Air pollution over the last 50 years

This year's World Environment Day on June 5th is focussing on Air Pollution and what can be done globally to reduce air pollution to help combat climate change. 

Air pollution is not a new problem – in fact, experts now know humans have been responsible for an increase in pollutants for at least 2,100 years. By extracting layers of ice which have accumulated in Greenland over many millennia and analysing the methane trapped within them, scientists have been able to link increased levels with activity we know civilisations such as the Ancient Romans and the Han Dynasty in China were undertaking at the time. 

Despite humans being aware of pollution for many decades (and having caused it for many more), our knowledge has grown exponentially over the last 50 years. So too have the efforts to reverse the trend by environmental groups, scientists, Governments and world leaders. Since Filtermist first began producing oil mist filters to help workplaces reduce their emissions in 1969, we have seen huge developments – but there are still regions of the world where pollution levels are increasing far above those acceptable as set down by legislation, and there are still individuals and employers who don’t comprehend the full scale of the problem and the negative impacts of pollutants like oil mist and dust.

Air pollution is defined as a ‘mix of particles and gases that can reach harmful concentrations both inside and outside’ – excess pollution has an impact on the environment (including contributing to rising temperatures across the globe) and humans too: through diseases caused by poor air quality. Hundreds of thousands of deaths each year are attributed to pollutants.

In this guide, we take a look at how emission levels, our knowledge and the regulations have changed in the past 50 years since Filtermist launched – and what could happen in the future if they are not reversed.

Emissions over the years:

There are many different substances which class as air pollution when released into the atmosphere, including carbon monoxide, sulphur dioxide and particulate matter (PM). The latter has been the primary concern of Filtermist since its inception 50 years ago, given this category includes oil mist particles which can be emitted as a by-product of various metal machining processes across multiple industries. PM can be divided into categories depending on the size of each individual particle: PM10 comprises of particles less than 10µm which can enter the lungs when inhaled, while PM2.5 can permeate the gas-exchange regions of the lungs and enter into the blood stream.

Since the 1970s, the majority of countries have seen a decline in exposure to PM2.5, at least partially thanks to stricter regulations. But countries including India, China and Greece have all seen an increase3. In the UK, emissions have dropped significantly from 639,000 tonnes of PM10 and 498,000 tonnes of PM2.5 each year to 169,000 and 106,000 respectively.

In America, fewer than 20 per cent of city residents are exposed to PM10 and PM2.5 levels above the WHO Air Quality Guidelines. In higher-income countries in Europe, more than 60 per cent are exposed to higher levels, rising to more than 90 per cent when we look at lower- and middle-income European countries. However, the situation is worse in the Eastern Mediterranean, Africa, South-East Asia, and lower- and middle-income countries in the Western Pacific where between 95 and 100 per cent of cities are exposed to these above-guideline levels.

It’s not just a minor problem either, some of the cities are exposed to levels between six and ten times what the guidelines advise is acceptable.

Levels have undoubtedly risen over the past 50 years, even when comparing data from a much shorter period (2008 to 2013) there is an eight per cent rise in annual mean concentrations of PM2.5. While high-income regions have seen a decrease, there has been a marked increase in pollution levels in low and medium-income regions.


In the late 60s there was very little in the way of regulation in the UK, until the Health and Safety at Work Act was passed in 1974, followed by the introduction of the Health and Safety Executive. Now employers are required to comply with the Control of Substances Hazardous to Health Regulations 2002, as well as EU IPPC (Integrated Pollution Prevention and Control 2008).

The worldwide Gothenburg Protocol was introduced in 1999, providing comprehensive guidance including control techniques relating to different types of emissions. The National Emissions Ceiling Directive was first introduced in 2001 – under both of these regulations, the UK Government has been working to cut PM2.5 emissions by 30 per cent between 2005 and 2020.

There are various bodies across the world which regulate oil mist and dust emissions as well as other pollutants – these include CARSAT in France (representatives visit companies to raise awareness of air quality and recommend system installations), Germany’s professional association Berufsgenossenschaft (who issue advice and check employers are sticking to emission limits – businesses are required to reduce emissions as far as technology will allow) and the Ministry of Labour and Social Policies in Italy (whose regulations are used as a reference, but are not actually legally enforceable). In the USA, each state sets its own limits, but there are three separate organisations which provide guidance (American Conference of Governmental Industrial Hygienists, Occupational Safety and Health Administration of the US Department of Labour, and the National Institute for Occupational Safety and Health).

Global warming:

Global warming - or climate change - is also not a new phenomenon. Looking at the average temperatures for the 20th century, there was already evidence of it occurring in the early 1940s. But since the 80s, the problem has escalated.

Links have been made between the causes of air pollution and global warming: namely, human activity. Scientists from across the world working as part of the Intergovernmental Panel on Climate Change have been instrumental in researching these links. In 2013 their fifth report stated they were 95 per cent certain human activity (such as industrial emissions) was the cause of the planet getting warmer over the last 50 years.

Disease and morbidity:

The number of people diagnosed with diseases attributable to air pollution has risen dramatically in the last five decades. This is partly due to more understanding about the types of illnesses that can be caused by pollutants, partly because increased medical knowledge leads to better detective rates, but also sadly because of the rise in air pollution in certain regions of the globe.

Conditions affecting the lungs are most closely linked with poor air quality, given the obvious impact of breathing in harmful pollutants. It’s now estimated that more than 65 million people have moderate or severe Chronic Obstructive Pulmonary Disease (COPD) which can be caused by oil mist and dust in the workplace, and other pollutants detected in either indoor or outdoor environments. COPD can also be caused by smoking – although in the US alone it’s estimated up to 20 per cent of those with COPD have never smoked10. Currently, more research is being undertaken to identify other causes such as genetic conditions, as well as exploring the extent of the impact of occupational exposure to pollutants (including oil mist, dust and fume) on the rates of diagnosis.

The number of people diagnosed with COPD globally rose by 44.2 per cent between 1990 and 2015 and experts predict this rate will continue to rise over the next 50 years too, given there is no known cure. In fact, it’s predicted by 2030 the condition will be the third leading cause of death worldwide, outranked only by ischaemic heart disease and strokes.

In previous decades, not enough was known about the links between air pollution and morbidity, but new research takes into account the fact that pollutants cause cardiovascular problems as well as respiratory issues. This means experts now estimate 800,000 deaths are caused by pollutants each year in Europe alone.

The Future:

There has been a wealth of new legislation and guidance introduced in the last 50 years, and experts have amassed extensive further knowledge about the scale of the problem of air pollution. This can only be good news as the more we know, the more everyone is able to work to tackle the issue – from Governments joining together to issue global protocols, to individual business owners fitting oil mist and dust extraction units to their machinery to safeguard their employees’ future health.

And yet as we look forward to the next 50 years, it’s clear much more needs to be done to slow down the amount of pollutants we breathe day in, day out, inside and outdoors.

If we don’t take action, it’s expected 3.6 million people a year will die as a result of PM emissions by 2050. By the end of the century, the world is predicted to be at least four degrees warmer than it was pre-industrialisation – and that trend will only continue if we don’t curb the amount of air pollution humans are producing, and are exposed to.

References available on request.