Research finds Irish homes see a spike in indoor air pollution at night

Today, Dyson unveils the results of its first Global Connected Air Quality Data project. The project analyses indoor air quality information collected by 2.5m Dyson purifiers from 2022 to 2023 to measure air quality in real homes across the world, to a high degree of granularity, breaking down pollution into gas and particle pollutants, and profiling trends over days, months, seasons and the full year. The data comes from Dyson purifiers connected to the MyDyson app; the volume of data exceeds half a trillion data points and paints a precise picture of indoor air quality in cities and countries globally to help build understanding and awareness of indoor air pollution.

From a wealth of data, this project focuses on two types of pollutant – PM2.5, and Volatile Organic Compounds (VOCs).

PM2.5 refers to particles as small as 2.5 microns in diameter, 1/25th the diameter of a typical human hair. These particles are invisible to the naked eye, can be inhaled and are an area of increasing scientific and health research. Sources include combustion, wood burners, or gas cooking and heating – pet dander, ash and dust.

VOCs are gas pollutants including Benzene and Formaldehyde which can be emitted from activities like cleaning or gas cooking as well as from products including deodorants and body sprays, candles, furniture and furnishings.

“Our connected air quality data allows us insight into the real problem of indoor air pollution in homes across the world. This gives us a direct understanding of the challenges Dyson purifiers face in real environments and the knowledge to engineer ever-better machines to tackle those challenges. But the data we capture isn’t just an engineering tool – on an individual basis, this data is shared back through the MyDyson app in real-time and via monthly reports, to help our owners improve their air quality understanding.” – Matt Jennings, Engineering Director for Environmental Care.

“We all think of air pollution as being an outdoor or roadside problem. Indoor air pollution research is growing but continues to be underdeveloped. Dyson's findings give us a valuable insight into the real pollution levels in homes across the world, helping us to understand the patterns of pollution daily, monthly, and seasonally. The Dyson data is an incredibly powerful education tool and the opportunities for positive impact are boundless – understanding the pollution around us is the first step to reducing our pollution exposure.” – Professor Hugh Montgomery, Chair of Intensive Care Medicine at University College London, and Chairperson of Dyson’s Scientific Advisory Board. 

Nearly all homes experienced indoor air quality worse than outdoor with Ireland peaking in December and March but Dublin city specifically peaked in January and March.

All but four of the countries studied exceeded outdoor PM2.5 levels for six months or more. In February, most countries experienced the largest gap between indoor PM2.5 as compared to outdoor, where indoor exceeded outdoor levels by the highest proportion compared to all other months. All but four countries studied exceeded outdoor PM2.5

Ireland ranked 28th globally for indoor/outdoor ratio of PM2.5 levels with China, Austria, and Spain at the top.

Dublin City showed nearly double who guideline PM2.5 levels

The city of Dublin had slightly higher levels of PM2.5 than the rest of the country with the average being 9.81 µg/m3 PM2.5, which was still below the global average. However, this measurement still exceeded the WHO long term exposure guidelines of what is deemed safe long term PM2.5 levels. In fact, Dublin came out as having nearly double the amount of what WHO guidelines for PM2.5 levels are. In Dublin city in January 20022, 12.54 µg/m3 PM2.5 levels were documented, which is 2.5 times over what the WHO guidelines suggest.

December and March saw the highest spike of PM2.5 levels in homes in Dublin.

Dyson air purifier data showed that winter across all countries was the most polluted season indoors overall. Given that 90% of our time is spent indoors, the results showed PM2.5 peaked throughout the colder months with January being the most polluted month globally.

Evening pollution was higher than any other time of day in most countries, including Ireland, with spikes between 7pm and 11pm recorded on Irish Air Purifiers. This stat coincides with the time of day that many people spend in their homes.

Exposure is the measure of air pollution concentration over time, which within the air quality research community is a key consideration – a spike of air pollution (a very high level for a short period of time) is not necessarily worse than prolonged exposure to ‘poor’ or even ‘fair’ air quality. Therefore, data from Dyson purifiers suggests that this longer, more polluted period may account for increased exposure to PM2.5 in homes.

Dyson Purifier Hot+Cool™ HP09 Formaldehyde cools & purifies

Volatile Organic Compound (VOCs) levels in Ireland

European cities also top the rankings of VOC levels indoors: Munich takes top spot, followed by Beijing, and then its fellow German cities – Cologne in 3rd and Berlin 4th.

Dublin and Madrid are particularly high – occupying spaces 11 and 12, both higher than Shenzhen, Busan, Tokyo, Manila, Hong Kong SAR and other larger EMEA cities like Paris, London and Amsterdam.

Dublin, Paris and Milan rank above megacities like Tokyo and Seoul, and above all US cities as well as London.

VOCs annual average: Europe claims top rankings

In contrast to PM2.5, it is European countries that experienced the highest annual VOC levels according to Dyson Purifiers. Austria tops the list, followed by Romania, Germany, Switzerland, Poland and Turkey. Italy appears in 8th and Ireland in 10th. Many countries that ranked highly for average annual PM2.5 do not rank highly for VOCs: Thailand, UAE, Malaysia and South Korea do not appear in the top half of countries by annual VOCs. In fact, the US, France, Spain and Denmark all rank higher.

Similarly, European cities also experienced high levels of VOCs indoors compared to other regions. Munich is the highest ranked city, followed by Beijing, Cologne, Berlin and Vienna. Only Beijing is in the top five cities for both annual PM2.5 and VOCs, whilst Delhi, Istanbul, Shanghai and Mexico City feature in the top ten for average level of both types of pollutant.

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