Characteristics of atmospheric ammonia and its relationship with vehicle emissions in a megacity in China

Wang, Ruyu; Ye, Xingnan; Liu, Yuxuan; Li, Haowen; Yang, Xin; Chen, Jianmin; Gao, Wei; Yin, Zi

doi:10.1016/j.atmosenv.2018.03.047

Cited by 41 publications

(15 citation statements)

References 45 publications

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“…A secondary peak occurred between 9 and 11 am. The diurnal changes exhibited a negative correlation ( R = 0.22, p < 0.01) between hourly mean NH 3 concentration and RH, and an exponential positive correlation ( R 2 = 0.64, p < 0.01) between hourly mean NH 3 concentration and T. The exponential relationships between indoor NH 3 and T were consistent with those of previous studies, 42,43 indicating that indoor NH 3 levels were controlled by absorption kinetics, with T playing an important role 2 . However, during the daytime operation of central air conditioning and fresh air units, indoor air circulation, and indoor‐outdoor air exchange both increased, and the RH exhibited a decreasing trend.…”

Section: Resultssupporting

confidence: 87%

“…Central air conditioning regulates indoor T and RH, and air freshening units facilitate indoor-outdoor air exchange, thereby affecting indoor NH 3 . 2 T. The exponential relationships between indoor NH 3 and T were consistent with those of previous studies, 42,43 indicating that indoor NH 3 levels were controlled by absorption kinetics, with T playing an important role. 2 However, during the daytime operation of central air conditioning and fresh air units, indoor air circulation, and indoor-outdoor air exchange both increased, and the RH exhibited a decreasing trend.…”

Section: Variations In Indoor Nhsupporting

confidence: 90%

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Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Zhang

Lin

Ma³

et al. 2021

Indoor Air

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Online measurements of indoor and outdoor ammonia (NH3) were conducted at a university building in Haidian District, Beijing, to investigate their variation characteristics, indoor‐outdoor differences, influencing factors, and possible contribution of indoor NH3 to atmospheric NH3. Indoor NH3 mixing ratios varied greatly among the rooms of the same building. Indoor NH3 mixing ratio peaked at 1.43 ppm in a toilet. Both indoor and outdoor NH3 mixing ratios exhibited higher values during summer and lower values during winter and correlated significantly with relative humidity and temperature. Moreover, their daily mean mixing ratios were significantly correlated with each other. But indoor and outdoor NH3 in cold months exhibited quite different diurnal variations. During the measurement period, indoor NH3 mixing ratios were substantially higher than those outdoors, by an average factor of 3.1 (1.0–6.6). This indicates that indoor NH3 could be a source of outdoor atmospheric NH3. The contribution of indoor NH3 to atmospheric NH3 was estimated at 0.7 ± 0.5 Gg NH3‐N·a−1, accounting for approximately 1.0 ± 0.7% of total emissions in Beijing and being comparable to industry, biomass combustion, and soil emissions, but lower than transportation emissions. The influence of COVID‐19 control measures caused indoor and outdoor NH3 mixing ratios to decrease by 22.8% and 19.3%, respectively—attributable to decreased human activity and traffic flow.

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Section: Resultssupporting

confidence: 87%

Section: Variations In Indoor Nhsupporting

confidence: 90%

Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Zhang

Lin

Ma³

et al. 2021

Indoor Air

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“…S. Liu et al: Synergetic effects of NH 3 and NO x on toluene SOA formation Ammonia (NH 3 ) is the most abundant and ubiquitous alkaline inorganic gas in the atmosphere and one of the critical factors influencing SOA formation (Wang et al, 2016(Wang et al, , 2018bChen et al, 2019). Some studies have noted that the presence of NH 3 can contribute to the formation of more aerosol mass through photooxidation (Na et al, 2007;.…”

