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For many decades, acid deposition used to pose a significant regional air pollution challenge in China. After substantial emission control of anthropogenically derived sulfur and nitrogen containing gasses, both sulfur and nitrogen deposition, as well as the acid rain-affected area, have significantly decreased compared to their peak levels. Forests, particularly in the humid subtropics, are sensitive to acid deposition, as evidenced by soil acidification, sulfate and nitrate leaching in stream water, and elevated soil nitrous oxide emission. Reduction in the total deposition of sulfur and nitrogen, caused a significant decline in sulfate and nitrate leaching from subtropical forest and subsequently in sulfate and nitrate concentrations in stream water, although there was about a 5-year delay. This delay may be attributed to the desorption of accumulated sulfate and continued elevated mineralization of accumulated nitrogen pools. Emissions of nitrous oxide, a potent greenhouse gas, also declined in nitrogen-saturated subtropical forest soils, as soil water nitrate concentration decreased. Therefore, subtropical forests in China suffering from elevated acid deposition have begun to recover. Yet, the current levels of sulfur and nitrogen deposition continue to exceed the critical loads, i.e., the assigned threshold levels in accordance with emission control policies, in more than 10% of the country’s land area, respectively, indicating remaining risks of acidification and eutrophication. Thus, further emission reductions are urgently needed, also because they will help achieving goals related to air quality and nitrous oxide emissions. [ABSTRACT FROM AUTHOR]

Although biochar application to soils has been found to increase soil quality and crop yield, the biochar dispersion extent and its impacts on native soil organic carbon (SOC) has received relatively little attention. Here, the vertical and lateral migration of fine, intermediate and coarse-sized biochar (<0.5, 0.5–1 and 1–5 mm, respectively), applied at low and high doses (1.5–2 and 3–4% w/w, respectively), was tracked using stable isotope methods, along with its impact on native SOC stocks. Biochar was homogeneously mixed into the surface layer (0–7 cm depth) of a loamy sandy Acrisol in Zambia. After 4.5 y, 38–75% of the biochar carbon (BC) was lost from the applied layer and 4–25% was detected in lower soil layers (7–30 cm). Estimating BC mineralization to be no more than 8%, 25–60% was likely transported laterally out of the experimental plots. This conclusion was supported by observations of BC in the control plot and in soils up to 2 m outside of the experimental plots. These processes were likely progressive as recovery of BC in similar plots 1 year after application was greater in both surface and lower soil layers than after 4.5 y. Fine and intermediate-sized BC displayed the greatest downward migration (25.3 and 17.9%, respectively), particularly when applied at lower doses, suggesting its movement through soil inter-particle spaces. At higher dosages, fine and intermediate-sized particles may have clogged pore, so coarse biochar displayed the greatest downward migration when biochar was applied at higher doses. In the BC treatment plot soil profiles, native SOC stocks were reduced by 2.8 to 24.5% (18.4% on average), i.e. positive priming. However, some evidence suggested that the soils may switch to negative priming over time. The dispersion of biochar in soil should be considered when evaluating biochar's agronomic benefits and environmental effects. [ABSTRACT FROM AUTHOR]

China currently has the highest acid deposition globally, yet research on its status, impacts, causes and controls is lacking. Here, we compiled data and calculated critical loads regarding acid deposition. The results showed that the abatement measures in China have achieved a sharp decline in the emissions of acidifying pollutants and a continuous recovery of precipitation pH, despite the drastic growth in the economy and energy consumption. However, the risk of ecological acidification and eutrophication showed no significant decrease. With similar emission reductions, the decline in areas at risk of acidification in China (7.0%) lags behind those in Europe (20%) or the USA (15%). This was because, unlike Europe and the USA, China's abatement strategies primarily target air quality improvement rather than mitigating ecological impacts. Given that the area with the risk of eutrophication induced by nitrogen deposition remained at 13% of the country even under the scenario of achieving the dual targets of air quality and carbon dioxide mitigation in 2035, we explored an enhanced ammonia abatement pathway. With a further 27% reduction in ammonia by 2035, China could largely eliminate the impacts of acid deposition. This research serves as a valuable reference for China's future acid deposition control and for other nations facing similar challenges. [ABSTRACT FROM AUTHOR]

