1. What is PM1 or Ultra Fine Particulate Matter (UFPM)? 

PM stands for particulate matter (also known as particle pollution), a mixture of solid particles and liquid droplets prevalent in the air. Dust, dirt, soot, and smoke are examples of large particles that can be seen with the naked eye. For air quality regulatory purposes, these atmospheric particles are defined by their diameter.

PM1, or ultra-fine particulate matter with a diameter of 1 micron or less, is an often overlooked yet critical component when discussing air pollution. These ultra-fine particles are so small and are more than 400 times thinner than a human hair (too small to be detectable by the human eye). They can easily penetrate deep into the lungs and even enter the bloodstream. Particulate matter is one of six criteria air pollutants for which there are national air quality standards to limit their levels in the outdoor air.

At first glance, particulate matter might seem pretty simple to grasp. It’s just dust and tiny particles floating around in the air, right? There’s no need to dig out those old high school chemistry books for this one! But the reality is, particulate matter is a lot more complex than it appears. Its environmental and health impacts are significant, and it’s something we should all be paying closer attention to. 

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.

So, what exactly is particulate matter (PM1)? Where does it come from? This article covers information on PM1, its sources in the ambient air, health and environmental impact, possible corrective measures, the need for PM1 monitors, and different methods of PM1 monitoring.

2. Sources

When we think about air pollution, we usually picture factories and power plants as the main sources. While they do contribute to particulate matter, there are plenty of other sources out there, too. In fact, particulate matter can come from both primary sources, like emissions, or secondary sources, where particles form through chemical reactions in the air.

Particulate matter PM1 is either directly emitted from a source (primary PM) or is formed through the chemical reactions of gases such as oxides of sulfur (SOx), nitrogen oxides (NOx), organic compounds, etc. 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

Secondary PM1 is generally formed 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. 

Did you know this? When vehicle tires rub against road surfaces, the tires and the road wear down (Järlskog et al., 2022). This wear-and-tear process releases tiny particles into the air (Harrison et al., 2021; Järlskog et al., 2022).

3. Health & Environmental Impact of PM1

 

Health Impact

Particulate matter consists of microscopic solids or liquid droplets that are small enough to be inhaled and cause major health issues. Some particles smaller than 10 micrometers in diameter can penetrate deep into your lungs and even enter your bloodstream. Particles with a diameter of less than 2.5 micrometers, often known as fine particles or PM2.5 or PM1, offer the greatest health danger.

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 O2 and CO2 are exchanged). Some PM1 particles pass through the alveoli cell membranes, enter the bloodstream, and can reach other 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. 

Were you aware of this? A 2021 Harvard study found that air pollution from burning fossil fuels caused 10.2 million extra deaths worldwide in 2012. The study also estimates that in 2018, 350,000 premature deaths in the U.S. were linked to fossil fuel pollution.

When inhaled for short periods, PM1 irritates the eyes, nose, throat, and upper respiratory tracts, coughing, sneezing, and shortness of breath. 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 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. 

 

Environmental impact

Particulate matter has been found in numerous scientific studies to reduce visibility while also negatively impacting climate, ecosystems, and materials. PM, primarily PM2.5, affects visibility by altering the way light is absorbed and scattered in the atmosphere. 

Regarding climate change, certain components of the ambient PM mixture promote global warming (e.g., black carbon). In contrast, others have a cooling effect (e.g., nitrate and sulfate), resulting in ambient PM having both warming and cooling capabilities. 

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. 

 

4. Possible corrective measures 

The primary step is air particulate monitoring to identify the areas with high particulate levels. You can utilize air quality alerts to protect yourself and others when PM reaches hazardous levels. In addition to this, the following corrective measures can be taken: 

• Look at your local AQI readings.
• Limit outdoor activities and close windows and vents during times of high air pollution.
• Skip the morning exercise if AQI exceeds its limit.
• Wear a pollution mask.
• Eliminate the use of the fireplace, wood stove, gas-powered lawn, or garden equipment.  
• Invest in an air quality monitoring system.
• Eat nutritious: Eating an apple won’t fight pollution, but antioxidant-rich foods like berries, nuts, greens, and fish oils can help combat oxidative stress from PM2.5 inhalation, reducing its impact on our bodies.
• Avoid areas with traffic congestion, construction activities, or unpaved roads. Breathing such polluted air daily also leads to health effects in the long run. 

