What is PM1
“PM” (Particulate Matter) is not a single pollutant but refers to a complex mixture of solids and aerosols. Which are of varying shape, size, and chemical composition. Which may contain many chemical species like organic compounds, inorganic ios, metallic compounds, elementary carbon, etc.
These atmospheric particles are definable by their diameter for air quality regulatory purposes.
The ultra-fine inhalable particles that are less than or equal to 1 micrometer in diameter are collectively known as PM1. They are more than 400 times thinner than a human hair (too small to be detectable by the human eye) that can penetrate directly through the lungs into the bloodstream when inhaled.
PM1 are extremely fine particles and a major subset of PM2.5 that are likely to reach deeper into the body than PM2.5. Which makes them even more harmful as they can reach other organs through the bloodstream. PM1 particles in the atmosphere remain suspended in the air due to their negligible mass. Making them more susceptible to exposure. Because of their very small size, PM1 undergoes various transformations due to coagulation, condensation, evaporation, and/or deposition in the atmosphere. After a long time mainly by activation in clouds and subsequent precipitation, they can be ultimately removed.
The emission of particulate matter PM1 is direct emission from a source (primary PM) or through the chemical reactions of gases such as oxides of sulfur (SOx), nitrogen oxides (NOx), organic compounds, etc. which are present in the atmosphere (secondary PM). The natural sources of PM1 particulate matter are marine aerosol, soil erosion, volcanic eruptions, and forest fires. Anthropogenic sources of PM1 include:
- Burning fossil fuels such as gasoline, oil, diesel, coal or wood, etc.
- Agricultural processes
- Cooking and cigarette smoke.
- Emission from motor vehicle exhaust, specifically diesel-powered.
- Emission from power plants and industrial combustion processes
The formation of secondary PM1 is generally via photochemical reactions of gases and condensation of semi-volatile vapors in the atmosphere. They usually consist of sulfuric acid, ammonium sulfates and nitrates, organic compounds, and a range of trace metals.
Health & Environmental Impact of PM1
The potential of particulate matter to affect human health depends directly on the size of particulate matter. When inhaled, the particles with up to 2.5 μm diameter generally pass through the nose and throat and travel deep into the lungs through the respiratory tract. However, PM1 particles i.e. particles with a diameter < 1 μm, are so small that they can travel deeper into the lungs to the alveoli (i.e. the tiny sacs in the lungs where the exchange of O2 and CO2 take place). Some PM1 particles pass through the alveoli cell membranes, enter the bloodstream, and reach parts of the body. They can damage the inner walls of the arteries and can penetrate the tissues, potentially spreading through the organs and damaging them.
PM1 irritates the eyes, nose, throat, and upper respiratory tracts, coughing, sneezing, and shortness of breath when inhaled for short periods. It aggravates already present respiratory diseases such as asthma and can result in premature mortality, acute and chronic bronchitis, other respiratory symptoms, etc.
Exposure to PM1 pollution, for a long period (i.e. months or years), can cause permanent respiratory problems. Problems such as asthma, chronic bronchitis, and heart disease and cause reduced lung function growth in children. Prolonged exposure to PM1 contributes to severe diseases like heart attacks, lung cancer, edema, etc. leading to premature death.
The major environmental impacts of PM1 pollution are visibility reduction and smog. Particulate matter, specifically the ones with a diameter < 2.5 μm alters the absorption and scattering of light in the atmosphere affecting visibility. Additionally, the settling of the air-borne particles on plants, soil, and water ecosystems has 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.
Atmospheric particles affect the heating and cooling of the atmosphere. Some components of PM such as black carbon promote climate warming while some components such as sulfates and nitrates have cooling properties. These particles are also the major precursors of smog.
Possible corrective measures
The primary step is air particulate monitoring to identify the areas with high particulate levels. In addition to this, one can take the following corrective measures:
- Limit outdoor activities and close windows and vents during times of high air pollution.
- Avoid keeping your vehicle idle for long.
- 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 air particulate monitoring
Different working principles for air particulate monitoring in the ambient environment are Gravimetric, Beta Attenuation (BAM), and Laser scattering.
High-volume Gravimetric Method
The air particulate monitors based on the gravimetric principle take in the ambient air for 24 hours at a constant flow rate through a size-selective inlet that only allows the particulate matter of an aerodynamic diameter of 1µm or less to pass through. Collection of the particulate matter is on a pre-weighed filter 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 the known flow rate, sampling period, and the total volume of the air sampled is used to calculate the PM1 concentration.
Beta Attenuation Monitor (BAM)
The air particulate monitoring based on the BAM principle measures the particle mass density using beta radiation attenuation. The particulates in the ambient air drawn into the air particulate 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 get attenuated as a function of the particulate mass. The beta count reduces with an increase in the PM1 mass and is recorded by the detector and converted to concentration.
The air particulate monitor is based on the physical principle of light scattering. It is also known as optical particle counter (OPC), which measures dust particle’s illumination by laser light at a 90° angle. Collection of the light scattered from each particle at approximately 90° by a mirror and detection is by a photo-diode. This signal is then fed into a multi-channel size classifier. Here a pulse height analyzer is used to classify each pulse that is proportional to the particle size. The counts in the channel corresponding to PM1 are converted to the concentration of PM1.
Among all the above principles of air particulate monitoring. PM monitors working on the principle of laser scattering are typically preferable for ambient air monitoring. As they yield quick and accurate measurements and are inexpensive in comparison with the others.
Oizom’s working principle for air particulate monitoring
Oizom’s DUSTROID is an online particulate monitoring system. It 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.
Professionals are using our Real-time particulate monitor DUSTROID across several cities, campuses, and universities. The device is helping in drawing actionable insights to tackle the rise in ambient PM1 concentrations.
In the case of professionals who want to monitor particulate matter 1 in harsh and industrial environments, Oizom offers robust PM1 Monitor AQbot-PM.
5 reasons why air particulate matter 1 (PM1) monitoring is important
- PM1 is a complex mixture of microscopic solids and aerosols. They can easily pass through the nose and throat, penetrate deep into the lungs, and enter the bloodstream reaching other organs of the body.
- The release of particulate matter into the atmosphere is from vehicular exhaust, power plants, combustion processes such as burning fossil fuels, waste, etc. Their formation in the atmosphere is from various chemical reactions of air pollutants such as NOx and SOx.
- When inhaled, it irritates the eyes, nose, throat, and airways. It can penetrate tissues causing severe diseases like heart attacks, lung cancer, edema, etc. leading to premature death. , etc.
- Air particulate monitoring is an efficient way to detect high concentrations of particulate matter and prevent high-level exposures.
- Real-time air particulate monitoring helps in determining the quality of air. As well as formulating an action plan to control high levels of PM pollution.