Aerosol science history – Willeke and Baron (2001), Ch. 1
Romans – foul air of Rome → Aerosol science intrinsically linked to air pollution
1273 – Coal burning banned in London.
1500 – Leonardo da Vinci – first recorded use of laboratory aerosols.
1661 – Tract on air pollution in England submitted to Charles II - Fumifugium
1700s – High mortality of hard rock miners.
1841 – Epsy invented ‘nephelescope’ and observed water cloud formation in lab. He was
not aware that condensation occurred on particles.
1847 – Becquerel hypothesized about existence of fine particles in air,
1850s – Tyndall used ‘sunbeams’ to determine indoor air pollution,
1860s – Tyndall detected fine particles by dark field illumination. Invented the
tyndallometer, nephelometer, ultra microscope, optical particle counter, and
indirectly thermal precipitator – noted dark region above a heated body, later
observed by Rayleigh, Lodge, Aitken – discovery of thermophoresis
1875 – Coulier the first to show condensation in unfiltered air,
1880 – John Aitken developed an expansion type portable dust (CN) counter with full
credit to Coulier. First portable aerosol counter.
1897 – Wilson used cloud chamber to study homogeneous nucleation.
1880s – Electrostatic precipitation – electric discharge into smoke laden atmosphere
coagulated the smoke – electrophoresis.
1881 – ultramicroscopy of smoke
1900s – First attempts at using filters and gravimetry which were dominated by large
particles. Silicotic lung tissue – 70% of particles < 1.0 µm → fine dust counters.
First aerosol diffusion battery.
1918 – “Aerosol” coined in analogy with hydrosol – Donnan,
1920s – Silica (quartz) recognized as producing pulmonary diseases, silicosis,
pneumoconiosis → dust counters in industry.
1919 – Konimeter – dust collected by impaction on glass slides and counted with
microscopy → fine dust counters. Number concentration more important than
mass.
Fibrous aerosol:
1920s – Medical proof of a causal effect between asbestos fibers and fatality of asbestos
workers.
1927 – Peribronchial fibrosis fully recognized – asbestosis.
1935 – Bronchial carcinoma → Need for measure and control of asbestosis officially
recognized.
1970s – Optical fiber counter – Baron, 1980s – improvements, 1990s – satisfactory
instrumentation available.
1940s – Cascade impactors, precipitators (thermal/electrical) – Problems were many –
rebound, re-entrainment, deagglomeration, sampling and collection efficiencies
varied widely with differences of ± 100%. Isokinetic sampling not recognized or
understood until after 1960. Thermal precipitators (instruments of choice) were
discovered to be size selective.
> 1960 – Although all essential aerosol sampling techniques had been discovered and
applied, no instruments survive to be useful today. This period preceded lasers,
computers, spectroscopic analysis tools.
Sampling methods:
Filtration: 1950 – membrane filters most important standard
1960 – pore filters developed (nucleopore filters).
Elutriators, Centrifuges: Particles sorted by sized based on settling velocity (elutriators)
or centrifugal force (centrifuge).
Condensation nuclei (CN) counting: Aitken’s methods improved upon. Junge (1935)
used a camera in place of a microscope. 1950s – GE lab automated CN counters
(CNCs) – Vonnegut (1947).
Ultra microscopy: Tyndall’s phenomenon used to count flashes of light passing a slit,
which is used to define the sample volume.
Tyndallometry: Measure of light scattered from all particles in a sample volume through
an angle of 30º. Nephelometer – angle increased to ~ 170º.
Optical particle counters (OPCs): 1940s – Gucker refined the light detector on an ultra
microscope to count particles > 0.3 µm. 1960s – commercial development – the
Royco counter. 1970s - Rosen developed the Wyoming OPC.
Mineralogical and chemical analysis – microscopy, x-ray diffraction. Now mass
spectrometers.