Proyecto Lumina : nueva luz para la educación con personas adultas

Abstract

The North China Plain (NCP) has experienced heavy air pollution in the past several decades featured by high levels of fine particulate matter (PM_2.5). PM_2.5 removal from the atmosphere in the NCP by dry deposition was estimated from 1999 through 2013 using the inferential method, which combined PM_2.5 air concentrations retrieved from satellite remote sensing and dry deposition velocities (V_d) calculated using a bulk particle dry deposition model. Dry deposition of the three major inorganic ions in PM_2.5, namely NH₄⁺ (ammonium), NO₃^- (nitrate), and SO₄^2- (sulfate), with their concentrations in 2000 and 2010 obtained from WRF-Chem model simulations, were also investigated considering their important roles in PM_2.5 formation and ecosystem health. High levels of modeled and satellite-retrieved PM_2.5 air concentrations, the secondary inorganic aerosols (the sum of NH₄⁺, NO₃^-, and SO₄^2-), and their respective deposition fluxes were identified from the southern NCP to Beijing-Tianjin metropolitans. The deposition fluxes derived from the inferential method and WRF-Chem increased considerably in the 2000s due to rising PM_2.5 atmospheric levels across the NCP. The enhancement of dry deposition velocities of PM_2.5 and three aerosol species in the NCP were associated nicely with increasing vegetation coverage and wind speed. We show that both air concentrations of PM_2.5 and secondary inorganic aerosols and rising dry deposition velocities related to extensive afforestation activities contributed to their deposition fluxes and an inclining trend of PM_2.5 removal from the atmosphere.