How to pollution-proof your roast dinner

It's one of life's great pleasures: spending a Sunday afternoon preparing a roast dinner with all the trimmings for family and friends.

But this week we learned that preparing a traditional roast dinner with the kitchen windows shut - something most of us do in winter - causes the pollution levels inside our homes to become worse than central London on a congested day. The solution? We should boil our meat to lower indoor pollution levels, according to the researchers.

And you can forget about perfectly crisped roasties too: the researchers who worked on the study found that roasting vegetables to give them that delicious charred effect contributes greatly to indoor pollution levels, with Brussels sprouts in particular being singled out.

It comes after a study from the University of Texas found that even slightly burnt or grilled toast was also harmful.

In May 2018, Dame Sally Davies, the UK’s chief medical officer, estimated that air pollution was responsible for the deaths of around 40,000 people in the UK every year.

Fossil fuel power stations, car exhausts, and even cans of paint or hairspray release millions of microscopic particles into the atmosphere. These particles have been linked to a range of diseases including asthma, heart disease, strokes, lung cancer, and may even harm brain development in children according to a recent study from the University of Wolverhampton.

Traditionally we’ve only thought of air pollution on a grand scale; images of cities like Delhi, Beijing, New York, and London spring to mind. But increasingly, experts are turning their attention to our homes, whether they're in the city or the countryside.

The new research about roasts has found the roasting process releases harmful particulates into the air which are small enough to embed deep into the lungs and even enter the bloodstream.

A turkey roast can release particulates up to 200 micrograms per cubic meter (m/cm). The World Health Organisation suggests a safe limit for these kinds of particulates is 10 m/cm, although central London averages 15.2m/cm. That means after you’ve made a roast dinner, the air in your kitchen is over 13 times more polluted than the centre of London.

“The effects particle matter released indoors are just the same as outdoors, they can impact on the cardiovascular system, respiratory system and over the long term have effects on cancer rates and dementia,” explains Alistair Lewis, a professor of atmospheric chemistry at the University of York.

And once you’ve cooked a meal, those particulates don’t disperse automatically. “Through some of our research with Lancaster University, we have seen that ultra fine particles arising from cooking activities can stay in the homes for a long time, sometimes more than five hours,” adds Douglas Booker, CEO of National Air Quality Testing Services, who’ll soon be unveiling the results of his research project with cleaning brand Tincture on indoor pollutants. “Some of the experiments that our PhD student Charlotte Farr has carried out has shown that ultra fine particles emitted from toasting bread, and cooking bacon and eggs, can reach concentrations more than 100x background levels, and can persist for more than five hours.”

Thankfully though, a “busy city with high particle concentrations is still likely to be more harmful to a person's health” in the long term than cooking a roast dinner once a week in your kitchen, according to Erlend Bolle, chief technology officer at air quality monitoring brand Airthings. However, that’s not to say we shouldn't take note of this latest study.

“We know that inhaling particles, regardless of what they’re made of, is detrimental to health,” said Professor Marina Vance, who led the research at the University of Colorado Boulder. “Is it equally bad as inhaling exhaust from vehicle emissions? That we don’t know that yet.”

So what can you do to pollution-proof your kitchen? Well, the advice from the scientists behind the story is to boil rather than roast your dinner if possible, especially when it comes to vegetables.

When roasting vegetables chefs tend to look for a charring effect which means the the food is being burnt and releasing those particulates. Brussels sprouts are particularly bad for roasting as they tend to blacken much more quickly than other vegetables.

You’ll also want to make sure you’re using the extractor fan while you’re cooking so that the harmful particulates aren’t venting out directly into the air you’re breathing.

Plants are also a great way to improve your home’s air quality, but some are more efficient than other at soaking up air pollution. Areca palms, bamboo palms, rubber plants, dracaena “Janet Craig”, and peace lilies are all plants are known to be particularly good at purifying the air.

Booker advises that, though it is an “unpopular” solution, you should also stop using candles, noting “they are big emitters of ultra fine particles which we cannot see.”

The other great way to clean up your indoor air is to simply open a window. Lewis explains that different kinds of houses will be able to disperse particulate matter at different rates: “A drafty old house might have a value of 1ACH (Air Change per Hour), an energy efficient one maybe 0.1 ACH. If you live in a sealed modern house, with double glazing, small rooms, and have a wood burning stove going, and you're cooking with all your windows shut, then the pollution indoors is likely to be much higher than it will be outside. Within the UK opening the windows will almost always bring in cleaner air, with the exception of people who live right by very busy junctions or roads.

“It’s not that cooking has suddenly become bad for people’s health, but that over time our homes have become very air tight, and this means that what we release inside struggles to get flushed out.

“These actions may seem trivial,” admits Booker. “But given that we spend 90 per cent of our time indoors, repeating these actions over a lifetime will substantially reduce your exposure to pollution.”

So open a window, invest in a houseplant and boil those veggies once in a while; your lungs may thank you for it one day.

Are you concerned about pollution levels in your kitchen? Will you be boiling your veggies for your next roast dinner?  

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