Air Pollution

Air Quality and Health

The detrimental effects of air pollution on health are staggering, surpassing even the combined mortality rates of global health challenges like AIDS, tuberculosis, and malaria. On a daily basis, an adult inhales approximately 11,000 liters of air, making the quality of this air a critical factor for health. Pollutants, especially particulate matter from combustion activities and ground-level ozone formed from emissions, play a significant role in this regard. The Institute for Health Metrics and Evaluation's Global Burden of Disease project highlighted an alarming figure of 5 million premature deaths in 2017 due to air pollution. The World Health Organization's data from 2016 further underlines the severity, attributing around 7 million premature deaths globally to air pollution. These deaths are primarily caused by a range of diseases triggered or exacerbated by air pollution.

Air pollution poses the greatest risk to specific demographic groups, particularly older adults, children, and individuals with pre-existing respiratory conditions. Even short-term exposure to high levels of particulate matter, such as those from wildfires, can lead to lasting respiratory impairments. Research also points to the broader impacts of air pollution on human health, including negative effects on male fertility, fetal development, and cognitive functions. These cognitive effects can range from short-term issues like confusion and mood swings to long-term risks such as increased susceptibility to dementia. The link between air pollution and cancer is also significant, as pollutants from waste incineration and fossil fuel processing are known carcinogens.

The global distribution of the health impacts of air pollution is uneven. According to a study by the World Health Organization (WHO), over 91% of premature deaths associated with outdoor air pollution occur in low- and middle-income countries. This statistic is mirrored in the realm of indoor air pollution, predominantly caused by the burning of solid fuels like coal and wood for cooking and heating. Such indoor pollution has a disproportionate effect on women and children in these countries. Furthermore, air pollution's indirect health impacts are profound. Recent epidemiological studies suggest that air pollution can increase vulnerability to respiratory infections and weaken the immune response to other infectious diseases. Additionally, certain pollutants, such as mercury from coal plants and dioxins from waste incineration, can contaminate soil and water, entering the food chain and leading to various diseases, including cancer, endocrine disruption, and other health issues. The impact of air pollutants extends beyond human health, affecting plants and forests, thus impacting biodiversity, crop productivity, nutritional content, and other essential aspects of human well-being.

Air Quality and Climate Change

Addressing air pollution is not just a health imperative but also a crucial part of tackling climate change. The interplay between air pollution and climate change is complex and significant. Pollutants like black carbon, ground-level ozone, and methane are not only detrimental to health but also potent warming agents in the atmosphere. The Climate and Clean Air Coalition notes that these three components contribute to up to 45% of the total global warming observed to date. Black carbon, in particular, has a pronounced effect in the Arctic, where it accelerates warming and melting. The uneven heating of the atmosphere caused by localized concentrations of black carbon also disrupts wind patterns and creates urban "heat islands."

The good news is that many of the pollutants contributing to warming, such as black carbon and methane, have relatively short lifespans in the atmosphere compared to carbon dioxide. This means that actions to reduce emissions can have an immediate and noticeable impact on pollution levels, yielding benefits for climate, health, and the environment. For instance, targeting "super-pollutants" and hydrofluorocarbons in refrigeration could prevent over half a degree of global warming by 2050, and significantly mitigate warming in the Arctic.

Conversely, some pollutants, like sulphates and other lighter-colored particulate matter, can have a temporary cooling effect on the environment by blocking solar radiation. While this has led to proposals to use such particles to slow global warming, the approach is fraught with uncertainty and potential negative consequences, such as reduced agricultural growth and renewable energy generation due to decreased solar radiation. Furthermore, particulate matter can disrupt cloud formation and precipitation patterns in unpredictable ways.

Climate change itself also affects air quality. Elevated temperatures accelerate chemical reactions that worsen air pollution, while changing meteorological patterns affect emissions and increase the frequency of wildfires. The specific impacts vary based on pollutant types and locations, but generally, climate change is expected to exacerbate air pollution in already heavily polluted areas. This poses additional challenges for air quality control. The primary cause of both air pollution emissions and greenhouse gas emissions is the combustion of fossil fuels. Consequently, measures to mitigate greenhouse gas emissions also tend to improve air quality. Empirical evidence has shown that the health benefits of such actions can equal or exceed the costs involved in reducing greenhouse gas emissions, particularly in certain parts of the world.

