Quantitative analysis of influencing factors to aerosol pH and its responses to PM and O pollution in a coastal city.

Aerosol acidity (pH) plays an important role in the multiphase chemical processes of atmospheric particles. In this study, we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coastal city of southeast China. We performed quantitative analysis on the various influencing factors on aerosol pH, and explored the responses of aerosol pH to different PM and O pollution levels.

The observation of atmospheric HONO by wet-rotating-denuder ion chromatograph in a coastal city: Performance and influencing factors.

Due to the significance of atmospheric HONO as a reservoir for radicals and the presence of substantial unknown sources of HONO, there is a pressing need for accurate and consistent measurement of its concentration. In this study, we compared the measurements obtained from the monitor for aerosols and gases in ambient air (MARGA) based on wet chemical method with those from the incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) based on optical method to assess the suitability of the MARGA instrument for accurate HONO detection. The diurnal patterns obtained by the two instruments are similar, with peaks at 8 a.

Resolving Ultraviolet-Visible Spectra for Complex Dissolved Mixtures of Multitudinous Organic Matters in Aerosols.

Light-absorbing organic aerosols, referred to as brown carbon (BrC), play a vital role in the global climate and air quality. Due to the complexity of BrC chromophores, the identified absorbing substances in the ambient atmosphere are very limited. However, without comprehensive knowledge of the complex absorbing compounds in BrC, our understanding of its sources, formation, and evolution mechanisms remains superficial, leading to great uncertainty in climatic and atmospheric models.

Meteorological impacts on the unexpected ozone pollution in coastal cities of China during the unprecedented hot summer of 2022.

Surface ozone pollution under climate warming has become a serious environmental issue. In the summer of 2022, abnormal warming spread over most of the Northern Hemisphere and resulted in the abnormal increase in O concentrations. In this study, we focused on the coastal cities in China and investigated the O trends in July during 2015 to 2022.

Sources appointment and health risks of PM-bound trace elements in a coastal city of southeastern China.

To gain a comprehensive understanding of sources and health risks of trace elements in an area of China with high population densities and low PM concentrations, 15 trace elements (Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Sn, Ba, Pb) in PM were monitored from December 2020 to November 2021 in a representative city, Xiamen. The concentrations of trace elements in Xiamen displayed an obvious seasonal variation and were dominated by K, Fe, Al, Ca and Zn. Based on Positive Matrix Factorization analysis, source appointment revealed that the major sources of trace elements in Xiamen were traffic, dust, biomass and firework combustion, industrial manufacture and shipping emission.

New Insights on the Formation of Nucleation Mode Particles in a Coastal City Based on a Machine Learning Approach.

Atmospheric particles have profound implications for the global climate and human health. Among them, ultrafine particles dominate in terms of the number concentration and exhibit enhanced toxic effects as a result of their large total surface area. Therefore, understanding the driving factors behind ultrafine particle behavior is crucial.

Atmospheric oxidation capacity and O formation in a coastal city of southeast China: Results from simulation based on four-season observation.

The pollution of atmospheric ozone in China shows an obvious upward trend in the past decade. However, the studies on the atmospheric oxidation capacity and O formation in four seasons in the southeastern coastal region of China with the rapid urbanization remain limited. Here, a four-season field observation was carried out in a coastal city of southeast China, using an observation-based model combining with the Master Chemical Mechanism, to explore the atmospheric oxidation capacity (AOC), radical chemistry, O formation pathways and sensitivity.

Molecular Composition of Anthropogenic Oxygenated Organic Molecules and Their Contribution to Organic Aerosol in a Coastal City.

Organic aerosols (OA) have gained attention as a substantial component of atmospheric aerosols owing to their impact on atmospheric visibility, climate, and human health. Although oxygenated organic molecules (OOMs) are essential contributors to OA formation, the sources, transformations, and fates of the OOMs are not fully understood. Herein, anthropogenic OOMs (AOOMs), anthropogenic volatile organic compounds (AVOCs), and OA were concurrently measured in Xiamen, a coastal city in southeastern China.

Photochemistry in the urban agglomeration along the coastline of southeastern China: Pollution mechanism and control implication.

The concentrations of ground-level ozone (O) in China have undergone a rapid increase in recent years, resulting in adverse impacts on the air quality and climate change. However, limited research has been conducted on the coastal urban agglomerations with increasingly serious O pollution. Therefore, in order to better understand in situ photochemistry, comprehensive field observations of O and its precursors, coupled with the model simulation, were conducted in autumn of 2019 at six sites in an urban agglomeration along the coastline of southeastern China.

The effect of nitrous acid (HONO) on ozone formation during pollution episodes in southeastern China: Results from model improvement and mechanism insights.

Two ozone (O) processes, summer episode dominated by local production and autumn episode dominated by regional transport, were chosen to investigate the role of HONO in different pollution processes. Meteorological conditions, diurnal variation of O, potential source contribution factor (PSCF) analysis, concentration weighted trajectory (CWT) models, and the distribution of the eight-hour maximum values of O on mainland China all prove that summer O was mainly locally generated while autumn O episode was more susceptible to regional transport. The gaps between observations and simulation results with the default HONO chemistry in Master Chemical Mechanism (MCM) of Observation Based Model (OBM) were higher in summer episode (0.

Functional properties of glutelin from seed cake: Improvement by alkali-assisted phosphorylation through changes in protein structure.

To explore the effect and its mechanism of alkali-assisted phosphorylation on the functional properties of seeds cake glutelin (CSCG), CSCG was treated with different concentration of sodium trimetaphosphate (STMP, 1.0, 2.0, 3.

