广州市城区站点冬季PM2.5时间变化及碳氮同位素组成特征

于2018年冬季在广州城区磨碟沙站点开展细颗粒物(PM_2.5)样品采集,并获得PM_2.5中水溶性离子、含碳组分、稳定碳氮同位素的组成及时间变化特征,重点讨论了PM_2.5浓度升高时段的化学组成特征变化,进而利用稳定碳氮同位素变化特征探究了主要污染来源。结果表明：采样期间,研究站点PM_2.5平均质量浓度为22.1μg/m³,共出现两个PM_2.5浓度水平升高时段,所对应的平均质量浓度分别达46.0μg/m³和63.0μg/m³。风速降低、温度升高等不利气象条件是导致上述时段PM_2.5浓度上升的重要原因。在上述时段,伴随着PM_2.5浓度的升高,NO^-₃和NH⁺₄浓度均出现显著升高,NO^-₃与SO^2-₄的摩...     

Dicarboxylic acids and related compounds in fine particulate matter aerosols in Huangshi,central China

PM_2.5 (particulate matter with an aerodynamic diameter <2.5 μm) samples were collected in Huangshi, central China, from March 2012 to February 2013 and were analyzed for dicarboxylic acids (diacids) and related compounds (DARCs). Oxalic acid (C₂; 416 ng m^?3) was the most abundant species, followed by phthalic (Ph; 122 ng m^?3), terephthalic (tPh; 116 ng m^?3), succinic (C₄; 70.4 ng m^?3), azelaic (C₉; 67.9 ng m^?3), and adipic (C₆; 57.8 ng m^?3) acids. Relatively high abundances of Ph and tPh differed from the distribution in urban and marine aerosols, indicating contributions from nearby anthropogenic sources. Glyoxylic acid (ωC₂; 41.4 ng m^?3) was the dominant oxoacid, followed by 9-oxononanoic (ωC₉; 40.8 ng m^?3) and pyruvic (Pyr; 24.1 ng m^?3) acids. Glyoxal (Gly; 35.5 ng m^?3) was the dominant α-dicarbonyl. Highest average concentrations were found for C₂, ωC₂, and C₉ in autumn, for C₄, for Pyr and C₆ in spring, for Ph, ωC₉, and Gly in summer, whereas the lowest values were observed in winter. Seasonal variations and correlation coefficients of DARCs demonstrate that both primary emissions and secondary production are important sources. Principal component analysis of selected DARCs species suggests that a mixing of air masses from anthropogenic and biogenic sources contribute to the Huangshi aerosols.

Implications: Both primary emissions and secondary production are important sources of diacids and related compounds in PM_2.5 from Huangshi, central China. Principal component analysis of selected diacids in Huangshi aerosols suggests that mixing of air masses from anthropogenic and biogenic sources contribute to ambient aerosols in central China.