Date Published: January 30, 2019
Publisher: Public Library of Science
Author(s): Anatoliy A. Zhirnov, Nina N. Kudryashova, Olga B. Kudryashova, Nataliya V. Korovina, Anatoliy A. Pavlenko, Sergey S. Titov, Amitava Mukherjee.
Advanced air quality control requires real-time monitoring of particulate matter size and concentration, which can only be done using optical instruments. However, such techniques need regular calibration with reference samples. In this study, we suggest that puffball fungus (Lycoperdon pyriforme) spores can be utilized as a reference standard having a monodisperse size distribution. We compare the Lycoperdon pyriforme spores with the other commonly used reference samples, such as Al2O3 powder and polystyrene latex (PSL) microspheres. Here we demonstrate that the puffball spores do not coagulate and, thus, maintain the same particle size in the aerosol state for at least 15 minutes, which is enough for instrument calibration. Moreover, the puffball mushrooms can be stored for several years and no agglomeration of the spores occurs. They are also much cheaper than other calibration samples and no additional devices are needed for aerosol generation since the fungal fruiting body acts as an atomizer itself. The aforementioned features make the fungal spores a highly promising substance for calibration and validation of particle size analyzers, which outperforms the existing, artificially produced particles for aerosol sampling. Furthermore, the L. pyriforme spores are convenient for basic research and development of new optical measurement techniques, taking into account their uniform particle size and absent coagulation in the aerosol.
Air pollution is one of the major risk factors for public health. One of the components of air pollution both outdoors and indoors is fine particulate matter (PM). Micrometer-sized particles are especially hazardous, as they can infiltrate into biological tissues of lungs and blood vessels leading to cardiovascular disease [1, 2], respiratory disease [2, 3] and even cancer . Microparticles are typically categorized into two groups: PM10 (10 μm particles and smaller) and PM2.5 (2.5 μm and smaller). The International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) classifies these fine PM as a Group 1 carcinogen  and the WHO, therefore, encourages the reduction of fine particulates in the atmosphere.
In this section, the L. pyriforme spores are compared with the other two common aerosol reference standards chosen for a comparative purpose for the following reasons:
We have compared spores of Lycoperdon pyriforme with two different, commonly used reference aerosol samples:
This study introduces the spores of Lycoperdon pyriforme as a reference sample which, as the experiments have shown, outperforms artificially produced counterparts in many aspects. This bioaerosol is monodisperse and highly stable, has a long shelf-life time and low cost. Fungal spores were previously reported as a cell-counting tool in biological experiments , but their exceptional aerosol properties have not been studied before. Overall, fungal spores can significantly facilitate research and development of aerosol measurement techniques, especially optical methods that are currently in high demand .