In this blog post for the UK’s Clean Air Day, we aim to raise awareness about the detrimental impact of air pollution on our mental well-being and emphasise the crucial role that precision analytical technologies play in monitoring and enhancing air quality.
What is Air Pollution?
Air pollution is the presence of harmful substances in the air that can have detrimental effects on human health and the environment. Although much man-made air pollution originates from road traffic, other key sources include industrial emissions, bonfires and domestic solid fuel burning. From such sources, there are five main pollutants that contribute to air pollution:
- Fine particulate matter (PM2.5 or PM10): Particulate matter refers to microscopic solid or liquid particles that are suspended in the air. These can be human-made, such as from traffic emissions and the burning of fossil fuels, or natural, such as from sea spray or mineral dust from soils. Coarse particulate matter, PM10, can cause irritation to the eyes, nasal and upper respiratory passages. While small particulate matter, known as PM2.5, is a greater health concern because the smaller particles can travel deep into the lungs, cross into the bloodstream and be transported to the brain and other organs.
- Nitrogen oxides (NOx): These gases are released by the combustion process, particularly burning fossil fuels and contribute to the formation of smog and acid rain. They can irritate the respiratory system and lead to respiratory diseases.
- Sulphur dioxide (SO2): This gas is produced by burning fossil fuels containing sulfur, such as coal and oil. It can cause respiratory problems and contribute to the formation of acid rain.
- Ammonia (NH3): Ammonia is primarily released from agricultural activities and can react with other pollutants in the air to form fine particles and smog.
- Non-methane volatile organic compounds (NMVOC): These are organic chemicals that can be emitted from various sources, such as industrial processes, vehicle emissions, and household products. They can contribute to the formation of ground-level ozone and have adverse health effects.
How does air pollution affect human health?
Air pollution is the top environmental risk to human health in the UK, and ranks fourth in all risks after cancer, heart disease, and obesity [1]. While the physical health impacts of air pollution have been recognised for years, recent research has shed light on its effects on mental health and the brain.
Research has increasingly shown that prolonged exposure to air pollution can significantly impact mental health and well-being. The presence of pollutants in the air has been linked to various mental health conditions and a decline in overall psychological well-being [2-4]. For instance, one study, involving 13,000 people in London, found that a relatively small increase in exposure to NO2 led to a 32% increase in the risk of needing community-based treatment, and an 18% increase in the risk of being admitted to hospital [3].
Scientists are still striving to fully comprehend the precise mechanisms through which air pollution affects mental health and cognition, but many believe that inflammation plays a crucial role. Chronic inflammation in the brain can damage neurons that are involved in the brain and nervous system's regulatory responses, which in turn can impact mental health [5]. PM2.5, for example, can penetrate deep into the respiratory system and reach the bloodstream. Once in the bloodstream, these particles can travel to the brain and trigger oxidative stress and neuroinflammation, leading to the development or exacerbation of mental health disorders such as depression, anxiety, and cognitive decline [6].
Considering that 99% of the global population breathes air that fails to meet the World Health Organisation's (WHO’s) essential guidelines for clean air [8], it is imperative that we comprehend the true impact of air pollution on our daily lives.
How is Air Pollution Monitored?
To effectively tackle air pollution, it is crucial to implement robust monitoring and measurement systems to assess the levels of pollutants in the air. Accurate monitoring of air quality serves as an essential tool in reducing air pollution, safeguarding public health, and ensuring compliance with regulations. Furthermore, it facilitates the identification of pollution sources, monitors climate change patterns, and supports research and development efforts.
In the UK, the Automatic Urban and Rural Network (AURN) serves as the largest automatic monitoring network, comprising of automatic air quality monitoring stations (AQMS) designed to measure meteorological parameters, including wind speed, wind direction, rainfall, radiation, temperature, barometric pressure, and ambient conditions. Additionally, AQMS can incorporate a range of ambient analysers to continuously monitor the concentration of air pollutants such as SO2, NOx, CO, ozone, and PM. Used widely in the UK, HORIBA’s AQMS can be tailor-made to deliver real-time precise measurements according to customer specifications for many challenging ambient air monitoring requirements.
Measuring the concentration of different air pollutants requires specific methods adapted to each pollutant. For instance, to precisely measure and record atmospheric concentrations of NO, NO2, and NOx, systems like the APNA-370 utilise chemiluminescence. Whereas, UV fluorescence is employed in systems such as the APSA-370 to detect atmospheric SO2.
However, measuring PM poses significant challenges due to the small size of the particles, the removal of unwanted large particles (in this case, >2.5 µm or >10 µm), as well as the effect of temperature and air pressure on measurements. Various techniques are available for quantifying the mass concentration of PM. However, it is crucial that the chosen method provides real-time data with short time resolution (<1h) that can be utilised for public information. One widely adopted approach for measuring ambient PM10 concentrations in national networks across Europe is the use of ß-attenuation particle analysers, such as the APDA 372. These analysers enable continuous measurement with minimal operator attention, making them highly practical for monitoring purposes.
By monitoring air pollution effectively, we can take targeted actions to comply with environmental regulations to reduce pollution levels and safeguard public health.
How clean is the air in the UK?
The WHO recently changed its air quality guidelines in response to the increasing scientific evidence of the harm to health caused by toxic air [9]. However, the UK’s legal limit for NO2 is four times higher than the new WHO limit, and is often not met in most urban areas. Similarly, the UK's legal limit for PM2.5 is four times higher than the WHO limit, while the limit for PM10 is 2.7 times higher.
