The Effects of Climate Change on Allergies and Asthma Cases
Since the discovery of global warming or climate change, scientists have been warning the public of the possible implications this phenomenon could bring. They highlight erratic and severe weather patterns, changing ecosystems and the persistence of diseases that cannot easily be treated. While skeptics remain ignorant over these warnings and governments trying to make amends over their national policies, statistics show that these warnings should be taken seriously especially with regards to respiratory diseases such as asthma and allergies. However, it is a question as to what impacts climate change has towards the prevalence on allergies and asthma cases worldwide. With the onset of climate change, allergies and asthma cases become more severe as people become more exposed to allergen and irritants due to changing temperatures and weather patterns and increased pollution.
Asthma can be defined as a “disease of the bronchial tubes in the lungs, wherein patients experience ‘wheezing’ or high-pitched whistling sound heard while breathing.” The Global Asthma Network (2014) added that some asthma cases often show patients experiencing difficulty in breathing and coughing due to the continuous persistence of obstruction in their pathways or irritation. Patients who develop asthma have experienced its symptoms since childhood and even if they did not show these signs, asthma can develop even in adulthood. Several studies have been done throughout the years regarding the statistics of asthma cases worldwide. In the study of the Global Burden of Disease Study (GBD), at least 334 million people have asthma worldwide from 2008 to 2010. However, the statistics provided by the GBD is contested by some experts considering the data used by the study is not accurate given the available records of asthma cases for both children and adults per country. In the International Study of Asthma and Allergies in Childhood (ISAAC), the group estimated that at least 14% of children worldwide have experienced asthmatic symptoms and their prevalence varies per country. The prevalence of asthma cases is located mostly in the Latin American countries, Australasia, Europe, North America and South Africa. On the other hand; however, the lowest rate of prevalence of asthma cases is in the Indian subcontinent, Asia-Pacific, Northern and Eastern Europe and the Mediterranean (see appendix A). Further studies show that asthma cases are severe depending on the age of the patient as the study of the Institute for Health Metrics and Evaluation (IHME) showed that asthma disability and mortality is high for children ages 10-14 and the elderly ages 75 to 79. The impact of asthma is also similar to either male or female patients and it increases as they grow older based on the study. For ages 45 and older, for example, the impact of asthma is potential disability and for those older than 45 – ages 60 to 80+ - the possibility of premature death through asthma attacks is very high (see appendix B) .
Allergies or allergic diseases, on the other hand, are conditions wherein a patient’s immune system becomes hypersensitive once they get close to a specific substance like food, pollen and dust. According to Pawankar (2014), allergic diseases can vary substantially as not all allergies are the same and it can be triggered by various types of allergen. Some examples of allergic diseases are anaphylaxis, allergic rhinitis, eczema, food and drug allergies. Based on the studies highlighting trends of allergies, at least 200 to 250 million people are estimated to have food allergies worldwide and 400 million have allergic rhinitis. Within these cases, scientists discovered that allergic diseases sometimes occur at the same time in some patients. Since these allergic diseases tend to appear ever so often in certain patients, an integrated approach is necessary to determine the proper diagnosis for patients and how it could be treated.
If nothing is done to reduce the asthma and allergy rates worldwide, the World Health Organization sees the possibility that these cases would increase per year. For asthma cases, the WHO estimates that by 2025, the number of patients will increase up to 400 million. The WHO also reported that at least 250,000 deaths are recorded each year and the main cause for these deaths is due to asthma. Additional concerns are also raised by the WHO with regards to the age group mostly affected by the increasing prevalence of asthma and allergies as present trends show that children are vulnerable to these diseases. In the US, for example, a total of at least 14 million missed days are recorded per school year by children with asthma or allergies. In developing countries, the continuous asthma or allergy prevalence also shows the possibility of major consequences to the child’s education and eradication of poverty. Furthermore, several studies highlight that the economic burden and losses due to either asthma or allergies is very high as many people would miss work and schooling due to these diseases. Australia, for example, highlight that the direct cost – medication and healthcare - of all types of allergies to the country amounts to A$1.1 billion while indirect costs – cost to society – amount to A$8.3 billion in 2007 (see Appendix C) .
