Particulate nitrate photolysis in the atmosphere

Environmental Science Atmospheres, Год журнала: 2022, Номер 2(2), С. 111 - 127

Опубликована: Янв. 1, 2022

Particulate nitrate photolysis can lead to the formation of secondary inorganic and organic aerosols that affect climate, air quality, human health.

Язык: Английский

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Extensive field evidence for the release of HONO from the photolysis of nitrate aerosols

Science Advances, Год журнала: 2023, Номер 9(3)

Опубликована: Янв. 18, 2023

Particulate nitrate ([Formula: see text]) has long been considered a permanent sink for NOx (NO and NO2), removing gaseous pollutant that is central to air quality influences the global self-cleansing capacity of atmosphere. Evidence emerging photolysis [Formula: text] can recycle HONO back gas phase with potentially important implications tropospheric ozone OH budgets; however, there are substantial discrepancies in "renoxification" rate constants. Using aircraft ground-based observations remote Atlantic troposphere, we show evidence renoxification occurring on mixed marine aerosols an efficiency increases relative humidity decreases concentration text], thus largely reconciling very large constants found across multiple laboratory field studies. Active release from aerosol atmospheric oxidants such as O3 both polluted clean environments.

Язык: Английский

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Nitrogen oxides in the free troposphere: implications for tropospheric oxidants and the interpretation of satellite NO₂ measurements

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(2), С. 1227 - 1257

Опубликована: Янв. 24, 2023

Abstract. Satellite-based retrievals of tropospheric NO2 columns are widely used to infer NOx (≡ NO + NO2) emissions. These rely on model information for the vertical distribution NO2. The free background above 2 km is particularly important because sensitivity increases with altitude. Free also has a strong effect OH and ozone concentrations. Here we use observations from three aircraft campaigns (SEAC4RS, DC3, ATom) four atmospheric chemistry models (GEOS-Chem, GMI, TM5, CAMS) evaluate capabilities simulating in troposphere attribute it sources. measurements during Studies Emissions Atmospheric Composition, Clouds, Climate Coupling by Regional Surveys (SEAC4RS) Deep Convective Clouds Chemistry (DC3) over southeastern U.S. summer show increasing concentrations upper 10 km, which not replicated GEOS-Chem, although consistent measurements. Using concurrent NO, NO2, DC3 flight thunderstorm outflow, that biased high, plausibly due interference thermally labile reservoirs such as peroxynitric acid (HNO4) methyl peroxy nitrate (MPN). We find calculated NO–NO2 photochemical steady state (PSS) more reliable profiles models. GEOS-Chem reproduces shape PSS-inferred throughout SEAC4RS but overestimates about factor 2. underestimates MPN alkyl concentrations, suggesting missing organic chemistry. On other hand, standard Tomography Mission (ATom) Pacific Atlantic oceans, indicating source oceans. can account this including photolysis particulate sea salt aerosols at rates inferred laboratory studies field nitrous (HONO) Atlantic. median column density ATom campaign 1.7 ± 0.44 × 1014 molec. cm−2, simulated range 1.4–2.4 implying uncertainty using modeled clean areas stratosphere–troposphere separation 1 cm−2. lightning main primary tropics southern midlatitudes, emissions dominate northern midlatitudes winter Particulate up 5 ppbv (parts per billion volume) extratropics model, would largely correct low bias relative ozonesonde observations. Global increase 19 %. contribution observed satellites contiguous 25 11 % 65 9 summer, according profiles. This needs be accounted when deriving satellite

Язык: Английский

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Amplified role of potential HONO sources in O<sub>3</sub> formation in North China Plain during autumn haze aggravating processes

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(5), С. 3275 - 3302

Опубликована: Март 11, 2022

Abstract. Co-occurrences of high concentrations PM2.5 and ozone (O3) have been frequently observed in haze-aggravating processes the North China Plain (NCP) over past few years. Higher O3 on hazy days were hypothesized to be related nitrous acid (HONO), but key sources HONO enhancing during remain unclear. We added six potential sources, i.e., four ground-based (traffic, soil, indoor emissions, NO2 heterogeneous reaction ground surface (Hetground)) two aerosol-related (the aerosol surfaces (Hetaerosol) nitrate photolysis (Photnitrate)) into WRF-Chem model designed 23 simulation scenarios explore unclear sources. The results indicate that producing enhancements showed a rapid decrease with height, while NO + OH decreased slowly height. Photnitrate contributions enhanced aggravated pollution levels. enhancement due was about 10 times greater than clean dominated daytime (∼ 30 %–70 % when ratio frequency (Jnitrate) gas nitric (JHNO3) equals 30) at higher layers (>800 m). Compared days, contribution daily maximum 8 h averaged (DMA8) increased by 1 magnitude process. contributed only ∼ 5 Jnitrate/JHNO3 %–50 near NCP days. Surface volatile organic compound-sensitive chemistry, altitudes m) NOx-sensitive chemistry. had limited impact (<15 %) even 120. These suggest significant formation, more comprehensive studies atmosphere are still needed.

