Search Results
Humic Substance Photosensitized Degradation of Phthalate Esters Characterized by 2H and 13C Isotope Fractionation
2023, Min, Ning, Yao, Jun, Li, Hao, Chen, Zhihui, Pang, Wancheng, Zhu, Junjie, Kümmel, Steffen, Schaefer, Thomas, Herrmann, Hartmut, Richnow, Hans Hermann
The photosensitized transformation of organic chemicals is an important degradation mechanism in natural surface waters, aerosols, and water films on surfaces. Dissolved organic matter including humic-like substances (HS), acting as photosensitizers that participate in electron transfer reactions, can generate a variety of reactive species, such as OH radicals and excited triplet-state HS (3HS*), which promote the degradation of organic compounds. We use phthalate esters, which are important contaminants found in wastewaters, landfills, soils, rivers, lakes, groundwaters, and mine tailings. We use phthalate esters as probes to study the reactivity of HS irradiated with artificial sunlight. Phthalate esters with different side-chain lengths were used as probes for elucidation of reaction mechanisms using 2H and 13C isotope fractionation. Reference experiments with the artificial photosensitizers 4,5,6,7-tetrachloro-2′,4′,5′,7′-tetraiodofluorescein (Rose Bengal), 3-methoxy-acetophenone (3-MAP), and 4-methoxybenzaldehyde (4-MBA) yielded characteristic fractionation factors (−4 ± 1, −4 ± 2, and −4 ± 1‰ for 2H; 0.7 ± 0.2, 1.0 ± 0.4, and 0.8 ± 0.2‰ for 13C), allowing interpretation of reaction mechanisms of humic substances with phthalate esters. The correlation of 2H and 13C fractions can be used diagnostically to determine photosensitized reactions in the environment and to differentiate among biodegradation, hydrolysis, and photosensitized HS reaction.
Nucleation of jet engine oil vapours is a large source of aviation-related ultrafine particles
2022, Ungeheuer, Florian, Caudillo, Lucía, Ditas, Florian, Simon, Mario, van Pinxteren, Dominik, Kılıç, Doğuşhan, Rose, Diana, Jacobi, Stefan, Kürten, Andreas, Curtius, Joachim, Vogel, Alexander L.
Large airports are a major source of ultrafine particles, which spread across densely populated residential areas, affecting air quality and human health. Jet engine lubrication oils are detectable in aviation-related ultrafine particles, however, their role in particle formation and growth remains unclear. Here we show the volatility and new-particle-formation ability of a common synthetic jet oil, and the quantified oil fraction in ambient ultrafine particles downwind of Frankfurt International Airport, Germany. We find that the oil mass fraction is largest in the smallest particles (10-18 nm) with 21% on average. Combining ambient particle-phase concentration and volatility of the jet oil compounds, we determine a lower-limit saturation ratio larger than 1 × 105 for ultra-low volatility organic compounds. This indicates that the oil is an efficient nucleation agent. Our results demonstrate that jet oil nucleation is an important mechanism that can explain the abundant observations of high number concentrations of non-refractory ultrafine particles near airports.
Editorial: Impact of the COVID-19 lockdown on the atmosphere
2022, Fadnavis, Suvarna, Roxy, M.K., Griessbach, Sabine, Heinold, Bernd, Kaskaoutis, Dimitris G., Gautam, Ritesh
[no abstract available]
From Transfer to Knowledge Co-Production: A Transdisciplinary Research Approach to Reduce Black Carbon Emissions in Metro Manila, Philippines
2020, Tõnisson, Liina, Kunz, Yvonne, Kecorius, Simonas, Madueño, Leizel, Tamayo, Everlyn Gayle, Casanova, Dang Marviluz, Zhao, Qi, Schikowski, Tamara, Hornidge, Anna-Katharina, Wiedensohler, Alfred, Macke, Andreas
Air pollution, which kills an estimated 7 million people every year, is one of the greatest environmental health risks of our times. Finding solutions to this threat poses challenges to practitioners and policymakers alike. Increasing awareness on the benefits of transdisciplinary research in solution-oriented sustainable development projects has led to the establishment of the research project “A Transdisciplinary Approach to Mitigate Emissions of Black Carbon” (TAME-BC). This paper introduces the TAME-BC research setup that took place with Metro Manila, Philippines, case study. The approach integrates BC measurements with technological, socio-political, and health aspects to improve the scientific state of the art, policymaking, transport sector planning, and clinical studies related to air pollution health effects. The first pillar in the setup presents an (1) air quality assessment through aerosol measurements and instrumentation, complemented by a (2) description and assessment of the current policies, technologies, and practices of the transport sector that is responsible for pollution levels in the Philippines, as well as a (3) BC exposure and associated health impacts assessment. The fourth pillar is intercrossing, fostering (4) knowledge co-creation through stakeholder involvement across scales. We argue that this transdisciplinary approach is useful for research endeavors aiming for emission mitigation in rapidly urbanizing regions beyond Metro Manila.
