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