Ambient concentrations of PANs and other related air pollutants were monitored at an urban site in Beijing each August from 2006 to 2014. The NO_x concentration decreased at a rate of 1.7 nL/(L/yr) (about 4%/yr), and the PAN concentration decreased at a rate of 0.03 nL/(L/yr) (about 3%/yr), while the O₃ concentration increased at a rate of 1.5 nL/(L/yr) (about 4%/yr), indicating that the measures taken to cut NO_x were effective for controlling PAN concentration. Beijing needs to strengthen the control of VOCs with reducing NO_x emissions for reducing O₃ concentration.

Using HistCite and Endnote tools, a systematic biblimetric analysis on bioaerosol research was carried in this study. The leading journals, research institutions and countries in bioaerosol field were identified. The major bioaerosol research areas and trends were summarized and analyzed through bioaerosol-related key words. The information obtained here not only helps researchers in China better understand bioaerosol research progress and trends, but also is useful for atmospheric chemistry and health related studies.