Molecular compositions and optical properties of dissolved brown carbon in biomass burning, coal combustion, and vehicle emission aerosols illuminated by excitation–emission matrix spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry analysis

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(4), С. 2513 - 2532

Опубликована: Март 2, 2020

Abstract. Brown carbon (BrC) plays an essential impact on radiative forcing due to its ability absorb sunlight. In this study, the optical properties and molecular characteristics of water-soluble methanol-soluble organic (OC; MSOC) emitted from simulated combustion biomass coal fuels vehicle emissions were investigated using ultraviolet–visible (UV–vis) spectroscopy, excitation–emission matrix (EEM) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with electrospray ionization (ESI). The results showed that these smoke aerosol samples burning (BB) (CC) had a higher absorption efficiency at 365 nm (MAE365) than emission samples. A stronger MAE365 value was also found in MSOC (WSOC), indicating low polar compounds would possess light capacity. Parallel factor (PARAFAC) analysis identified six types fluorophores (P1–6) WSOC including two humic-like substances (HULIS-1) (P1 P6), three protein-like (PLOM) (P2, P3, P5), one undefined substance (P4). HULIS-1 mainly aging exhaust particles; P2 only abundant BB aerosols; P3 ubiquitous all tested P4 fossil P5 more intense fresh particles. chromophores (six components; C1–6) exhibited consistent WSOC, suggesting method could be used indicate origins chromophores. FT-ICR spectra CHO CHON most components but S-containing appeared abundance CC aerosols aerosols, while considerably fewer largely detected MSOC. unique formulas different sources van Krevelen (VK) diagram presented distributions. To specific, medium H ∕ C O ratio, opposite ratio. Moreover, capacity positively associated unsaturation degree weight source aerosols. above are potentially applicable further studies EEM-based or molecular-characteristic-based apportionment atmospheric

Язык: Английский

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Temporal variations of six ambient criteria air pollutants from 2015 to 2018, their spatial distributions, health risks and relationships with socioeconomic factors during 2018 in China

Environment International, Год журнала: 2020, Номер 137, С. 105556 - 105556

Опубликована: Фев. 10, 2020

Air pollution events occurred frequently in China, and tremendous efforts were devoted to the reduction of air recent years. Here, analysis ambient monitoring data six criteria pollutants from 367 Chinese cities during 2015–2018, showed that PM2.5, PM10, SO2 CO reduced significantly by 22.1%, 13.5%, 46.4% 21.5%, respectively, NO2 was less significant (6.3%) while O3 level instead increased over China (13.7%). Spatial distribution, seasonal, monthly diurnal variations 2018, implicated effective control measures, discussed details, especially for five key densely populated regions Jing-Jin-Ji (JJJ), Fen Wei Plains (FWP), Yangtze River Delta (YRD), Sichuan Basin (SCB) Pearl (PRD). Moreover, excess health risks (ERs) estimated such two times higher if World Health Organization (WHO) quality guideline rather than adopted. PM10 PM2.5 dominant contributor ERs, case with both exceeding threshold values occupied ~1/3 total days, yet contributed ~2/3 ERs. For health-risk based index (HAQI) further calculated combining multiple pollutants, it found high HAQI mostly distributed North Plain (NCP). ~15%, ~85% ~95% people YRD, FWP JJJ exposed polluted (HAQI > 100), population-normalized added inequality, a small region SCB had much (>280). Investigations on socioeconomic factors show population, population density built-up area presented an inverted U-shape, suggesting existence Environmental Kuznets Curve (EKC), positive relationship between share secondary industry. Multiple regression suggested most prominent factor HAQI, followed gross domestic product (GDP). The findings here demonstrate great details current characteristics its associated therefore providing important implications strategies near future different China.

Язык: Английский

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Water-Insoluble Organics Dominate Brown Carbon in Wintertime Urban Aerosol of China: Chemical Characteristics and Optical Properties

Environmental Science & Technology, Год журнала: 2020, Номер 54(13), С. 7836 - 7847

Опубликована: Июнь 1, 2020

The chromophores responsible for light absorption in atmospheric brown carbon (BrC) are not well characterized, which hinders our understanding of BrC chemistry, the links with optical properties, and accurate model representations to global climate oxidative capacity. In this study, properties chromophore composition three fractions different polarities were characterized urban aerosol collected Xi'an Beijing winter 2013–2014. These show large differences composition, but similar Beijing. Water-insoluble (WI-BrC) fraction dominates total at 365 nm both (51 ± 5%) (62 13%), followed by a humic-like (HULIS-BrC) high-polarity water-soluble BrC. major identified HULIS-BrC nitrophenols carbonyl oxygenated polycyclic aromatic hydrocarbons (OPAHs) 2–3 rings (in 18 species), accounting 10% 14% Beijing, respectively. comparison, WI-BrC PAHs OPAHs 4–6 16 contributing 6% 8%

Язык: Английский

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Oxidative degradation of phenols and substituted phenols in the water and atmosphere: a review

Advanced Composites and Hybrid Materials, Год журнала: 2022, Номер 5(2), С. 627 - 640

