Introduction:
In the past century, the substantial increase in air pollutant emissions, driven by economic and industrial expansion, has led to a significant air quality challenge as a concern worldwide. The rising concentrations of greenhouse gases (CO2) in the atmosphere have already caused considerable warming, resulting in more frequent and intense heat waves, temperature fluctuations, air pollution episodes, droughts, floods, and wildfires, all of which pose risks to respiratory health. These climate and air quality shifts have measurable impacts on the mortality rates associated with respiratory diseases. Over the last five decades, global temperatures have markedly increased due to human activities' surge in greenhouse gas emissions.
What Is Climate Change and Its Impact on the Environment?
The significant rise in air pollutant emissions due to economic and industrial growth in the last century has elevated air quality to a critical environmental concern in many developed countries, with emerging challenges in other parts of the world. Numerous studies have linked air pollution to exacerbating asthma symptoms, including increased bronchial hyperresponsiveness, emergency department visits, hospital admissions, and medication usage.
Additionally, certain air pollutants, notably carbon dioxide (CO2) and ozone (O3), are among the greenhouse gases contributing to global warming. Over the past few years, the Earth’s temperature has markedly risen due to increased greenhouse gas emissions, predominantly from human activities.
This warming trend is accompanied by shifts in precipitation patterns, including increased frequency and intensity of extreme weather events such as heat waves, droughts, thunderstorms, floods, and hurricanes, posing significant challenges.
Severe meteorological events, resulting in temperatures above 34 degrees and excess deaths, underscore the urgency of addressing climate change. Future climate scenarios project more frequent and intense heat waves globally, increasing the risk of desertification and wildfires, particularly in urban areas where climate change exacerbates outdoor air pollution due to its close correlation with local temperature, wind, and precipitation patterns.
Climate change-induced water scarcity in specific regions and water degradation may lead to population displacement and consequent migration-related health impacts. Notably, atopy and asthma show higher prevalence rates in developed and industrialized nations compared to less affluent countries, with migration age and duration influencing the likelihood of developing these conditions.
How Is Climate Change Related to Respiratory Health?
Climate changes are linked to air pollution, and an individual’s reaction to air pollution is influenced by various factors, including the source and composition of the pollution as well as climatic conditions. Specific episodes of rhinitis and asthma exacerbations related to air pollution can be attributed to climatic elements that facilitate the buildup of pollutants, such as ozone, at ground level. However, the impact of air pollutants on lung function is determined by factors like the environmental concentration of the pollutant, the duration of exposure, and the total ventilation of exposed individuals.
One complicating factor is that laboratory assessments may need to accurately measure real-world exposure, where individuals inhale atmospheric pollution mixtures present in polluted cities. Consequently, while it is plausible that ambient air pollution contributes to the onset and increased prevalence of respiratory allergies, it is challenging to demonstrate this at a public health level. Moreover, it is essential to recognize that an individual’s response to pollution exposure is influenced by the source and components of air pollution production and by atmospheric factors that promote the accumulation of pollutants.
What Is the Impact of Climate Change on Allergic Respiratory Diseases?
A growing body of evidence supports the influence of climate change on allergic respiratory diseases. Atmospheric and climate changes, including human-induced global warming, affect both the biosphere and the human environment. Various epidemiological and experimental studies have shown a connection between asthma and environmental factors, such as meteorological variables, airborne allergies, and air pollution.
The correlation between climate change, allergenic plants, and pollen distribution can be as follows:
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Increased and accelerated plant growth.
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Greater pollen production per plant.
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Higher levels of allergenic proteins are found in pollen.
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Earlier onset of plant growth, leading to earlier pollen production.
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Prolonged and earlier onset of pollen seasons.
Pollen allergies serve as a common model for the interplay between air pollution and allergic respiratory diseases, including rhinitis and asthma. There are also proven correlations between urbanization, high vehicle emissions, a Westernized lifestyle, and an increased prevalence of pollen-induced respiratory allergies among urban populations compared to rural dwellers.
Meteorological factors such as temperature, wind speed, humidity, and occurrences of thunderstorms, along with their climatic patterns (warm or cold anomalies, dry or wet periods), can impact both the biological and chemical components of this interaction. Air pollution can also exacerbate airway inflammation, amplifying allergen-induced responses by breaching mucosal barriers.
Climate changes may exacerbate respiratory allergic diseases by prolonging and intensifying pollen seasons, increasing the frequency of heavy precipitation events, and exacerbating urban air pollution episodes. However, the relationship between air pollution, pollen exposure, and respiratory allergy outcomes is contingent upon an individual’s response to air pollution, which is influenced by the source and composition of pollutants and climatic factors.
Thunderstorms and Allergic Respiratory Responses:
Observations indicate that thunderstorms during pollen seasons can trigger severe asthma attacks in individuals with pollen allergies. According to current climate change projections, there will be an increase in the frequency and intensity of heavy rainfall events, including thunderstorms, in the coming decades, likely leading to more severe asthma attacks in adults and children.
Associations between thunderstorms and asthma morbidity have been documented. This condition is referred to as “thunderstorm asthma," which is characterized by asthma outbreaks possibly triggered by the dispersion of respirable allergenic particles, such as pollen and spores, due to osmotic rupture.
Extreme Temperatures:
Heat waves lead to excess deaths, particularly among respiratory patients. Rising temperatures increase the risk of wildfires and desertification, emitting harmful pollutants that exacerbate respiratory illnesses. Drought conditions worsen air quality, posing health risks like respiratory infections. Urban areas are especially vulnerable due to the correlation between climate change and outdoor air pollution. Exposure to wildfire smoke is strongly associated with an increase in respiratory and cardiovascular hospital admissions and emergency department visits, particularly linked to levels of particulate matter.
Indoor and Outdoor Air Pollution:
Air pollution, indoors and outdoors, significantly impacts respiratory health. Pollutants such as inhalable particles and ozone exacerbate asthma symptoms and increase the risk of respiratory conditions. Outdoor air pollution, particularly from vehicle exhaust and ground-level ozone, has been linked to persistent airway and lung tissue damage, contributing to severe asthma symptoms and increased respiratory hospital admissions and deaths.
Allergic Responses:
The impact of climate change on respiratory allergies is uncertain, but changes in the timing, duration, and intensity of pollen seasons are expected. Global warming may increase allergen exposure and exacerbate respiratory problems, particularly when combined with air pollution. Variations in vegetation and allergenic pollen production are anticipated, potentially affecting different regions differently based on factors such as ultraviolet radiation and rainfall patterns.
Conclusion:
Climate change poses significant challenges for allergic respiratory diseases. Changes in pollen seasons increase allergen exposure, and respiratory symptoms are exacerbated due to air pollution, which highlights the urgent need for mitigation and adaptation strategies. Policymakers, healthcare professionals, and communities must collaborate in implementing measures to address climate change and protect respiratory health.