Язык: Английский

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Enhanced Nitrite Production from the Aqueous Photolysis of Nitrate in the Presence of Vanillic Acid and Implications for the Roles of Light-Absorbing Organics

Environmental Science & Technology, Год журнала: 2021, Номер 55(23), С. 15694 - 15704

Опубликована: Ноя. 17, 2021

A prominent source of hydroxyl radicals (

Язык: Английский

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Atmospheric measurements at Mt. Tai – Part II: HONO budget and radical (RO_x + NO₃) chemistry in the lower boundary layer

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(2), С. 1035 - 1057

Опубликована: Янв. 21, 2022

Abstract. In the summer of 2018, a comprehensive field campaign, with measurements on HONO and related parameters, was conducted at foot (150 m a.s.l.) summit Mt. Tai (1534 in central North China Plain (NCP). With implementation 0-D box model, budget six additional sources its role radical chemistry station were explored. We found that model default source, NO + OH, could only reproduce 13 % observed HONO, leading to strong unknown source strength up 3 ppbv h−1. Among sources, NO2 uptake ground surface dominated (∼ 70 %) nighttime formation, photo-enhanced reaction 80 daytime formation. Their contributions sensitive mixing layer height (MLH) used for parameterizations, highlighting importance reasonable MLH exploring ground-level formation models necessity gradient measurements. A ΔHONO/ΔNOx ratio 0.7 direct emissions from vehicle exhaust inferred, new method quantify contribution observations proposed discussed. Aerosol-derived including aerosol particulate nitrate photolysis, did not lead significant their lower than OH. photolysis early morning initialized photochemistry station. It also substantial throughout daytime, higher O3 OH initiation. Moreover, we atmospheric oxidizing capacity while modeled NO3 appeared be night. Peaks time series average diurnal variation reached 22 9 pptv, respectively. NO3-induced reactions contribute 18 potential (P(HNO3)) 11 isoprene (C5H8) oxidation whole day. At night, led 51 44 P(HNO3) or C5H8 oxidation, respectively, implying significantly affect secondary organic inorganic this high-O3 region. Considering severe pollution NCP very limited measurements, suggest besides HOx primary precursors (O3, alkenes, etc.), should understand air similar regions.

Язык: Английский

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A critical review of sulfate aerosol formation mechanisms during winter polluted periods

Journal of Environmental Sciences, Год журнала: 2022, Номер 123, С. 387 - 399

Опубликована: Июль 16, 2022

Язык: Английский

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Homogeneous and heterogeneous photolysis of nitrate in the atmosphere: state of the science, current research needs, and future prospects

Frontiers of Environmental Science & Engineering, Год журнала: 2022, Номер 17(4)

Опубликована: Ноя. 1, 2022

Abstract Nitrate is an important component of atmospheric particulate matter and affects air quality, climate, human health, the ecosystem. was previously considered a permanent sink for nitrogen oxides (NO x ). However, this viewpoint has been challenged in recent years because growing research evidence shown transformation nitrate into NO (i.e., renoxification). The photolysis nitrate/HNO 3 , especially phase or adsorbed on particles, can be significant renoxification process atmosphere. formation aerosol not only change diurnal variation but also provide long-distance transport form nitrate, which local regional chemistry quality. This review summarizes advances fundamental understanding under various conditions, with focus mechanisms key factors affecting process. implications are discussed future recommended.

Язык: Английский

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Insight into the Overlooked Photochemical Decomposition of Atmospheric Surface Nitrates Triggered by Visible Light

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(43)

Опубликована: Авг. 19, 2022

The nitrogen oxides (NOx) formed by photochemical reaction of surface nitrates raise significant concerns. However, little is known about the effect visible light (>380 nm) on nitrate decomposition and mechanism. Herein, investigated under light. results indicate that photocatalysis contributes significantly to decomposition. Monodentate (m-NO3- ) can be decomposed into NOx photogenerated electrons starting from weakly coordinated N-O bond. Water vapor promotes generation because more stable bidentate (b-NO3- will converted m-NO3- hydroxyl groups through hydrogen bonding interactions. Alternatively, b-NO3- directly NO2- NO attack, but this process subject photocatalytic oxidation. This work brings a new focus atmospheric sources provides nuanced understanding processes.

Язык: Английский

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Particulate Nitrate Photolysis as a Possible Driver of Rising Tropospheric Ozone

Geophysical Research Letters, Год журнала: 2024, Номер 51(5)

Опубликована: Март 8, 2024

Abstract Tropospheric ozone is an air pollutant and a greenhouse gas whose anthropogenic production limited principally by the supply of nitrogen oxides (NO x ) from combustion. in northern hemisphere has been rising despite flattening NO emissions recent decades. Here we propose that this sustained increase could result photolysis nitrate particles (pNO 3 − to regenerate . Including pNO GEOS‐Chem atmospheric chemistry model improves consistency with observations. Our simulations show concentrations have increased since 1960s because ammonia falling SO 2 emissions, augmenting extratropics about 50% better match observed trend. will likely continue through 2050, which would drive continued even as decrease. More work needed understand mechanism rates photolysis.

Язык: Английский

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