Air pollution and deposition of ambient aerosols in human airways are associated with a number of detrimental health effects. National ambient air quality standards of inhaled particles are mainly based on the and particulate concentration and sizes. While the impact of the climatic or weather conditions on the possibilities potentially leading to enhanced deposition of ambient submicron aerosols in the respiratory tract is not taken into account.

The aim of this study is to show that some specific weather and climatic conditions (air temperature and humidity) can induce the short-term supersaturation effects of water vapor in the upper airways and this can lead to subsequent “enhanced” deposition of inhaled ambient aerosols in the respiratory tract.

All available data on the effects of supersaturation and condensational growth in the human airways were summarized and analyzed. It was found that inhalation of cool air of temperature T < 22˚C, or saturated air of T < 25-27˚C can lead to increased vapor supersaturation in the airways. Thus, it was shown that rainy and wet weather, or cold seasons in a temperate climate, or rainy seasons in subtropical and tropical climates can induce the supersaturated conditions in airways. It was found that hygroscopic and non-hygroscopic particles might grow in size due to enhanced condensational growth under supersaturated conditions in airways. In particular, a total deposition of 300nm particles in the airways might raise from ~13% (when supersaturation is not taken into account) up to ~90% due to enhanced condensational growth. It was found that such underestimation of deposition efficiency might be typical for most studies.

Thus, while significant advances have been made in understanding the aerosol dosimetry in the last decades, many aspects of adverse effects on respiratory health as weather conditions and environmental or occupational air contaminants require further development.