The interdecadal worsening of weather conditions affecting aerosol pollution in the Beijing area in relation to climate warming

Abstract

<p><strong>Abstract.</strong> The weather conditions affecting aerosol pollution in Beijing and its vicinity (BIV) in wintertime have worsened in recent years, particularly after 2010. The relation between interdecadal changes in weather conditions and climate warming is uncertain. Here, we analyze long-term variations of an integrated pollution-linked meteorological index (which is approximately and linearly related to aerosol pollution), the extent of changes in vertical temperature differences in the boundary layer (BL) in the BIV, and northerly surface winds from Lake Baikal during wintertime to evaluate the potential contribution of climate warming to changes in meteorological conditions directly related to aerosol pollution in this area; this is accomplished using NCEP reanalysis data, surface observations, and long-term vertical balloon sounding observations since 1960. The weather conditions affecting BIV aerosol pollution are found to have worsened since the 1960s as a whole. This worsening is more significant after 2010, with PM<sub>2.5</sub> reaching unprecedented high levels in many cities in China, particularly in the BIV. The decadal worsening of meteorological conditions in the BIV can partly be attributed to climate warming, which is defined by more warming in the higher layers of the boundary layer (BL) than the lower layers. This worsening can also be influenced by the accumulation of aerosol pollution, to a certain extent (particularly after 2010), because the increase in aerosol pollution from the ground leads to surface cooling by aerosol-radiation interactions, which facilitates temperature inversions, increases moisture accumulations, and results in the extra deterioration of meteorological conditions. If analyzed as a linear trend, weather conditions have worsened by ~ 4 % each year from 2010 to 2017. Given such a deterioration rate, the worsening of weather conditions may lead to corresponding amplitude increase in PM<sub>2.5</sub> in the BIV during wintertime in the next five years (i.e., 2018 to 2022). More stringent emission reduction measures will need to be conducted by the government.</p>

Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes

“…Field studies showed that high PM 2.5 concentrations increase the air stability due to the ARI, leading to decreased PBL height (15, 36, 96, 107, 108). Zhang et al (36) illustrated clearly that the increase in aerosol pollution from the ground can lead to surface cooling by ARI, which facilitates temperature inversions, increases moisture accumulations, and results in extra deterioration of meteorological conditions. A positive feedback cycle involving the interaction between PM, PBL, and water vapor constitutes a self-amplification mechanism to trap PM near the surface.…”

“…Global warming associated with increasing greenhouse gases in the atmosphere affects the frequency and severity of haze formation by modulating weather conditions. Zhang et al (36) pointed out that the decadal worsening of meteorological conditions can partly be attributed to climate warming. Cai et al (18) found that with future global warming (2050 to 2099) the frequency of unfavorable weather conditions for severe haze events similar to that in January 2013 increases by 50% relative to the historical weather conditions (1950 to 1999), under the scenario of Representative Concentration Pathway (RCP) 8.5 (i.e., radiative forcing of 8.5 W⋅m −2 in 2100).…”

“…The haze extremes in China have provided a unique scientific platform to gain insights into many aspects of the relevant atmospheric chemical and physical processes (i.e., formation, transformation, transport, and removal of PM), and considerable scientific advances have been made in understanding PM pollution and its interactions with atmospheric processes (8, 9, 11, 12, 14, 15, 17, 33–37). Several previous reviews have focused on different aspects of the formation, chemical characteristics, and control strategies for haze pollution in China (3, 5, 38–40).…”

Aerosol–photolysis interaction reduces particulate matter during wintertime haze events

“…Persistent and pervasive haze with extremely high levels of PM 2.5 , caused by rapid industrialization and urbanization, frequently engulfs Northern China during wintertime (16). Onlinecoupled meteorology and chemistry models have quantitatively revealed that ARI plays a significant role in the heavy haze formation, with PM 2.5 contribution exceeding 20% (17)(18)(19)(20). Nevertheless, during haze events, high loadings of aerosols in the PBL substantially attenuate solar radiation to suppress photochemical processes and hinder the secondary aerosol formation, offsetting ARI effects on PM 2.5 pollution.…”

Application of Turbulent Diffusion Term of Aerosols in Mesoscale Model

“…Prosperous economic development and intensive expansion have led to a series of heavy aerosol pollution events in recent decades, which are characterized by high loadings of aerosol particles with an aerodynamic diameter less than 2.5 µm (PM 2.5 ) (Guo et al., 2014; Huang et al., 2014). PM 2.5 not only has detrimental impacts on air quality and human health (Chen et al., 2017; Hong et al., 2019), but also influences the regional weather and climate change (Cai et al., 2017; Tao et al., 2012; Zhang et al., 2018). PM 2.5 pollution mainly occurs within the planetary boundary layer (PBL).…”