What is PM100?
“PM” (Particulate Matter) is not a single pollutant, but refers to a complex mixture of solids and aerosols of varying shape, size, and chemical composition and may contain many chemical species like organic compounds, inorganic ios, metallic compounds, elementary carbon, etc. These atmospheric particles are defined by their diameter for air quality regulatory purposes.
The particulate matter that is less than or equal to 100 micrometres in diameter is collectively known as PM100. They are also known as “inhalable dust” as this fraction of the particulate matter can enter the nose and/or mouth while breathing and gets deposited in the air passages between the mouth, the nose, and the larynx. Once released into the atmosphere, they tend to settle as they are heavier. Examples include wood particles, dust, etc.
Particulate matter PM100 is either directly emitted into the atmosphere from various sources. The natural sources of particulate matter are wind-blown dust from open land, dirt, soil erosion, etc. Anthropogenic sources of PM100 include:
- Crushing, grinding, splitting activities
- Dust emitted from unpaved and paved roads
- Uncontrolled construction activities
- Dust and dust from factories, agriculture, landfills
- Emission from industrial processes
- Metal and steel production as well as the reloading of bulk material
Health & Environmental Impact of PM100
The potential of the particulate matter to affect human health depends directly on the size of particulate matter. The particles with < 100μm diameter generally enter the nose and throat. The majority of these dust are caught in the nasal hairs and are removed by blowing nose, coughing or sneezing, however some may penetrate head airways, and enter lung airways.
When inhaled, if PM100 particles are not exhaled or cleared out from the respiratory tract, they remain in the same location and may cause adverse health effects such as by allergic reactions, heart diseases, silicosis, etc. It can irritate the nose, throat, and even eyes. Short term exposure to PM100 aggravates already present respiratory diseases such as asthma while long term exposure can affect respiratory mortality. Some of the inhaled particulate matter are toxic and can imply additional risks because of their hazardous properties. Examples of such particles include certain dust from hardwood which may cause nasal cancer, dust from crushing and grinding of lead containing alloys can be absorbed into the body causing systemic poisoning, metal dust containing mercury, lead, cadmium or chromium may lead to pulmonary fibrosis, etc.
The major environmental impacts of PM100 pollution are visibility reduction and deposition. High levels of PM100 causes visible air pollution affecting the aesthetics of the surrounding environment before they settle down. The settling of the air-borne PM100 on plants, soil, and water ecosystems have harmful effects on them. The metal and organic compounds reduce plant growth and yield while the deposition of PM into water bodies affects its quality and clarity.
Possible corrective measures
The primary step is dust monitoring to identify the areas with high particulate levels In addition to this, the following corrective measures can be taken:
- Limit outdoor activities and close windows and vents during times of high air pollution.
- Avoid areas with traffic congestions, construction activities, or unpaved roads. Breathing such polluted air daily also leads to health effects in the long run.
- Eliminate the use of the fireplace, wood stove, gas-powered lawn, or garden equipment.
- Eliminate open burning of leaves, trash or other materials
Measurement methods of Dust monitoring
Different working principles for dust monitoring in the ambient environment are Gravimetric, Beta Attenuation (BAM), and Laser scattering
High-volume Gravimetric Method – The dust monitors based on the gravimetric principle takes in the ambient air for 24 hours at a constant flow rate through a size-selective inlet that only allows particulate matter with an aerodynamic diameter of 100µm or less to pass through. The particulate matter is collected onto a pre-weighed filter conditioned at constant temperature and humidity conditions. After the 24-hour sampling period, the filter is conditioned again under the same temperature-humidity conditions and reweighted. The difference in the weight corresponds to the mass collected on the filter, which along with known flow-rate, sampling period, and the total volume of the air sampled is used to calculate the PM100 concentration.
Beta Attenuation Monitor (BAM) – The dust monitoring based on the BAM principle measures the particle mass density using beta radiation attenuation. The particulates in the ambient air drawn into the dust monitor are deposited on a paper-band filter and exposed to beta rays (i.e. electrons with energies in the 0.01 to 0.1 MeV range) which gets attenuated as a function of the particulate mass. The beta count reduces with an increase in the PM mass and is recorded by the detector and converted to concentration.
Laser Scattering – The dust monitor based on the physical principle of light scattering, also known as optical particle counter (OPC), measures dust particles illuminated by laser light at a 90° angle. The light scattered from each particle is collected at approximately 90° by a mirror and detected by a photo-diode. This signal is then fed into a multi-channel size classifier where a pulse height analyzer is used to classify each pulse that is proportional to the particle size. The counts in the channel corresponding to PM100 are converted to the concentration of PM100.
Among all the above principles of PM100 monitoring, PM monitors based on laser scattering are typically found to be preferred for ambient air monitoring as they yield quick and accurate measurements and are inexpensive in cor
Oizom’s working principle for Dust monitoring
Oizom’s DUSTROID is an online particulate monitoring system that measures the concentration of various particulate sizes ranging from 1 micron to 100 microns such as PM1, PM2.5, PM10, and PM100 in the ambient air. Our PM sensor works on the principle of laser scattering. The active sampling powered sensor-based air quality monitor DUSTROID can be used for dust monitoring in areas with dust-laden activities like construction, mining, quarrying, ports, metallurgical processes, and many more. The data gathered from Dustroid can assist in setting up a threshold for the particulates and activate the air purification systems immediately.
5 reasons why Dust monitoring is important:
- PM is a complex mixture of solid and aerosols with a very small size that can easily enter the nose and/or mouth while breathing.
- Particulate matter is emitted into the atmosphere from combustion processes, cruising or grinding activities, resuspension of dust and dirt from roads, soil, etc.
- When inhaled, it irritates the eyes, nose, throat, and the airways and the toxic substances in the PM may lead to other adverse health impacts such as nasal cancer, pulmonary fibrosis, etc.
- Dust monitoring is an efficient way to detect high concentrations of particulate matter and prevent high-level exposures.
- Real-time dust monitoring helps in determining the quality of air as well as formulating an action plan to prevent/reduce PM exposures.