Observations of aerosol concentration, properties and chemical composition
Sandro Fuzzi
Institute for Atmospheric Sciences and Climate
National Research Council
Bologna, Italy
Bologna on a typical summer day
Measuring aerosol properties
• Contrary to gaseous molecules whose presence in the atmosphere is univocally defined by one number (concentration), atmospheric aerosol is composed by a population of particles, each one with its own nature and properties
Atmosphericparticles
Measurement principles
absorb and scatter visible light, absorb and emit IR radiation, absorb UV light;
grow up upon absorption of water vapor; can be seen using an optical or an electronic microscope; can be collected up to weighable mass; are made up of compounds which can be analyzed by
chemical methods; can be ionized in a mass spectrometer.
Aerosols …
Moreover, there are a number of methods to determine specific aerosol components (radionuclides, trace elements, biological particles)
In-situ measurementsand remote sensing
in-situAdvantages: detailed information on the aerosol size-distribution and chemical composition. Ground-based platform ideal for monitoring purposed.Disadvantages: limited spatial and time coverage (especially in the FT and over the oceans)
Remote sensing (only optical methods)1) Columnar properties of the aerosol using photometers and radiometers;2) Aerosol concentration vertical profile from laser back-scattering (LIDAR)
Aerosol number/mass concentration ranges
Type of aerosol
Particle
number (N/cm3)
Mass
concentration (g/m3)
Plume
107
102-105
Urban area 104-105 50-200 Rural area 103-104 10-50 Remote continental area 1000-2000 5-10 Remote marine area ca. 500 1-5 Anctarctic Plateau ca. 50 1
AEROSOL BULK MEASUREMENT
SIZE-SEGREGATEDMEASUREMENT
SINGLE-PARTICLE ANALYSIS
Aerosol sampling for chemical analysis
Measurement strategy
1. MONITORING NETWORKS:a. for Air Quality
b. for Climate
2. FIELD CAMPAIGNS
Lat.N 27°57' Lon. E 86°48‘ Altitude 5079 m asl Lat.N 27°57' Lon. E 86°48‘ Altitude 5079 m asl http://evk2.isac.cnr.ithttp://evk2.isac.cnr.it
The Pyramid The Pyramid ObservatoryObservatory
in the in the HimalayasHimalayas