Pollution mechanisms and photochemical effects of atmospheric HCHO in a coastal city of southeast China.

Formaldehyde (HCHO) is a vital reactive carbonyl compound, which plays an important role in the photochemical process and atmospheric oxidation capacity. However, the current studies on the quantification of HCHO impacts on atmospheric photochemistry in southeast coastal areas of China with an obvious upward trend of ozone remain scarce and unclear, thus limiting the full understanding of formation mechanism and control strategy of photochemical pollution. Here, systematic field campaigns were conducted at a typical coastal urban site with good air quality to reveal HCHO mechanism and effects on O pollution mechanism during spring and autumn, when photochemical pollution events still frequently appeared.

Particle number size distribution and new particle formation in Xiamen, the coastal city of Southeast China in wintertime.

New particle formation (NPF) has a great impact on regional and global climate, air quality and human health. This study uses a Scanning Mobility Particle Sizer (SMPS) for simultaneous measurement of particle number size distribution (PNSD) in wintertime to investigate NPF in the coastal city of Xiamen. The mean particle number concentration, surface area concentration and volume concentration were 7.

Source apportionment of carbonaceous aerosols in diverse atmospheric environments of China by dual-carbon isotope method.

Carbonaceous aerosols are major components in PM of both polluted and clean atmosphere. Accurate source apportionment of carbonaceous aerosols may support effective PM control. Dual-carbon isotope method (C and C) was adopted to identify the contribution of three main air pollution sources biogenic and biomass (f), liquid fossil (f) and coal (f).

Source apportionment of PM and sulfate formation during the COVID-19 lockdown in a coastal city of southeast China.

Revealing the changes in chemical compositions and sources of PM is important for understanding aerosol chemistry and emission control strategies. High time-resolved characterization of water-soluble inorganic ions, elements, organic carbon (OC), and elemental carbon (EC) in PM was conducted in a coastal city of southeast China during the COVID-19 pandemic. The results showed that the average concentration of PM during the city lockdown (CLD) decreased from 46.

Air pollution increases human health risks of PM-bound PAHs and nitro-PAHs in the Yangtze River Delta, China.

Identifying the nature and extent of atmospheric PM-bound toxic organic pollutants is beneficial to evaluate human health risks of air pollution. Seasonal observations of PM-bound polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in the Yangtze River Delta (YRD) were investigated, along with criteria air pollutants and meteorological parameters. With the elevated PM level, the percentage of 4-ring PAHs and typical NPAH including 3-Nitrobiphenyl (3-NBP) and 2-Nitrofluoranthene (2-NFLT) increased by 19-40%.

Chemical composition and sources of submicron aerosol in a coastal city of China: Results from the 2017 BRICS summit study.

Chemical compositions of non-refractory submicron aerosol (NR-PM) were measured via an Aerodyne Aerosol Chemical Speciation Monitor at the coastal city Xiamen during the 2017 BRICS summit from August 10 to September 10. Mean hourly concentration of NR-PM was 13.55 ± 8.

Characteristics of peroxyacetyl nitrate (PAN) in a coastal city of southeastern China: Photochemical mechanism and pollution process.

Peroxyacetyl nitrate (PAN) can effectively indicate photochemical pollution, and also plays a vital role in regional oxidant balance. One-year continuous monitoring of PAN in a coastal city of southeastern China was investigated. The mean concentration of PAN in winter (0.

The characteristics of air pollution induced by the quasi-stationary front: Formation processes and influencing factors.

The quasi-stationary front is a significant weather system which influences East Asia in spring. The air quality deteriorated along with the moist circumstance when the quasi stationary front dominated the area. Surface meteorological parameters, air pollutants and PM chemical species were observed during the air pollution episode.

Enhancement in Particulate Organic Nitrogen and Light Absorption of Humic-Like Substances over Tibetan Plateau Due to Long-Range Transported Biomass Burning Emissions.

To elucidate the influence of long-range transported biomass burning organic aerosols (BBOA) on the Tibetan Plateau, the molecular compositions and light absorption of HUmic-Like Substances (HULIS), major fractions of brown carbon, were characterized during the premonsoon season. Under the significant influence of biomass burning, HULIS concentrations increased to as high as 26 times of the background levels, accounting for 54% of water-soluble organic carbon (WSOC) and 50% of organic carbon (OC). The light absorption of HULIS also enhanced up to 42 times of the background levels, contributing 61% of the WSOC absorption and 50% of OC absorption.

The air pollution governed by subtropical high in a coastal city in Southeast China: Formation processes and influencing mechanisms.

To investigate the impact of the Western Pacific subtropical high (WPSH) on the air pollution episode of Xiamen, a coastal city in Southeastern China, this study focused on formation processes and influencing mechanisms of an air pollution episode from 17th to 23rd September 2017. The results showed that the WPSH fluctuated in this period and intensified this air pollution with local emissions. The episode was divided into four stages according to WPSH center locations to diagnose the air pollution.

Characteristics of atmospheric volatile organic compounds (VOCs) at a mountainous forest site and two urban sites in the southeast of China.

Volatile organic compounds (VOCs) are important trace gases in the atmosphere, affecting air quality (e.g. ozone and secondary organic aerosol formation) and human health.

Secondary organic aerosol of PM in a mountainous forest area in southeastern China: Molecular compositions and tracers implication.

Secondary organic aerosol (SOA) plays an important role in global climate change and air quality. PM (particles with aerodynamic diameters ≤2.5 μm) samples were collected at a mountainous forest site (Mt.

Potential of secondary aerosol formation from Chinese gasoline engine exhaust.

Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds (VOCs). However, little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine.