WHO Air Quality Guidelines
The WHO Air Quality Guidelines serve as global standards to assess and manage air pollution. They cover major harmful pollutants such as fine particulate matter (PM2.5 and PM10), nitrogen dioxide (NO₂), ozone (O₃), sulphur dioxide (SO₂), and carbon monoxide (CO). Yet, air pollution remains one of the biggest environmental health risks worldwide.
Based on extensive scientific research, these guidelines help governments, policymakers, and individuals reduce exposure to air pollution. Following them can significantly lower the risk of diseases such as heart disease, stroke, lung cancer, and respiratory illnesses.
What Are the WHO Air Quality Guidelines?
The WHO Air Quality Guidelines provide evidence-based recommendations on pollutant levels that are safe for human health. They aim to guide countries in developing air quality standards that protect people and the environment.
Air pollution is a leading cause of disease and premature death worldwide. According to WHO, exposure to polluted air leads to around 7 million deaths each year from conditions like heart disease, stroke, chronic obstructive pulmonary disease (COPD), lung cancer, and respiratory infections.
The guidelines focus on key pollutants commonly found in both urban and rural areas:
- Particulate matter (PM2.5 and PM10)
- Nitrogen dioxide (NO₂)
- Ozone (O₃)
- Sulphur dioxide (SO₂)
- Carbon monoxide (CO)
Why Does WHO Publish Air Quality Guidelines?
According to the WHO, clean air is a basic human right. Yet, billions of people continue to breathe polluted air that threatens their health and quality of life.
The WHO Air Quality Guidelines help countries identify safe pollutant levels and set targets for cleaner air. Although the guidelines are not legally binding, they act as a scientific benchmark for governments to develop and enforce their own air quality laws and standards.
WHO regularly updates these guidelines as new research emerges on how air pollution affects human health.
WHO Air Quality Guidelines 2021 Updates
In September 2021, the World Health Organisation (WHO) released its most stringent update to the Air Quality Guidelines (AQG), reflecting new scientific evidence that even low levels of air pollution can adversely affect health.
Key 2021 WHO Air Quality Guideline Values:
| Pollutant | Averaging Time | 2005 AQG | 2021 AQG |
| PM2.5 | Annual mean | 10 µg/m³ | 5 µg/m³ |
| PM10 | 24-hour Mean | 20 µg/m³ | 15 µg/m³ |
| NO2 | Annual Mean | 40 µg/m³ | 10 µg/m³ |
| O3 | Peak Season 8-hour Mean | 100 µg/m³ | 60 µg/m³ |
| SO2 | 24-hour Mean | 20 µg/m³ | 40 µg/m³ |
| CO | 24-hour Mean | 10 mg/m³ | 4 mg/m³ |
Why Are the WHO Guidelines Important for Public Health?
According to the WHO, there is no safe level of exposure to air pollution. Even small increases in pollutant levels can lead to serious health risks, particularly for children, the elderly, and those with pre-existing health conditions.
Meeting the WHO guideline values could:
- Reduce hospital admissions for asthma and lung diseases
- Lower heart attack and stroke cases
- Increase overall life expectancy
- Improve health for vulnerable populations
By striving to meet WHO-recommended air quality levels, countries can reduce disease burden and promote healthier, longer lives.
Conclusion
The WHO Air Quality Guidelines (2021) set the most up-to-date, science-backed thresholds to protect human health from air pollution. Adopting these standards in the UK and globally would support cleaner air, healthier communities, and longer lifespans.
According to WHO, tackling air pollution is both a health and climate priority, and progress depends on collective action from governments, businesses, and individuals. Cleaner air means healthier lives for everyone.
Note: All information in this blog is based on the World Health Organisation (WHO) Air Quality Guidelines.
Frequently Asked Questions
What are the WHO standards for air quality?
The WHO air quality guidelines are internationally recognised science-based recommendations that guide governments and organisations in reducing harmful air pollutants to protect public health worldwide.
What does the WHO standards for air quality focus on?
WHO also sets indoor air quality guidelines focusing on pollutants commonly found indoors, such as carbon monoxide, nitrogen dioxide, benzene, formaldehyde, and particulate matter. These guidelines help reduce health risks from indoor pollution and improve air safety inside homes and buildings.
What is a safe PM 2.5 level?
The 2021 WHO guideline recommends an annual average PM2.5 concentration not exceeding 5 micrograms per cubic meter (µg/m³) as safe. This limit is set to protect people from the health effects of fine dust particles.
What causes high PM 2.5 levels indoors?
High indoor PM2.5 levels can result from tobacco smoke, cooking fumes, burning candles or incense, indoor heating, poor ventilation, and infiltration of outdoor pollution through windows or doors.
Do air purifiers remove PM10?
Yes, air purifiers with HEPA filters can effectively remove PM10 particles (larger airborne dust and allergens) from indoor air, improving air quality and reducing respiratory irritants.