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Atmospheric ammonia has great environmental implications due to its important role in ecosystem and nitrogen cycle, as well as contribution to formation of secondary particles. China is recognized as a hotspot of NH 3 pollution owing to agricultural and livestock intensification. In the quest to achieve a comprehensive understanding of atmospheric ammonia load and to quantify its environmental impacts in China, relying solely either on existing measurements or on model simulations falls short. Their limitations, either in spatial coverage and integrity or in data quality, fails to meet the needs. Available reanalysis products exhibit a marked deficiency in ammonia data. We therefore aim to propose an integrated ammonia reanalysis product in China, adeptly melding satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) NH 3 retrievals with chemical transport model simulation, capitalizing on the robust Ensemble Kalman Filter (EnKF) data assimilation methodology. The product is validated in high quality via the comparison against independent measurements from ground monitoring stations. Spanning a decade from 2013 to 2022, our reanalysis uncovers not just the spatial intricacies of NH 3 concentrations but also their temporal dynamics. Our findings pinpointed the spatial disparities in atmospheric ammonia intensities, highlighting regional hotspots in the NCP, SCB, and Northeast China, and identified annual and seasonal patterns. Our research provides crucial insights for shaping future NH 3 pollution prevention and control strategies in China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In recent years, atmospheric ammonia (NH 3 ) concentrations have increased in China. Ammonia control has become one of the next hot topics in air pollution mitigation with the increasing cost of acid gas emission reduction. In this study, using Infrared Atmospheric Sounding Interferometer (IASI) satellite observations, we analyzed the spatiotemporal distribution, the urban-rural gradient of the vertical column densities (VCDs) of NH 3 and the contribution of influencing factors (meteorology, social, atmospheric acid gases, and NH 3 emissions) in China from 2008 to 2019 using hotspot analysis, circular gradient analysis, geographical and temporal weighted regression, and some other methods. Our results showed that NH 3 VCDs in China have significantly increased (31.88 %) from 2008 to 2019, with the highest occurring in North China Plain. The average NH 3 VCDs in urban areas were significantly higher than those in rural areas, and the urban-rural gap in NH 3 VCDs was widening. The results of circular gradient analysis showed an overall decreasing trend in NH 3 VCDs along the urban-rural gradient. We used a geographically and temporally weighted regression model to analyze the contribution of various influencing factors to NH 3 VCDs: meteorology (30.13 %), social (27.40 %), atmospheric acid gases (23.20 %), and NH 3 emissions (19.28 %) factors. The results showed substantial spatiotemporal differences in the influencing factors. Atmospheric acid gas was the main reason for the increase in NH 3 VCDs from 2008 to 2019. A more thorough understanding of the spatiotemporal distribution, urban-rural variations, and factors influencing NH 3 in China will aid in developing control strategies to reduce PM 2.5 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ammonia, one of the most polluted gases in poultry houses, has always been an urgent problem to solve. Exposure to ammonia can threaten the respiratory tract, induce inflammation, and decrease growth performance. To date, there are few studies investigating the effects of ammonia on skeletal muscle growth. In this experiment, a total of 144 broilers were randomly divided into two groups, and 0 ppm and 35 ppm atmospheric ammonia were administered in the chambers. The trial lasted for 21 days. The breast muscle, thigh muscle, dressed weight, and serum biochemical indexes were measured. The skeletal muscle fibre morphology was observed using light microscopy, and the expressions of genes associated with skeletal muscle development and myosin heavy chain genes were assessed. After 7 days of ammonia exposure, the broilers' weight in the ammonia group decreased. On the 21st day of the experiment, in the ammonia group, the breast muscle weight, thigh muscle weight, and dressed weight decreased, the blood urea nitrogen content increased, skeletal muscle fibre diameter shortened, the expression of myostatin increased, and the expression of myosin heavy chain-FWM and myosin heavy chain-FRM decreased significantly. This article suggests that 35 ppm atmospheric ammonia seriously affects the skeletal muscle gain rate of broilers, and the myostatin pathway could be a potential regulation of the growth rate of muscle fibre under ammonia exposure.

