Combustion-driven inorganic nitrogen in PM from a city in central China has the potential to enhance the nitrogen load of North China.

Inorganic nitrogen (NH and NO) is a significant component of PM, influencing not only regional ecological systems but also on other regions through the migration of air masses. However, few studies have simultaneously investigated the sources of NH and NO, and their potential transport pathways remain poorly understood. Here, daily PM samples were collected in Jiaozuo, a key city in the air pollution transmission channel to the north China, from 1 September to 5 December, 2017.

Thermal degradation of 18 amino acids during pyrolytic processes.

Biomass pyrolysis greatly impacts climates, ecosystem dynamics, air quality, human health, global carbon and nitrogen cycle. The emissions of nitrogen-containing compounds from biomass pyrolysis highly depend on the protein nitrogen existing in biomass. However, the quantitative kinetic information, including the rate constant and apparent activation energy of individual amino acid induced by pyrolysis are still yet to be well-constrained.

Stable carbon isotope reveals high impact of fishing ship activities on total carbon from PM in Qingdao, China.

Although total carbon (TC) is an important component of fine particulate matter (PM: particulate matter with aerodynamic diameter of <2.5 μm); its sources remain partially unidentified, especially in coastal urban areas. With ongoing development of the global economy and maritime activities, ship-generated TC emissions in port areas cannot be neglected.

Dual isotope analysis reveals the COVID-19 lockdown impact on nitrate aerosol sources and formation pathways in Shanghai.

Nitrate (NO) is an important contributor to PM which can adversely affect the environment and human health. A noticeable decrease in NO concentrations has been reported due to the lockdown measures implemented to curb the spread of Corona Virus Disease 2019 (COVID-19). However, questions remain, regarding the nonlinear relationship between NO and NO.

Kinetic nitrogen isotope effects of 18 amino acids degradation during burning processes.

Understanding the nitrogen isotopic variations of individual amino acids (AAs) is essential for utilizing the nitrogen isotope values of individual amino acids (δN-AA) as source indicators to identify proteinaceous matter originating from biomass combustion processes. However, the nitrogen isotope effects (ε) associated with the degradation of individual amino acids during combustion processes have not been previously explored. In this study, we measured the nitrogen isotope values of residual free amino acids -following a series of controlled combustion experiments at temperatures of 160-240 °C and durations of 2 min to 8 h, as described in Part 1.

Characterizing leaf-deposited particles: Single-particle mass spectral analysis and comparison with naturally fallen particles.

The size and composition of particulate matter (PM) are pivotal in determining its adverse health effects. It is important to understand PM's retention by plants to facilitate its atmospheric removal. However, the distinctions between the size and composition of naturally fallen PM (NFPM) and leaf-deposited PM (LDPM) are not well-documented.

Enhanced aerosols over the southeastern Tibetan Plateau induced by open biomass burning in spring 2020.

The Tibetan Plateau is the third pole of the world, with an essential role in regulating Northern Hemisphere climate. Previous studies showed that atmospheric aerosols over the Tibetan Plateau are influenced by biomass burning (BB) products from South and Southeast Asia. In fact, open biomass burning (OBB) is also an important form of BB in Southeast Asian countries, causing serious springtime air pollution yearly.

Evaluation of black carbon source apportionment based on one year's daily observations in Beijing.

Combustion-derived black carbon (BC) is increasingly recognized as a significant pollutant that can have adverse effects on the atmospheric environment, human health, and regional climate. Fossil fuel combustion is the main source of BC, yet understanding of the relative contributions to BC from coal and liquid fuel combustion remains incomplete. Moreover, few studies have assessed the relative contributions based on long-term continuous daily field observations.

The impacts of reservoirs on the sources and transport of riverine organic carbon in the karst area: A multi-tracer study.

Reservoirs have been constructed as clean energy sources in recent decades with various environmental impacts. Karst rivers typically exhibit high dissolved inorganic carbon (DIC) concentrations, whether and how reservoirs affect carbon cycling, especially organic carbon (OC)-related biogeochemical processes in karst rivers, are unclear. To fill this knowledge gap, multiple tracer methods (including fluorescence excitation-emission matrix (EEM), ultraviolet (UV) absorption, and stable carbon (δC) and radiocarbon (ΔC) isotopes) were utilized to track composition and property changes of both particulate OC (POC) and dissolved OC (DOC) along river-transition-reservoir transects in the Southwest China karst area.

Seasonal variation of nitrogen biogeochemical processes constrained by nitrate dual isotopes in cascade reservoirs, Southwestern China.

