Pollutionwatch: December 2007

Conditions in December divided the month into three distinct periods. The first and last 10 days of the month saw wet, windy and generally unpleasant conditions holding sway over most of the country. The rain and strong winds keeping air pollution well dispersed with the only problems being in Port Talbot in Wales and Marylebone Road in London. On the 11th however, a strong anticyclone developed over the UK and by the following day this had grown to form a huge ridge of high pressure stretching from the north of Scandinavia, right down through France and Spain into northern Africa. This system remained dominant over Europe for the next 10 days. It led to clear skies and light winds that brought cold air down from the Arctic. At night temperatures across the UK were dropping as low as minus10 degrees. These conditions led to a classic winter pollution episode. Cold air close to the ground kept pollution trapped in, and with little or no wind, pollution concentrations rose rapidly over most of the country - particularly in towns and close to roads. The worst day was the 12th, when particle concentrations at 13 monitoring sites across the country broke the air quality standards, and Camden saw concentrations rise into the 'High' band. Concentrations then reduced slightly (although still remaining significantly elevated) before peaking a second time between the 19th and 21st. From the 22nd onwards a new series of weather systems began moving in from the Atlantic again bringing wet and windy, but clean conditions to the country until the end of the month.

Pollutionwatch: November 2007

November is traditionally the worst month in the UK for particle pollution due to smoke from fireworks and bonfires. However, winter conditions also led to repeated pollution episodes throughout the month. The effects of pollution from Guy Fawkes' night is heavily influenced by two main factors. Firstly, weather conditions determine if the pollution is dispersed by the wind or washed out by the rain. Secondly, if the 5th of November is on or close to a weekend, the majority of firework events will happen around the same time - greatly increasing the concentrations of pollution being put into the air. If, however, it lies in the middle of the week, events are spread across the week, and the two weekends either side, greatly reducing the pollution load at any one time. This year the 5th was on the Monday, and high pressure brought cold, calm conditions which led to huge peaks in pollution on the Saturday, Sunday and Monday nights. On the Sunday night, the air quality standard for particles was broken at 32 out of the 55 particle monitoring stations in the UK monitoring network, with 5 sites recording 'high' concentrations and 4 recording 'very high' levels. The worst affected places were in the middle of the UK, in Manchester, Leicester, Stoke and Nottingham. Following a spell of unsettled weather, another area of high pressure passed across the UK leading to spells of 'high' pollution in both London and Scotland between the 14th and the 20th. Then to round the month off, Marylebone Road in London saw 'moderate' levels of particles on the 27th and Port Talbot in Wales had 'high' levels on the 30th.

Pollutionwatch: October 2007

October saw yet another month of relatively clean air over the UK. However, particle concentrations broke the air quality standard in London throughout most of the month on the Marylebone Road, and occasionally in Camden. Scotland also saw frost and fog bringing raised pollution levels between the 21st and 23rd. Last month saw the beginning of a major restructuring of the UK's national pollution monitoring networks. Widespread monitoring of air pollution in the UK began in 1961 with the measurement of black smoke and sulphur dioxide to study the problems caused by widespread domestic and industrial coal burning in Britain's cities that used to lead to the classic winter smogs. Gradually, the number of both the monitoring stations and the pollutants measured increased. Differences also emerged between networks of monitors in cities for monitoring pollutants that originating from small chimneys and vehicles, and those in rural areas analysing regional pollutants (like acid rain).

Developments in both science and policy have since changed where and how we need to measure air pollution. Successes in cleaning up the UK's air have meant that we no longer need to monitor some pollutants as much as we used to. These include carbon monoxide, which has been significantly reduced through the use of catalytic converters on motor vehicles, and sulphur dioxide, reduced by removing sulphur from petrol, diesel and other fuel oils and by stopping coal burning in many urban areas through the introduction of smoke free zones. By cutting back monitoring of these pollutants, limited resources can then be used to improve the ways in which we measure the pollutants which are currently of most concern, such as particles.

Pollutionwatch: April 2007

With the above average sunshine and exceptionally warm weather throughout much of April, it was little surprise to find that the summer smog season has started. On the 27th the government issued its first summer smog warning of the year for the final weekend of the month. Despite the warning, the predicted 'high' concentrations of ozone failed to materialise. 'Moderate' levels were reported from over a dozen monitoring stations on the 28th, 29th and 30th, however, this was a small handful compared to the 40+ stations reporting moderate concentrations earlier in the month on the 1st, 2nd, 15th and 21st (when no warning was given). This demonstrates one of the main difficulties in forecasting air pollution levels - particularly when the purpose is both to provide health warnings and to encourage people to avoid or reduce polluting activities, such as driving, having bonfires or barbeques, or using solvent based paints and varnishes. When a warning is issued in the approach to a predicted episode, if the predicted high concentrations fail to materialise it is impossible to tell whether there was a problem in the forecast, or if sufficient people heeded the advice and reduced polluting emissions sufficiently to avoid the problem. In addition to the ozone problems there was also a minor particle episode between the 12th and the 16th. Concentrations rose across most of the UK, and up to seven sites broke the air quality standards on each day. The increase in regional levels meant that concentrations were pushed into the 'high' band near to the steelworks in Port Talbot where moderate concentrations are frequently recorded.

