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Start Over Author "Wang, Yujun" Journal environmental science & technology
20 results on '"Wang, Yujun"'

6. Contribution of Vehicle Emission and NO2 Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Author

Li, Sheng, primary, Song, Wei, additional, Zhan, Hao, additional, Zhang, Yanli, additional, Zhang, Xinran, additional, Li, Weiran, additional, Tong, Shengrui, additional, Pei, Chenglei, additional, Wang, Yujun, additional, Chen, Yanning, additional, Huang, Zuzhao, additional, Zhang, Runqi, additional, Zhu, Ming, additional, Fang, Hua, additional, Wu, Zhenfeng, additional, Wang, Jun, additional, Luo, Shilu, additional, Fu, Xuewei, additional, Xiao, Shaoxuan, additional, Huang, Xiaoqing, additional, Zeng, Jianqiang, additional, Zhang, Huina, additional, Chen, Duohong, additional, Gligorovski, Sasho, additional, Ge, Maofa, additional, George, Chritian, additional, and Wang, Xinming, additional

Published
2021
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15. Contribution of Vehicle Emission and NO2Surface Conversion to Nitrous Acid (HONO) in Urban Environments: Implications from Tests in a Tunnel

Author

Li, Sheng, Song, Wei, Zhan, Hao, Zhang, Yanli, Zhang, Xinran, Li, Weiran, Tong, Shengrui, Pei, Chenglei, Wang, Yujun, Chen, Yanning, Huang, Zuzhao, Zhang, Runqi, Zhu, Ming, Fang, Hua, Wu, Zhenfeng, Wang, Jun, Luo, Shilu, Fu, Xuewei, Xiao, Shaoxuan, Huang, Xiaoqing, Zeng, Jianqiang, Zhang, Huina, Chen, Duohong, Gligorovski, Sasho, Ge, Maofa, George, Chritian, and Wang, Xinming

Abstract

Nitrous acid (HONO) is an important photochemical precursor to hydroxyl radicals particularly in an urban atmosphere, yet its primary emission and secondary production are often poorly constrained. Here, we measured HONO and nitrogen oxides (NOx) at both the inlet and the outlet in a busy urban tunnel (>30 000 vehicles per day) in south China. Multiple linear regression revealed that 73.9% of the inlet–outlet incremental HONO concentration was explained by NO2surface conversion, while the rest was directly emitted from vehicles with an average HONO/NOxratio of 1.31 ± 0.87%, which was higher than that from previous tunnel studies. The uptake coefficient of NO2, γ(NO2), on the tunnel surfaces was calculated to be (7.01 ± 0.02) × 10–5, much higher than that widely used in models. As tunnel surfaces are typical of urban surfaces in the wall and road materials, the dominance of HONO from surface reactions in the poorly lit urban tunnel demonstrated the importance of NO2conversion on urban surfaces, instead of NO2conversion on the aerosol surface, for both daytime and night-time HONO even in polluted ambient air. The higher γ(NO2) on urban surfaces and the elevated HONO/NOxratio from this study can help explain the missing HONO sources in urban areas.

Published
2021
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18. Long-term Application of Agricultural Amendments Regulate Hydroxyl Radicals Production during Oxygenation of Paddy Soils

Author

Chen, Ning, Huang, Danyu, Zeng, Yu, Wang, Juan, Liu, Guangxia, Liu, Xiantang, Wu, Tongliang, Gao, Yan, Fang, Guodong, Wang, Yujun, and Zhou, Dongmei

Abstract

Hydroxyl radicals (•OH) play a significant role in contaminant transformation and element cycling during redox fluctuations in paddy soil. However, these important processes might be affected by widely used agricultural amendments, such as urea, pig manure, and biochar, which have rarely been explored, especially regarding their impact on soil aggregates and associated biogeochemical processes. Herein, based on five years of fertilization experiments in the field, we found that agricultural amendments, especially coapplication of fertilizers and biochar, significantly increased soil organic carbon contents and the abundances of iron (Fe)-reducing bacteria. They also substantially altered the fraction of soil aggregates, which consequently enhanced the electron-donating capacity and the formation of active Fe(II) species (i.e., 0.5 M HCl-Fe(II)) in soil aggregates (0–2 mm), especially in small aggregates (0–3 μm). The highest contents of active Fe(II) species in small aggregates were mainly responsible for the highest •OH production (increased by 1.7–2.4-fold) and naphthalene attenuation in paddy soil with coapplication of fertilizers and biochar. Overall, this study offers new insights into the effects of agricultural amendments on regulating •OH formation in paddy soil and proposes feasible strategies for soil remediation in agricultural fields, especially in soils with frequent occurrences of redox fluctuations.

Published
2024
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