Important role of ammonia on haze formation in Shanghai

Ye, Xingnan; Ma, Zhen; Zhang, Jiachen; Du, Huanhuan; Chen, Jianmin; Chen, Hui; Yang, Xin; Gao, Wei; Geng, Feng

doi:10.1088/1748-9326/6/2/024019

Cited by 110 publications

(106 citation statements)

References 20 publications

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“…2), the stable synoptic conditions which favored accumulation of emitted pollutants and rapid formation of secondary species were essential to the formation of the severe PM 2.5 pollution . The high daily average relative humidity (58.3-81.0%) on these three days also favored secondary inorganic aerosol formation through hygroscopic growth of ambient particles and heterogeneous reactions of gaseous precursors (Ye et al, 2011). Concentrations of K + and Cl -, influenced by anthropogenic activities such as biomass burning (Cheng et al, 2014) and coal combustion (Evans et al, 2011), also showed obvious increases during the two episodes.…”

Section: Relationship Between Nh 3 and Nh 4 + During Typical Pm 25 Pmentioning

confidence: 87%

“…However, what concerned people more was the impact of atmospheric NH 3 on particulate pollution. Ye et al (2011) studied the haze formation in Shanghai and found that the NH 3 played a vital role in the enhancement of particulate sulfate and nitrate during the haze episode. Gong et al (2013) found that elevated NH 3 levels were synchronous with enhancements in NH 4 + and SO 4 2-around midday in Houston during summertime and suggested NH 3 likely influenced both mass and number concentrations of particles.…”

Section: Introductionmentioning

confidence: 99%

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Variation of Urban Atmospheric Ammonia Pollution and its Relation with PM2.5 Chemical Property in Winter of Beijing, China

Zhao

Wang

Tan

et al. 2016

Aerosol Air Qual. Res.

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To understand the air pollution problem in megacities such as Beijing, field measurement investigating the variation of NH 3 and its association with PM 2.5 chemical property was conducted from 25 November to 24 December 2013. The results indicated that the daily concentration of wintertime NH 3 tended to be high on the days with relatively high temperatures and low wind speeds. Affected by the synoptic condition, NH 3 concentration showed a bimodal diurnal variation pattern, which tended to peak at around 09:00 and 22:00 of the day. As the sole precursor for NH 4 + , NH 3 exerted a significant impact on the ion chemistry of PM 2.5 through enhancing the nighttime NH 4 Cl formation and promoting both homogeneous and heterogeneous formation of NO 3 -. During heavy pollution episodes with PM 2.5 concentrations over 200 µg m -3 , the NH 3 levels and NH 4 + /NH 3 ratios grew simultaneously with the increase of PM 2.5 levels, indicating that NH 3 is one of the key reasons for heavy pollution events. Revealed by the features of measured ionic species in PM 2.5 , in conjunction with the acidity analysis using thermodynamic model, our results suggested that NH 3 was frequently sufficient in wintertime atmosphere of urban Beijing and the fine particulates were neutralized nearly fully by NH 3 .

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Section: Relationship Between Nh 3 and Nh 4 + During Typical Pm 25 Pmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Variation of Urban Atmospheric Ammonia Pollution and its Relation with PM2.5 Chemical Property in Winter of Beijing, China

Zhao

Wang

Tan

et al. 2016

Aerosol Air Qual. Res.

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“…haze (Ye et al, 2011;Meng et al, 2014;Wei et al, 2015). Global ammonia emission has more than doubled since preindustrial times, mainly because of agricultural intensification (Galloway et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Role of ambient ammonia in particulate ammonium formation at a rural site in the North China Plain

et al. 2018

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Abstract. The real-time measurements of NH 3 and trace gases were conducted, in conjunction with semi-continuous measurements of water-soluble ions in PM 2.5 at a rural site in the North China Plain (NCP) from May to September 2013 in order to better understand chemical characteristics of ammonia and the impact of secondary ammonium aerosols on formation in the NCP. Extremely high NH 3 and NH + 4 concentrations were observed after a precipitation event within 7-10 days following urea application. Elevated NH 3 levels coincided with elevated NH + 4 , indicating that NH 3 likely influenced particulate ammonium mass. For the sampling period, the average conversion / oxidation ratios for NH + 4 (NHR), SO 2− 4 (SOR), and NO − 3 (NOR) were estimated to be 0.30, 0.64, and 0.24, respectively. The increased NH 3 concentrations, mainly from agricultural activities and regional transport, coincided with the prevailing meteorological conditions. The high NH 3 level with NHR of about 0.30 indicates that the emission of NH 3 in the NCP is much higher than needed for aerosol acid neutralisation, and NH 3 plays an important role in the formation of secondary aerosols as a key neutraliser. The hourly data obtained were used to investigate gas-aerosol partitioning characteristics using the thermody-

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“…This event motivated the release of the Action Plan on Prevention and Control of Air Pollution with the goal of reducing PM 2.5 (particulate matter smaller than 2.5 µm in aerodynamic diameter) concentration by 15-25 % (2012) by 2017 in three major city clusters (http://english.mep.gov.cn/News_service/ infocus/201309/t20130924_260707.htm). In order to reduce the PM 2.5 concentration, extensive studies have been conducted to investigate the sources and formation mechanisms of haze pollution in recent years (Ye et al, 2011;Sun et al, 2016;Qiao et al, 2016;Hu et al, 2016;Li et al, 2016;Guo et al, 2014Guo et al, , 2013Zheng et al, 2015;Wang et al, 2016;Peng et al, 2016). However, the haze formation mechanisms and source appointment of fine particles remain uncertain.…”

Section: Introductionmentioning

confidence: 99%

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

Xie

et al. 2017

Atmos. Chem. Phys.

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Abstract. We characterize a representative particulate matter (PM) episode that occurred in Shanghai during winter 2014. Particle size distribution, hygroscopicity, effective density, and single particle mass spectrometry were determined online, along with offline analysis of water-soluble inorganic ions. The mass ratio of SNA / PM 1.0 (sulfate, nitrate, and ammonium) fluctuated slightly around 0.28, suggesting that both secondary inorganic compounds and carbonaceous aerosols contributed substantially to the haze formation, regardless of pollution level. Nitrate was the most abundant ionic species during hazy periods, indicating that NO x contributed more to haze formation in Shanghai than did SO 2 . During the representative PM episode, the calculated PM was always consistent with the measured PM 1.0 , indicating that the enhanced pollution level was attributable to the elevated number of larger particles. The number fraction of the near-hydrophobic group increased as the PM episode developed, indicating the accumulation of local emissions. Three "banana-shaped" particle evolutions were consistent with the rapid increase of PM 1.0 mass loading, indicating that the rapid size growth by the condensation of condensable materials was responsible for the severe haze formation. Both hygroscopicity and effective density of the particles increased considerably with growing particle size during the bananashaped evolutions, indicating that the secondary transformation of NO x and SO 2 was one of the most important contributors to the particle growth. Our results suggest that the accumulation of gas-phase and particulate pollutants under stagnant meteorological conditions and subsequent rapid particle growth by secondary processes were primarily responsible for the haze pollution in Shanghai during wintertime.

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Important role of ammonia on haze formation in Shanghai

Cited by 110 publications

References 20 publications

Variation of Urban Atmospheric Ammonia Pollution and its Relation with PM2.5 Chemical Property in Winter of Beijing, China

Variation of Urban Atmospheric Ammonia Pollution and its Relation with PM2.5 Chemical Property in Winter of Beijing, China

Role of ambient ammonia in particulate ammonium formation at a rural site in the North China Plain

Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements

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