Keeping the air that we breathe clean

The negative impacts of air pollution, particularly global warming, are constantly being discussed, with carbon dioxide frequently in the spotlight as a greenhouse gas of concern. However, it is by no means the only culprit; short-lived climate pollutants (SLCPs) – such as methane, black carbon, tropospheric ozone and hydrofluorocarbons – are responsible for up to 45 per cent of global warming,1 but these are not the only emissions of concern.

Noxious gases, airborne particulate matter and volatile organic compounds (VOCs) also have a devastating impact on human health. Pollutants entering the lungs and bloodstream can cause a host of illnesses, including strokes, chronic respiratory diseases, lung cancers and heart attacks. This article takes a look at the health problems caused by air pollution, the steps being taken to reduce its impact on the global population, and the monitoring solutions required to document the effects of mitigation strategies.

It is a sobering thought that, according to estimates from the World Health Organization (WHO), less than one per cent of cities in low and middle income countries comply with its recommended thresholds for air pollution. Even more concerning, around seven million deaths per year globally can be attributed to poor air quality, making it the single greatest environmental risk to human health.2 There is clearly a need for mitigation strategies to minimise the release of all types of airborne pollutants.

The scale of the problem

Air quality has been a concern for centuries, starting as far back as the industrial revolution of the late 1700s. Technology has advanced considerably in the years since, resulting in more plentiful and diverse potential sources of airborne pollution, including manufacturing and industrial applications, agriculture, motor vehicles and power plants. The WHO established global air quality guidelines in a drive to counteract the effects of the worst pollutants, including fine and course particulate matter, ozone, nitrogen dioxide, sulphur dioxide, and carbon monoxide. Despite these guidelines, an estimated 99 per cent of the global population is actually breathing air that exceeds the recommended limits for at least some of these pollutants.3 Densely populated cities in developing countries tend to suffer the lowest air quality for a variety of reasons, including less rigorous pollution regulation, poor enforcement, concentrated emission sources, and tightly packed buildings that prevent smog dispersion. One of the most obvious examples of this is Delhi in India. Delhi has some of the worst air quality in the entire world, with Air Quality Index (AQI) recordings frequently reaching the maximum value of 999. Exposure to such toxic levels of air pollution is estimated to be the equivalent of smoking more than two packets of cigarettes a day, and is contributing to the severe lung damage observed in as many as four in every 10 of the city’s juvenile population.4

Driving standards upwards

Countries around the world are becoming ever-more aware of the dangers of poor air quality and the need to protect human health, looking for ways to control pollution levels and enable people to take action to keep themselves safe. For example, Seoul in South Korea has a unique way of communicating the city’s air quality to its inhabitants, illuminating the Namsan Tower in blue whenever the fine dust density level is below 45 microgrammes per cubic metre, so that people know they can safely go outside and enjoy the fresh air.5

The United Nations (UN) is committed to substantially reducing the number of illnesses and deaths caused by polluted air, water and ground by 2030, giving particular attention to inner-city air quality and waste management. The UN Environment Assembly has implemented resolution 3/8 on Preventing Air Pollution, requiring the UN Environment Programme to ‘undertake an assessment of progress being made by member states to adopt and implement key actions that can significantly improve air quality’.6 As well as this, the UN General Assembly has encouraged its member states to adopt resolutions such as ‘The future we want’7 and ‘Transforming our world: 2030 agenda for sustainable development’,8 which contain environmental protection and air quality subsections. Initiatives that raise awareness of the importance of air quality – such as ‘The international day of clean air for blue skies’9 – sit alongside these international pledges, confirming the UN’s determination to improve air quality.

Keeping abreast of air quality

Accurate tracking of changes in air quality is essential to assess the impact of mitigation strategies, requiring state-of-the-art technologies to enable real-time monitoring of the most common and hazardous pollutants. However, different technologies are required to accurately measure different pollutants. Electrochemical analysers are perfectly suited to the measurement of noxious gases – such as nitrogen dioxide, carbon monoxide and ozone – offering sufficient sensitivity to detect even minute concentrations of these harmful pollutants. In contrast, optical counters, which function by measuring the amount of scattering caused by individual particles as they pass through a beam of light, are generally the go-to solution for determining the concentration of particulates in the air. And photoionisation detectors, where the unique ionisation fingerprints of organic compounds are identified using an ultraviolet lamp, are generally the preferred option for VOC measurements. Fortunately, innovative products are available that combine multiple measurement techniques in a single portable unit – for example, the Thermo Scientific™ TVA2020 Toxic Vapor Analyzer – which enable the detection of virtually all organic and inorganic compounds, allowing straightforward measurement of a wide range of airborne pollutants across numerous applications, from the determination of traffic pollution to borderline emissions monitoring of natural gas processing plants.

These technologies are perfectly suited to localised measurements, allowing accurate determination of air pollution at ground level, and are complemented by space-based tropospheric observations, such as those carried out by the Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite instrument.10 This extra-terrestrial approach can give an indication of air pollution levels on a national scale, with the added benefit of being able to track the transport of harmful chemicals across international borders by global weather patterns.

Looking to the future

Countries worldwide have a collective responsibility to tackle air pollution, and it is vital that both the UN and government institutions around the world continue to take the initiative in establishing and implementing strategies to meet this challenge. This will require rigorous monitoring programs to assess the efficacy of the measures introduced, including the use of dedicated air quality monitors capable of simultaneously detecting the concentration levels of noxious gases, VOCs, and particulates. The resulting data, complemented by space-based tropospheric observations, will generate crucial evidence to demonstrate whether or not the global community is succeeding in reducing toxic emissions and improving air quality, helping to prevent millions of premature deaths every year.


  1. Short-lived climate pollutants (SLCPs). The Climate and Clean Air Coalition. Accessed 30.01.23

  1. 7 million premature deaths annually linked to air pollution. World Health Organization. Accessed 30.01.23
  2. Billions of people still breathe unhealthy air: new WHO data. World Health Organization. Accessed 30.01.23
  3. Delhi's air pollution is triggering a health crisis. BBC News. Accessed 30.01.23
  4. Check the Air Quality in Seoul with N-Tower and Twitter. Accessed 30.01.23

  1. Actions on air quality report update. United Nations. Accessed 30.01.23
  2. The future we want – outcome document. United Nations. Accessed 30.01.23
  3. Transforming our world: the 2030 agenda for sustainable development. United Nations. Accessed 30.01.23
  4. International day of clean air for blue skies. United Nations. Accessed 30.01.23
  5. TEMPO: A New Era of Air Quality Monitoring from Space. United States Environmental Protection Agency. Accessed 30.01.23