Here’s why you might be swallowing more air pollution than your next door neighbour

Too much of this, probably. Image: Getty.

Each year, tens of thousands of people in the UK die early due to air pollution, which is linked to asthma, heart disease and lung cancer. The health risk presented by air pollution depends on how much dirty air we breathe over time.

Pollution levels in UK cities regularly exceed the limits set by the World Health Organisation. But people’s exposure to pollution can vary greatly between people living on the same street, or even the same house.

Currently, health authorities estimate exposure to air pollution based on outdoor pollution at a person’s home address. But we don’t just sit outside our front doors all day – we each follow our personal daily schedules. The environment at home, in transit and at work or school all affect our exposure to pollution. Knowing this can help governments to create more effective policies and provide better advice to the public on how to reduce their exposure.

By equipping volunteers with portable pollution sensors, scientists have shown that exposure to air pollution during the day can vary substantially. For example, commuting during peak hour can account for a significant proportion of the pollution we’re exposed to – even though commuting only takes up a small part of our day.

By contrast, being indoors is often associated with lower exposure to pollution, because buildings provide some protection against outdoor pollutants. But gas cookers, wood burners and household cleaning products can also create high levels of indoor pollution.

How habits influence exposure

With all these different sources and levels of pollution around us, our daily activities and habits have a big influence on how much polluted air we breathe. Even couples who live together can have different exposures: a person who stays at home may experience up to 30 per cent less pollution than their partner who commutes to work.

A 24-hour measurement of a person’s pollution exposure, which varies throughout the day. Image: McCreddin et al./creative commons.

Small changes in our daily routines can significantly reduce our exposure to air pollution. In a study in London, participants were able to decrease their exposure during commuting by 25 per cent to 90 per cent by choosing alternative routes or modes of transport. Active commuters who walk or cycle are usually less exposed to pollution than people travelling by car or bus – this might be because vehicles travel in a queue, so air pollution from the vehicle directly in front gets drawn in through ventilation systems and trapped inside. The air is also much cleaner on overground trains than on the underground.

Displaying public information about pollution hot spots and ways to avoid them can help. The Wellbeing Walk is a signposted backstreet walking route taking ten to 15 minutes between London’s Euston and King’s Cross stations, which exposes walkers to 50 per cent less pollution than the main road. Since its launch in 2015, the number of people taking the healthier path has tripled. There need to be many more initiatives like this in cities.

Modelling human movements

Being able to tell when and where people are most exposed to pollution makes it possible to compare the benefits of different solutions. That’s why scientists have created computer models to simulate different scenarios. By combining information on outdoor pollution, pollution on transport and people’s travel routes, these models help us understand how people’s movements contribute to their personal exposure.

Computer exposure models for cities, including London, Leicester and Hong Kong among others, are beginning to give us a better picture of how people are exposed to harmful pollution. But the answers they provide are often complicated.

For example, the model for London suggests that on average citizens are exposed to less pollution than previously estimated. But many individuals still experience extremely high pollution during long periods on transport – so a lengthy commute by car, bus or underground could mean you’re among the most affected.

What’s more, the model does not yet account for pollution created indoors through cooking or wood burning. Including these additional sources of pollution may well shake up the results.


More data, please

The UK’s clean air strategy aims to halve the number of people exposed to particulate pollution above World Health Organisation guidelines by 2025. But surprisingly little is known about pollution levels inside our homes, schools and workplaces. If the strategy is to meet its goal, the government will need more data and better methods to estimate people’s exposure to air pollution.

Any model needs to be confirmed using actual measurements, to ensure we can trust what the model predicts about our exposure. Although the technology is advancing, portable pollution sensors are still bulky and heavy. Recruiting volunteers to carry these sensors wherever they go can be difficult. Phone-integrated sensors could make this easier in the future, but their reliability is still debated among scientists.

The ConversationImproving outdoor air quality is currently a top priority in cities across Europe – and rightly so. But measurements and computer models are indicating that our exposure to pollution is much more varied and complex than currently estimated. We should build on this knowledge to develop measures that deliver the greatest reduction in human exposure and empower citizens to make healthier choices in their daily routines.

Johanna Buechler, Air Quality Policy Researcher at Department for Environment, Food and Rural Affairs and Research Associate, UCL.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

When should you forget the bus and just walk?

Might as well talk, tbh. Image: Getty.

It can often be tempting to jump on a bus for a short journey through the city, especially when it’s raining or you’re running behind schedule. Where there are dedicated bus lanes in place, it can feel as though you speed past gridlocked traffic. But as city authorities begin new initiatives to get people walking or cycling, that could all change – and so could you.

British people are wasting tens of hours in traffic every year: London comes top, with the average commuter spending 74 hours in traffic, followed by Manchester, with 39 hours and Birmingham and Lincoln, both with 36 hours.

It might surprise some people to learn that cities are intentionally slowing down private vehicles, in order to shift people to other, more efficient, modes of transport. In fact, Transport for London removed 30 per cent of the road capacity for private vehicles in central London between 1996 and 2010. That trend continues today, as the organisation gives over more space for buses, cyclists and pedestrians.

London’s road capacity, over time. Image: Transport for London/author provided.

Clamp down on cars

The loss of road capacity for cars has occurred across most UK cities, but not on the same scale everywhere. The good news is that the changes, when made, appear to have reduced actual car congestion. It seems that by making it less attractive to use your car, you’ll be more likely to use other transport. In fact, the average speed of buses and cyclists can be up to twice as fast as normal traffic in cities such as London.

The relationship between walking and improved health has been proven to such an extent that it seems everyone – your doctor, your family, regional and national government – wants to increase physical activity. The savings in health care costs, are via improved fitness, reduced pollution and improved mental health, and its impact on social care are huge.

For instance, Greater Manchester wants to increase the number of people who get the recommended level of exercise (only about half currently do). The most advanced of these plans is London’s, which has the specific goal of increasing the number of walks people take by a million per day.

So, the reality is that over the next few years, walking will gradually appear more and more “normal” as we are purposefully nudged towards abandoning our rather unhealthy, sedentary lifestyles.


The long journey

Consider this: the typical bus journey in the UK is almost three miles, with an average journey time of around 23 minutes. The equivalent walk would take approximately 52 minutes, travelling at just over three miles per hour. It seems obvious that the bus is much faster – but there’s much more to consider.

People normally walk at least a quarter of a mile to and from the bus stop – that’s roughly ten minutes. Then, they have to wait for a bus (let’s say five minutes), account for the risk of delay (another five minutes) and recover from the other unpleasant aspects of bus travel, such as overcrowding.

This means that our 23 minute bus journey actually takes 43 minutes of our time; not that much less than the 52 minutes it would have taken to walk. When you think of the journey in this holistic way, it means you should probably walk if the journey is less than 2.2 miles. You might even choose to walk further, depending on how much value you place on your health, well-being and longevity – and of course how much you dislike the more unpleasant aspects of bus travel.

The real toss up between walking and getting the bus is not really about how long it takes. It’s about how we change the behaviour and perceptions we have been conditioned to hold throughout our lives; how we, as individuals, engage with the real impacts that our travel decisions have on our longevity and health. As recent converts to walking, we recommend that you give it a go for a month, and see how it changes your outlook.

The Conversation

Marcus Mayers, Visiting Research Fellow, University of Huddersfield and David Bamford, Professor of Operations Management, University of Huddersfield.

This article is republished from The Conversation under a Creative Commons license. Read the original article.