Browsing by Subject "ions"

Atmospheric aerosols are among the main components of the atmosphere, emitted by natural and anthropogenic sources, they play a significant role in climatic and health effects. With the current state of climate change and the consequences on human health, aerosols are among the central topics in atmospheric chemistry and environmental research. Studying the aerosol size distribution in the suburban areas is crucial to understand the direct impact of natural sources, chemical processes, and human activities on the aerosol distribution, impacting in turn human life and Earth ecosystem stability. In this thesis I investigated the aerosol and ion distribution at two suburban areas in Helsinki, the SMEAR-III station and the Viikki SMEAR-Agri station. The main instrument used in this thesis to measure the size distribution is the Neutral cluster and Air Ion Spectrometer (NAIS), while supporting information from gas monitors and mass spectrometry was used for gas-phase compounds. The aerosol and ion distribution features are studied regarding the local environmental differences between the stations and their connection to potential sources and atmospheric chemical processes. New Particle Formation (NPF) is a process contributing to the concentration of aerosols in the atmosphere, while aerosols can also be emitted or formed from anthropogenic sources such as traffic and industrial emissions. Gaseous vapours such as sulfur dioxide, sulfuric acid, nitrogen oxides, and highly oxygenated organic molecules contribute to atmospheric chemical reactions leading to aerosol formation. Thus, the connections between NPF events and gas-phase compounds with the aerosol and ion distribution was investigated. The findings of this thesis highlight the environmental features of each station leading to slight differences in the aerosols and ions distribution. Insights into the aerosol sources through connection between gaseous vapours, NPF events, traffic, and the aerosols and ions distribution are given.