Size segregated ionic species collected in a harbour area.

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Aerosol Science

Background:

• Port aerosols are influenced by various emission sources, including maritime activities and atmospheric processes.
• Understanding the seasonal variations and size distributions of water-soluble ions is crucial for assessing air quality and environmental impact.

Purpose of the Study:

• To investigate seasonal variations in size distributions of water-soluble ions in aerosols collected at the port of Alicante.
• To assess the influence of bulk materials handling on aerosol composition.
• To identify the sources and formation pathways of key aerosol components.

Main Methods:

• Analysis of water-soluble ions (sulfate, ammonium, potassium, calcium, sodium, magnesium, chloride, oxalate, nitrate) in size-segregated aerosol samples.
• Collection of samples using a multistage cascade impactor during summer and winter.
• Statistical analysis to determine size distributions and seasonal trends.

Main Results:

• Sulfate, ammonium, and potassium ions showed peaks in condensation and droplet modes year-round.
• Calcium, sodium, magnesium, and chloride ions peaked around 4 μm.
• Oxalate fraction increased in coarse mode during summer, linked to volatilization and reactions.
• Nitrate distributions were coarse-mode dominant, with submicron peaks in winter due to ammonium nitrate formation.
• Harbor activities significantly impacted coarse-fraction calcium concentrations.

Conclusions:

• Seasonal variations and particle size significantly influence the behavior of water-soluble ions in port aerosols.
• Bulk materials handling is a notable source of coarse-mode calcium at the port.
• Atmospheric processes, such as secondary aerosol formation, play a key role in the seasonal distribution of ions like nitrate.