Opinion: Coordinated Development of Emission Inventories for Climate Forcers and Air Pollutants

Emissions into the atmosphere of fine particulates, their precursors, and precursors to tropospheric ozone, not only impact human health and ecosystems, but also impact the climate by altering Earth’s radiative balance. Accurately quantifying these impacts across local to global scales, historically, and in future scenarios, requires emission inventories that are accurate, transparent, complete, comparable, and consistent. In an effort to better quantify the emissions and impacts of these pollutants, also called short-lived climate forcers (SLCFs), the Intergovernmental Panel on Climate Change (IPCC) is developing a new SLCF emissions methodology report. This report would supplement existing IPCC reporting guidance on greenhouse gas (GHG) emissions inventories, currently used by inventory compilers to fulfill national reporting requirements under the United Nations Framework Convention on Climate Change (UNFCCC) and new requirements of the Enhanced Transparency Framework (ETF) under the Paris Agreement starting in 2024. We review the relevant issues, including how air pollutant and GHG inventory activities have historically been structured, as well as potential benefits, challenges, and recommendations for coordinating GHG and air pollutant inventory efforts. We argue that while there are potential benefits to increasing coordination between air pollutant and GHG inventory development efforts, we also caution that there are differences in appropriate methodologies and applications that must jointly be considered.

The Morbidity Costs of Air Pollution through the Lens of Health Spending in China

This study offers one of the first causal evidence on the morbidity costs of fine particulates (PM2.5) for all age cohorts in a developing country, using individual-level healthcare spending data from the basic medical insurance program in Wuhan, China. Our instrumental variable (IV) approach uses thermal inversion to address potential endogeneity in PM2.5 concentrations and shows that PM2.5 imposes a significant impact on medical expenditures. The IV estimate suggests that a 10 μg/m3 reduction in monthly average PM2.5 leads to a 2.79% decrease in the value of health spending and a 0.70% decline in the number of transactions in pharmacies and health facilities. The effect is more salient for males, children, and older adults. Moreover, our estimates provide a lower bound of people's willingness-to-pay, which amounts to CNY 51.85 (or USD 8.38) per capita per year for a 10 μg/m3 reduction in PM2.5.

An Analysis of Remote Sensing Data to Evaluate the Problem of Atmospheric Aerosol Pollution in Africa

The particulate matter (PM) directly endangers the human health. Remotely sensed tiny atmospheric particles, aerosols, are presented in this research as atmospheric air pollutants. Globally overviewed for the first instances, and then a focus put on Africa and Asia, the selected aerosols are fine particulates (PM2.5), black carbon (BC), and Sulfate (SO4). According to the existing literature, the motivation to research on air pollutants came from the fact that the polluted air globally kills many people, by attacking cardiovascular system. The online accessible remote sensing’s data has been mostly collected from the second version of modern era retrospective analysis for research and applications (MERRA-2), a model selected for its update as well as the fact that its data are directly assimilated from the most renown remote sensors: Moderate resolution Imaging Spectroradiometer (MODIS) and the advanced very high-resolution radiometer (AVHRR). MERRA-2 also compiles data from different aerosol robotic networks (AERONETs). With a vast region of interest, and considering the big temporal resolution, reduced spatio-temporal resolutions facilitated the focused research. Goddard interactive online visualization and analysis infrastructure (GIOVANNI) bridged our research objectives with the data; Geographical Information Systems (Arc GIS) is a main software tool. Map-based as well as time series results for PM2.5 and other atmospheric air pollutants are presented; health dangers associated with the dust from erstwhile research highlighted. Finding that the annually-averaged mass concentration of the dust’s PM2.5 is significantly greater than the mean recommended concentration, 25 μg/m3, in all the seasons of the center of the research region of interest (Africa), this research recommends further research on dust aerosols mitigation strategies, during the seasons of heaviest air pollutants in particular.

Cationic Nanocellulose as Promising Candidate for Filtration Material of COVID-19: A Perspective

The threat of the novel coronavirus (COVID-19) pandemic is worrying as millions of people suffered from this outbreak. The COVID-19 can be airborne by attaching to human nasal or saliva secretion of an infected person or suspended fine particulates in the air. Therefore, in order to minimize the risks associated with this pandemic, an efficient, robust and affordable air‐borne virus removal filters are highly demanded for prevention of spreading viruses in hospitals, transportation hubs, schools, and/or other venues with high human turn‐over. Respirators such as N95, N99 and N100 as well as surgical masks have been widely used. To date, there is no filter standards or special filter technologies tailored for effectively adsorbing the airborne viruses. Studies had shown the electrostatic fibers were capable to entrap the negatively charged viruses including COVID-19. Researchers believed that the positive surface charge of filtration material is an important key to efficiently adsorb the negatively charged viruses. Nanocellulose has emerged as a new class of biobased material with promising potential application in the filtration of viruses. Nanocellulose which is uniform in diameter and has excellent nanofibrillar morphology. To the best of our knowledge, lack of study is done to determine the efficiency of cationic nanocellulose as filtration material of COVID-19.

