Jardin_zoom SF

What is air pollution?

It sounds pretty straightforward… but it’s surprisingly complex!  

We’ve all felt the negative effects of air pollution: whether it’s breathing in that sickly-sweet odor of hot asphalt, a hacking cough as you get out of the subway, or itchy eyes when you stop at a red light. But how polluted can our cities really be? Most of the time, the air looks as clear as that of an alpine mountainside on a crisp winter’s morning.

The truth of urban living is, the air’s often filled with gases and particles that just aren’t welcome. We include six in our app: particulate matter, nitrogen dioxide, ozone, sulphur dioxide, carbon monoxide and volatile organic compounds. Quite the rogues’ gallery!

Even trickier… it changes all the time.

Just like the weather, air pollution is in constant flux. A little gust of wind or a ray of sunshine, a morning traffic jam or an increase in residential heating—that’s all it takes for air quality to turn upside down in a matter of minutes. For better or worse!

That’s why it’s so important to keep a close eye on how it develops. Obviously, not everyone has the time to keep checking pollution levels. Now, thanks to Plume, you can get real-time notifications during a peak!

There are many different varieties of air pollution. Particulate matter, ozone, nitrogen dioxide… For a full list of those covered by the Plume Air Report, see our pollutant FAQ.


Where does pollution come from?

First of all… from us!

Let’s not kid ourselves. Vehicle traffic, energy use, heating, industry, agriculture… none of these things do any wonders for air quality. But human activity isn’t the only factor!

Don’t blame the weatherman…

…but meteorological conditions play an important role!

  • Sun: You already take care to avoid sunburn when the weather is warm, but you should also keep an eye out for ground-level ozone. The production of this pollutant involves a reaction between ground-level exhaust gases and UV rays.
  • The inversion layer: Generally speaking, the atmosphere gets colder as you get higher up. But in some cases, it can be hotter up there! This heat creates a “lid” of warm air in the atmosphere, called an inversion layer. This prevents pollutants from dispersing, meaning they stay trapped closer to the ground.
  • As for the wind, it can scatter pollutants. It’s a fickle friend, sometimes staying calm when we most need it, but as far as air quality is concerned it can also be a vital ally!

How can I avoid air pollution at home?

Air quality is just as important indoors as it is outdoors. We spend 90% of our time inside, and during that time we aren’t necessarily breathing any better. How can you better protect yourself at home? Here’s our advice for keeping a clean air household.

Throw those curtains wide!

  • Ventilate your home on a daily basis: The ideal scenario would be to open all the external windows and doors for 10 to 15 minutes a day—whatever the season—so as to renew fully the air in your home. It’s also a good idea to ventilate after cooking or cleaning the house. Pro tip: Use the Plume Air Report to choose the best moment to ventilate when outdoor air pollution is lowest!
  • Regularly clean the air vents in damp rooms: You’ll probably have one in your bathroom or kitchen. These vents can be super useful for controlling humidity in your home, but let’s be honest, what’s the point of having them if they’re always so filthy?

Show indoor pollution sources no mercy!

  • Mold: Okay, so no one is saying you live in a hut in the woods. But even the cleanest houses can sometimes fall victim to mold. It emits volatile organic compounds (or VOCs) that can cause asthma and allergies, especially in children. One magical remedy: white vinegar and elbow grease! To prevent mold occurring before it even arrives, consider buying a dehumidifier.
  • Household products: These can be crammed with irritating substances such as ink, glue or solvents. Research local environmental standards, and keep an eye out when reading the label! For example, the European ECOLABEL ensures that detergents contain less than 0.01% irritating substances. You can also use “allergy-proof” products try looking for local co-operatives or brands. It’s better to go for multi-use products, to avoid combining multiple irritants. Make sure to store these products in a safe, ventilated area. Avoid sprays. When it doubt, the old remedies are the best ones. Try savon noir or white vinegar instead!
  • Decorating baby’s room before the big day? Paints and other solvents used in painters’ products can emit VOCs. Allow time for them to disperse, and in order to limit their impact, ventilate like there’s no tomorrow! Ideally, undertake renovations in the summer—you’ll be able to ventilate longer. Make sure you still open your windows if it’s winter, as heating can help volatile organic compounds to spread. Don’t forget to close all containers immediately after use to avoid excessive levels of pollutants being released.
  • Don’t smoke. You were hoping we’d forget to mention this one, huh? Never forget that tobacco smoke contains benzene, formaldehyde and particulate matter, all substances classified as carcinogenic and that worsen allergic reactions. Think of the children! If you do, have your cigarettes outside and clean thoroughly any textiles that come in contact with smoke on a regular basis!
  • Be wary of home fragrances (such as incense, deodorisers and scented candles). They smell good, but many fragrances can be allergy-inducing. There are official lists of safe-to-use products, and harmful substances should be mentioned on product labels.
  • Don’t overheat your home: Heat enables gas release, causing VOCs to spread even more widely. You’ll also save money! Heating your home just one degree less causes a 7% drop in consumption. The ideal indoor temperature is between 19°C and 21°C.
  • Close the door between the garage and your house. This prevents particulate matter and nitrogen dioxide produced by your car from entering your home when you start your engine.

“But the damage is done!” I hear you cry

Don’t worry, air pollution can still be driven out!

  • Vacuum carpets and rugs regularly to eliminate mites. Remember to change the bags in your vacuum cleaner and opt for brands with quality filters.


What to do in case of a pollution peak?

I’m outside, am I in mortal danger?

Everybody stay calm! Simply avoid intense physical activities they make you more vulnerable to pollution by increasing the volume of air you breathe and opening your pulmonary alveoli.

Use the Plume Air Report to schedule your activities for when pollution is lowest. Avoid major roads, and try to breathe through your nose—which filters particulate matter better. (Isn’t Mother Nature amazing?) Use your run as an opportunity for a quick stop-off at a park, river or pedestrianized area!

What mode of transport should I take?

Leave your car at home! As well as being bad for the environment, taking your car out during a pollution peak is bad for your health. Research shows that the inside of a car prevents pollutants from dispersing. It’s a real cocktail in there! The damage is much more intense inside your car than outside it, greatly increasing your exposure.

Nevertheless, if you have to drive:

  • Close your windows if you are in heavy traffic. Set up closed-circuit air conditioning in order to recycle and filter the air in your vehicle. If you don’t have AC, it’s also possible to temporarily stop your car’s ventilation system in high pollution areas.
  • Open your windows to clean out air pollution when driving down less congested streets!

Your bike is your best friend! Contrary to popular belief, bikes are the means of transport that least exposes you to air pollution! Ride on cycle lanes whenever you can, breathe through your nose and don’t push yourself too hard. Your lungs (and your thighs!) will thank you! Be careful not to cycle too fast, so as not to get out of breath.