UPSC Express

Fine Particles, Particulate Matter 2.5:

• Fine particulate matter (PM2.5) is an air pollutant that is a concern for people’s health when levels in air are high.
• PM2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated.
• Outdoor PM2.5 levels are most likely to be elevated on days with little or no wind or air mixing.

What is Particulate Matter 2.5 (PM2.5)?

• The term fine particles, or particulate matter 2.5 (PM2.5), refers to tiny particles or droplets in the air that are two and one half microns or less in width.
• Outdoor air levels of fine particles increase during periods of stagnant air (very little wind and air mixing), when the particles are not carried away by wind, or when winds bring polluted air into the state from sources outside the state. In general, as the levels of PM2.5 in outdoor air increase, the air appears hazy and visibility is reduced.

Where does PM2.5 come from?

• There are outdoor and indoor sources of fine particles.
• Outside, fine particles primarily come from car, truck, bus and off-road vehicle (e.g., construction equipment, snowmobile, locomotive) exhausts, other operations that involve the burning of fuels such as wood, heating oil or coal and natural sources such as forest and grass fires. Fine particles also form from the reaction of gases or droplets in the atmosphere from sources such as power plants. As fine particles can be carried long distances from their source, events such as wildfires or volcanic eruptions can raise fine particle concentrations hundreds of miles from the event.
• Some indoor sources of fine particles are tobacco smoke, cooking (e.g., frying, sautéing, and broiling), burning candles or oil lamps, and operating fireplaces and fuel-burning space heaters (e.g., kerosene heaters).

How can PM2.5 affect health?

• Particles in the PM2.5 size range are able to travel deeply into the respiratory tract, reaching the lungs.
• 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.
• Studies also suggest that long term exposure to fine particulate matter may be associated with increased rates of chronic bronchitis, asthma, reduced lung function and increased mortality from lung cancer and heart disease.
• People with breathing and heart problems, children and the elderly may be particularly sensitive to PM2.5.
• Chronic exposure to high pollution is associated with an increased risk of miscarriage and early labor in pregnant women and low birth weight.