Analysis of the effect of abiotic stressors on BVOC emissions from urban green infrastructure in northern Germany
2022, Feldner, J., Ramacher, M.O.P., Karl, M., Quante, M., Luttkus, M.L.
Many plants are well known to emit biogenic volatile organic compounds (BVOCs). Under certain conditions BVOCs strongly enhance the photochemical formation of ozone (O3) and impact the levels of atmospheric photo-oxidants. Urban environments under the influence of climate change may face an increasing risk of elevated ozone formation potentials, because abiotic stressors such as heat and drought can stimulate BVOC emissions. However, it is largely uncertain how a combination of heat episodes and reduced soil water potentials affects air quality in cities. The effect of abiotic stress on BVOC emissions and urban O3 formation was assessed for the coastal metropolitan area of Hamburg in Germany during the vegetation period of 2018, characterized by remarkable drought and heat periods. BVOC emissions were modelled using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) version 3 that accounts for several abiotic stresses. Isoprene is the single VOC with the highest share (∼60%) in the BVOC emissions of the study area. Drought stress was identified as the most important abiotic stressor that modulates BVOC emissions in this area. Modelled biogenic emissions calculcated with MEGAN3 were included together with emissions of relevant anthropogenic sectors in simulations with the chemistry transport model EPISODE-CityChem to calculate ozone concentrations under a scenario of prolonged drought stress. As a major result we identified that isoprene concentrations in Hamburg were reduced by 65% (range 6% to 95%) under drought stress during the growing period compared to non-stress conditions. Reduction of isoprene concentrations due to drought stress spatially coincided with a reduction of ozone concentrations. To asses the importance of chemical reactions involved in the formation of ozone, concentrations of isoprene, methacryloyl peroxy nitrate (MPAN) and methacrolein (MACR) have been analysed. The drought stress effect on isoprene emissions led to reductions of MACR and MPAN by approximately 80% and 20%, respectively. Since a VOC limited regime is found presently for Hamburg, it is likely that further reductions in anthropogenic NOx emissions and/or increased BVOC emissions driven by extended green infrastructure and long-term temperature increases may lead to an enhanced photochemical production of ozone in Hamburg in the future.
High Gas-Phase Methanesulfonic Acid Production in the OH-Initiated Oxidation of Dimethyl Sulfide at Low Temperatures
2022, Shen, Jiali, Scholz, Wiebke, He, Xu-Cheng, Zhou, Putian, Marie, Guillaume, Wang, Mingyi, Marten, Ruby, Surdu, Mihnea, Rörup, Birte, Baalbaki, Rima, Amorim, Antonio, Ataei, Farnoush, Bell, David M., Bertozzi, Barbara, Brasseur, Zoé, Caudillo, Lucía, Chen, Dexian, Chu, Biwu, Dada, Lubna, Duplissy, Jonathan, Finkenzeller, Henning, Granzin, Manuel, Guida, Roberto, Heinritzi, Martin, Hofbauer, Victoria, Iyer, Siddharth, Kemppainen, Deniz, Kong, Weimeng, Krechmer, Jordan E., Kürten, Andreas, Lamkaddam, Houssni, Lee, Chuan Ping, Lopez, Brandon, Mahfouz, Naser G. A., Manninen, Hanna E., Massabò, Dario, Mauldin, Roy L., Mentler, Bernhard, Müller, Tatjana, Pfeifer, Joschka, Philippov, Maxim, Piedehierro, Ana A., Roldin, Pontus, Schobesberger, Siegfried, Simon, Mario, Stolzenburg, Dominik, Tham, Yee Jun, Tomé, António, Umo, Nsikanabasi Silas, Wang, Dongyu, Wang, Yonghong, Weber, Stefan K., Welti, André, Wollesen de Jonge, Robin, Wu, Yusheng, Zauner-Wieczorek, Marcel, Zust, Felix, Baltensperger, Urs, Curtius, Joachim, Flagan, Richard C., Hansel, Armin, Möhler, Ottmar, Petäjä, Tuukka, Volkamer, Rainer, Kulmala, Markku, Lehtipalo, Katrianne, Rissanen, Matti, Kirkby, Jasper, El-Haddad, Imad, Bianchi, Federico, Sipilä, Mikko, Donahue, Neil M., Worsnop, Douglas R.
