Figure 2 | Scientific Reports

Figure 2

From: High levels of ammonia do not raise fine particle pH sufficiently to yield nitrogen oxide-dominated sulfate production

Figure 2

Equilibrium particle pH versus a wide range of ammonia (NH3) based on average aerosol and meteorological conditions (RH, T) at each site. The open symbols are the study mean pH and NH3, and shaded backgrounds show the upper limit of the pH range for each study (shading color matches color of study line given in the legend). Note that Xi’an polluted and WINTER PM1 lines overlap showing inherent consistency between the two (also true for Beijing). For the WINTER study (the only aircraft data shown), the point represents a predicted NH3 level 0.1 μg m−3 (pH = 2), whereas the reported campaign average pH (0.8 ± 1.0) is lower due to lower pH aloft (2).

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