Formaldehyde and Acetaldehyde at Different Elevations in Mountainous Areas in Hong Kong

Ling, Zhenhao; Guo, Hai; Chen, Gexiang; Lam, S. H. M.; Fan, Saijun

doi:10.4209/aaqr.2015.09.0571

Cited by 35 publications

(23 citation statements)

References 38 publications

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“…A photochemical box model, coupled with master chemical mechanism (version 3.2), including the degradation of 143 primary VOCs and the latest IUPAC inorganic reactions [28,29], was used to simulate the in situ formation of PAN and the relationship with its precursors. Detailed description of the model can be found elsewhere [23,30]. The MCM mechanism used in the model is a near-explicit chemical mechanism, which could describe the degradation of NMHCs and formation of PAN at the molecular scale.…”

Section: Photochemical Box Model Incorporating the Master Chemical Mementioning

confidence: 99%

“…The remaining pathway for production of PA radical was very minor (about 2%), contributed to from the oxidation of other OVOCs and MPAN (methacryloyl peroxy nitrate, a secondary product formed through the acylperoxy radical (MACO 3 ) with NO 2 ). In general, secondary sources of both acetaldehyde and MGLY significantly dominated over the corresponding primary sources [23,[46][47][48]. Therefore, primary precursors (named first-generation precursors hereafter) that produce important secondary sources, such as acetaldehyde and MGLY, through photochemical reactions, are significant and indirect contributors to PAN production, and need to be further identified.…”

Section: The Pan-precursor Relationshipmentioning

confidence: 99%

“…Intensive field measurements were conducted during 5-27 July 2006 at the backgarden site (BGS, 23.548 • N 113.066 • E) during the Program of Regional Integrated Experiments of Pearl River Delta Region (PRIDE-PRD2006) Air Quality Monitoring Campaign. The measurement site is a super-site located in a rural area about 60 km to northwest of Guangzhou city (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

“…Atmosphere 2018, 9, x FOR PEER REVIEW 3 of 16 information for developing a historical understanding on the PAN photochemistry in this region, and on the evaluation of the effective control measures for photochemical pollution in recent years in PRD [23].…”

Section: Introductionmentioning

confidence: 99%

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PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

et al. 2018

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Peroxy acetyl nitrate (PAN) is an important photochemical product formed from the reactions between volatile organic compounds (VOCs) and nitrogen oxides (NO x ) under sunlight. In this study, a field measurement was conducted at a rural site (the backgarden site, or BGS) of the Pearl River Delta (PRD) region in 2006, with the 10 min maximum PAN mixing ratios of 3.9 ppbv observed. The factors influencing the abundance of PAN at the BGS site was evaluated by the process analysis through the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model. The results suggested that the increase of PAN abundance at the BGS site was mainly controlled by the gas-phase chemistry, followed by vertical transport, while its loss was modulated mainly by dry deposition and horizontal transport. As the dominant important role of gas-phase chemistry, to provide detailed information on the photochemical formation of PAN, a photochemical box model with near-explicit chemical mechanism (i.e., the master chemical mechanism, MCM) was used to explore the relationship of photochemical PAN formation with its precursors based on the measured data at the BGS site. It was found that PAN formation was VOC-limited at the BGS site, with the oxidation of acetaldehyde the most important pathway for photochemical PAN production, followed by the oxidation and photolysis of methylglyoxal (MGLY). Among all the primary VOC precursors, isoprene and xylenes were the main contributors to PAN formation. Overall, our study provides new insights into the PAN photochemical formation and its controlling factors, and highlighted the importance of gas chemistry on the PAN abundance in the PRD region.Atmosphere 2018, 9, 372 2 of 16 nitrogen oxides (NO x ), PAN could also be formed in air far away from these sources. PAN is relatively stable at low temperatures; however, it can be decomposed when the atmospheric temperature is high [2]. As a NO 2 reservoir species, it reduces NO 2 concentrations near the emission sources but releases NO 2 in regions remote from fresh emission sources [3]. It is, hence, concerning that PAN can affect NO x abundance and, ultimately, influence tropospheric ozone formation on local and regional scales.PAN is formed from the reaction of NO 2 and peroxy acetyl (PA) radical which is produced through photolysis and oxidation of a small number of oxygenated volatile organic compounds (OVOCs) (e.g., acetaldehyde (CH 3 CHO), acetone, methacrolein (MACR), methyl vinyl ketone (MVK), methyl ethyl ketone, and methylglyoxal (MGLY)) initiated by OH, NO 3 , and O 3 . Therefore, the abundances of aforementioned OVOCs will directly impact PAN levels in the atmosphere. Since PAN was first discovered in photochemical smog in Los Angeles in the 1950s, numerous studies have investigated the distribution and source contributions of PAN through field measurements and model simulations [3][4][5][6]. The characterization includes the abundance of PAN, the relationship with its precursors, and the contributions of regional transport i...

