Monitoring of air pollution levels related to Charilaos Trikoupis Bridge

Emerging challenges of air pollution and particulate matter in China, India, and Pakistan and mitigating solutions

This study examines point and non-point sources of air pollution and particulate matter and their associated socioeconomic and health impacts in South Asian countries, primarily India, China, and Pakistan. The legislative frameworks, policy gaps, and targeted solutions are also scrutinized. The major cities in these countries have surpassed the permissible limits defined by WHO for sulfur dioxide, carbon monoxide, particulate matter, and nitrogen dioxide. As a result, they are facing widespread health problems, disabilities, and causalities at extreme events. Populations in these countries are comparatively more prone to air pollution effects because they spend more time in the open air, increasing their likelihood of exposure to air pollutants. The elevated level of air pollutants and their long-term exposure increases the susceptibility to several chronic/acute diseases, i.e., obstructive pulmonary diseases, acute respiratory distress, chronic bronchitis, and emphysema. More in-depth spatial-temporal air pollution monitoring studies in China, India, and Pakistan are recommended. The study findings suggest that policymakers at the local, national, and regional levels should devise targeted policies by considering all the relevant parameters, including the country's economic status, local meteorological conditions, industrial interests, public lifestyle, and national literacy rate. This approach will also help design and implement more efficient policies which are less likely to fail when brought into practice.

Deriving environment-friendly speed limit scheme using an integrated traffic simulation framework

Traffic authorities have taken various measures to mitigate vehicular-source pollution emissions, among which setting speed limits has been proved to be effective. However, most of the existing macroscopic research proposes idealized mathematical models to design optimal speed limit from the perspective of network equilibrium, and the simplified pollution emission functions cannot accurately reflect the emission mechanism. In order to improve the accuracy of emission calculation and obtain more reliable speed limit schemes in a large-scale network, an integrated traffic simulation approach was proposed herein to derive environment-friendly road speed limit schemes. First, this article built an integrated simulation framework to portray traffic operations and emissions comprehensively. Subsequently, a toy network was employed to demonstrate how to obtain environment-friendly speed limit schemes using this framework. Then this article utilized it to determine the corresponding optimal speed limit schemes on the Second Ring road network in Beijing under different scenarios. The results indicated that traffic authorities should impose adaptive rather than fixed speed limits according to traffic period and emission reduction priority. Moreover, imposing the derived speed limit schemes, the amounts of total emissions, hydrocarbons, carbon monoxide, nitrogen oxides, carbon dioxide, and fine particulate matter decreased by 2.24%, 0.72%, 0.13%, 1.61%, 2.32%, and 5.35% during peak hour, and by 8.31%, 0.60%, 1.92%, 7.16%, 8.60%, and 8.72% during off-peak hour, respectively.Implications: In order to alleviate traffic pollutions emission issues more effectively from the traffic management perspective, we put forward an integrated traffic simulation approach to derive the environmental friendly road speed limit schemes. We combined MOVES and PARAMICES to build the integrated traffic simulation framework to portray road traffic operations and emissions elaborately. To verify the effectiveness of our method on real large road network, we used this method to find out the corresponding optimal speed limit schemes within the combination scheme set on Second Ring road network in Beijing under different traffic demand scenarios. Comparing with the current speed limit scheme, our derived speed limit scheme contributed to lowering emission. The amounts of total pollution emissions, hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO_x), carbon dioxide (CO₂), and fine particulate matter (PM_2.5) decreased by 2.24%, 0.72%, 0.13%, 1.61%, 2.32%, and 5.35% during peak hours, and by 8.31%, 0.60%, 1.92%, 7.16%, 8.60%, and 8.72% during off-peak hours, respectively.

Recent Advances in Studying Air Quality and Health Effects of Shipping Emissions

The increase of global commerce and tourism makes the shipping sector an important contributor of atmospheric particles and gaseous pollutants. These have impacts on both health and climate, especially in populated coastal areas. Maritime activities could be an important driver for economic and social development, however, they are also an environmental pressure. Several policies were implemented in the last decades, at local/regional or international levels, mainly focused on reducing the content of sulphur in marine fuels. The last international IMO-2020 regulation was enforced on 1 January 2020. This work reviews some recent studies on this topic delineating current knowledge of the impacts of maritime emissions on air quality and health and the future projections relative to the benefits of the implementation of the new IMO-2020 regulation. In addition, future perspectives for further mitigation strategies are discussed.

