Initial Cost Barrier of Ammonia Control in Central China

Abstract

Ammonia control has received increasing attention as a measure to decrease particulate concentrations. Modeling analysis of observation data from central China over the period of September 2015 to August 2016 shows clear asymmetric responses of particulate pH and mass to ammonia emissions. With a change of ±80% of NH x (NH 3 + NH 4 + ), the corresponding ΔpH are +0.5 and −3.0, respectively, and the corresponding particulate NH 4 + changes are +2.62% and −61.8%, respectively. This asymmetry implies that there is a Critical Total Ammonia Concentration, above which particulate pH and mass are insensitive to ammonia control. Analysis of the observation data suggests that the Critical Total Ammonia Concentration is −25%. The estimated cost for an NH x reduction of 25% is $140 -320 million for Hubei province, which is the initial cost barrier before ammonia control can effectively affect particulate pH and mass in central China. This cost barrier will increase as NO x and SO 2 emissions decrease.

Effectiveness of emission control in reducing PM<sub>2.5</sub> pollution in central China during winter haze episodes under various potential synoptic controls

“…NW-type circulation mainly occurs in the early winter (December and January). This synoptic pattern is also reported as one of the main types to affect the aerosol distributions over eastern China (Zheng et al, 2015). Circulation at 500 hPa is controlled by one trough and one ridge, with the weak ridge located in the northwest of China and the shallow trough located in the northeast of China (Fig.…”

“…5) and the weak ascending in the vertical direction ( Fig. 7) at Jingzhou mean that it is not conducive to the dispersion of local pollutants (Zheng et al, 2015). The high PM 2.5 concentrations are mainly accumulated by local emissions.…”

“…4d), with low surface wind speed (0-3 m/s). Together with the large relative humidity, which can promote the hygroscopic growth of particulate matter (Twohy et al, 2009;Zheng et al, 2015), the haze pollution is persistent and serious at Jingzhou. The impact of low-pressure systems on winter heavy air pollution has also been reported in the northwestern Sichuan Basin (Ning et al, 2018).…”

“…The contribution of emission sources has been widely recognized as the decisive factor of PM 2.5 pollution over urban agglomerations, including industrial exhaust, urban transportation, residential emission, power plants, agricultural activities, and bio-combustion (Huang et al, 2014;Tian et al, 2016;Wu et al, 2018;An et al, 2019). The outbreak, persistence, and dissipation of particle pollution generally depends on meteorological conditions and regional synoptic patterns controlled by the large-scale or synoptic-scale atmospheric circulation (Chuang et al, 2008;Zhang et al, 2012;Russo et al, 2014;Zheng et al, 2015;Shu et al, 2017;Li et al, 2019).…”

Significant contrasts in aerosol acidity between China and the Unites States

“…Group B can be regarded as an intermediate group between Groups A and C. But the sensitivities of pH to TNH3 changes in group B are the highest among the three groups when reducing TNH3, which could be due to the rapid increase in ε(NH4 + ) in this group as TNH3 decreases (Fig. 8b), that leads to a faster loss of NH4 + (Zheng et al, 2019). Note that although the relative abundance of NH4 + in group 370 B is smaller than in group C, the transition from group B to group C due to TNH3 increase does not always happen.…”