Using Statistical Modeling for Collection Development at the Library of the College of Engineering of Nanjing Agricultural University

Sources of NH4+ in PM2.5 and Their Seasonal Variations in Urban Tianjin China: New Insights From the Seasonal δ15N Values of NH3 Source

“…As shown in Table 1 and Figure 2, we have collected 6 categories of NH 3 source samples ( n = 128) in this study, δ 15 N values and NH 3 concentrations of these source samples ranged from −39.1 to 4.1‰, and 13.4 to 4,180.2 μg m −3 , respectively. The δ 15 N values of NH 3 from different sources in our study were within the range of previous reports by active sampling (Lv, 2020; Meng, 2021; Shao, 2020; Walters et al., 2020), suggesting the effectiveness of our sampling results. However, the average δ 15 N values of NH 3 from different sources in our study were higher than the results in previous reports obtained by passive sampling (Figure 2), mainly attributed to the susceptibility of the results of the passive sampling method to population diffusive isotope fractionation of NH 3 isotopologues (Pan et al., 2020).…”

“…This suggests that they cannot be grouped together as a single source in the estimated source contributions of NH 4 + using the SIAR model. In addition, the δ 15 N‐NH 3 values released from the burning of different plant species showed slightly variations, similar results were found in previous studies (Chang & Ma, 2016; Lv, 2020; Shao, 2020). This disparity has been primarily attributed to the influence of different fuel components and combustion conditions (Bray et al., 2018).…”

“… Comparison of δ 15 N values in NH 3 sources between this study and previous studies (Berner & David Felix, 2020; Bhattarai et al., 2020; Chang et al., 2016; Felix et al., 2013; Freyer, 1978; Heaton, 1987; Kawashima, 2019; Kawashima & Kurahashi, 2011; Lv, 2020; Meng, 2021; Savard et al., 2017; Schulz et al., 2001; Shao, 2020; Smirnoff et al., 2012; Song et al., 2021; Ti et al., 2018; Walters et al., 2020; Xiao, Wu, et al., 2020). …”