Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air. PM can include a mixture of dust, pollen, soot, smoke, and liquid droplets according to the United States Environmental Protection Agency (EPA).
Why do we care about these small particles in the atmosphere? Depending on the size of PM, it can be harmful to human health. PM with a diameter of more than 10 microns are the larger particles of PM. These include particles like dust, pollen mold, etc. These are the least harmful because these particles are inhalable. Particles that are less than 10 microns in diameter pose a greater threat to human health says the EPA. Fine particles, or particles that are less than 2.5 microns in diameter are the most harmful to human health. These particles include combustion particles, organic compounds, and various metals. According to the NYS Department of Health, these fine particles can come from vehicle exhausts, burning of fossil fuels such as wood, heating oil or coal, and natural sources such as forest and grass fires. Another source are reactions of gases or droplets in the atmosphere from power plants.
Fine particles with a diameter of less than 2.5 microns can be traveled at further distances by the wind than larger particles. This is because these particles are lighter and are carried easier by the wind.
In general, we can try to forecast where PM particles are going based on winds. The trade winds and the westerly jet streams spread PM particles around the globe. An image created by NOAA shows all the different types of particles being spread at a specific time below. In the image, the orange represents dust particles, blue represents sea spray particles, white represents smoke or pollutants, and green represents smoke being released from the burning of natural things such as trees.
It is also important to know how harmful fine particles can affect human health. The NYS Department of Health states that “exposure to fine particles can cause short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath. Exposure to fine particles can also affect lung function and worsen medical conditions such as asthma and heart disease.”
It is important to keep track of PM in our atmosphere. No need to worry, not all PM is harmful and there are air quality regulations set by the EPA. This ensures that there is only a certain amount of PM allowed to be released into the air by human activities (such as the burning of fossil fuels) to keep the environment safe for us.
Credit: (United States Environmental Protection Agency (EPA), NYS Department of Health, NOAA)
©2019 Weather Forecaster Brittany Connelly