Aerosol mixing state revealed by transmission electron microscopy pertaining to cloud formation and human airway deposition

Abstract

Aerosol mixing state is one of the most important factors determining the impacts of aerosol particles on aerosol-cloud-climate interactions and human health. The size, composition, and morphology of about 32,000 single particles are analyzed using transmission electron microscopy (TEM) to evaluate per-particle mixing state. Based on the TEM analysis, we quantify aerosol mixing state and examine the impacts of per-particle mixing state on cloud condensation nuclei (CCN) properties and particle deposition efficiency along the human respiratory tract. Assuming homogeneous chemical composition across the aerosol population, a common practice in many global and regional models to various extents, we show that such simplification of mixing state representation could potentially lead to remarkable errors, a maximum of about 90% and 35%, in CCN concentrations and deposition efficiency calculations respectively. Our results from ambient per-particle observations highlight the importance of considering aerosol mixing state in both air quality models and climate models.

Moving beyond Fine Particle Mass: High-Spatial Resolution Exposure to Source-Resolved Atmospheric Particle Number and Chemical Mixing State

“…Our results indicate that external mixing is associated with a high number concentration. Health effects of chemical mixing state are largely unexplored and therefore uncertain, but some studies have revealed a potential health influence of particle mixing state (Ching et al 2019;Ching and Kajino 2018).…”

Human Inhalation Exposure to Aerosol and Health Effect: Aerosol Monitoring and Modelling Regional Deposited Doses

“…The childcare facilities have led the way in demonstrating many of the links between environmental exposures and health outcomes. Some bioaerosols could also be adsorbed to the inhalable aerosols and transported in environments that have potential pollutant sources [16,30,31]. This study showed that PM concentrations, especially respirable-sized PM, are related to the culturable bioaerosol based on the size-selective concentration.…”

“…During indoor and outdoor air quality monitoring, it was confirmed that outdoor harmful pollutants were penetrating indoors [21]. Inhalable aerosols that have penetrated the respiratory tract have different deposition rates [6,16] depending on the location of the respiratory system, and deposition levels and transport patterns provide important clues for assessing the potential health effects of aerosols [15,18].…”

“…On the other hand, the biological fraction (bioaerosol) among the various components of PM [13] can have a significant impact on human health [6,[13][14][15][16], including infectious diseases, acute toxic effects, allergies and cancer [14,17,18]. Many bacterial infectious diseases such as Legionellosis, Tuberculosis, Anthrax, etc., are due to chronic and even temporary exposure to bioaerosols [19].…”

“…Many bacterial infectious diseases such as Legionellosis, Tuberculosis, Anthrax, etc., are due to chronic and even temporary exposure to bioaerosols [19]. This is because some aerosols, including bacteria and fungi, pollen, and viruses, remain in the atmosphere [13,15,16] and have a long atmospheric residence time, especially bacteria [15], including surviving and non-surviving bacteria [14,19], mainly due to the coarse particles (PM 10-2.5 ) in the atmosphere.…”