The air quality inside nursing homes can have a serious effect on the lung health of residents, a new study has found.

Researchers collected data on five indoor air pollutants in 50 different nursing homes across seven European countries, including France, Denmark and Poland.

The pollutants - formaldehyde, NO2, O3, PM10 and PMO.1 - came from a range of sources including cleaning products, disinfectants, furniture, heaters and building materials.

The researchers also carried out tests on 600 residents of these nursing homes, including lung function tests. The average age of the residents was 82 years.

The study found that residents who were exposed to high levels of NO2 and PM10 were much more likely to be affected by coughing and breathlessness. Those exposed to high levels of PMO.1 were more likely to be affected by wheezing, while high levels of formaldehyde were associated with COPD (chronic obstructive pulmonary disease).

The researchers noted that these links were found even if concentrations of indoor air pollutants were deemed moderate and did not exceed current international guidelines.

The problems appeared to be worse in nursing homes with poor ventilation and in residents who were over the age of 80.

The researchers pointed out that as people get older, their bodies become more susceptible to the risks of air pollution. They said that since people are living longer nowadays, more people are living in nursing homes and residents can be exposed to higher levels of indoor air pollution due to their reduced mobility/activity.

"Our findings have shown an independent effect of several indoor air pollutants on the lung health of the elderly living in nursing homes. This is a worrying problem since the body's ability to cope with harmful air pollutants decreases as we age.

"Nursing homes should do more to prevent indoor air pollution by limiting its sources and by improving ventilation in their buildings. The respiratory health of residents should also be checked on a regular basis," commented the study's lead author, Dr Isabella Annesi-Maesano.

The researchers called for more investigations to be carried out in nursing homes in different countries.

Details of these findings are published in the European Respiratory Journal.