PM₂.₅ refers to fine particles with a diameter of 2.5 micrometres or smaller. Due to their small size, these particles can remain suspended in the air for long periods and travel over large distances, making them a key indicator of air pollution, particularly in outdoor environments.
PM₂.₅ particles are primarily produced by combustion processes, including vehicle emissions, residential heating, industrial activities, and biomass burning. Indoors, they can originate from sources such as cooking, heating, candles, and smoking, or infiltrate from outdoor air.
Because of their size, PM₂.₅ particles can penetrate deep into the lungs and even enter the bloodstream. This makes them particularly harmful to human health compared to larger particles.
Short-term exposure to elevated PM₂.₅ levels can cause irritation of the respiratory system, trigger asthma attacks, and increase hospital admissions related to heart and lung conditions. Long-term exposure is associated with more serious health risks, including an increased risk of premature death, especially in individuals with existing cardiovascular or respiratory diseases. It may also negatively affect lung development in children.
According to the World Health Organization (WHO), the recommended exposure limits for PM₂.₅ are:
• Short-term (24-hour average): below 15 µg/m³
• Long-term (annual average): below 5 µg/m³
Maintaining PM₂.₅ levels within these limits is critical, as both short-term exposure peaks and long-term elevated concentrations can significantly impact health.
PM₂.₅ consists of fine particles with a diameter of 2.5 micrometres or smaller. These particles are mainly produced by combustion processes, including vehicle emissions, residential heating, industrial activities, and biomass burning.
PM₂.₅ is a key indicator of air pollution in outdoor environments due to its ability to remain suspended in the air for longer periods and travel over large distances. Because of their small size, these particles can penetrate deep into the lungs and are associated with a wide range of health risks.