Researchers make surprising discovery about the air we breathe inside our homes: 'Increasingly important'

New research reveals that the air inside your home could contain more pollutants than the air outside, even when outdoor air quality is good, as relayed by Phys.org.

What's happening?

Scientists at the University of Birmingham used low-cost sensors over a two-week period to measure particulate matter in three different homes. They discovered that the pollution levels inside each house were higher and more variable than the outdoor levels.

One home exceeded the World Health Organization's 24-hour limit for PM2.5 (particulate matter with a diameter of less than 2.5 micrometers) on nine days during the study period.

"Our study shows the need to monitor indoor air pollution, as people can have unhealthy air at home even if outdoor air is good. PM levels varied significantly between homes, indicating that monitoring just one location isn't enough," said co-author Catrin Rathbone.

Why is indoor air pollution concerning?

With more people spending time at home, understanding the air quality inside our houses has become increasingly critical for our health.

The researchers identified five factors contributing to indoor particulate matter — two related to indoor activities, such as increased movement by residents, and three linked to external factors, such as nearby restaurant kitchen vents.

"With more time spent working from home, understanding the factors that affect air quality within households is increasingly important. The methods we used accurately modeled indoor PM levels, helping to improve exposure estimates at a low cost," commented co-author Owain Rose.

They found that larger particles (PM10) tend to settle faster than smaller particles (PM1 and PM2.5), which can remain suspended in the air longer and potentially cause more harm when inhaled.

The health impacts of harmful indoor air quality include respiratory issues, allergies, and more serious long-term health problems. Since most people spend about 90% of their time indoors, the air we breathe at home directly affects our daily well-being.

What's being done about indoor air pollution?

Researchers are developing accessible ways for people to monitor and improve their indoor air quality. The study team used Non-negative Matrix Factorization to model indoor pollution levels using affordable sensors.

Do you worry about the quality of the air inside your home? Yes — often 😬 Yes — but only sometimes 😕 Only when it's bad outside 😮‍💨 No — I never do 😌 Click your choice to see results and speak your mind.

"Our approach is easily scaled due to its low cost and would allow air quality management in homes across Britain and beyond. This could lead to more accurate pollution exposure models and better-informed public health policies," explained Francis Pope, a co-author and University of Birmingham professor.

For everyday homeowners, several practical steps can help reduce indoor air pollution.

Improving ventilation by opening windows when outdoor air quality is good, using air purifiers with HEPA filters, and reducing sources of indoor pollutants, such as gas stoves, can make a difference.

Regular cleaning to reduce dust accumulation and avoiding household products that release volatile organic compounds can also create a healthier home environment for you and your family.

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