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Updated: Aug 26, 2022

What is PM 2.5 ?

The term fine particles, or particulate matter 2.5 (PM 2.5), refers to tiny particles or droplets in the air with a diameter of 2.5 μm in size. PM 2.5 is smaller, travels farther, and stays in the air for days and weeks longer. The recommended range of PM2.5 by WHO is 5 μg/m3 for the annual mean and 15 μg/m3 for 24-hour mean. PM 2.5 levels in the air ranged from 11 to 30 μg/m3.

Where does PM 2.5 originate ?

The burning of coal, oil, gasoline, transformation of NOx, SO2 as well as tobacco smoke, cooking (frying and sautéing), and natural gas stoves are the main sources of indoor PM 2.5. The ambient PM 2.5 are comes from power plant emissions, forest fires, and vehicle exhaust. Diesel engine NOx emissions are significant because they can create chemical reactions in the environment that result in the creation of PM2.5 and ozone. The majority of significant outdoor diesel emissions are produced by ships, trains, and trucks that operate in and nearby ports, rail yards, and busy roads.

What happens if we breathe in PM 2.5 ?

PM 2.5 has the ability to penetrate the deepest (alveolar) parts of the lung and reach the circulation, directly harming a number of organ tissues.

  • Short-term health impacts of exposure to tiny particles include breathing difficulties, coughing, sneezing, runny noses, and eye, nose, throat, and lung discomfort.

  • The effects of exposure to PM 2.5 on children include poor IQ in primary school kids, an increased risk of autism, delays in psychomotor development, increased anxiety and depressive.

  • For every 10 μg/m3 of PM2.5, there is a 6–13% increase in the risk of cardiopulmonary mortality over the long term.

  • Inhaling PM 2.5 can also cause early mortality (estimated to reduce the life expectancy of the population by about 8.6 months on average), svere chronic heart and lung conditions, including asthma, elevated respiratory symptoms, and impaired lung function in children.

  • Numerous studies indicate that being exposed to Diesel Particulate Matter may potentially stimulate the development of new allergies. The elderly, who frequently have chronic health issues, as well as children whose lungs are still maturing, are those who are most susceptible to non-cancer health impacts.

  • Smoking is a well-known primary source of indoor PM2.5, increasing the concentration in homes with smokers by 25 to 45 μg/m3, with the concentration being higher in the winter than the summer. Symptoms of inhaling PM2.5 include dyspnea, chest pain and discomfort, coughing, and wheezing.

  • Children have a very high chance of developing respiratory problems like asthma, and impaired lung function if they are exposed to excessive PM2.5 levels (65 μg/m3 for 24 hours).

  • People who are exposed to PM2.5 are more likely to develop neurological illnesses such dementia, Alzheimer's disease, autism spectrum disorders, and Parkinson's disease. High levels of particulate matter (PM2.5) impaired glucose homeostasis and energy metabolism while causing an increase in inflammation in insulin-responsive organs.

  • According to a study based on a survey of Boston residents, exposure to PM2.5, which has an average concentration of 15.5 μg/m3, causes a reduction in heart rate variability and transmission of nerve impulses.


The main type of air pollution that is harmful to both people and the environment is called particulate matter. Because smaller particles can easily enter the bloodstream through alveoli, their effects are greater than those of bigger particles. Particles between 1 and 5 μm are deposited in the alveoli, and those between 5 and 10 μm are most likely deposited in the trachea bronchial tree. These particles may even infiltrate the lung and interfere with gas exchange there. Respiratory illnesses, cardiovascular ailments, and neurological issues can all be brought on by low level exposure to more than 10 μg/m3.







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