The effects of climate change on respiratory allergy and asthma induced by pollen and mold allergens.

The impact of climate change on the environment, biosphere, and biodiversity has become more evident in the recent years. Human activities have increased atmospheric concentrations of carbon dioxide (CO2 ) and other greenhouse gases. Change in climate and the correlated global warming affects the quantity, intensity, and frequency of precipitation type as well as the frequency of extreme events such as heat waves, droughts, thunderstorms, floods, and hurricanes. Respiratory health can be particularly affected by climate change, which contributes to the development of allergic respiratory diseases and asthma. Pollen and mold allergens are able to trigger the release of pro-inflammatory and immunomodulatory mediators that accelerate the onset the IgE-mediated sensitization and of allergy. Allergy to pollen and pollen season at its beginning, in duration and intensity are altered by climate change. Studies showed that plants exhibit enhanced photosynthesis and reproductive effects and produce more pollen as a response to high atmospheric levels of carbon dioxide (CO2 ). Mold proliferation is increased by floods and rainy storms are responsible for severe asthma. Pollen and mold allergy is generally used to evaluate the interrelation between air pollution and allergic respiratory diseases, such as rhinitis and asthma. Thunderstorms during pollen seasons can cause exacerbation of respiratory allergy and asthma in patients with hay fever. A similar phenomenon is observed for molds. Measures to reduce greenhouse gas emissions can have positive health benefits.

[Thunderstorm and asthma outbreaks during pollen season]. / Temporali e attacchi d'asma durante le stagioni polliniche.

An increasing body of evidence shows the occurrence of asthma epidemics, sometimes also severe, during thunderstorms in the pollen season in various geographical zones. The main hypothesis explaining association between thunderstorms and asthma claims that thunderstorms can concentrate pollen grains at ground level; these grains may then release allergenic particles of respirable size in the atmosphere after their rupture by osmotic shock. During the first 20-30 minutes of a thunderstorm, patients suffering from pollen allergy may inhale a high concentration of the allergenic material dispersed into the atmosphere, which can, in turn, induce asthmatic reactions, often severe. Subjects without asthma symptoms but affected by seasonal rhinitis can also experience an asthma attack. All subjects affected by pollen allergy should be alerted to the danger of being outdoors during a thunderstorm in the pollen season, as such events may be an important cause of severe bronchial obstruction. Considering this background, it is useful to predict thunderstorms during pollen season and, thus, to prevent thunderstorm-related clinical event. However, it is also important to focus on therapy, and it is not sufficient that subjects at risk of asthma follow a correct therapy with bronchodilators, but they also need to inhale corticosteroids, using both in case of emergency.

Climate change, air pollution, and allergic respiratory diseases: an update.

PURPOSE OF REVIEW: The rising trend in prevalence of allergic respiratory disease and bronchial asthma, observed over the last decades, can be explained by changes occurring in the environment, with increasing presence of biologic, such as allergens, and chemical atmospheric trigger factors able to stimulate the sensitization and symptoms of these diseases. RECENT FINDINGS: Many studies have shown changes in production, dispersion, and allergen content of pollen and spores because of climate change with an increasing effect of aeroallergens on allergic patients. SUMMARY: Over the last 50 years, global earth's temperature has markedly risen likely because of growing emission of anthropogenic greenhouse gas concentrations. Major changes involving the atmosphere and the climate, including global warming induced by human activity, have a major impact on the biosphere and human environment.Urbanization and high levels of vehicle emissions are correlated to an increase in the frequency of pollen-induced respiratory allergy prevalent in people who live in urban areas compared with those who live in rural areas. Measures of mitigation need to be applied for reducing future impacts of climate change on our planet, but until global emissions continue to rise, adaptation to the impacts of future climate variability will also be required.