Dimethyl sulfide (DMS) influences climate via cloud condensation nuclei (CCN) formation resulting from its oxidation products (mainly methanesulfonic acid, MSA, and sulfuric acid, H2SO4). Despite their importance, accurate prediction of MSA and H2SO4from DMS oxidation remains challenging. With comprehensive experiments carried out in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at CERN, we show that decreasing the temperature from +25 to -10 °C enhances the gas-phase MSA production by an order of magnitude from OH-initiated DMS oxidation, while H2SO4production is modestly affected. This leads to a gas-phase H2SO4-to-MSA ratio (H2SO4/MSA) smaller than one at low temperatures, consistent with field observations in polar regions. With an updated DMS oxidation mechanism, we find that methanesulfinic acid, CH3S(O)OH, MSIA, forms large amounts of MSA. Overall, our results reveal that MSA yields are a factor of 2-10 higher than those predicted by the widely used Master Chemical Mechanism (MCMv3.3.1), and the NOxeffect is less significant than that of temperature. Our updated mechanism explains the high MSA production rates observed in field observations, especially at low temperatures, thus, substantiating the greater importance of MSA in the natural sulfur cycle and natural CCN formation. Our mechanism will improve the interpretation of present-day and historical gas-phase H2SO4/MSA measurements.
The Latin America Early Career Earth System Scientist Network (LAECESS): addressing present and future challenges of the upcoming generations of scientists in the region
2022, Yáñez-Serrano, Ana María, Aguilos, Maricar, Barbosa, Cybelli, Bolaño-Ortiz, Tomás Rafael, Carbone, Samara, Díaz-López, Stephanie, Diez, Sebastián, Dominutti, Pamela, Engelhardt, Vanessa, Gomes Alves, Eliane, Pedraza, Jenniffer, Saturno, Jorge, Tzompa-Sosa, Zitely A.
Early career (EC) Earth system scientists in the Latin America and the Caribbean region (LAC) have been facing several issues, such as limited funding opportunities, substandard scientific facilities, lack of security of tenure, and unrepresented groups equality issues. On top of this, the worsening regional environmental and climatic crises call for the need for this new generation of scientists to help to tackle these crises by increasing public awareness and research. Realizing the need to converge and step up in making a collective action to be a part of the solution, the Latin America Early Career Earth System Scientist Network (LAECESS) was created in 2016. LAECESS’s primary goals are to promote regional networking, foster integrated and interdisciplinary science, organize soft skills courses and workshops, and empower Latin American EC researchers. This article is an initial step towards letting the global science community grasp the current situation and hear the early career LAC science community’s perspectives. The paper also presents a series of future steps needed for better scientific and social development in the LAC region.
Evolution of Ozone Pollution in China: What Track Will It Follow?
