It is very well known that air pollution causes death, and a wide spectrum of health conditions, with considerable burden for the world’s population [1]. There is evidence also for the association of air pollution with SARS-CoV-2 transmission, COVID-19 infection severity, and its mortality [2–4].
The World Health Organization (WHO) has launched air quality guidelines (AQG) 2021 about 15 years after 2005 AQGs for short- and long-term exposure to a range of air pollutants, such as particulate matter (PM2.5 and PM10), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO) [5]. In brief, most 2021 AQGs are lower compared to 2005 using updated WHO methodology, and given the fact that new evidence shows health effects occur even at lower exposure levels [6–8]. The updated WHO AQGs are based on thorough systematic reviews and meta-analyses of evidence up to mid-2020 [5].
Of notable updates, the 2021 AQG compared to 2005 for annual mean exposure to PM2.5 reduced from 10 to 5 µg/m3, PM10 reduced from 20 to 15, and NO2 reduced from 40 to 10 µg/m3. Furthermore, there is new 2021 AQG for peak season O3 (60 µg/m3) and 24-hour exposure to CO (4 mg/m3). The AQG for 24-hour exposure to SO2 increased from 20 µg/m3 in 2005 to 40 µg/m3 in 2021, which is due to updated evidence and methodology for AQGs. Amongst other updates, the 2021 AQGs also provide good practice statements for certain types of PM, such as black carbon/elemental carbon, ultrafine particles, and dust- and sandstorms. It is notable that WHO AQGs further provide Interim Targets (ITs) for most pollutants for stepwise progress towards achieving the AQGs. As WHO emphasized, it is very important to note that the 2005 WHO AQGs remain valid for pollutants and those averaging times not covered in 2021 update [5].
As shown in Figure 1, it is evident that there is inequality in exposure to air pollution across the world with low- and middle-income countries (LMICs) experiencing higher exposure levels for most pollutants. Currently, large world populated areas do not meet the WHO AQG 2021 for annual mean exposure to PM2.5, annual mean NO2, and seasonal maximum O3, and many countries are even in a position that need to consider IT1 for PM2.5 (35 µg/m3) as the first step to achieve, which is indeed challenging. NO2 is considerably higher within urban areas, and ground level O3 has high values across the Middle East and India (Figure 1).
FIGURE 1
The conformity of 2019 annual mean PM2.5, 2019 seasonal maximum O3, and 2011 annual mean NO2 with the WHO Air Quality Guidelines (AQG) 2021 and interim targets (IT) across the world. Human populations do not populate the white areas within the countries. Source: PM2.5 adapted from Shaddick et al. (2018) [9] and Global Burden of Disease (GBD) 2019 Risk Factor Collaborators [1, 9], O3 adapted from Chang et al. (2019) and GBD 2019 Risk Factor Collaborators [1, 10], and NO2 adapted from Larkin et al. (2017) [11].
The WHO AQGs 2021 have important implications for WHO member states and public health. With the launch of WHO AQGs 2021, WHO has provided the member states with a tool that need to be adopted to protect public health from air pollution as a so-called “silent killer.” As stated in a joint statement by Hoffmann et al. [12], which is endorsed by more than hundred medical, public health, scientific and patient representative societies, such as European Respiratory Society (ERS) and the International Society of Environmental Epidemiology (ISEE), immediate action is needed to use these guidelines for emission reduction policy making and adopt these science-based guidelines and interim targets as national air quality standards. Clearly, healthy lungs and healthy hearts need clean air [3, 13].
It is not only the duty of governments to achieve these goals, but also it is a societal responsibility for all individuals to move in the right direction and reduce the unacceptable burden of air pollution (millions of lost lives, years of life disabled and lost, and related costs). The extent of the reduction is directly translated into improvement in public health. This require actions that are in line with climate action as one of the 17 Sustainable Development Goals established by the United Nations in 2015 [14].
Statements
Author Contributions
The author confirms being the sole contributor of this work and has approved it for publication.
Acknowledgments
The author acknowledge Prof. Michael Brauer from the University of British Columbia for providing the gridded air pollution data of GBD 2019. HA is supported by Novo Nordisk Foundation Challenge Programme: Harnessing the Power of Big Data to Address the Societal Challenge of Aging (NNF17OC0027812).
Conflict of Interest
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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Summary
Keywords
air pollution, conformity, particulate matter, nitrogen dioxide, ozone
Citation
Amini H (2021) WHO Air Quality Guidelines Need to be Adopted. Int J Public Health 66:1604483. doi: 10.3389/ijph.2021.1604483
Received
22 September 2021
Accepted
01 October 2021
Published
15 October 2021
Volume
66 - 2021
Edited and reviewed by
Nino Kuenzli, Swiss Tropical and Public Health Institute (Swiss TPH), Switzerland
Updates
Copyright
© 2021 Amini.
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*Correspondence: Heresh Amini, heresh.amini@sund.ku.dk
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