• Which Pollutants Are the Worst for Human Health?

Air Monitoring

Which Pollutants Are the Worst for Human Health?

May 25 2022

The last two centuries have seen remarkable progress for the human race. Advances in science and technology have made the world a truly connected place, while urbanisation has accelerated our progress even more quickly. However, the downsides of a ballooning population and increased industrial activity include greater emissions of harmful gases, including a number of pollutants toxic to human health.

For that reason, governments around the world have implemented Air Quality Indexes – better known as AQIs – in order to monitor and document levels of pollution within their territory. This has allowed for a greater understanding of concentrations of specific contaminants, as well as their attendant effects on public health. Armed with that information, we can now say which pollutants are of the greatest cause for concern. Three of the most dangerous ones are listed below.

Particulate matter

Also known as particle pollution, or sometimes simply abbreviated to PM, particulate matter is a catch-all term used to refer to a wide variety of contaminants that are suspended in the air. These include dust, pollens, nitrates, sulphates, soil, metals or organic chemicals, among others, and are dangerous precisely because they are so small.

PM10 have a diameter of 10 microns or less and can be easily inhaled into the lungs, while PM2.5 are a quarter of that size – roughly equivalent to 30 times thinner than a human hair – and can even infiltrate the bloodstream. Once there, they can wreak potentially harmful effects on the internal organs, including causing or exacerbating cardiovascular and respiratory conditions.


When most people hear the word ‘ozone’, they instinctively think of the protective layer in our stratospheric which protects us from the UV radiation of the sun. However, there is another type of ozone which exists in the troposphere (at ground level) that is a dangerous contaminant in its own right.

Thanks to the new perspective in emissions monitoring given to us by modern scientific methods, we now know that ozone is not emitted into the atmosphere, but rather formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) come into contact with direct sunlight. A principal component of smog, ground-level ozone most commonly occurs in the summer and can cause throat irritations and coughs, as well as triggering asthma attacks in sufferers of the disease.

Carbon monoxide

You may well have heard of carbon monoxide as the silent killer. That’s because the gas is colourless, odourless and does not produce any notable symptoms in the human body – until, of course, it’s too late. Exposure to high levels of carbon monoxide over even a relatively short period of time can be deadly in a space that is not well ventilated. It’s for this reason that UK legislation requires all homes to be fitted with a carbon monoxide detector.

In outdoor conditions, however, carbon monoxide is rarely (if ever) found in large enough concentrations to precipitate death, but it can still pose a health risk. What’s more, it’s also adept at trapping the heat from the sun, thus contributing to global warming and climate change.

If you’d like to learn more about these and other contaminants – and the ways in which we monitor and control them – the upcoming Air Quality and Emissions (AQE) Show will answer any questions you might have. Scheduled to take place in Telford in the UK in October, the event is open to all and interested parties are invited to visit the link above to find out more.

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International Environmental Technology 32.3 - May/June 2022

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