Quantitative assessment of the variability in chemical profiles from source apportionment analysis of PM10 and PM2.5 at different sites within a large metropolitan area

The study aims to assess the differences between the chemical profiles of the major anthropogenic and natural PM sources in two areas with different levels of urbanization and traffic density within the same urban agglomeration. A traffic site and an urban background site in the Athens Metropolitan Area have been selected for this comparison. For both sites, eight sources were identified, with seven of them being common for the two sites (Mineral Dust, non-Exhaust Emissions, Exhaust Emissions, Heavy Oil Combustion, Sulfates & Organics, Sea Salt and Biomass Burning) and one, site-specific (Nitrates for the traffic site and Aged Sea Salt for the urban background site). The similarity between the source profiles was quantified using two statistical analysis tools, Pearson correlation (PC) and Standardized Identity Distance (SID). According to Pearson coefficients five out of the eight source profiles present high (PC > 0.8) correlation (Mineral Dust, Biomass Burning, Sea Salt, Sulfates and Heavy Oil Combustion), one presented moderate (0.8 > PC > 0.6) correlation (Exhaust) and two low/no (PC < 0.6) correlation (non-Exhaust, Nitrates/Aged Sea Salt). The source profiles that appear to be more correlated are those of sources that are not expected to have high spatial variability because there are either natural/secondary and thus have a regional character or are emitted outside the urban agglomeration and are transported to both sites. According to SID four out of the eight sources have high statistical correlation (SID < 1) in the two sites (Mineral Dust, Sea salt, Sulfates, Heavy Oil Combustion). Biomass Burning was found to be the source that yielded different results from the two methodologies. The careful examination of the source profile of that source revealed the reason for this discrepancy. SID takes all the species of the profile equally into account, while PC might be disproportionally affected by a few numbers of species with very high concentrations. It is suggested, based on the findings of this work, that the combined use of both tools can lead the users to a thorough evaluation of the similarity of source profiles. This work is, to the best of our knowledge, the first time a study is focused on the quantitative comparison of the source profiles for sites inside the same urban agglomeration using statistical indicators.

Measurements of Local Sources of Particulates with a Portable Monitor along the Coast of an Insular City

The air quality of modern cities is considered an important factor for the quality of life of humans and therefore is being safeguarded by various international organizations, concentrating on the mass concentration of particulate matter (PM) with an aerodynamic diameter less than 10, 2.5 and 1 μm. However, the different physical and anthropogenic processes and activities within the city contribute to the rise of fine (<1 μm) and coarse (>1 μm) particles, directly impacting human health and the environment. In order to monitor certain natural and anthropogenic events, suspecting their significant contribution to PM concentrations, seven different events taking place on the coastal front of the city of Limassol (Cyprus) were on-site monitored using a portable PM instrument; these included both natural (e.g., dust event) and anthropogenic (e.g., cement factory, meat festival, tall building construction, tire factory, traffic jam, dust road) emissions taking place in spring and summer periods. The violations of the limits that were noticed were attributed mainly to the various anthropogenic activities taking place on-site, revealing once more the need for further research and continuous monitoring of air quality.

Comparison of the impact of ships to size-segregated particle concentrations in two harbour cities of northern Adriatic Sea