The recently developed time-of-flight aerosol chemical speciation monitor with a capture vaporizer and a PM 2.5 aerodynamic lens (TOF-ACSM-CV-PM 2.5) aims to improve the collection efficiency and chemical characterization of aerosol particles with a diameter smaller than 2.5 µm. In this study, comprehensive cross-comparisons were performed between real-time online measurements and offline filter analysis with 24 h collection time. The goal was to evaluate the capabilities of the TOF-ACSM-CV-PM 2.5 lens, as well as the accuracy of the TOF-ACSM-CV-PM 2.5. The experiments were conducted at Cabauw Experimental Site for Atmospheric Research (CESAR) during the RITA-2021 campaign. The non-refractory fine particulate matter (PM 1.0 and PM 2.5) was measured by two collocated TOF-ACSM-CV-PM 2.5 instruments by placing them behind a PM 2.5 and PM 1.0 inlet, respectively. A comparison between the ACSMs and PM 2.5 and PM 1.0 filter samples showed a much better accuracy than ±30 % less given in the previous reports, with average differences less than ±10 % for all inorganic chemical species. In addition, the ACSMs were compared to the Monitoring Instrument for Aerosol and Gas (MARGA) (slope between 0.78 and 0.97 for inorganic compounds, R2≥ 0.93) and a mobility particle size spectrometer (MPSS), measuring the particle size distribution from around 10 to 800 nm (slope was around 1.00, R2= 0.91). The intercomparison of the online measurements and the comparison between the online and offline measurements indicated a low bias (< 10 % for inorganic compounds) and demonstrated the high accuracy and stability of the TOF-ACSM-CV-PM 2.5 lens for the atmospheric observations of particle matter. The two ACSMs exhibited an excellent agreement, with differences less than 7 %, which allowed a quantitative estimate of PM 1.0 vs. PM 2.5 chemical composition. The result showed that the PM 1.0 accounted for about 70 %–80 % of the PM 2.5 on average. The NO 3 mass fraction increased, but the organic carbon (OC) mass fraction decreased from PM 1.0 to PM 2.5 , indicating the size dependence on chemical composition. [ABSTRACT FROM AUTHOR]

Soils on many smallholder farms in Southern Africa are severely depleted in plant nutrients, in particular phosphorus (P), following years of maize monocropping with little or no fertilizer input. Past studies suggest that pigeon pea (Cajanus cajan (L.) Millsp.) may increase plant-available P. Pigeon pea is not a common crop in much of Southern Africa, and the effect of locally grown pigeon pea varieties on plant-available P is unknown. We assessed the changes in plant-available P after growing pigeon pea varieties MPPV-2, MPPV-3, and Babati White in Zambia, viz. Lixisols of Choma and Mkushi, Acrisols of Chipata and Kasama, and Arenosols of Kaoma. The selected soils were not fertilized. Baseline soils (0–20 cm), sampled after long-term maize monocropping and soils from the same fields after growing pigeon pea were collected from field trials in Kaoma, Chipata, Choma, and Mkushi and analyzed for plant-available P. Further, a greenhouse study was conducted with soils from Kasama, Choma, Kaoma, and Chipata, under which soil P was determined before and after growing pigeon pea, soybean (Dina), and maize (SC 419) without fertilizer addition. Pigeon pea under field studies had no significant (p > 0.05) effect on plant-available P in Choma, Kaoma, and Chipata. In Mkushi, pigeon pea cropping resulted in a 47.5% significant decline (p ≤ 0.05) in plant-available P, amounting to a loss of 11.2 kg ha−1. The greenhouse study showed a significant decline (p ≤ 0.001) in plant-available P after seven weeks of maize growth, while there was no significant (p > 0.05) effect on plant-available P after soybean and pigeon pea cropping. The latter was primarily due to the significantly higher P uptake associated with larger biomass production of maize after seven weeks in the greenhouse. During the initial seven weeks, pigeon pea biomass had significantly higher P concentrations than maize. Thus, P deficiency symptoms were exhibited in maize, while pigeon pea appeared healthy. However, mobilized P, calculated as the sum of plant P and soil P after cropping minus soil P before planting, was significantly lower (p ≤ 0.01) in pigeon pea compared to soybean and maize. Synthesizing field and greenhouse experiments suggests that there is a low net decline of plant-available P from soils after pigeon pea cropping. Therefore, rotation with these pigeon pea varieties could be beneficial to resource-poor farmers due to low P removal and its ability to grow in P-deficient soil. [ABSTRACT FROM AUTHOR]

