Dry deposition of atmospheric nanoparticles

Abstract

The increasing number of pollutants emitted or released during and after the industrial revolutions caused major changes that were harmful to the environment and the health of the population. The harms resulting from air pollution were evident in the most industrialized regions, due to the large amount of pollutants emitted in these regions. Environmental protection agencies have highlighted the harmful effects of air quality on human health and have become a concern in recent years due to the growing episodes of air pollution in many cities around the world. In this way, the pollutants emitted undergo or may undergo the deposition process, this process is responsible for removing pollutants from the atmosphere. The most common mechanisms for removing atmospheric particulate matter are dry deposition and wet deposition. These mechanisms are related to the size and behavior of the particulate matter. This chapter is presented a study case that the dry deposition flux determination for the ions present in the PM1 (particles < 1 μm) in regions with mixed crops, grass, and urban areas. The particulate matter (PM) concentration, size distribution, and chemical characterization were evaluated and were associated with the emission sources. The dry deposition velocities were calculated using Zhang and Nho-Kim, Michou and Peuch parameterization models. The highest PM1 concentrations were related to the highest number of burning sites. The highest PM concentration of 202.3 μg m−3 with a 160 nm median mass diameter was found. The air mass trajectories indicated that the particulate matter sampled may have been influenced by the particulate matter transport, mainly from regions where many industries use the biomass to generate energy. The lowest dry deposition velocities were presented by the particles with a diameter range between 400 nm and 1.2 μm, for all the land use categories (LUC). The lowest dry deposition velocities were calculated for urban areas, which indicates that the particulate matter in this region stays longer in the atmosphere and so it is easily inhaled and deposit in the lungs and blood circulation, which increased health risks. The anthropogenic actions are negatively impacting the environment as well the human health. Therefore, it is important to evaluate the particulate matter emissions, as well its ionic composition, the air mass trajectories, and the ionic species deposition fluxes to estimate the impacts of the anthropogenic actions, with the aim of creating and/or adapting the standards and laws for each country, always following the criteria established by WHO for air quality.