The Berthelot reaction is a classic method for detection of ammonium (NH 4 ) and atmospheric ammonia (NH + ) and atmospheric ammonia (NH 3 ) by using salicylic acid (SA) as the chromogenic substrate. However, there lacks a method for improving the activity of the Berthelot reaction to enhance the analytical performance for detection of NH 4 + and NH 3 . Here, five SA analogues with electron-withdrawing groups (-F) and electron-donating groups (-CH 3 and -OCH 3 ) at different positions of the aromatic ring have been chosen as the alternative to SA for Berthelot reaction. Among these analogues, 4-methoxysalicylic acid (4-OCH 3 -SA) shows the best colorimetric response and color change at a NH 4 + concentration of 30 μM, and the sensitivity of 4-OCH 3 -SA-based colorimetric assay for NH 4 + increases 1.75-fold compared with that of SA-based colorimetric method. This enhancement effect is attributed to the strong electron-donating property of 4-OCH 3 group, activating the two-step electrophilic aromatic substitution reaction in the Berthelot reaction. Additionally, visual and sensitive detection of NH 3 is realized, along with a low limit of detection down to 0.037 ppm. Furthermore, we demonstrate that this assay is reliable and practical for detection of NH 4 + and NH 3 in real water and air samples with good accuracy., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Odorous gas (e.g. atmospheric ammonia) in low ventilation public places, such as public toilets and waste transfer stations, causes severe health problems. Many technologies are developed to purify the atmospheric ammonia, among which the microbial agents are supposed to be a green and economical approach. In this study, we developed a yeast, Pichia sp. J1, and a lactic acid bacterium (LAB), Lactobacillus paracasei B1, co-culture agent for atmospheric ammonia removing. The on-site application results indicated the yeast and LAB mixed fermented agent had a maximum ammonia removing efficiency of 98.78%, which is significantly higher than the pure cultures (78.93% for B1 and 75.00% for J1), indicating the co-culture agent is an excellent biological product for ammonia removal. The excellent performance of the agent is closely related to the synergy behaviors between the yeast and LAB. In the co-culture agents, some of the LAB cells adhered closely to the yeast, and the growth and lactic acid producing ability of LAB were significantly promoted by yeast. Genomic analysis indicated the complementary of nutrients, i.e. carbon and nitrogen resources, signal transduction, and adhesion proteins (regulates adhesion behavior) played roles in regulating the synergy effects. Our study offers a novel biological solution of odorous gas purification., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Atmospheric ammonia (NH 3 ), a common alkaline gas found in air, plays a significant role in atmospheric chemistry, such as in the formation of secondary particles. However, large uncertainties remain in the estimation of ammonia emissions from nonagricultural sources, such as wastewater treatment plants (WWTPs). In this study, the ammonia emission factors from a large WWTP utilizing three typical biological treatment techniques to process wastewater in South China were calculated using the US EPA's WATER9 model with three years of raw sewage measurements and information about the facility. The individual emission factors calculated were 0.15 ± 0.03, 0.24 ± 0.05, 0.29 ± 0.06, and 0.25 ± 0.05 g NH 3  m -3 sewage for the adsorption-biodegradation activated sludge treatment process, the UNITANK process (an upgrade of the sequencing batch reactor activated sludge treatment process), and two slightly different anaerobic-anoxic-oxic treatment processes, respectively. The overall emission factor of the WWTP was 0.24 ± 0.06 g NH 3 m -3 sewage. The pH of the wastewater influent is likely an important factor affecting ammonia emissions, because higher emission factors existed at higher pH values. Based on the ammonia emission factor generated in this study, sewage treatment accounted for approximately 4% of the ammonia emissions for the urban area of South China's Pearl River Delta (PRD) in 2006, which is much less than the value of 34% estimated in previous studies. To reduce the large uncertainty in the estimation of ammonia emissions in China, more field measurements are required., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Elevated atmospheric NH₃ may affect photosynthesis rates and biomass production of crops and the effect may be responsible for the soil nitrogen (N) levels. Plants were exposed to 0 and 1000 nL L⁻¹ with and without N (+N and - N) in open-top chambers (OTCs) to investigate effects of atmospheric NH₃ on photosynthetic and chlorophyll fluorescence parameters of maize plants., Results: At two N levels, NH₃ exposure at 1000 nL L⁻¹ led to an increase in plant height, biomass production, net photosynthetic rates (P(n)) and stomatal conductance (g(s)) compared to ambient NH₃. Exposure to 1000 nL L⁻¹ NH₃ resulted in a significantly higher photochemical quenching (q(p)) and non-photochemical quenching (q(np)), while minimal fluorescence (F(o)), maximum fluorescence (F(m)) and maximum photochemical efficiency (F(v)/F(m)) were not affected. For shoots, N concentrations for - N-1000 and + N-1000 treatments were 49-50% and 26-30% higher, respectively, than those of - N-0 and + N-0 treatments., Conclusion: No visible damage was observed and plants growing on low soil N took up more leaf-derived N than those fertilised at higher N level. Therefore, atmospheric NH₃ can be considered as a quick fertiliser for crops and should be estimated in a further study with soil N fertilisers in order to reduce the dosage., (© 2013 Society of Chemical Industry.)