When speaking about pollution people mostly speak of particulate matter (PM). This makes sense because it’s the main contributing factor to outdoor pollution, but there are many more factors that contribute to indoor air pollution. The ones that are the most hurtfull to our human system are VOCs, extensive Co2 and Mold and Mildew. 

In the context of indoor air pollution particulate matter stems from outside of the home. It creeps in to our homes through cracks in buildings, poorly filtered ventilation systems or simply when we open our windows. PM primarily stems from cars, trucks, buses and every operation that involves the burning of fuels such as wood, heating oil, coil and natural sources such as forests or when farmers in Thailand burn their rice straws. 

Particulate matter has different sizes and we mainly organize it in the categories of PM10 and PM2.5. PM10 is the larger one and it’s generally 10 micrometers in size whilst PM2.5 is 2.5 micrometers in size. To put these sizes in perspective, the average hair size of a human is 70 micrometers, so both PM sizes are completely invisible to the human eye. 

The dangers of these particles is just this. They are tiny enough to travel deeply into our respiratory system and reach our lungs. On their way down there they cause short term effects like irritation in the nose, throat and eyes, as well as shortness of breath and coughing. Multiple studies also show PM possibly leads to asthma, lung cancer and heart disease. 

So! How do we solve this problem and lower the PM levels of our homes? 

If we live in a extremely polluted area like Bangkok or London, the absolut first thing we need to do is to close the windows since this will stop the majority PM intake. But the second this is done there’s immediately no ventilation at all. This simply means that there is no fresh air coming into the building and that the used air is not leaving the building. This will therefore now lead to a number of other indoor pollutants to grow inside of the building, such as extensive Co2, mold and VOCs. It’s because of this of highest priority that some kind of ventilation system is installed. You can read about the ventilation systems that’s generally best here.