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Section: Photochemical Box Model Incorporating the Master Chemical Mementioning

confidence: 99%

Section: The Pan-precursor Relationshipmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

et al. 2018

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“…The health effects of VOCs were shown detailed in Qian and Dai (2013). Formaldehyde is the most ubiquitous and typical indoor air pollutant, and was proved to be the carcinogen (Tao et al, 2015;Yu et al, 2015;Ling et al, 2016), which can irritate the skin and the respiratory tract, leading to the occurrence of dysosmia, allergy, and immune dysfunction.…”

Section: Introductionmentioning

confidence: 99%

Indoor Air Pollution Levels in Decorated Residences and Public Places over Xi’an, China

Tian

Ren

Shen

et al. 2017

Aerosol Air Qual. Res.

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To investigate the indoor air quality (IAQ) over Xi'an, the concentrations of volatile organic compounds (VOCs, including formaldehyde, benzene, toluene, o-xylene, p-xylene, n-butyl acetate, ethylbenzene, styrene, n-undecane, and total VOCs) in 471 residential rooms and 58 public rooms during 2014-2015 were determined. All the data were measured at a variety of 6-48 months after the decorations of these rooms. The results showed that formaldehyde was the most serious pollutant in almost all the monitored rooms. The concentrations of formaldehyde in residences and public places ranged from 0. ). However, the TVOC concentrations in most sites were lower than the Chinese National Standard (GB/T 18883-2002) value. In residences, the formaldehyde and TVOC concentrations in bedrooms were slightly higher than those in living rooms and other rooms. The relationships among formaldehyde and TVOC concentrations with indoor temperature, relative humidity (RH), and decorative materials (curtain, wall decoration, wood floor, and panel furniture) were also investigated. Formaldehyde levels showed strong positive correlation with indoor temperature and RH. However, the TVOC levels had a relatively weak correlation with indoor air temperature and RH. The wall decoration and panel furniture were the main sources of indoor formaldehyde, while wood floor and panel furniture were the main sources of TVOC. In addition, indoor air pollution of three selected newly decorated houses with 11 rooms was monitored monthly for one year to evaluate the relationship between indoor pollution levels and ventilation time. It was found that the concentrations of formaldehyde and TVOC decreased with ventilation time, and the duration was one year after decoration especially after summer ventilation.

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Observations and Explicit Modeling of Summertime Carbonyl Formation in Beijing: Identification of Key Precursor Species and Their Impact on Atmospheric Oxidation Chemistry

et al. 2018

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Carbonyls are an important group of volatile organic compounds (VOCs) that play critical roles in tropospheric chemistry. To better understand the formation mechanisms of carbonyl compounds, extensive measurements of carbonyls and related parameters were conducted in Beijing in summer 2008. Formaldehyde (11.17 ± 5.32 ppbv), acetone (6.98 ± 3.01 ppbv), and acetaldehyde (5.27 ± 2.24 ppbv) were the most abundant carbonyl species. Two dicarbonyls, glyoxal (0.68 ± 0.26 ppbv) and methylglyoxal (MGLY; 1.10 ± 0.44 ppbv), were also present in relatively high concentrations. An observation‐based chemical box model was used to simulate the in situ production of formaldehyde, acetaldehyde, glyoxal, and MGLY and quantify their contributions to ozone formation and ROx budget. All four carbonyls showed similar formation mechanisms but exhibited different precursor distributions. Alkenes (mainly isoprene and ethene) were the dominant precursors of formaldehyde, while both alkenes (e.g., propene, i‐butene, and cis‐2‐pentene) and alkanes (mainly i‐pentane) were major precursors of acetaldehyde. For dicarbonyls, both isoprene and aromatic VOCs were the dominant parent hydrocarbons of glyoxal and MGLY. Photolysis of oxygenated VOCs was the dominant source of ROx radicals (approximately >80% for HO2 and approximately >70% for RO2) in Beijing. Ozone production occurred under a mixed‐control regime with carbonyls being the key VOC species. Overall, this study provides some new insights into the formation mechanisms of carbonyls, especially their parent hydrocarbon species, and underlines the important role of carbonyls in radical chemistry and ozone pollution in Beijing. Reducing the emissions of alkenes and aromatics would be an effective way to mitigate photochemical pollution in Beijing.

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Formaldehyde and Acetaldehyde at Different Elevations in Mountainous Areas in Hong Kong

Cited by 35 publications

References 38 publications

PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

PAN–Precursor Relationship and Process Analysis of PAN Variations in the Pearl River Delta Region

Indoor Air Pollution Levels in Decorated Residences and Public Places over Xi’an, China

Observations and Explicit Modeling of Summertime Carbonyl Formation in Beijing: Identification of Key Precursor Species and Their Impact on Atmospheric Oxidation Chemistry

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