In early November 2019 the international news featured the people of Delhi struggling with truly awful levels of air pollution. A Minister declared that the conditions were 'unbearable' and India’s highest court accused the government of side-stepping the issue. Meanwhile, 30 flights were diverted away from the city on one day, emergency legislation was brought in to restrict private car usage, schools were closed, construction work stopped, five million masks were handed out and a public health emergency was declared.
This comes about only a month or so after similar conditions were endured by people in large swathes of Indonesia. The cause was different, but the effects were similar. In India, Delhi’s high pollution is a regular event which is usually associated with crop stubble burning, the use of wood and cheap biomass domestic fuel, vehicle traffic and industry. In Indonesia the cause was forest clearance, mainly clearing the rain forest to create huge plantations of oil palms.
Air pollution events like these tend to happen when the direct cause combines with the right weather conditions. This means a dry period of high pressure and low wind speeds, which lead to poor atmospheric 'mixing' so that harmful gases and particulates tend to hang around.
So, is this just a temporary hassle that will clear when the weather changes? And what’s it got to do with the UK? The answers are 'no' and 'a lot' respectively. A 2009 report from the World Health Organisation estimated that 300,000-400,000 people die every year as a direct consequence of air pollution in India alone. Since then, air quality has got steadily worse; it has been reported that half the children in Delhi have abnormalities in their lung functions.
In the UK, poor air quality is a significant risk. It is on the National Risk Register and it is rated 'high'. This might seem odd. In folk memory you’d have to go back to the mid-1950s, and the era of urban smog 'pea-soupers', to find a really telling example. In fact, a 4-day smog in London in 1952 is thought to have killed up to 6,000 people. Since then changes in fuel usage and clean air legislation have made such events a thing of the past. Almost.
If we get weather conditions associated with poor atmospheric mixing it can produce a concentration of ozone at ground level and/or a local build-up of particulates – mostly from traffic pollution. Both are bad for you! They can exacerbate existing health conditions, leading to more illness or death. This can increase pressure on the healthcare system and cause both economic and environmental damage that could last for much longer than the event itself. Conditions are not likely to look like London in the 1950s or Delhi last week, unless we get a large Saharan dust storm or a very big wildfire. Our last Saharan dust storm was in April 2019 and it was relatively mild. This is an example of how our air quality can be temporarily damaged by events taking place elsewhere, and sometimes quite far away – weather being no respecter of national boundaries.
Overall, the potential effects are serious enough to demand emergency planning and a prepared response.
But what’s the evidence? The principal cause for concern is, of course, human welfare. In 2006 we had two spells of heatwave lasting almost a fortnight each. These led to high levels of ozone and airborne particulates. As a result, just under 1200 people died and another 1500 needed hospital treatment. 2015 saw two particle pollution episodes that caused poor air quality across the UK, and two other instances of raised ozone levels. So, it is a risk and it is significant – even in a country like ours with relatively high standards of air quality and relatively low levels of atmospheric pollution.
So, what are we doing about it? This falls into 3 basic categories of preparedness and planning:
- Regulation (to mitigate likelihood)
- Monitoring, warning and informing (to mitigate impact)
- Ensuring access to health advice and services for those at risk (also to mitigate impact)
The government has an air quality plan for tackling urban traffic pollution. It can be seen here.
The Department for Environment, Food and Rural Affairs (DEFRA) manages the national Daily Air Quality Index. This is a very straightforward and useful monitoring tool, which is used in conjunction with expert medical advice when pollution levels are high enough to warrant it. It is supported by a Twitter feed and a telephone helpline (0800 556677). You can use the latter to hear a readout of the air quality index measurement in your area of the UK – which is updated hourly. This is based on measurement of the 5 main pollutants, including harmful gases and particulates.
If you think you or others might be at risk, we suggest you go to the National Risk Register.
Pages 27 and 28 cover this risk. Follow the links to other several government and Met Office sources for a wealth of very accessible advice on how you can keep yourself and others well informed and safe.