Detailed information on in-harbour shipping contribution to size segregated particles in coastal cities are scarce, especially in the busy Mediterranean basin. This poses issues for human exposure and air quality in urban harbour agglomerates, where only criteria pollutants (i.e. PM₁₀ and/or PM_2.5) are usually monitored. In this work, particle number and mass size distributions, in a large size range (0.01-31 μm), were obtained in two coastal cities of northern Adriatic Sea: Venice (Italy) and Rijeka (Croatia). Three size ranges were investigated: nanoparticles (diameter D < 0.25 μm); fine particles (0.25<D < 1 μm), and coarse particles (D > 1 μm). Absolute concentrations were larger in Venice for all size ranges showing, using analysis of daily trends, a large influence of local meteorology and boundary-layer dynamics. Contribution of road transport was larger (in relative terms) in Rijeka compared to Venice. The highest contributions of shipping were in Venice, mainly because of the larger ship traffic. Maximum impact was on nanoparticles 7.4% (Venice) and 1.8% (Rijeka), the minimum was on fine range 1.9% (Venice) and <0.2% (Rijeka) and intermediate values were found in the coarse fraction 1.8% (Venice) and 0.5% (Rijeka). Contribution of shipping to mass concentration was not distinguishable from uncertainty in Rijeka (<0.2% for PM₁, PM_2.5, and PM₁₀) and was about 2% in Venice. Relative contributions as function of particles size show remarkable similitudes: a maximum for nanoparticles, a quick decrease and a successive secondary maximum (2-3 times lower than the first) in the fine range. For larger diameters, the relative contributions reach a minimum at 1-1.5 μm and there is a successive increase in the coarse range. Size distributions showed a not negligible contribution of harbour emissions to nanoparticle and fine particle number concentrations, compared to PM_2.5 or PM₁₀, indicating them as a better metric to monitor shipping impacts compared to mass concentrations (PM_2.5 or PM₁₀).

Exterior air quality monitoring for the Eurasia Tunnel in Istanbul, Turkey

Traffic is a major concern for the city of Istanbul due to the rapid increase in population and car ownership. Eurasia Tunnel, which has a capacity around 100,000 light vehicles/day, is the fourth highway link between Asia and Europe, established to relieve the existing pressure on the transport system. As an important alternative to other Bosphorus Strait crossings, the tunnel offers directly reduced traffic durations in the city especially during rush hours and indirectly provides reduced fuel consumption, thereby less harmful gas emissions into the atmosphere. The main objective of this study is to evaluate the air quality effects of the Eurasia Tunnel on the city of Istanbul through investigating the air quality 1 year before and 2 years after operation, and comparing the hourly and daily pollutant levels with tunnel traffic. Monitoring data were examined to detect the relationships between selected pollutant concentrations, to evaluate meteorology effects on the pollutants and to identify air quality impact of the Eurasia Tunnel. Analyses revealed that air pollutants concentrations do not increase with increase in tunnel traffic. Moreover, since the tunnel entered operation, average hourly CO, PM₁₀ and PM_2.5 concentrations at monitoring stations located close to the stacks have decreased 16-30%, 44-46% and 12-24%, respectively. Average NO₂ concentrations increased about 9-24%, but these concentrations still remain below the 1-hour standard. All in all, Eurasia Tunnel has no significant effect on the Istanbul's air quality.

Trace Elements and Polycyclic Aromatic Hydrocarbons Variation Along the Guang-Shen Expressway Before and After the 2016 Qingming Festival in Guangzhou

PM_2.5 samples (particles with aerodynamic diameter < 2.5 μm) were collected along the Guang-Shen expressway around the Qingming Festival, one of the most congested periods in China, which started from April 2-4, in 2016. Twenty-five trace elements and 16 priority polycyclic aromatic hydrocarbons (PAHs) of the samples were analyzed. Their major sources at different periods were identified. The concentrations of PAHs distinctly increased with growing traffic flow 2 days before the Qingming Festival (March 31th and April 1st), decreased gradually on the first 2 days of the 3-day festival (April 2nd and 3rd) and rose again on the last day (April 4th). The proportion changing of higher molecular weight containing 5- and 6-ring PAHs (HMW PAHs) closely related to the traffic flow variation were consistent with the concentration variation of PAHs during the experimental period. Indicators of gasoline/diesel engines emission, i.e., Mo, Co, Mn, and Pb showed similar concentration variation with PAHs. The concentrations of trace elements, mainly derived from wear instead of combustion process, such as Cu, Zn, Ti, and Sb, raised significantly during the rainy days. Incremental lifetime cancer risk (ILCR) values were calculated to evaluate the health risk caused by PAH around the Qingming Festival. The ILCR values increased by 3-10 times 2 days before and on the last day of the festival comparing with other days, as a result of traffic related sources, including engine emission and wearing of tires. It concluded by recommending the necessity of traffic diversion to alleviate the health risk to drivers and nearby residents during important festivals.