Section: Introductionmentioning

confidence: 99%

Synergetic effects of NH3 and NOx on the production and optical absorption of secondary organic aerosol formation from toluene photooxidation

et al. 2021

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Abstract. NH3 is the most important alkaline gas in the atmosphere and one of the key species affecting the behaviors of atmospheric aerosols. However, the impact of NH3 on secondary organic aerosol (SOA) formation remains poorly understood, especially the dynamic evolution of chemical compositions in the SOA formation process. In this study, a series of chamber experiments were performed to probe the individual and common effects of NH3 and NOx on toluene SOA formation through OH photooxidation. The chemical compositions of toluene SOA were characterized using the Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS). The SOA yield increased from 28.1 % in the absence of NH3 to 34.7 % in the presence of NH3 but decreased to 19.5 % in the presence of NOx. However, the highest SOA yield of 42.7 % and the lowest carbon oxidation state (OSC) occurred in the presence of both NH3 and NOx, indicating that the higher-volatility products that formed in the presence of NOx could partition into the particle phase when NH3 was added. This resulted in a synergetic effect on SOA formation when NH3 and NOx co-existed. The heterogeneous reaction was the main pathway by which NH3 participated in SOA formation in the photooxidation process. The synergetic effect of NH3 and NOx was also observed in SOA optical absorption. A peak at 280 nm, which is characteristic of organonitrogen imidazole compounds, was observed in the presence of NH3, and its intensity increased when NOx was added into the chamber. This work improves our understanding of how the synergistic interactions between NH3 and NOx influence SOA formation and offers new insights into mitigating haze pollution.

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“…China has been the one of largest ammonia emitters in the world [1]. An investigation of the NH 3 emission sources and contribution rate in 2006 shows that the total ammonia emissions of China are 980 t/a, more than 96% and 45% of Europe and the USA, respectively, and contributes to global and Asian emissions by approximately 15% and 35%, respectively; of which, livestock manure accounts for approximately 54% of the total emissions [2]. In terms of the global ammonia emissions, animal husbandry is clearly the major contributor for ammonia pollution, as it accounts for 70.9% of the total [3].…”

Section: Introductionmentioning

confidence: 99%

Heterostructure Cu2O/(001)TiO2 Effected on Photocatalytic Degradation of Ammonia of Livestock Houses

Wang

Zhu

et al. 2019

Catalysts

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In this paper, a heterogeneous composite catalyst Cu2O/(001)TiO2 was prepared by the impregnation-reduction method. The crystal form, highly active facet content, morphology, optical properties, and the photogenerated electron-hole recombination rate of the as-prepared catalysts were investigated. The performance of Cu2O/(001)TiO2 was appraised by photocatalytic degradation of ammonia under sunlight and was compared with lone P25, Cu2O, and (001)TiO2 at the same reaction conditions. The results showed that 80% of the ammonia concentration (120 ± 3 ppm) was removed by Cu2O/(001)TiO2, which was a higher degradation rate than that of pure P25 (12%), Cu2O (12%), and (001)TiO2 (15%) during 120 min of reaction time. The reason may be due to the compound’s (Cu2O/(001)TiO2) highly active (001) facets content that increased by 8.2% and the band gap width decreasing by 1.02 eV. It was also found that the air flow impacts the photocatalytic degradation of ammonia. Therefore, learning how to maintain the degradation effect of Cu2O/(001)TiO2 with ammonia will be important in future practical applications.

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Characteristics of atmospheric ammonia and its relationship with vehicle emissions in a megacity in China

Cited by 41 publications

References 45 publications

Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Synergetic effects of NH<sub>3</sub> and NO<sub><i>x</i></sub> on the production and optical absorption of secondary organic aerosol formation from toluene photooxidation

Heterostructure Cu2O/(001)TiO2 Effected on Photocatalytic Degradation of Ammonia of Livestock Houses

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Characteristics of atmospheric ammonia and its relationship with vehicle emissions in a megacity in China

Cited by 41 publications

References 45 publications

Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Indoor NH3 variation and its relationship with outdoor NH3 in urban Beijing

Synergetic effects of NH&lt;sub&gt;3&lt;/sub&gt; and NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; on the production and optical absorption of secondary organic aerosol formation from toluene photooxidation

Heterostructure Cu2O/(001)TiO2 Effected on Photocatalytic Degradation of Ammonia of Livestock Houses

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Synergetic effects of NH<sub>3</sub> and NO<sub><i>x</i></sub> on the production and optical absorption of secondary organic aerosol formation from toluene photooxidation