Of the various forms of air pollution, Particulate Matter is the deadliest as they can penetrate deep into the lungs and thoracic chambers. Let us see what this particulate matter is and why it is a matter of great concern.

There are different types of particulate matter

  • Suspended Particulate Matter (SPM)
  • Thoracic and Respirable Particles
  • Inhalable Coarse Particles (diameter between 2.5 micrometres to 10 micrometres – PM 10)
  • Fine Particles (diameter 2.5 micrometres or less – PM 2.5)
  • Ultrafine Particles
  • Soot

Sources of Particulate Matter

Natural causes of particulate matter constitute volcanic dust, dust storms, sea spray, forest fires, and living vegetation and so on.

Another source of particulate matter is human activities like industrial pollution, vehicular exhausts, power plants, tobacco smoke, and release of volatile organic compounds like air-conditioner and refrigeration exhausts, insect sprays, and cooking.

The size of the particulate matter rather than the chemical composition is the crucial factor here. The size determines where the particulate matter comes to rest in the respiratory tract. The cilia and the mucus in the nose and the thoracic region can filter out the SPM and thoracic Respirable particles.

The dangerous ones are the PM 10 and PM 2.5 that can penetrate the bronchi and the lungs thereby causing health problems.

The PM 2.5 can penetrate into the gas exchange region of the lungs. Thus, it can cause problems like respiratory infections, asthma, and even heart disease.

How big are the PM 2.5 and PM 10?

Micrometre or micron is a unit of measurement for distance. PM 2.5 constitutes particulate matter of size 2.5 microns or less.

Similarly, PM 10 refers to the particulate matter of size 10 microns and less. The width of a strand of human hair is around 100 microns. It will give you an idea of the size of PM 2.5 and PM 10.

Health problems when you inhale PM 2.5 and PM 10

Traffic Jam in Delhi

Particles that have a size greater than 10 microns do not reach the respiratory tract as the cilia and mucus can trap them. The dangerous ones are the smallers.

Inhaling such particulate matter can cause various health problems like asthma, lung cancer, premature delivery, low birth weight, congenital disabilities, cardiovascular diseases, and respiratory diseases.

There have been instances of DNA mutation, heart diseases, and early death because these ultrafine particles can penetrate the lungs and bloodstream unfiltered.

Particulate matter can also affect vegetation as these particles can clog the pores and interfere with photosynthesis. It can lead to stunted growth and mortality in plants.

Air quality standard for PM 2.5 in outdoor air

PM 2.5 and PM 10 affect every country in the world. Hence, each country has set its limits for particulates in the air. The following table (courtesy Wikipedia) will make matters clear.

CountryPM 10PM 2.5
Yearly averageDaily averageYearly averageDaily average
AustraliaNone50 microns/m38 microns/m325 microns/m3
China70 microns/m3150 microns/m335 microns/m375 microns/m3
European Union40 microns/m350 microns/m325 microns/m3None
Hong Kong50 microns/m3100 microns/m335 microns/m375 microns/m3
JapanNone100 microns/m315 microns/m335 microns/m3
South Korea50 microns/m3100 microns/m315 microns/m335 microns/m3
Taiwan65 microns/m3125 microns/m315 microns/m335 microns/m3
USANone150 microns/m312 microns/m335 microns/m3

What are the factors that affect PM 2.5 levels?

A rural stove

Climatic factors affect PM 2.5 levels. Wind can change the levels considerably. They can both carry the particles away and bring them in as well.

When there is a higher concentration of PM 2.5 in the outdoor air, the air appears hazy with reduced visibility levels. You experience similar conditions during fog or high humidity. The concentration of PM 2.5 is more during the winter season because the air becomes heavy.

Similarly, our indoor activities determine the levels of PM 2.5 inside the house. Lighting of oil lamps, candles, and cooking activities like frying or sautéing can increase PM 2.5 levels. Similarly, use of insect sprays, aerosol sprays, and air conditioners can also increase the levels.

What is the solution?

The best solution is to install an air purifier in the house. You get air purifiers of sound quality in the market. Choose the one most appropriate to your requirement and ensure that your family gets healthy air to breathe.

Sources: Wikipedia, npi.gov.au, Health.ny

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