Air Pollution in Cities

Urban areas are at the forefront of the air pollution challenge and are critical to its resolution. Cities are home to the majority of the world's population and are projected to grow substantially, with an additional 2.5 billion people expected to live in urban areas by 2050. These areas are significant contributors to air pollution, with a high concentration of emission sources such as vehicles, buildings, industrial activities, waste, and wastewater. Additionally, the sheer number of people engaged in everyday activities like cooking, heating, lighting, and cleaning adds to the pollution burden. Even urban trees, which provide benefits like cooling and stormwater control, can contribute to pollution; on hot days, tree leaves emit volatile organic compounds that help form ozone.

The problem is compounded by the interaction between urban emissions and pollution from surrounding areas, such as agriculture, forest fires, crop burning, and power plants. However, cities are also uniquely positioned to lead the fight against air pollution. They are centers of technological and administrative innovation, developing new ways to cook, heat, light, transport, and manufacture with fewer emissions. Their density also enables more efficient, low-emission mobility options and allows for changes in urban planning and land use that reduce reliance on motorized transportation.

While cities have significant potential to improve air quality, they cannot do it alone. Mayors and other city leaders may be eager to tackle air pollution, but they often lack the necessary policy tools and resources. Some measures, like rerouting traffic or discouraging car use, are within their purview, but more significant transitions to cleaner fuels or stricter emissions standards typically require national policy interventions. Cities can improve public transit safety and connectivity and invest in projects like fleet conversion, but these initiatives often require support, transfers, or approvals from higher levels of government. Additionally, while cities can design the built environment and establish zoning regulations that redistribute pollution, reducing emissions at the source often requires action and financial commitment beyond their boundaries. Effective regulatory coordination is crucial; attempts to limit industrial or point-source pollution in one jurisdiction can lead polluters to relocate to areas with less stringent regulations.

Agriculture and Air Quality

The relationship between agriculture and air quality is a complex and significant one. On the one hand, air pollution has a detrimental impact on agriculture, reducing crop yields and affecting food security. On the other hand, agricultural practices contribute to air pollution, creating a cyclical problem. Ozone pollution is particularly harmful to plants, damaging their cells and impairing photosynthesis. Particulate matter and haze reduce the amount of sunlight available for plant growth, further impacting agricultural productivity. The global disparity between potential and actual crop yields due to ozone is notable, with losses calculated at 12% for soybeans, 7% for wheat, and over 4% for rice. Between 2010 and 2012, ozone levels were high enough to cause a loss of 250 million tons of crops, and global ozone levels continue to rise.

The Americas experience the most significant wheat losses, while Asia sees the highest rice losses. Maize losses are widespread globally. The impact extends beyond staple crops, affecting specialized crops like guavas and beans as well.

Agriculture's contribution to air pollution is multifaceted. The Climate & Clean Air Coalition reports that agriculture and forestry are responsible for approximately 40% of the world's black carbon and methane emissions from human activities. Crop burning and forest fires are major sources of particulate matter, but other factors contribute as well. Overuse of nitrogen-based fertilizers leads to ammonia emissions, which can combine with urban pollutants to form particulate matter in cities. These emissions also cause acid rain and eutrophication, leading to algal blooms in downwind water bodies. Rice production contributes to pollution through methane emissions from inundated fields and nitrous oxide release during periodic flooding. Methane is a contributor to ozone depletion, and both methane and ozone are greenhouse gases.

The manure produced in animal husbandry is a significant source of ammonia emissions, and livestock digestion is a major global source of methane, surpassing oil and gas production. Transitioning to plant-based diets is one effective way to reduce agricultural emissions. Additionally, there are several approaches to mitigating emissions from animal agriculture, including changing cattle feeding practices, improving manure storage and spreading techniques, and reducing emissions from animal housing. Adopting cultivation methods that use less fertilizer and minimize tilling and burning practices can also help reduce farming-related emissions.

Mobility and Air Pollution

The equation for solving mobility-related air pollution is straightforward: reduce physical movement and increase electricity use. Mobility is integral to our lives. Before COVID-19, the International Air Transport Association reported over 8.3 trillion passenger-kilometres flown in 2018. In 2015, transportation moved over 108 trillion tonne-kilometres of goods via sea, road, rail, and waterways. Mobility is essential for accessing jobs, healthcare, education, and community involvement, and it boosts the efficiency of decentralized supply chains, influencing the spatial distribution of economies and opportunities. However, this comes with a significant environmental cost. The transportation sector is a major contributor to air pollution and greenhouse gas emissions globally. The European Environment Agency notes that it accounts for nearly half of nitrogen dioxide and nitric oxide emissions in the region, primarily from road transport. Elsewhere, the contribution varies, but emissions from freight and heavy-duty vehicles often represent a disproportionate share compared to their overall presence in vehicle fleets.