2022, Guo, Jia, Zhang, Xiaoshan, Gao, Yi, Wang, Zhangwei, Zhang, Meigen, Xue, Wenbo, Herrmann, Hartmut, Brasseur, Guy Pierre, Wang, Tao, Wang, Zhe
Increasing surface ozone (O3) concentrations has emerged as a key air pollution problem in many urban regions worldwide in the last decade. A longstanding major issue in tackling ozone pollution is the identification of the O3 formation regime and its sensitivity to precursor emissions. In this work, we propose a new transformed empirical kinetic modeling approach (EKMA) to diagnose the O3 formation regime using regulatory O3 and NO2 observation datasets, which are easily accessible. We demonstrate that mapping of monitored O3 and NO2 data on the modeled regional O3-NO2 relationship diagram can illustrate the ozone formation regime and historical evolution of O3 precursors of the region. By applying this new approach, we show that for most urban regions of China, the O3 formation is currently associated with a volatile organic compound (VOC)-limited regime, which is located within the zone of daytime-produced O3 (DPO3) to an 8h-NO2 concentration ratio below 8.3 ([DPO3]/[8h-NO2] ≤ 8.3). The ozone production and controlling effects of VOCs and NOx in different cities of China were compared according to their historical O3-NO2 evolution routes. The approach developed herein may have broad application potential for evaluating the efficiency of precursor controls and further mitigating O3 pollution, in particular, for regions where comprehensive photochemical studies are unavailable.
The Association Between Particulate Air Pollution and Respiratory Mortality in Beijing Before, During, and After the 2008 Olympic and Paralympic Games
2021, Breitner, Susanne, Su, Chang, Franck, Ulrich, Wiedensohler, Alfred, Cyrys, Josef, Pan, Xiaochuan, Wichmann, H.-Erich, Schneider, Alexandra, Peters, Annette
To improve ambient air quality during the 2008 Summer Olympic and Paralympic Games, the Chinese Government and Beijing’s municipal government implemented comprehensive emission control policies in Beijing and its neighboring regions before and during this period. The goal of this study was to investigate the association between particulate air pollution and cause-specific respiratory mortality before, during and after the period of the Olympic Games. Further, we wanted to assess whether changes in pollutant concentrations were linked to changes in respiratory mortality. We obtained daily data on mortality due to respiratory diseases (coded as J00-J99 according to the International Classification of Diseases and Related Health Problems 10th revision [ICD10]) and pneumonia (ICD10: J12–18), meteorology, particulate matter less than 10 µm or 2.5 μm in diameter (PM10, PM2.5) and particle number size distribution from official monitoring networks and sites located on the Peking University campus between May 20 and December 1, 2008. We assessed the effects of particulate air pollution on daily respiratory mortality using confounder-adjusted Quasi-Poisson regression models. Furthermore, we estimated air pollution effects for three periods—before (May 20 to July 20, 2008), during (August 1 to September 20, 2008) and after (October 1 to December 1, 2008)—by including interaction terms in the models. We found associations between different particle metrics and respiratory and pneumonia mortality, with more pronounced effects in smaller particle size ranges. For example, an interquartile range increase of 7,958 particles/cm3 in ultrafine particles (particles <100 nm in diameter) led to a 16.3% (95% confidence interval 4.3%; 26.5%) increase in respiratory mortality with a delay of seven days. When investigating the sub-periods, results indicate that a reduction in air pollution during the Olympics resulted in reduced (cause-specific) respiratory mortality. This reduction was especially pronounced for pneumonia mortality. The findings suggest that even a short-term reduction in pollution concentrations may lead to health benefits and that smaller particles in the ultrafine size range may be particularly important for respiratory health.
Knowledge Transfer with Citizen Science: Luft-Leipzig Case Study
2021, Tõnisson, Liina, Voigtländer, Jens, Weger, Michael, Assmann, Denise, Käthner, Ralf, Heinold, Bernd, Macke, Andreas
Community-based participatory research initiatives such as “hackAir”, “luftdaten.info”, “senseBox”, “CAPTOR”, “CurieuzeNeuzen Vlaanderen”, “communityAQ”, and “Healthy Air, Healthier Children” campaign among many others for mitigating short-lived climate pollutants (SLCPs) and improving air quality have reported progressive knowledge transfer results. These research initiatives provide the research community with the practical four-element state-of-the-art method for citizen science. For the preparation-, measurements-, data analysis-, and scientific support-elements that collectively present the novel knowledge transfer method, the Luft-Leipzig project results are presented. This research contributes to science by formulating a novel method for SLCP mitigation projects that employ citizen scientists. The Luft-Leipzig project results are presented to validate the four-element state-of-the-art method. The method is recommended for knowledge transfer purposes beyond the scope of mitigating short-lived climate pollutants (SLCPs) and improving air quality.