The article refers to data collected and analysed independently during lockdown from around the world by two organisations that produce air quality monitors and air purifiers.

Two companies: Airthings, a Norway-based manufacturer of smart air-quality monitors used data from Europe and the USA. Dyson, who produce air purifiers including those for houses, analyzed data from four different continents.

Although the information is evidence-based and the result of two separate projects, the data were collected and analysed by commercial companies who could benefit financially from increased concern about air pollution at home. Because the findings have not been published in a peer-reviewed scientific journal, their reliability is reduced. However, there is other evidence that indoor air pollution has risen during the pandemic, including an estimate by King’s College London that particulate pollution in UK homes may be up to 20% higher because people are cooking more to replace meals eaten out.

Further research and more widely spread data, together with peer reviewed methodology and analysis techniques would be needed to establish more reliable evidence-based results. If the increase in pollutants is confirmed, there is plenty of existing evidence that high levels of indoor pollutants such as VOCs, particulate matter and NO2 have a negative impact on our health, especially that of children.

The analyzed data were collected in Scandinavia, the United States and from up to four other (unknown) continents.

The first study’s monitors collected data from more than 1,000 homes in Europe and an unspecified number of houses in ten US States. The air purifier data was from 11 cities on four continents which are not named.