6. 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 particulate matter with an aerodynamic diameter of 1µm 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 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, which is recorded by the detector and converted to concentration.

Laser Scattering – The air particulate 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 PM1 are converted to the concentration of PM1.

[Source: https://www.researchgate.net/figure/Principle-of-optical-particle-counter]

7. Oizom’s sensor working principle for air particulate monitoring

At Oizom, we offer various Particulate Matter (PM) sensors, including PM1, PM2.5, PM10, and PM100, designed for accurate air quality monitoring across various particle sizes.

Our Particulate Matter sensor module is engineered to accurately measure PM1, PM2.5, PM10, and PM100 concentrations in ambient air, providing real-time data on atmospheric particulate matter levels. The sensor’s advanced support electronics ensure compactness and reliability, making it a robust solution for continuous air quality monitoring.

These sensors work on laser scattering technology with a heated inlet to eliminate moisture and ensure accurate air quality data. The integration of a heavy-duty fan and advanced lasers guarantees precise data and durability, making these sensors ideal for outdoor applications requiring real-time air quality insights.

These advanced particulate matter sensor modules are utilized in our outdoor air quality monitoring systems, such as Polludrone and AQBot. Additionally, these modules are a key component in our specialized ambient dust monitor Dustroid. These versatile sensors are used in a variety of applications, including national air quality monitoring, environmental health impact assessments, construction site monitoring, mining, smart cities, and air quality research projects. By providing real-time particle concentration data, Oizom’s PM sensor modules support a wide array of environmental monitoring needs, ensuring accurate and reliable air quality data for diverse applications.

Our particulate monitoring sensors are calibrated with reference stations, housing Beta Attenuation Monitor, BAM-1020, which significantly enhances the data accuracy and reliability of our sensors, ensuring high-quality air quality monitoring results.

8. Why Choose Oizom PM Sensor?

1. Compact: Our sensors are small and easy to install, perfect for use in any space, making them ideal for portable air quality monitoring. The PM1 sensors come pre-calibrated and can be quickly replaced in just a few minutes by removing and replacing the old sensor with a new one.
2. Durable: The PM sensor has an expected lifespan of 18 months.
3. The dust measurement by the laser scattering principle overestimates the PM concentration levels in condensing high humidity conditions. The data accuracy in such conditions is maintained by dehumidification of the air sample using a heated inlet. 
4. It reduces the relative humidity of the air sample by 30-40%, eliminating its interference in the particulate measurement.
5. PM sensors work on laser-based scattering principles and Advanced algorithms. 

9. Reasons why air particulate monitoring is important:

• PM1 is a complex mixture of microscopic solids and aerosols that can easily pass through the nose and throat, penetrate deep into the lungs, and enter the bloodstream, reaching other body organs. 
• Particulate matter is emitted into the atmosphere from vehicular exhaust, power plants, and combustion processes such as the burning of fossil fuels, waste, etc. They are also formed in the atmosphere by various chemical reactions of other air pollutants such as NOx and SOx. 
• When inhaled, it irritates the eyes, nose, throat, and airways and can penetrate tissues, causing severe diseases like heart attacks, lung cancer, edema, etc., leading to premature death. , etc.  
• Ultra-fine particulate matter monitoring is an efficient way to detect high particulate matter concentrations and prevent high-level exposures.

• Real-time monitoring of PM1 helps determine the air quality index and formulate an action plan to control high levels of PM pollution. 

FAQs

1. What is PM1?

PM1 refers to ultra-fine particulate matter with a diameter of 1 micrometer or less, making it the smallest type of particulate pollution.

2.Why is PM1 concerning for health?

PM1 particles can enter the bloodstream through the lungs, potentially causing cardiovascular and respiratory diseases and even affecting other organs.

3. How is PM1 different from PM2.5 and PM10?

PM1 is much smaller than PM2.5 and PM10, allowing it to penetrate deeper into the body, posing higher health risks.

4. How can PM1 be monitored?

PM1 can be measured using advanced real-time air quality monitoring devices that detect ultra-fine particles.

5. What are the primary sources of PM1?

PM1 is mainly produced by combustion processes such as vehicle emissions, industrial activities, and burning fuels like wood or coal.