The sulfur biogeochemical cycle controls the sulfur dynamics in the soil. In contrast to almost all deposited sulfur leaching out in temperate catchments, approximately 80% of the deposited S is retained in the catchments in subtropical regions. However, the mechanisms for sulfur retention were unclear, hindering the understanding of potential threats of legacy sulfur with environmental changes. Here, we demonstrated that sulfate reduction (as sulfide fixed in soil) was a prominent yet overlooked mechanism for sulfur retention in addition to the widely recognized sulfate adsorption in soil, based on a study on soil sulfur storage and stable isotope signatures within entire soil profiles in a typical subtropical catchment in China. Using a dual‐isotopic model, the sulfate reduction flux was further determined to be 30% of the S deposition. Due to a lot of deposited sulfur fixed via sulfate reduction, the release of soil legacy sulfur would be less in response to decreasing sulfur deposition compared to the projections only considering adsorption. However, the remobilization of large amounts of reduced S should be regarded as a threat to the environment under climate change in the future. Plain Language Summary: Sulfur budget in catchments reveals substantial retention of around 80% of deposited sulfur in subtropical soils, mitigating acidification arising from heightened sulfur deposition. The substantial sulfur retention was previously ascribed to sulfate adsorption. However, our study unveils sulfate reduction as a prominent yet overlooked retention mechanism, evidenced by soil sulfur storage estimates and stable isotope signatures across complete soil profiles in a typical subtropical Chinese catchment. Sulfate adsorption displays reversibility with declining atmospheric deposition. However, sulfate reduction exhibits relatively stable except during periods of frequent drought attributed to climate change or the soil excavation induced by land‐use change. Key Points: A dual isotopic mass balance model was built to quantify the transformations of S in the ecosystemsSulfur retention accounted for approximately 80% of deposition based on the sulfur input–output budgets for 17 sites in subtropical ChinaSulfate reduction was a prominent mechanism for sulfur retention in addition to widely recognized sulfate adsorption [ABSTRACT FROM AUTHOR]

Human activities have released a large amount of nitric oxides (NOx) into the atmosphere, leading to elevated regional atmospheric NOx concentration and nitrogen (N) deposition. Several studies have observed a downward NOx or NOy (NOx and its oxidation products) flux to the forest canopy, but attributed it to the photochemical reactions and conversion from gaseous N to particulate N. Here, we focus on the possibility of NOx sink by forest canopy based on an observed downward NOx flux of 0.28 kg N ha−1 yr−1 in a temperate forest of northeastern China, using hourly monitoring of NOx fluxes. In combination with results from previous studies, we find that the downward NOx or NOy fluxes ranged from 0.2 to 1.4 kg N ha−1 yr−1 in temperate forests and from 5.3 to 8.5 kg N ha−1 yr−1 in subtropical forests and they were positively related to atmospheric NOx concentration, mean annual air temperature and annual precipitation across eight forest sites from around the world. If assuming 50% of downward NOx or NOy was directly taken up by the canopy, we estimate a NOx or NOy sink of 0.2 and 1.1 Tg N yr−1 by global respective temperate and subtropical forests, representing an effective scavenger of atmospheric NOx and a considerable N source to forests. We suggest that interception of NOx or NOy by forest canopy should be considered in global NOx budgets and their contribution to the global forest N pool in global Earth System's models. Plain Language Summary: Canopy interception of reactive N has gained wide attention in recent several years, however, its quantification is still unclear. In the present work, we demonstrate the NOx downward movement in a typical temperate forest in northeastern China was partially driven by canopy biological uptake, and then combined results of our in situ observation of canopy NOx flux with other existing 10 monitoring sites worldwide. We estimated an N input of 0.2 and 1.1 Tg N yr−1 in global respective temperate and subtropical forests via downward NOx movement, representing an effective scavenger of atmospheric NOx and a considerable N source to forests. Key Points: The potential importance of canopy NOx uptake by forests for atmospheric NOx concentration and forest N pools is unclearCombining present and previous study results, we estimated a canopy N input of 0.2–1.1 Tg yr−1 in global temperate and subtropical forestsWe suggest that interception of NOx by forest canopy should be considered in global NOx budgets and forest N pools [ABSTRACT FROM AUTHOR]

Background and purpose: COVID‐19 is associated with multiple neurological manifestations. The clinical presentation, trajectory, and treatment response for three cases of myoclonus during COVID‐19 infection, with no previous neurological disease, are decsribed. Metods: Analysis of cerebrospinal fluid from the cases using indirect immunohistochemistry. Results: Antibodies against rodent brain tissue, and similarities in staining patterns were observed, indicating the presence of antineuronal immunoglobulin G autoantibodies targeting astrocytes in the hippocampus. Conclusion: Our results demontrate cerebrospinal fluid antineuronal antibodies indicating an an autoimmune involvment in the pathogenesis in COVID‐19 associated myoclonus. [ABSTRACT FROM AUTHOR]