Pollutionwatch: August 2007

Some days last month almost felt like summer! In some parts of the UK at least. However, the good weather never lasted long enough to let either heat or pollution to build up. This meant that for most of the UK it was the coldest August in ten years, and there were only 3 days with any significant pollution. The main patch of good weather came right at the start of the month, although even this was patchy in many places, particularly the northwest of England, Wales, Scotland and Northern Ireland. High pressure over central Europe meant that the south of England got reasonably consistent fine weather, with sunshine and light breezes from the continent leading to build ups of ozone in the afternoons on the 1st, 5th and 11th.

Whilst the UK suffered from somewhat uninspiring weather, at times it seemed like we were the only ones not to be baking, burning and choking in the sun. The Mediterranean was particularly badly hit with widespread problems with smoke pollution in addition to the more immediately hazardous fires. Apart from the widely reported fires in Greece, Algeria and Sicily also suffered from widespread fires and smoke as well as many places in South America, particularly the Amazon; Montana, Idaho and Southern California in the US; and also in Eastern China.

Back in the UK, although we rarely suffer from wild fires, even smoke from bonfires should have been rare this summer. New waste management legislation was passed last year making it illegal to dispose of domestic waste "in a manner likely to cause pollution of the environment or harm to human health", and thus effectively outlawing most bonfires.

Pollutionwatch: July 2007

The Met Office's use of the term 'generally unsettled' hardly begins to describe the desperately wet and windy conditions that kept air pollution to a minimum throughout July. This was in total contrast to last July when 3 separate smog warnings had to be issued. Last month saw the launch of the latest update to the UK's Air Quality Strategy. The document outlines future policies for the UK governments to follow to further improve air quality. Despite great improvements being made in air quality since the 1950s, air pollution is still estimated to reduce the average UK lifespan by 7-8 months. Ten years after the original Strategy, the new version provides a good staging post to evaluate the air quality management programme in the UK. However, it appears to offer little in the way of anything new to tackle the problems that have led to almost half of UK local authorities declaring Air Quality Management Areas. It relies very much on providing incentives for the uptake of new, cleaner technologies. But whilst evidence suggests that these policies have been very cost effective in the past, it may be that many of the easy gains from this approach have already been made. There are some new directions put forward in the Strategy. These include: setting out a new approach aimed at reducing overall pollution levels in urban areas rather than localised hotspots where concentrations are highest; clearly indicating the links that must be made between managing air pollution and climate change (especially with the use of bio-fuels); and emphasising the importance of air pollution impacts on eco-systems as well as on human health. The new AQS can be downloaded from http://www.defra.gov.uk

Pollutionwatch: June 2007

Despite June appearing to have been a dreadful month throughout, the first week or so had sufficient good weather for the UK to experience significant ozone episodes (where 10 or more monitoring stations reported 'moderate' concentrations of the pollutant) right up until the 12th. Thereafter, conditions became so dull, wet and blustery that only the very occasional pollution problem was recorded. Whilst the UK suffered from record rain levels (albeit with higher than average temperatures), much of southern Europe was suffering from a record heatwave. Pollution levels soared in the eastern Mediterranean under the hot sunny conditions due to the formation of secondary pollutants like ozone by chemical reactions in the atmosphere. Conditions were made worse as forest fires broke out in Italy, Greece and Turkey and a number of Saharan dust events where winds brought particles up from northern Africa. If, as most scientists now believe, these sorts of extreme conditions will be more frequent due to climate change, last months weather shows the extent to which we will have to change our lifestyles not just to reduce emissions of greenhouse gases, but also to adapt to the new weather patterns. This adaptation needs to be undertaken carefully in order to ensure that we don't just protect ourselves from the new climate but also build in sustainable measures - for example cooling our urban areas by passive measures such as shading and natural ventilation, rather than simply increasing the availability of energy hungry air-conditioning. Some measures such as increasing the amount of green space will allow us to protect ourselves from both increased heat and rainfall.

