Clearing the Air: a Global Health Perspective on Air Pollution

Air pollution is responsible for one in eight deaths globally per year. The severity of air pollution and its effects on global health are frequently discussed in the literature but are poorly reflected in health policy and have not yet resulted in sufficient actionable change. Air pollution mitigation policies should embody the planetary health concept, which highlights the interdependence between the health of humans and the planet. There is an urgent need for the standardisation of air quality measurement and programmes on a global scale. A reduction in fine particulate matter has been shown to contribute to the greatest degree of public health benefits. Current efforts to improve urban air quality include a significant focus on the transition to sustainable energy and transportation through the electrification of transportation. There are two main fronts in the campaign against pollution, one being the reduction of anthropogenic emissions through public and government policy, and the other being the introduction of novel attempts to decrease pollution and other innovative research to develop new approaches that will ultimately improve global health.

wood are combusted, is the second largest contributor. 2 With the advent of warmer and drier climates, combustion of fossil fuels exacerbates climate change by increasing greenhouse gas emissions and consequently escalating the propagation of wildfires. 2 There is an urgent need to leave the planet a better place for future generations as short-term exposure to air pollution is associated with reduced lung function, delayed psychomotor development, and lowered IQ in children. 8 Air pollution should embody the planetary health concept, which highlights the interdependence between the health of humans and the planet. 12 Changes to natural systems, such as increased ground-level ozone, damage food crops through eutrophication and consequently acidify environmental waters and amplify mercury bioaccumulation in oceans ( Figure 1). 13 This causal sequence of global environmental changes from air pollution affects agricultural productivity, food security, and human health. 13

Environmental Health Inequality
Given that an estimated 7 million deaths per year are caused by air pollution, this threat is underappreciated by the public. 1 Some media reports are attempting to generate awareness around the topic, but most fail to communicate the severity of the issue. A recent study showed that fewer than 40% of news articles discussing air pollution mentioned the health risks posed for humans, and less than 10% discussed what actions individuals can take to minimise their risk of developing health complications. 14 The general ignorance surrounding air quality is apparent when using sub-Saharan Africa as an example. Studies have found that air pollution in Africa is responsible for more premature deaths on the continent than communicable diseases like HIV/AIDS and malaria, yet most public discourse and fear are centred around communicable diseases. 15 The recognition of the dangers posed by these diseases has led to the development of treatment and the establishment of preventative measures which have led to a decrease in overall mortality linked to these conditions. 15 While this is a step in the right direction, similar or greater attention should be given to the impacts of air pollution on the African population, to address this issue as communicable diseases have been addressed. The nations that comprise Sub-Saharan Africa are undergoing rapid urbanisation, increasing not only in the number of people exposed to outdoor air pollution, but also the overall pollution levels. 15 The biggest contribution to outdoor air pollution is the use of poor-quality fuels and older model cars sold by Europe, the United States, and Japan after the catalytic converters and air filters have been removed. These nations sell cars to Africa with environmental standards that are prohibited within their own jurisdictions. 15 Indoor air pollution is another major factor, stemming from traditional cooking practices and burning of household waste. As a result, women are exposed to seven times greater particulate pollution than men. 15 Thus, these countries are facing a triple threat from poor air quality -urbanisation and its health issues, the uninterrupted burden of infectious diseases, and the lack of national data regarding air quality. 15 There are very few studies on the health impacts of air pollution in sub-Saharan Africa; a recent assessment showed that 9 out of 12 were focused on South Africa. 15 While reports demonstrate that sub-Saharan Africa has the highest burden of disease as a result of poor air quality, these assessments rely on estimates from the rest of the world due to governments' lack of ability to monitor their own air quality.
Carbon leakage, the phenomenon in which countries reduce their emissions by outsourcing them to lower income countries, is an essential part of the discussion around air quality and global inequality. 16 This issue is most apparent in the case of the United States outsourcing their emissions to China. Importantly, this is also observable where developed nations that did not commit to the Kyoto protocol are outsourcing their emissions to developing nations. 16 Carbon leakage is an example of inequality in air pollution that is directly influenced by national policy.

Role of Healthcare Professionals
While the media and governments could be doing more to create a sense of urgency among the public, it can be argued that healthcare professionals are at least partly to blame for the lack of awareness surrounding this issue. Even physicians do not consider air pollution to be as significant as other risk factors causing disease. There are resources available online that report the quality of air in certain locations, but these resources are arguably useless if the public is not informed that the current state of air quality poses a legitimate threat. Physicians have a duty to inform their patients of risk factors that may be impacting their health negatively, and air pollution is no exception, yet there is minimal discussion of air pollution in health consultations. An increasing interest for climate change and its implications to be integrated into medical school curricula was shown in a recent study which reported that only 11% of medical schools across 112 countries have incorporated air pollution into their undergraduate educational programmes. 17 Healthcare professionals must use a holistic approach in providing lifestyle advice to patients as part of daily practice.

Mitigating Health Consequences of Air Pollution
Despite the enormity of air pollution and its burden on global health there are strategies, both reasonable and attainable, that can help mitigate this issue. For example, by implementing strict policy changes and aggressive air quality management programs, China succeeded in reducing particulate pollution by 29% between 2013 and 2019, increasing life expectancy by 1.5 years. 2 This was attributed to government strategies such as reducing emissions of coal plants or replacement with natural gas, generating renewable energy, reducing metal use in industry and car usage, utilising political incentives, and incorporating transparency with better enforcement. 2 The implementation of air quality monitors minimised underreporting of pollution, allowing the public to assess risk exposure. To contextualise China's success, the United States achieved this level of decline after three decades, and Europe after two. 2 There is an urgent need for the standardisation of air quality measurement and programmes on a global scale. A reduction in fine PM has been shown to contribute to the greatest degree of public health benefits. 18 Even a small reduction in concentration for a large population can decrease mortality. Not only do health benefits of improved air quality increase immediately after fossil fuel emissions are reduced, but these benefits also offset the costs associated with implementing policies and renewable energies. Carbon taxing can also be introduced in more countries to reduce carbon leakage. Improvements in air quality are easily counterbalanced with increasing pollution in other areas, emphasising the requirement for a comprehensive planetary health approach. 12 Current efforts to improve urban air quality include a significant focus on the transition to sustainable energy and transportation through the electrification of transportation. Conclusively, electrification is proposed as a means to improve local air quality. However, caution is required as electrification may increase power plant combustion and emissions around electrical generating units. 18 There is also need for simpler air quality measuring tools similar to those in China that can be utilised by the public to protect those most at risk. This approach allows the public to make better-informed decisions by evaluating their own risk. The COVID-19 emergency has contributed to a greater public awareness of the health benefits of cleaner air and less noisy urban environments. 19 It will be of interest to observe the long-term environmental legacy of the pandemic on individual travel and consumption behaviours. Novel technologies will play an important role in this regard. Whether recently launched wearable air purifiers will have a role in protecting individuals from the harmful effects of air pollution remain to be seen. 20

Conclusion
There are two main fronts in the campaign against pollution, one being the reduction of anthropogenic emissions through public and government policy, and the other being the introduction of novel attempts to decrease pollution and other innovative research to develop new approaches that will ultimately lead to the amelioration of global health. 2 A neglected strategy is to increase public and clinician awareness and understanding about air pollution and its health effects. Future research should examine the extent to which the COVID-19 pandemic has shifted public attitudes towards a greater commitment to environmental sustainability and cleaner air for all.