This household appliance can help with symptoms of allergies, asthma, colds and flu ... or it can make them even worse.
They created over a third of all the particle pollution in London in 2016.
47 UK towns and cities have broken the WHO's annual limit on air pollution.
7 million people every year are dying from exposure to outdoor and indoor air pollution.
'Imagine if more people left the car at home every day.'
'People are continuing to suffer unnecessarily.'
It's set to cost £20 billion a year.
Cleaning products, paints, perfumes could be causing as much air pollution as cars.
'It would inexcusable not to take the strongest action now.'
MPs will decide whether Michael Gove's strategy goes far enough.