Automatic monitoring of pollen, spores and other aerosols
The SwisenPoleno device is capable of measuring particles in the 1 to 300 μm range. In terms of aerosol size, it can be said to be capable of measuring coarse aerosols (>1 μm) according to the classification established by the United States Environmental Agency (USEPA).
These aerosols are typically carried by the wind, remaining suspended for minutes, hours, or even days depending on the particle size and wind conditions. Their distribution, therefore, is not limited to the emission source (which can be tens or hundreds of kilometers away) but is clearly influenced by meteorology.
Among other characteristics, aerosols can be classified based on their composition. Those whose sources are of biological origin are considered bioaerosols and include pollen, spores, plant debris, etc. Many of them are likely to cause allergies and general illnesses in a portion of the population.
Considering size (UNE EN 12341:2015 standard), aerosols can also be classified according to aerodynamic diameter (the diameter of a sphere with a density of 1 g/cm3 that has the same final velocity due to gravitational force as the observed particle). It is from this concept that different fractions are determined, all of which are of interest to human health:
- Inhalable fraction (< 30 μm).
- Extrathoracic fraction (between 10 μm and 30 μm).
- Thoracic fraction (< 10 μm).
- Tracheobronchial fraction (between 10 μm and 2.5 μm).
- Alveolar fraction (< 2.5 μm).
By convention, particles with a diameter greater than 10 μm are retained in the nasal passages, mouth, larynx, or pharynx. It is for fractions smaller than 10 μm that particle size becomes of health importance. The tracheobronchial fraction (between 10 μm and 2.5 μm) is deposited primarily in the trachea (10–6 μm) and bronchi (10–6 μm). The alveolar fraction (<2.5 μm) is deposited in the bronchi, bronchioles (3–1 μm), and alveoli (<1 μm).
Various scientific studies conclude that the concentration of particulate matter (PM) is directly proportional to pulmonary and cardiovascular pathologies, and, in the long term, to the development of certain cancers (linked to the presence of PAHs, hydrocarbons that, when reacting with nitrogen dioxide, can generate nitroarenes, which are highly mutagenic).
This is why continuous, real-time monitoring of the concentration of particulate matter fractions smaller than 2.5 μm and 10 μm (PM2.5 and PM10, respectively) is of great interest from the perspective of health, in particular, and environmental quality, in general.
Observation of pollen, spores and other aerosols.
As described in the section on the operating principle of the SwisensPoleno, a measuring station obtains morphological and biochemical characteristics of each particle using light scattering, digital holography, fluorescence, and polarization. Thus, a rich mosaic of information is obtained from each observed particle across a multitude of parameters (70+ variables).
Given the enormous potential of the SwisensPoleno technology (based on the idea that each type of aerosol has common characteristics), this opens up a huge research and development opportunity for aerosol observation, classification, and counting.
Examples of digital holographic images of pollen (top row). The bottom row is an enlargement of these images. The SwisensPoleno is capable of measuring pollen shape and size using machine learning algorithms and neural networks in real time. This information can be complemented with a wealth of data derived from fluorescence and polarization observations. This illustrates the technology’s great potential for recognizing pollen and other aerosols.
PM1, PM2.5, and PM10 fractions.
In addition to real-time monitoring of pollen and other potential bioaerosols, the SwisensPoleno (in its “Jupiter” version versus the “Mars” version) offers the additional functionality of determining particulate matter concentrations (PM1, PM2.5, and PM10). As mentioned above, this information is of great interest to the general population given the implications of particulate matter for health and environmental quality.
