The 101 of indoor air pollution

Cooler nights mean closed windows and that delicious snug feeling in bed. But less fresh air means more indoor air pollution. So what is it and should we be worried?

Jack Hunter has the answers and solutions.

We spend a lot of time indoors; up to 90% by one estimate. Yet the air inside can be two to five times more polluted than outside, according to a U.S. government study. One in six Europeans live in homes that make them sick, with air pollution partly to blame, according to European health groups.

Moisture, mould and microbes in our homes and workplaces take their toll on air quality, as do problem particles blowing in or created inside. Most indoor air pollution though is chemical.

Hundreds of more and less volatile chemical compounds buzz their way out of cleaning products, air fresheners and even furniture, paint, wallpaper, carpets and construction materials and potentially into us.

That ‘clean home’ or ‘new product’ smell some of us know and love is probably harmful, as is using incense sticks, scented candles or other so-called ‘air fresheners’.

How harmful is hard to say, because very little is known about exposure to chemical components from consumer products via indoor air, and information on carcinogenic, mutagenic and reproductive health threats from long-term exposure is not available for many of the chemicals.

Chemical cocktails

On top of this, when chemicals combine accidentally, their toxicity can multiply, the so-called ‘chemical cocktail’ effect. Understanding combined risk is complex, so usually it isn’t studied. Also, man-made nanoparticles – also called ‘ultrafine particles’ – are increasingly used in consumer products, though their impact as indoor air pollutants is still largely unknown.

But scientists do know enough to say indoor air pollutants can cause serious respiratory disorders, including asthma and cancer, and enough to name carbon monoxide, formaldehyde, benzene, nitrogen oxides and naphthalene as the worst, based on high risk that these substances will cause known adverse health effects as indoor pollutants.

Tobacco smoke, radon, lead and pesticides are also a concern, according to scientific advice for the European Commission. The work of these scientists and academics informs much of this article.

Tell-tale signs of bad air are irritated eyes and upper airways, though low air moisture may be the cause. Many different factors influence indoor air quality, such as ventilation, cleaning conditions, properties of buildings, products used in house-holds, cultural habits, climate and outdoor air. So much so, in fact, that there is greater variation of indoor air quality within a single city than between cities spanning the very north and south of Europe. 

It’s not just breathing

And breathing is not the end of the story. Phthalates from PVC flooring and surfaces, pesticides from insect strips and other chemical nasties, including flame retardants, PAHs, chlorophenols, organotins and metals can all adsorb to house dust.

This acts as a sink for toxic substances that can then float into the air or stick to surfaces, including toys, and be inhaled or eaten. This explains why babies, toddlers and pets, who dwell closer to the ground, get over 90% of their external chemical hit from dust, compared to about 14% for adults.

Babies and toddlers get most pesticides contamination this way, with serious enough neuro-developmental effects to worry scientists.

As so often in Europe, Nordic countries lead the work against chemical threats to our health and environment. A while ago, Danish authorities recreated a typical home to test 11 harmful chemical compounds contributing to air pollution from everyday consumer products placed in three test areas: a children’s room, a kitchen/family room and a utility room/hallway.

They found that 33 out of 45 different product groups emitted the chemicals, with incense, spray paint, printed matter and electronic equipment the most polluting.

‘Typical’ pollutant levels were in most cases deemed to be “acceptable”, while worst case exposures for some of the compounds exceeded accepted limits. The most problematic area was the children’s room.

Consumer products may contribute on average 10-20% of total chemicals in different indoor environments, roughly similar to that blowing in from outdoor sources. Cleaning products are another source. Most contain hazards like triclosan, suspected of interfering with our hormones; nanosilver, linked to neurological disorders; or give off formaldehyde, suspected of causing cancer, allergies and asthma. Allergenic substances, fragrances and preservatives that are harmful for health and the environment may also be in the mix but not often written on the packet. 

Concern is growing

Little surprise perhaps that 8 out of 10 Europeans say they are concerned about chemicals in everyday products in 2017, up from 43 percent in 2014.

The EU appears to be responding. Incoming Commission head Ursula von der Leyen has a zero pollution goal, covering chemicals and boosting sustainable products. The Commission has already targeted formaldehyde, one of the most commonly used volatile chemical ingredients found in products and a major indoor air pollutant. Formaldehyde release will be limited in consumer goods as soon as 2022, with only case by case exceptions.

Simple solutions

While we wait for regulation to play catch up, simple actions can already make a difference.

Avoiding exposure is the best cure. Frequent vacuum cleaning will help lock away toxic dust. But not all vacuum cleaners are born equal, so use a good one to avoid adding dust to the air. Open windows for around 10 minutes a few times a day and whenever you use paint, varnish, glues or other stuff with a lot of highly volatile chemical solvents.

Ideally, indoor humidity should be kept at between 40-60% and temperature 18-22°C to ward off moisture and dust mites.

Avoiding toxic problems is not always easy, but a French consumer association recently ranked cleaning products by toxicity. Or try using homemade cleaners with less aggressive natural ingredients.

Ecolabel offers protection

EU Ecolabel products are a safe bet, being certified to contain less harmful chemicals than most rival products on the market.

The EU Ecolabel covers furniture, bed mattress, paints, cleaning products, floor coverings and textiles usually ban or set strict limits on formaldehyde, for example.

Other labels help us avoid toxic construction materials. The ToxFox app lets German shoppers scan a wide range of products for the most harmful chemicals, and the Scan4Chem app will soon do the same in many other languages.

In general, new stuff gives off more chemicals than older stuff, so, like-for-like, second hand is better for indoor air. Babies are particularly vulnerable and specific parental advice is available in French here.