In a landmark case, air pollution was ruled the cause of death for a nine-year-old girl after she suffered an acute asthma attack in south London in 2013 [10]. According to the WHO, almost 80% of the millions of deaths related to PM2.5 could be avoided if today’s pollution levels were reduced to those in the new guidelines [11].
Are you concerned about your own health? Check out the average pollution levels at your home address
Despite significant decreases of air pollutants in the UK between 2010 and 2020, including an 18% decrease in PM2.5, 44% decrease in NOx, 70% in SO2, and a 14% decrease in NMVOC, air pollution remains the biggest environmental risk to human health [12].
To address this issue, the UK has set a legal target to achieve a maximum annual mean concentration of 10µg/m3 of PM2.5 by 2040, with an interim target of 12 µg/m3 by January 2028 [13]. Meeting these targets will require increased investment in monitoring, analysis, and publicising of air pollution data throughout the UK, as well as the continuation of vital initiatives like the implementation of Clean Air Zones in major cities.
Advancing Air Quality Solutions
Clean Air Day provides an opportunity for individuals, communities, and organisations to come together and take action to clean up the air we breathe. By raising awareness, implementing pollution reduction strategies, and utilising advanced air monitoring technologies like those offered by HORIBA, we can pave the way for a healthier and cleaner future.
HORIBA is committed to advancing our understanding of methods to improve air quality, which is why we are participating in the upcoming Air Quality Conference in Bristol on 21st June. This conference serves as a platform where key policymakers from local authorities, distinguished academia members, and environmentally focused private companies gather to exchange insights and explore innovative solutions for addressing air quality challenges.
Visit the Clean Air Hub to access a wealth of resources and learn how you can contribute to improving air quality in your area. Together, we can make a difference and ensure clean air for a healthier mind and a healthier planet.
Find out more about HORIBA’s advanced air quality monitoring technologies
References
[1] Clean Air Strategy 2019: executive summary [WWW Document]. GOV.UK. URL www.gov.uk/government/publications/clean-air-strategy-2019/clean-air-strategy-2019-executive-summary (accessed 7th of June 2023).
[2] Zeng, Y., Lin, R., Liu, L., Liu, Y., Li, Y., 2019. Ambient air pollution exposure and risk of depression: A systematic review and meta-analysis of observational studies. Psychiatry Research 276, 69–78. doi.org/10.1016/j.psychres.2019.04.019
[3] Newbury, J.B., Stewart, R., Fisher, H.L., Beevers, S., Dajnak, D., et al., 2021. Association between air pollution exposure and mental health service use among individuals with first presentations of psychotic and mood disorders: retrospective cohort study. The British Journal of Psychiatry 219, 678–685. doi.org/10.1192/bjp.2021.119
[4] Braithwaite, I., Zhang, S., Kirkbride, J.B., Osborn, D.P.J., Hayes, J.F., 2019. Air Pollution (Particulate Matter) Exposure and Associations with Depression, Anxiety, Bipolar, Psychosis and Suicide Risk: A Systematic Review and Meta-Analysis. Environmental Health Perspectives 127. doi.org/10.1289/EHP4595
[5] Hahad, O., Lelieveld, J., Birklein, F., Lieb, K., Daiber, A., Münzel, T., 2020. Ambient Air Pollution Increases the Risk of Cerebrovascular and Neuropsychiatric Disorders through Induction of Inflammation and Oxidative Stress. International Journal of Molecular Sciences 21, 4306. doi.org/10.3390/ijms21124306
[6] Shih, C.-H., Chen, J.-K., Kuo, L.-W., Cho, K.-H., Hsiao, T.-C., et al., 2018. Chronic pulmonary exposure to traffic-related fine particulate matter causes brain impairment in adult rats. Particle and Fibre Toxicology 15, 44. doi.org/10.1186/s12989-018-0281-1
[7] Zundel, C.G., Ryan, P., Brokamp, C., Heeter, A., Huang, Y., Strawn, J.R., Marusak, H.A., 2022. Air pollution, depressive and anxiety disorders, and brain effects: A systematic review. NeuroToxicology 93, 272–300. doi.org/10.1016/j.neuro.2022.10.011
[8] Billions of people still breathe unhealthy air: new WHO data [WWW Document]. URL www.who.int/news/item/04-04-2022-billions-of-people-still-breathe-unhealthy-air-new-who-data (accessed 7th of June 2023).
[9] What are the WHO Air quality guidelines? [WWW Document]. URL www.who.int/news-room/feature-stories/detail/what-are-the-who-air-quality-guidelines (accessed 7th of June 2023).
[10] Laville, S., 2020. Air pollution a cause in girl’s death, coroner rules in landmark case. The Guardian. URL www.theguardian.com/environment/2020/dec/16/girls-death-contributed-to-by-air-pollution-coroner-rules-in-landmark-case (accessed 7th of June 2023).
[11] New WHO Global Air Quality Guidelines aim to save millions of lives from air pollution [WWW Document]. URL www.who.int/news/item/22-09-2021-new-who-global-air-quality-guidelines-aim-to-save-millions-of-lives-from-air-pollution (accessed 7th of June 2023).
[12] Environmental Improvement Plan 2023 [WWW Document], 2023. GOV.UK. URL www.gov.uk/government/publications/environmental-improvement-plan (accessed 6th of June 2023).
[13] Particulate matter (PM10/PM2.5) [WWW Document]. GOV.UK. URL www.gov.uk/government/statistics/air-quality-statistics/concentrations-of-particulate-matter-pm10-and-pm25.
