In the pandemic situation, avoiding crowds is an effective way of protection. Even though the situation has improved, people should remain cautious. In order to get back to a new normal as soon as possible, researchers worked hard to find answers to elemental questions: What exactly is the role of aerosols in spreading the virus via respiration? What is the relation between distance of people and the transmission rate? How is prevention effectively working indoors?
To find reliable answers to these questions, reliable experimental results are needed, and these results need to be based on reliable measuring instruments for an accurate monitoring. This is where Palas® supported researchers with its advanced technology.
Accurate Measurement Data provided by Palas®
An experiment with Palas® instruments was carried out in four different concert halls at the same time. The four concert halls have a capacity between 400 to 1,650 seats. The experiment used a dummy instead of real people to simulate the aerosol and carbon dioxide emitted by people when breathing. The breathing speed was set to 2.4 meters per second. In this experiment two scenarios were simulated: One with masks (medical surgical masks, MACSEIS, MCG01) and the other without masks. The test instruments were placed in 6 different positions as shown in the figure (b) below for monitoring. As also shown in the figure (a) below, the experiment used blue light visualization effect to observe the breathing airflow of the dummy. At the same time, fresh air is introduced under each seat, and the discharged aerosol is upward through vertical ventilation (see figure (c)) to prevent aerosols from adjacent seats and spreading to each other. In this experiment, Palas® AQ Guard, Palas® Promo® 2000 and Palas® Fidas® Frog were used for multi-dimensional monitoring.
Experimental set-up: (a) dummy without a face mask; (b) seat layout and measurement points, (c) dummy wearing a surgical mask
The Testing Equipment by Palas®
Palas® AQ Guard is an aerosol monitoring device that can provide aerosol resolution and carbon dioxide measurement at the same time, providing an important reference value for monitoring viruses and air quality. Palas® Promo® 2000 and Palas® Fidas series have unique technical advantages of Palas®: its single particle aerosol distribution spectrometer technology (SPADS) can avoid the generation of boundary errors during the single particle measurement process, and at the same time, monitor and correct the coincidence errors to a great extent.
A Remarkable Effect made visible with Palas® Instruments
This experiment provides strong data that is useful when planning to bring back large-scale cultural gatherings to theaters and concert halls. According to the test results of the Palas® instruments, the importance of even slight and temporally changing air flow conditions on aerosol dispersion is shown. It becomes obvious that the concentration of aerosol and carbon dioxide in the air are relatively lower when wearing a mask compared to without wearing a mask. This also shows the strong effects of masks. There is another remarkable result shown in the experiment: Even if fresh air gets into the room, the diffusion of aerosols still is a threat people‘s health.
Aerosol and carbon dioxide concentrations measured at the positions for the dummy not wearing a mask and the dummy wearing a surgical face mask
Why Measuring Small Particles Matters
Humans typically emit respiratory droplets ranging from 0.1 μm to several tens of micrometers in diameter, depending on the respiratory activity. While large particles either fall down due to gravity within a few meters or are blocked by surgical face masks, small aerosols can stay airborne for quite a long time. Considering this fact, special attention should be paid to small particle sizes (diameter <1 μm) when evaluating indoor viral dispersion by aerosols. In the mentioned experiment, Palas® instruments have demonstrated their outstanding performance in monitoring both small and large aerosol particles. In the future, Palas®‘s various instruments will play a role in the efforts to bring back events to concert halls and indoor arenas.
AQ Guard Air Quality Monitor
Advantages:
·    Technology based on the type approved Fidas® 200 series (EN16450 and MCERTS);
·    Simultaneous measurement of Cn, PM1, PM2.5, PM4, PM10
·    High accuracy due to advanced algorithms
·    Long-term stability due to self-calibration for measurement of flow rate, particulates, and gaseous pollutants
·    Operates on AC, DC, or power-over-Ethernet
Applications:
·    Industry: production process, bulk material handling (mixing, unloading, storage, packaging etc.), and factory boundary monitoring
·    Construction sites: roads, railways, demolition site
·    Buildings: schools, kindergartens, hospitals, hotels, offices, public service buildings
·    Residential buildings near construction sites or other contaminated areas
·    Public transportation: airports, railway stations, tram and subway stations, cruise ships, cruise ships, cabinsÂ
Palas® Promo® 2000 Scattered-light Aerosol Spectrometer System
Advantages:
·    Measuring range of 0.2 to 100 µm (4 measuring ranges selectable in one device)
·    Up to 128 size channels per decimal
·    Concentration range of 1 p/cm3 to 106 p/cm3
·    Calibration curves for different refractive indices
·    Pressure-resistant up to 10 bars (optional)
·    Heatable to 250 °C (optional)
·    External control by RS 232 or Ethernet
·    Low maintenance
·    Reliable function
Applications:
·    Emission monitoring of installations
·    Control of grinding and classification processes
·    Monitoring of production processes in the food, pharmaceuticals and chemicals industries
·    Testing of complete filters, inertial and wet separate tors or electrostatic precipitators
Palas® Fidas® Frog Fine Dust Measurement Device
Advantages:
·    Continuous and simultaneous real-time measurement of PM1, PM2.5, PM10 and TSP-values
·    Additional particle number concentration and particle size distribution
·    Wide measuring range: 180 nm – 100 µm
·    Adjustable time resolution from 1s
·    Direct comparison of different measurements
·    Configuration of limit values possible
·    High quality of measuring data through implementation of the sensor / evaluation algorithm of EN certified Fidas® 200
·    Additional expanded range of applications by possible separation of the measuring device and the Tablet-PC for control (communication via WLAN)
·    Up to eight hours of measurement time in battery mode
·    Ergonomic design and low weight
·    Intuitive and simple operation
·    Integrated camera for documentation of the measurement
·    Export function for measured data
·    Possibility to generate a measurement report as pdf in Fidas® Frog
·    Remote monitoring and control via network integration easily possible
Applications:
·    Fine dust monitoring at alternating locations or in movement
·    Air quality monitoring indoors, at the workplace, or inside vehicles
·    Use as an aerosol spectrometer in setups where space is limited
Palas® provides high-precision aerosol monitoring instruments from nanometers to micrometers for a wide range of scientific research fields, whether it is particulate matter generated during combustion, haze that affects urban air quality, or aerosols in the air people breathe. To understand how aerosols are formed, how aerosols are spread, and the difference between aerosols and man-made aerosols, please participate in the Palas® 4 Science webinar on July 6th and July 27th, experts from Palas® Germany headquarter will answer all your question (English). Click to register for the Palas® 4 Science online seminar now.