Pollutionwatch: May 2008

April’s hot sunny weather held out for the first few days of May, leading to moderate ozone concentrations being recorded up to the 5th as far afield as southeast England, Lerwick in the Shetlands and Lough Navar in Northern Ireland. As far as air pollution was concerned, the rest of the month was literally a washout with large amounts of wet and windy weather ensuring lots of clean air just about everywhere. This year marks the 10th anniversary of the UK’s National Air Quality Strategy. Although it has not yet managed to help us achieve clean air for the entire population, we have managed to develop a comprehensive system for identifying air quality problems and beginning to draw up plans for tackling them. A team from the University of the West of England in Bristol, is currently working with South Africa in order to use this established skill base to help manage air pollution there. Current industrial air pollution control policies in South Africa are over 30 years old. Combined with problems resulting from the apartheid era planning system this has resulted in many people being directly exposed to extremely high pollution. In the townships and settlements, poverty means that coal is frequently used for heating and cooking. This combines with modern pollutants from the rapidly increasing use of both cars and trucks. The key to success in tackling these problems will be the ability to accurately detect which sources are contributing most pollution in any particular location so that the limited resources of what is still a developing country can be most efficiently targeted at protecting the health of its citizens.

Pollutionwatch: February 2007

The first week of February saw an area of high pressure bringing still, cold and clear conditions over much of the UK. Over this week, particle concentrations built up in many locations across the country. On the 3rd and 4th, a dozen monitoring sites in London, the midlands and Northern Ireland recorded moderate concentration of particles. Over the next two days, concentrations dropped slightly before shooting up on the morning of the 7th and remaining elevated for the rest of the day before dropping sharply in the early hours of the morning on the 8th. This sudden and short-lived episode on the 7th was most evident at roadside locations in London (including 3 sites where the ‘high pollution’ threshold was breached). However, Glasgow also recorded ‘high’ concentrations and many other towns measured peaks in the ‘moderate pollution’ band. The fact that it was mainly roadside locations showing this sudden increase suggests that rather than being directly caused by weather conditions, as most pollution episodes are, this was a secondary effect - the particles being measured were largely a result of councils gritting the roads in anticipation of the snow that had been forecast. This grit gets ground down and thrown into the air by the action of passing cars. Under normal conditions it is estimated that roughly 50% of particle pollution associated with vehicles is related to resuspended dust from road surfaces, so the deliberate gritting of roads makes a significant additional impact. In the early hours of the next morning the snow arrived, washing the dust out of the air and trapping it to the ground, before eventually melting and washing much of it away down the drains.

Pollutionwatch: January 2007

January was mainly wet and windy across the UK, with little in the way of pollution. Aside from an unseasonal ozone episode in Edinburgh on the 14th, the only notable pollution came in the last week of the month when the weather calmed down and high pressure brought comparatively dry and still air to England. These conditions allowed particle levels to rise over London, with air quality standards being exceeded at a number of roadside monitoring stations. Last month saw the release of the government's air quality indicator for sustainable development. The figures are provisional until around April, by which time all the data from the 100+ monitoring stations will have been fully checked, or ratified. However, the early indication is that last year was one of the most polluted years in the last decade - and is comparable to, or even worse than, 2003 when the protracted summer heatwave led many to consider it as 'extreme' in terms of pollution levels. Although 2006 saw fewer days when concentrations of ozone or particles breached standards (when pollution is classed as moderate, high or very high), over the whole year concentrations of particles at roadside sites were the highest since 1997 and ozone levels at urban background locations were the highest on record (since 1992). Much of this was associated with the hot weather in June and July. Current predictions for climate change indicate that although the weather in the UK is likely to generally get windier, when these summer heatwaves do occur they will be stronger and more persistent leading to both more polluted days and higher peak concentrations of pollutants.

Pollutionwatch: December 2006

Wet and windy weather kept pollution levels low across most of the UK last month. Only a handful of pollution problems were reported on the national monitoring network. Nitrogen dioxide problems occurred at Marylebone Road, London on the 5th and 6th, and unusually in Sheffield city centre on the 28th. Particle problems were more widespread, with targets being exceeded in Bury, Leamington Spa, Port Talbot, Redcar, Sheffield, Stoke and Wigan. The worst of these was in Leamington Spa on the 6th when particle concentrations reached 'High'. 2007 marks the tenth anniversary of the UK's Local Air Quality Management program. This is the process under which all local authorities in the UK have to undertake regular assessments of air quality in their areas and judge whether or not they will meet specified national targets for a range of basic pollutants. If it is considered 'likely' that these targets will be exceeded, councils must designate an Air Quality Management Area (AQMA) and set out a plan to attempt to achieve the objectives. Initially it was thought that less than a dozen AQMAs would need to be declared across the country. However the increased analysis of air pollution undertaken, along with greater understanding of where air pollution problems occur, has meant that by the end of last year around 200 out 433 local authorities have now declared AQMAs (mainly for nitrogen dioxide and particles). Whilst the process has not yet achieved many significant reductions in air pollution, it has greatly increased our knowledge of how great the problems are, and awareness is the first step that must be reached before solutions can be found.