Should You Go outside for Fresh Air? Chromatography Investigates

Most people have at some time or other been told by their mum. 

‘You can’t stay cooped up in here all day. Go outside for some fresh air’.

But with the newspaper headlines regularly shouting out about smog and other incidents of air pollution, we might have considered our mum crazy to suggest such a thing. Air quality in our town and cities is continually monitored and the information is used to inform the public about potentially harmful incidents.

But what about our houses. Most people spend a significant amount of their time inside their houses — so the air quality is also important. A recent study has looked at comparing indoor and outdoor air pollution in houses in Edmonton, Canada, and it turns out that mum might just have been right.

Capturing and measuring the air

The team captured indoor and outdoor air samples over seven 24 hour periods in both summer and winter from the homes involved. The houses monitored were all smoke free and the occupant’s daily activities were also noted to help the researchers to model the data better.

Gas chromatography in tandem with mass spectrometry (GC-MS) was used to analyse the samples for volatile organic compounds, VOCs. GC-MS is a key technique in analysing volatiles in a variety of samples matrices, and differences in sample preparation can lead to better results as discussed in the article, Trace Level VOC Analysis in Different Sample Matrices.

Is mum right?

The research, published in the journal Building and Environment, found over 190 different VOCs — with the researchers focussing on those that have been detected before rather than looking for new VOCs. The total amount of indoor VOCs detected during the winter was twice as large as those detected during the summer months with 1698 and 915 µg m^-3 respectively — this was probably as a result of better ventilation during the summer months.

There was little seasonal variation in the outdoor readings, with both summer and winter being approximately 90 µg m^-3 — showing the indoor VOCs to be significantly higher than the outdoor readings all year round.

Where do they come from?

A model was applied to the data to find out where the VOCs came from, with the following findings:

• 70% of indoor VOCs came from indoor sources
• Household products (44%) and combustion processes (10.5%) contributed most to the indoor VOCs, followed by environmental tobacco smoke and deodorizers.
• The major outdoor VOCs come from industrial and traffic emissions.

The data can be used to help form legislation on air quality and to decide what pollution abatement measures are needed — to improve the air both indoors and out.

Did you ever doubt your mum’s advice? Take a nice walk at lunchtime and fill your lungs with some fresh air.