Emissions control can be improved through engine optimization, cleaner fuels, and effective filtering technologies. The International Maritime Organization's emission restrictions and sulphur content regulations are expected to reduce ship emissions, which contribute to acid rain and particulate matter formation, by 77%. Supporting these efforts requires systemic investments in refinery capacity for cleaner fuels and the widespread adoption of cleaner engines, especially in low- and middle-income countries facing a surge in secondhand cars with polluting engines. Additional strategies include promoting alternative transportation modes. Strategic urban planning and zoning can optimize city density and accessibility. In virtually all cases, this involves economic incentives. Specifically for the sector, it necessitates a reevaluation of supply chains and the balance between digital and physical transport. At the local level, promoting public transit and electric vehicles is crucial, along with revitalizing lower-emitting rail and shipping systems to replace road freight.

Air Quality and the Circular Economy

Air pollution's impact, though often invisible, is globally significant. Addressing it through supply chain, recycling, and waste management reforms can lead to a circular economy, focusing on material reuse rather than disposal. A large part of pollution originates from distant consumption, disproportionately affecting poor communities near industrial areas. In China, 20% of particulate matter-related deaths are linked to goods manufactured for export, and over 50% of emissions are associated with goods consumed elsewhere. Similar trends are seen in other countries, like the U.S., where ethnic minorities face higher pollution levels relative to their consumption. The competitive push for cheap global manufacturing conflicts with protecting vulnerable areas.

Waste management practices also contribute to air pollution, affecting distant communities. The World Bank states that about one-third of global waste and 90% of waste in low-income countries is disposed of through open burning or dumping. These methods release various pollutants, impacting nearby communities and ecosystems. Unregulated recycling and poorly managed composting can also cause concentrated pollution. To avoid merely relocating pollution, a systemic approach to pollution management is essential. Embracing a circular economy and managing the lifecycle of resources can enhance traditional regulatory methods and focus investments more effectively.

Transitioning Energy for Air Quality

Clean, immediate power is essential for air quality. According to the International Energy Agency, energy production and consumption account for 85% of global particulate matter and most sulphur oxides and nitrogen oxides, harming health and the climate. Oil and gas contribute 25% of anthropogenic methane emissions, a significant climate warming gas. Coal power plants, emitting mercury, arsenic, particulate matter, and greenhouse gases, are linked to numerous premature deaths annually. Most power plants lack technologies to control these emissions. Vehicles, especially trucks and cars, are major urban air pollutants, and maritime activities leave visible pollution trails.

A thorough overhaul of the energy production and consumption process is needed to increase energy accessibility and reduce harmful emissions. Improving raw energy conversion efficiency, shifting to lower-emission energy sources, and regulating late-stage emissions are key steps. This means increasing electrification, as combustion is inefficient in vehicles, furnaces, and cooking appliances. Enhancing power cleanliness through renewable sources, regulating gas and coal emissions, and innovating to transform fossil fuel infrastructure are necessary.

Air Pollution Governance

Effective air pollution control requires more than individual efforts; it needs comprehensive, collaborative governance. Atmospheric mechanisms like wind, rain, and sunlight influence pollution patterns. Addressing this complex issue requires agile governance. Pollution sources vary, including cars, trucks, garbage burning, and industrial activities. Pollution crosses local, regional, and even hemispheric boundaries. Ammonia from agricultural fertilizers and nitrogen oxides from various sources contribute to global particulate matter levels.

Advancements in satellite technology are improving pollution identification, but enhancing air quality requires cross-domain collaboration. Leaders must work beyond borders, collaborating with neighboring regions to decrease emissions. Examples include the international Convention on Long-Range Transboundary Air Pollution and regional initiatives like California's South Coast Air Quality Management District and Mexico City’s Environmental Commission of the Megalopolis. A network of regional and sector-specific agreements can help manage transboundary pollution. Knowledge of control technologies and policy strategies, including air quality standards, emission standards for specific sources, and emission trading schemes, is growing. Learning from various experiences, towns, and nations can address their unique air pollution challenges and political contexts.