Environmentally Not So Friendly: Global Warming, Air Pollution, and Wildfires: JACC Focus Seminar, Part 1

Abstract

Environmental stresses are increasingly recognized as significant risk factors for adverse health outcomes. In particular, various forms of pollution and climate change are playing a growing role in promoting noncommunicable diseases, especially cardiovascular disease. Given recent trends, global warming and air pollution are now associated with substantial cardiovascular morbidity and mortality. As a vicious cycle, global warming increases the occurrence, size, and severity of wildfires, which are significant sources of airborne particulate matter. Exposure to wildfire smoke is associated with cardiovascular disease, and these effects are underpinned by mechanisms that include oxidative stress, inflammation, impaired cardiac function, and proatherosclerotic effects in the circulation. In the first part of a 2-part series on pollution and cardiovascular disease, this review provides an overview of the impact of global warming and air pollution, and because of recent events and emerging trends specific attention is paid to air pollution caused by wildfires.

Keywords: cardiovascular disease; light pollution; noise pollution; soil pollution; water pollution.

Figure 1.. Age distribution of excess mortality from ambient air pollution in different regions.

Taken from .

Figure 2.. Air pollution.

Examples of various sources of major air pollutants. CO = carbon monoxide, HNO₃ = nitric acid, H₂SO₄ = sulfuric acid, NH₃ = ammonia, NO₂ = nitrogen dioxide, O₃ = ozone, PM = particulate matter, SIA = secondary inorganic aerosol, SO₂ = sulfur dioxide, temp = increasing temperature, VOCs = volatile organic carbon species.

Figure 3.. Air pollution from wildfires.

a Annual wildfire-burned area (in millions of acres) from 1983 to 2021. The two lines represent two different reporting systems though the Forest Service stopped collecting statistics (orange line) in 1997 and is not planning to update them, those statistics are shown here for comparison. Source: United States Environmental Protection Authority , b Natural events in 2020 drastically changed global levels of air pollutants. The aerosol optical depth (AOD), detecting aerosols including smoke-derived particulate matter, across Australia was increased in January 2020 compared to January 2019 due to extensive bushfires. Image credit: NASA EarthObservations team based on data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center. Image previously published in , c Associations between wild fire exposure and cardiovascular mortality and morbidity. Reproduced from

Central Illustration. Increased air pollution, wildfires and extreme heat each raise health risks.

Each exacerbates the actions of the other by combining to cause cardiovascular death, acute and chronic coronary artery disease, heart failure, stroke, venous thrombosis, pulmonary embolism and arrhythmia.