black Carbon Emission from Fossil Fuel.

Fossil fuel combustion is one of the major sources of carbonaceous emission throughout the world. In this study, two light absorbing carbonaceous aerosol namely Black carbon (BC) and Brown carbon (BrC) from fossil fuel combustion under controlled laboratory condition was reported. Four different fossil fuels; octane, petrol, diesel and kerosene was taken as samples (Four different fossil fuels; octane, petrol, diesel, and kerosene samples were collected from filling station of Nilkhet, Dhaka City. Two wavelengths Aethalometer (OT21) had been taken for systematic analysis of Black carbon and Brown carbon. BC and BrC particulates were determined in terms of density, concentration, emission and emission factor. The concentrations of Black carbon in mgm-3 for respective fuel samples were kerosene (3.83), diesel (4.59), petrol (7.94), octane (13.18) while concentrations of Brown carbon were kerosene (7.77), diesel (7.98), petrol (13.61), octane (20.46). BrC concentrations were found to be higher than those of BC for all the fuel samples. Average concentrations of Black carbon and Brown carbon were 7.38 mgm-3 and 11.46 mgm-3 respectively. Thereafter, health risk assessment for chronic exposure to Black carbon was done (estimated/ evaluated/ calculated) according to the U.S. EPA human health risk assessment protocol. Experimental results were correlated with the data given by the Exposure Factors Handbook of EPA for assessing carcinogenic and non-carcinogenic risk associated with BC. Total carcinogenic risk (CR) was found to be 3.27 for adults and 1.34 for children. While total noncarcinogenic risk i.e hazard quotient (HQ) for adults and children were 243.32 and 594.32 respectively. Both CR and HQ values crossed the safe limit given by the US EPA protocol indicating high probability of the occurrence of adverse health effects. Journal of Engineering Science 12(2), 2021, 23-28

Effect of metal and non-metal doping on photocatalytic performance of titanium dioxide (TiO2): A Review

: Titanium dioxide (TiO2) is a known semiconducting material that has been effectively used in photo-catalytic processes to promote environmental sustainability. It can also reduce the environmental chaos caused by fossil fuel combustion to meet energy demands. Many studies have proposed modifications of the large band gap in TiO2, which causes visible light activation during photocatalytic reactions when exposed to UV light radiation. Therefore, many alterations such as the doping of nonmetals and metals to TiO2 have been investigated. In this review, we discuss advanced preparation techniques for TiO2 with various dopants and techniques. Characterization methods were performed to evaluate the structural, morphological, and optical properties of TiO2 doped with metal and nonmetal ions such as S, C, N, Fe, B, W, Ag, Nb, and Zn by various synthesis methods. We have also explored the experimental and other characteristics to determine the best doping component for use in real-time applications.