Powerful Material Technology Removes Barriers

Strengthening materials through grain refinement often results in reduced ductility necessitating means to augment their elongation to failure for engineering applications. Grain boundary engineering (GBE), encompassing novel thermo-mechanical processing has shown promise of simultaneously enhancing both strength and ductility of materials and fracture behavior, especially with low stacking fault energy materials. The ultrahigh strength and reasonable ductility originate from dislocations being effectively blocked at the nano-twinned boundaries resulting in dislocation accumulation and entanglement. This necessitates the careful design of alloys and nano-composites, an effective harnessing of these unique sub-micron features to the benefit of engineering downhole tools for strategic applications. Enabled by these novel material developments, here we present two such articles for the unconventionals. First, a frangible barrier to abet placement of casings and liners through trapping an air column below the barrier while supporting a fluid column in the casing above, providing an up-thrust, a buoyant force that significantly reduces drag and lateral casing weight during placement. This is a viable concept because "shales don't kick". Second is the unmet need for a clean perforating tunnel allowing reduced fluid friction thus better reservoir connectivity. This has been achieved through the development of a novel shape charge with a reactive liner which during the detonation event, additionally generates reactive metallic glassy phase(s) and high entropy alloy complex(s) and their segregation in the deposited jet debris that lines the perf-tunnel. During flowback, reaction with aqueous fluids selectively etch these phases and stimulates the disintegration of the impervious skin on the perf-tunnel into fine particulates subsequently removing them, leaving behind a clear, clean tunnel.

Scalable Machine Learning Approach to Classifying Transportation Noise at Two Urban Sites in Greater Boston, Massachusetts

The goal of this study was to characterize transportation noise by vehicle class in two urban communities, to inform studies of transport noise and ultra-fine particulates. Data were collected from April to September 2016 (150 days) of continuous recording in each urban community using high-resolution microphones. Training data was created for airplanes, trucks/buses, and train events by manual listening and extraction of audio files. Digital signal processing using STFT and Hanning windowing was performed in MATLAB, creating audio spectrograms with varying frequency: log vs linear frequency scales, and 4K vs 20K max frequency. For each of the four spectrogram sets, a neural net model using PyTorch was trained via a compute cluster. Initial results for a multi-class model provide an accuracy of 85%. Comparison between a selection of frequency scales and expanding to longer time periods is ongoing. Validation with airport transport logs and local bus and train schedules will be presented.

Analysis of fine particulates from fuel burning in a reconstructed building at Çatalhöyük World Heritage Site, Turkey: assessing air pollution in prehistoric settled communities

The use of wood, dung and other biomass fuels can be traced back to early prehistory. While the study of prehistoric fuel use and its environmental impacts is well established, there has been little investigation of the health impacts this would have had, particularly in the Neolithic period, when people went from living in relatively small groups, to living in dense settlements. The UNESCO World Heritage Site of Çatalhöyük, Turkey, is one of the earliest large ‘pre-urban’ settlements in the world. In 2017, a series of experiments were conducted to measure fine particulate (PM2.5) concentrations during typical fuel burning activities, using wood and dung fuel. The results indicate that emissions from both fuels surpassed the WHO and EU standard limits for indoor air quality, with dung fuel being the highest contributor for PM2.5 pollution inside the house, producing maximum values > 150,000 µg m−3. Maximum levels from wood burning were 36,000 µg m−3. Average values over a 2–3 h period were 13–60,000 µg m−3 for dung and 10–45,000 µg m−3 for wood. The structure of the house, lack of ventilation and design of the oven and hearth influenced the air quality inside the house. These observations have implications for understanding the relationship between health and the built environment in the past.

A New Method of Removing Fine Particulates Using an Electrostatic Force

Many studies have found that the concentration of fine particulates in the atmosphere has increased. In particular, when using the bus, the situation in which people are exposed to relatively high concentrations of fine particulates is increasing. The purpose of this study is to reduce exposure to these potentially harmful particulates by introducing open shelters at outdoor bus stops. In order to use it as an outdoor fine particulates reduction device, a brush filter using electrostatic force (EF) was used on an experimental scale and the generation of electrostatic force, according to the material, was examined. As electrostatic force was generated, the fine particulates collection performance was about 90% efficiency. In addition, it was confirmed that the efficiency of each particle size was improved by 57% through structural improvement. Finally, through experimentation, it was confirmed that the brush module can be used for about 70 days.