Atmospheric ammonia and its impacts on regional air quality over the megacity of Shanghai, China

Wang, Shanshan; Nan, Jialiang; Cs, Shi; Fu, Qingyan; Gao, Song; Wang, Dongfang; Cui, Huxiong; Saiz‐Lopez, Alfonso; Zhou, Bin

doi:10.1038/srep15842

Cited by 203 publications

(185 citation statements)

References 68 publications

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“…As the primary alkaline gas in atmosphere (Seinfeld & Pandis, 2006;Sun & Wexler, 1998;Wang et al, 2015), ammonia (NH 3 ) is mainly emitted from agricultural activities, including fertilizer application, livestock waste volatilization, and crop burning (Huang et al, 2012;Reis et al, 2009;Van Damme et al, 2014;Zhang et al, 2017). Industrial and vehicle emissions are also important sources in urban areas (Livingston et al, 2009;Suarez-Bertoa et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Initial Cost Barrier of Ammonia Control in Central China

Zheng

Wang

Bao

et al. 2019

Geophysical Research Letters

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Ammonia control has received increasing attention as a measure to decrease particulate concentrations. Modeling analysis of observation data from central China over the period of September 2015 to August 2016 shows clear asymmetric responses of particulate pH and mass to ammonia emissions. With a change of ±80% of NH x (NH 3 + NH 4 + ), the corresponding ΔpH are +0.5 and −3.0, respectively, and the corresponding particulate NH 4 + changes are +2.62% and −61.8%, respectively. This asymmetry implies that there is a Critical Total Ammonia Concentration, above which particulate pH and mass are insensitive to ammonia control. Analysis of the observation data suggests that the Critical Total Ammonia Concentration is −25%. The estimated cost for an NH x reduction of 25% is $140 -320 million for Hubei province, which is the initial cost barrier before ammonia control can effectively affect particulate pH and mass in central China. This cost barrier will increase as NO x and SO 2 emissions decrease.

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Section: Introductionmentioning

confidence: 99%

Initial Cost Barrier of Ammonia Control in Central China

Zheng

Wang

Bao

et al. 2019

Geophysical Research Letters

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“…Our previous study (Pan et al, ) provides a starting point to refine our understanding on the impacts of fossil fuel sources on urban NH 4 + , but that study was limited to haze episodes during the winter. During winter, when relative humidity is high and temperatures are low, conversion of gaseous NH 3 to particulate NH 4 + is favored (Wang et al, ). In contrast, NH 3 gas is usually more abundant than particulate NH 4 + under warm weather conditions (Ianniello et al, ).…”

Section: Introductionmentioning

confidence: 99%

Source Apportionment of Aerosol Ammonium in an Ammonia‐Rich Atmosphere: An Isotopic Study of Summer Clean and Hazy Days in Urban Beijing

Pan

Tian

et al. 2018

JGR Atmospheres

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Aerosol ammonium (NH4+) can be a major component of fine particles, especially during severe haze episodes. The abatement of ammonia (NH3) emissions is important for reducing fine particles, but NH3 sources remain poorly constrained and are largely unregulated in China and most other regions. This study uses stable isotopes to interpret the role NH3 sources play in generating different sized NH4+ aerosols in Beijing between 21 June and 4 July 2013 with fine particle concentrations of 20–242 μg/m3. The concentrations and nitrogen stable isotope composition of aerosol NH4+ (δ15N‐NH4+) were both elevated during the five haze episodes that were sampled. These increases were driven by enhancements in the fine mode as opposed to substantial increases in the coarse mode aerosol. After accounting for the isotope fractionation that occurs during gas‐to‐particle partitioning (17.7‰ to 28.2‰), the “initial” (prepartitioning) δ15N‐NH3 values were estimated to be −35‰ for a clean period (i.e., a nonhazy day) and ranged from −14.3‰ to −22.8‰ for hazy days. Source apportionment using the “IsoSources” isotopic mixing model indicated that the dominant contribution to NH3 shifted from agricultural sources during the clean period (86%) to fossil fuel emissions (54%–81%) during hazy days and when back trajectories rotate from the northwest to the west and/or south. These results together suggest that even in summer, fossil fuel‐related sources from Beijing and the surrounding areas are the major source of NH3 during haze events and that controlling these sources may be important for alleviating particulate matter pollution.

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“…CO is usually considered as an inactive chemical species during rapid haze formation and its enhancement with increased RH may be taken to reflect the 15 accumulation of primary pollutants in the shallower boundary layer (Tie et al, 2017). Thus, the total NHx is accumulated as a primary pollutant and undergoes a considerable gas-to-particle conversion (Wei et al, 2015;Wang et al, 2015). The NH3 to NH4 + ratio decreases from about 3 at a RH of 30% to about 1 at a RH of 80%.…”

Section: Driving Factors For Particle Ph 25mentioning

confidence: 99%

Fine particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models

Song¹,

Gao²,

Xu³

et al. 2018

Preprint

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Abstract. pH is an important property of aerosol particles but is difficult to measure directly. Several studies have estimated the pH values for fine particles in North China winter haze using thermodynamic models (i.e., E-AIM and ISORROPIA) and ambient measurements. The reported pH values differ widely, ranging from close to 0 (highly acidic) to as high as 7 (neutral).In order to understand the reason for this discrepancy, we calculated pH values using these models with different assumptions 25 with regard to model inputs and particle phase states. We find that the large discrepancy is due primarily to differences in the model assumptions adopted in previous studies. Calculations using only aerosol phase composition as inputs (i.e., reverse mode) are sensitive to the measurement errors of ionic species and inferred pH values exhibit a bimodal distribution with peaks between −2 and 2 and between 7 and 10. Calculations using total (gas plus aerosol phase) measurements as inputs (i.e., forward mode) are affected much less by the measurement errors, and results are thus superior to those obtained from the reverse mode 30 calculations. Forward mode calculations in this and previous studies collectively indicate a moderately acidic condition (pH from about 4 to about 5) for fine particles in North China winter haze, indicating further that ammonia plays an important role in determining this property. The differences in pH predicted by the forward mode E-AIM and ISORROPIA calculations may be attributed mainly to differences in estimates of activity coefficients for hydrogen ions. The phase state assumed, which can be either stable (solid plus liquid) or metastable (only liquid), does not significantly impact pH predictions of ISORROPIA. 35Atmos. Chem. Phys. Discuss., https://doi

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Atmospheric ammonia and its impacts on regional air quality over the megacity of Shanghai, China

Cited by 203 publications

References 68 publications

Initial Cost Barrier of Ammonia Control in Central China

Initial Cost Barrier of Ammonia Control in Central China

Source Apportionment of Aerosol Ammonium in an Ammonia‐Rich Atmosphere: An Isotopic Study of Summer Clean and Hazy Days in Urban Beijing

Fine particle pH for Beijing winter haze as inferred from different thermodynamic equilibrium models

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