Change of Composition, Source Contribution, and Oxidative Effects of Environmental PM_2.5 in the Respiratory Tract

Abstract

Fine particulate matter is a leading air pollutant, and its composition profile relates to sources and health effects. The human respiratory tract hosts a warmer and more humid microenvironment in contrast with peripheral environments. However, how the human respiratory tract impacts the transformation of the composition of environmental PM2.5 once they are inhaled and consequently changes of source contribution and health effects are unknown. Here, we show that the respiratory tract can make these properties of PM2.5 reaching the lung different from environmental PM2.5. We found via an in vitro model that the warm and humid conditions drive the desorption of nitrate (about 60%) and ammonium (about 31%) out of PM2.5 during the inhalation process and consequently make source contribution profiles for respiratory tract-deposited PM2.5 different from that for environmental PM2.5 as suggested in 11 Chinese cities and 12 US cities. We also observed that oxidative potential, one of the main health risk causes of PM2.5, increases by 41% after PM2.5 travels through the respiratory tract model. Our results reveal that PM2.5 inhaled in the lung differs from environmental PM2.5. This work provides a starting point for more health-oriented source apportionment, physiology-based health evaluation, and cost-effective control of PM2.5 pollution.

Variation of PM2.5 Redox Potential and Toxicity During Monsoon in Delhi, India

“…These findings suggest that organic redox-active compounds in PM 2.5 posed a primary oxidative hazard during monsoon. Furthermore, a recent study reported that the human respiratory tract can modify the composition of PM 2.5 by phasing out its semi-volatile nitrate and ammonium content, leading to a significant increase in the OP of inhaled PM 2.5 through enhanced metal solubility . This implies that the adverse health effects of oxidative stress from airborne PM 2.5 may be underestimated, necessitating further investigations, considering the influences of the respiratory tract and lung environment.…”

A Novel Flexible Geographically Weighted Neural Network for High-Precision PM2.5 Mapping across the Contiguous United States

“…Additionally, Canadian forest wildfires serve as significant sources of air pollution in North America, with smoke particles transported into the CONUS airspace by atmospheric movements [55]. The northeastern and western coastal regions are major population and urban centers, yet PM2.5 accumulates continuously during this period, undoubtedly increasing health risks for local residents [56].…”

Enhancing Seasonal PM2.5 Estimations in China through Terrain–Wind–Rained Index (TWRI): A Geographically Weighted Regression Approach

“…The atmosphere is one of the fundamental elements that humans rely on for survival and development [1,2]. Emerging studies have shown that long-term exposure to air pollutants, particularly PM2.5, increases the risk of respiratory and cardiovascular diseases [3][4][5]. PM2.5 primarily originates from human activities and is influenced by meteorological conditions [6][7][8].…”