The increase of affected river reaches by reservoirs has drastically disturbed the original hydrological conditions, and subsequently influenced the nutrient biogeochemistry in the aquatic system, particularly in the cascade reservoir system. To understand the seasonal variation of nitrogen (N) behaviors in cascade reservoirs, hydrochemistry and nitrate dual isotopes (δN-NO and δO-NO) were conducted in a karst watershed (Wujiang River) in southwest China. The results showed that NO-N accounted for almost 90% of the total dissolved nitrogen (TDN) concentration with high average concentration 3.

Changes in nitrate accumulation mechanisms as PM levels increase on the North China Plain: A perspective from the dual isotopic compositions of nitrate.

Nitrate (NO) has become recognized as the most important water-soluble ion in fine particulate (PM), and has been proposed as a driving factor for regional haze formation. However, nitrate formation mechanisms are still poorly understood. In this study, PM samples were collected from September 2017 to August 2018 in Shijiazhuang, a city located on the North China Plain, and NOconcentration, δO-NO and δN-NO values in PM were analyzed.

Enhanced biomass burning as a source of aerosol ammonium over cities in central China in autumn.

Atmospheric ambient gaseous ammonia (NH), the most abundant alkaline gas, affects public health and climate change through its key role in the formation of secondary aerosols via reactions with acidic gases. Estimation of the contributions of ammonia sources is very challenging in the urban atmosphere. Stable nitrogen isotope ratio (δN) measurements have shown that urban aerosol NH and gaseous NH are derived from fossil fuel combustion-related (FF) sources, such as coal combustion, NH slip, and vehicle exhaust, and volatilization-related sources, such as agriculture and urban water volatilization.

Climatic and anthropogenic regulation of carbon transport and transformation in a karst river-reservoir system.

The effect of dams on dissolved inorganic carbon (DIC) transport and riverine ecosystems is unclear in karst cascade reservoirs. Here, we analyzed water samples from a karst river system with seven cascade reservoirs along the Wujiang River, southwestern China, during one hydrological year. From upstream to downstream, the average concentration of DIC increased from 2.

Compound-specific δN composition of free amino acids in moss as indicators of atmospheric nitrogen sources.

Haplocladium microphyllum moss samples were collected in Nanchang, China. Free amino acid (FAA) concentrations and N isotope compositions (δN) in the samples were determined and compared with the bulk N concentrations and δN values. The aim was to determine whether δN values in moss (which are very variable) indicate the sources of atmospheric N.

Stable isotope analyses of precipitation nitrogen sources in Guiyang, southwestern China.

To constrain sources of anthropogenic nitrogen (N) deposition is critical for effective reduction of reactive N emissions and better evaluation of N deposition effects. This study measured δN signatures of nitrate (NO), ammonium (NH) and total dissolved N (TDN) in precipitation at Guiyang, southwestern China and estimated contributions of dominant N sources using a Bayesian isotope mixing model. For NO, the contribution of non-fossil N oxides (NO, mainly from biomass burning (24 ± 12%) and microbial N cycle (26 ± 5%)) equals that of fossil NO, to which vehicle exhausts (31 ± 19%) contributed more than coal combustion (19 ± 9%).

[N% and S% in Leaves of Vascular Plants and Lamb. for Indicating the Spatial Variation of Atmospheric Nitrogen and Sulfur Deposition].

N and S contents in leaves, Lamb. leaves, epilithic (Hedw.) Broth.

[Chemical characteristics of precipitation in South China Sea].

Rainwater samples were collected in the summer on "Shiyan 3" during the 2012 South China Sea Sectional Scientific Survey. The concentrations of anion and cation, and pH in precipitation were determined and backward trajectories of air mass were simulated to analyze the chemical characteristics of ions and examine the source of ions. The results indicated that the mean pH value of precipitation was 6.

[Sulfur isotopic signatures in leaves of Pinus massoniana Lamb. and source apportionment].

This study analyzed the inorganic sulfur (SSO4) and total sulfur (ST) content as well as the isotopic signatures (delta34SSO4 and 834ST) in leaves of Pinus massoniana lamb. collected from Guizhou and Yunnan areas. The results indicated that the SSO4 and ST content in leaves at Guiyang areas was significantly higher than that at Yunnan areas, and the content of inorganic sulfur in the leaves was found to be directly related to the concentration of ambient sulfur dioxide, but no correlation was seen between the ST content and the ambient sulfur dioxide, showing the SSO4 content in leaves was more reliable to reflect the ambient sulfur input.

[Platanus orientalis foliar N% and delta15 N responses to nitrogen of atmospheric wet deposition in urban area].

Leaves of Platanus orientalis were collected since Mar. 2009 till Apr. 2010, in an urban area at Guiyang.