Опубликована: Март 9, 2022

Язык: Английский

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Secondary Formation of Atmospheric Brown Carbon in China Haze: Implication for an Enhancing Role of Ammonia

Environmental Science & Technology, Год журнала: 2023, Номер 57(30), С. 11163 - 11172

Опубликована: Июль 5, 2023

Optical characteristics and molecular compositions of brown carbon (BrC) were investigated during winter 2019 at a rural site China with focus on nitro-aromatic compounds (NACs) imidazoles (IMs). The abundance gaseous nitrophenols relative to CO the campaign maximized noontime, being similar O3, while particulate NACs haze periods strongly correlated toluene NO2, suggesting that in region are largely formed from gas-phase photooxidation. Strong correlations IMs dry mass ratio EC/PM2.5 concentration levoglucosan observed, indicating events derived biomass burning emissions. However, an increase increasing aerosol liquid water content pH was observed humid events, along much lower abundances K+ PM2.5, mostly aqueous reactions periods. These exponentially increased NH3 owing reaction carbonyls free ammonia. Our findings for first time revealed enhancing effect ammonia BrC formation China, especially

Язык: Английский

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High Contribution of Secondary Brown Carbon to Aerosol Light Absorption in the Southeastern Margin of Tibetan Plateau

Geophysical Research Letters, Год журнала: 2019, Номер 46(9), С. 4962 - 4970

Опубликована: Апрель 29, 2019

Abstract The optical properties of atmospheric secondary brown carbon (BrC) aerosol are poorly understood because its chemical complexity, and this has hampered quantitative assessments the impacts light‐absorbing material on glaciers Tibetan Plateau. For study, a statistical approach was developed to investigate BrC light absorption over southeastern margin Secondary sources for were more important than primary ones. A diurnal cycle in explained by formation chromophores photochemical oxidation after sunrise followed photobleaching under oxidizing conditions as day progressed. Multimethod analyses showed that biomass burning northern Burma along Sino‐Burmese border most source BrC. mean integrated simple forcing efficiency 79 W/g, indicating can cause substantial radiative effects.

Язык: Английский

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The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(4), С. 2017 - 2030

Опубликована: Фев. 21, 2020

Abstract. To investigate the characteristics of atmospheric brown carbon (BrC) in semiarid region East Asia, PM2.5 and size-resolved particles urban atmosphere Xi'an, inland China, during winter summer 2017 were collected analyzed for optical properties chemical compositions. Methanol extracts (MeOH extracts) more light-absorbing than water (H2O wavelength 300–600 nm well correlated with nitrophenols, polycyclic aromatic hydrocarbons (PAHs) oxygenated PAHs (r > 0.78). The light absorptions (absλ=365 nm) H2O MeOH 28±16 49±32 M m−1, respectively, which are about 10 times higher those summer, mainly due to enhanced emissions from biomass burning house heating. Water-extracted BrC predominately occurred fine mode (< 2.1 µm) accounting 81 % 65 total absorption BrC, respectively. stable isotope composition measurements showed an increasing ratio absλ=365 nm-MeOH absλ=550 nm-EC along enrichment 13C haze development, indicating accumulation secondarily formed (e.g., nitrophenols) aerosol aging process. Positive matrix factorization (PMF) analysis that burning, fossil fuel combustion, secondary formation, fugitive dust major sources city, 55 %, 19 16 PM2.5,

Язык: Английский

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Substantial brown carbon emissions from wintertime residential wood burning over France

The Science of The Total Environment, Год журнала: 2020, Номер 743, С. 140752 - 140752

Опубликована: Июль 6, 2020

Язык: Английский

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Characterization of the light-absorbing properties, chromophore composition and sources of brown carbon aerosol in Xi'an, northwestern China

Atmospheric chemistry and physics, Год журнала: 2020, Номер 20(8), С. 5129 - 5144

Опубликована: Апрель 30, 2020

Abstract. The impact of brown carbon aerosol (BrC) on the Earth's radiative forcing balance has been widely recognized but remains uncertain, mainly because relationships among BrC sources, chromophores and optical properties are poorly understood. In this work, light absorption chromophore composition were investigated for samples collected in Xi'an, northwestern China, from 2015 to 2016. Both Ångström exponent (AAE) mass efficiency (MAE) show distinct seasonal differences, which could be attributed differences sources BrC. Three groups light-absorbing organics found important chromophores, including compounds that have multiple peaks at wavelengths > 350 nm (12 polycyclic aromatic hydrocarbons their derivatives) a single peak < (10 nitrophenols nitrosalicylic acids 3 methoxyphenols). These measured contribute average about 1.1 % 3.3 methanol-soluble 365 summer winter, respectively, 7 5 times higher than corresponding fractions total organic carbon. resolved by positive matrix factorization (PMF) using these instead commonly used non-light-absorbing markers as model inputs. Our results vehicular emissions secondary formation major (∼ 70 %) spring, coal combustion fall, biomass burning become 80 dominates 60 summer.

Язык: Английский

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Long-term brown carbon spectral characteristics in a Mediterranean city (Athens)

The Science of The Total Environment, Год журнала: 2019, Номер 708, С. 135019 - 135019

Опубликована: Ноя. 20, 2019

Язык: Английский

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