What is 'Suspended Particulate Matter'?

Suspended Particulate Matter is used to refer to all the solid and liquid particles suspended in air, many of which are hazardous. This complex mixture includes both organic and inorganic particles, such as dust, pollen, soot, smoke, and liquid droplets. These particles vary greatly in size, composition, and origin. But the smallest ones are the ones which cause the most harm to our health.Based on size, particulate matter is often divided into two main groups:

  • The coarse fraction contains the larger particles with a size ranging from 2.5 to 10 µm (PM10 - PM2.5).

  • The fine fraction contains the smaller ones with a size up to 2.5 µm (PM2.5). The particles in the fine fraction which are smaller than 0.1 µm are called ultrafine particles.

Growing number of studies in toxicology, epidemiology and other related fields have demonstrated that respirable particles are closely related to the incidence of human diseases and mortality rate. The “Harvard Six Cities Study”, published in 1996, revealed that PM2.5 was one of the causative factors of human non-accidental death.

Differences in size show just how small PM 2.5 and PM 10 are. This allows them to travel farther into the human body. PC: EPA, U.S.

Differences in size show just how small PM 2.5 and PM 10 are. This allows them to travel farther into the human body. PC: EPA, U.S.

People most at risk from particle pollution exposure include those with heart or lung disease (including asthma and chronic obstructive pulmonary disease-COPD), older adults, and children. Research indicates that pregnant women, newborns, and people with certain health conditions, such as obesity or diabetes, also may be more susceptible to PM-related effects. PM2.5(particles less than 2.5 micrometers in diameter) can penetrate deeply into the lung, irritate and corrode the alveolar wall, and consequently impair lung function.

Why are children more at risk? Children are more likely to be exposed to air pollution, because they often spend more time outdoors engaged in activity and play, and they breathe more air per pound of body weight than adults. They are more susceptible to the effects of air pollution, because their airways are still developing. In addition, children are more likely than adults to have asthma, which increases their risk.

Even if you are healthy, you may experience temporary symptoms such as irritation of the eyes, nose, and throat; coughing; phlegm; chest tightness; and shortness of breath. These symptoms should go away when air quality improves.

If you have lung disease – including asthma and COPD – you may not be able to breathe as deeply or as vigorously as normal, and you may experience coughing, chest discomfort, wheezing, shortness of breath, and unusual fatigue.

How will I know when conditions are better?

Air quality conditions can change rapidly. Check BreeZo for the most recent hourly air quality conditions. This information can help you determine when to take steps to reduce your exposure.

One helpful suggestion is to keep a lookout for emission sources like trash fires, solid fuel burning and industrial pollution. Other pollution sources include smoke from bushfires, windblown dust, and biogenic emissions from vegetation (pollen and mould spores).

Also pay attention to weather forecasts; these can help you plan your activities for times when air quality improves, such as when winds are forecast that clear the air. When the air clears, and AQI readings are low, take advantage of these times to get outdoors.