Harrow’s sophisticated air purification system

As the air quality deteriorates in the colder months, we all worry about the pollution levels. At Harrow we take the air quality very seriously and understand that this is a crucial concern for parents. As a new school we were able to ensure this was fully considered at the design stage. Our air filtration system is built into the air-conditioning/heating system and they work in synchronisation. The filters are custom-made and are changed regularly.

The filtration system  involves four grades of filters, the final one designed specifically to remove any PM2.5 particles. As it is incorporated into the air-conditioning/heating system, it is a feature of all the classrooms, laboratories, workshops, house rooms and sports and general areas, including the cafeteria and entrance lobby. The air quality, both within the school and immediately outside it, is monitored by a series of sensors, supplied by a specialist European company, which produce a reading not just for the general AQI, but also for the levels of the PM2.5 particles. This means we can implement our codes green (safe), amber (monitoring closely) and red (everybody inside) procedures based on the two readings.

Unless the doors are being opened a lot, we can guarantee the indoor AQI level to be below 40, even on bad pollution days, and it is often below 20. For instance, last week the outdoor readings were 180, our red alert level, which is lower than most other international schools. There was a loudspeaker announcement informing everyone that all outdoor activities were suspended. This happens every time the AQI hits red alert level. While the air quality headed over 180 outside, our 14 indoor monitors averaged between 34 and 38 throughout the afternoon.

We will shortly be starting to post the daily AQI readings for both inside and outside the school on our website. We want to assure our parents that we are doing all we can to minimize the effects of bad pollution days.