Given the statistics of asthma and allergy cases worldwide and the future trends of the diseases, scientists have highlighted that the onset of global warming or climate change plays a major impact in its continuous prevalence. Cecchi et al (2010) identified that climate change’s impacts in allergy and asthma cases can be seen in several aspects of aerobiological processes that fosters the persistence of either allergies or asthma. The first two aspects that is affected is the production and emission of allergenic pollen which changes because of existing production environments. Studies show that high CO2 exposure of pollen producing plants triggers changes in a plant’s pollen structure and production. In ragweed flowers, for example, increased CO2 exposure causes the plant to develop more allergens and prolong the symptoms caused by ragweed allergies. Pollen count also increases in terms of its production as climate change influences pollen season for many varieties of allergic plant species. In Europe, for example, the spring season is often delayed by 1 to 2 days but instances of early pollen production by certain plants like birch is reported. In cities or urban areas, high CO2 and temperature exposure creates a warm environment that certain species of plants prefer like Ambrosia for pollen production. As CO2 concentrations and warmer temperatures prevail, the intensity of allergen emission increases as temperatures and precipitation influences emission rate. In a study done in Switzerland, birch pollen rates per year and daily increased substantially over a 38-year period highlighting that birch trees in the country have emitted higher pollen concentrations per day .
Beggs and Bambrick (2006) and D’Amato, Liccardi, D’Amato and Cazzola (2002), the prolonged pollen production and emission season increases the potency of these allergens to the public and trigger higher rates of morbidity. Infants and young children may easily succumb to asthma and other allergic conditions, especially in intense pollen production seasons. In other cases, patients who contract the disease in their younger years would find the symptoms gradually worsen and lead to higher chances of morbidity . In a study done in Italy, the increased temperature in winter brought in early pollination and triggered longer allergic symptoms. Warmer seasons also fostered high seasonal allergic symptoms, especially in many Italian urban sectors .
In terms of dispersion or transport of allergens, D’Amato et al (2013) and Beggs (2010) stated that some studies – including the Intergovernmental Panel on Climate Change (IPCC)’s assessment – indicated that continuous warming temperatures influences the distribution of pollen upward for certain plant species, especially those that produces clinically important pollen. If the temperature continues to increase by up to 1.5 to 2.5 degrees Celsius per year, there is an expected change in the prominence of certain species of pollen geographically as some pollen types may disappear completely, while others would increase in number. Further changes in the distribution of allergen can also be attributed to the changing circulation patterns as some pollen may be subjected to long distance transport due to changing temperatures . It is suggested by some studies that high air temperatures can influence atmospheric instability, which then affects air flow that usually transports pollen in one area. However, it is important to consider that not all pollen or allergen is distributed in a similar manner and that changes in distribution may be due to other factors. In ragweed, for example, it is originally distributed in Central and Eastern Europe and its existence in other Eastern countries was brought by socio-economic problems such as disturbed land areas as seen in the collapse of communism. There are also cases of pollen or allergen that have decreased in some areas due to continuous urbanization .
Climate change also affects dispersion and transportation of pollen due to changing weather conditions, especially in cases of thunderstorms and cyclone seasons. According to D’Amato (2011), studies show that in every thunderstorm that occur and on high instances of precipitation due to typhoons or cyclones, pollen is released into the atmosphere as starch granules. This discovery of the capacity of severe thunderstorms and cyclones to assist in distributing pollen in huge quantities was discovered 15 years ago in the UK when an asthma outbreak was declared in Birmingham for 36 hours after a severe thunderstorm. At least 2 to 3 cases were added to the original 26 cases brought to the hospital after the thunderstorm. Australia also reported similar occurrences and in both cases, it was noted that there were no reports of high air pollution, but grass pollen was discovered as the main trigger for these attacks. The osmotic shock generated from thunderstorms caused grass pollen to release starch granules which possess high amounts of grass allergens. Since these granules are miniscule and not easy to track, these allergens can enter the airways and trigger bronchial allergic symptoms easily. In the London outbreak in 1994, scientists discovered that some of the patients examined and brought to hospitals did not originally did not experience seasonal rhinitis or asthmatic symptoms. In countries were outbreaks were not triggered by thunderstorms, it was noted that asthmatics and those with allergic disease history would start exhibiting severe signs of their symptoms once a thunderstorm or strong rains start .
Reid and Gamble (2009) also indicated that severe hurricanes induced by climate change had also induced high instances of allergic diseases. The major example of this trend is after hurricane Katrina, which left various areas of New Orleans underwater. Mold immediately spread throughout buildings and in the assessment of the Centers for Disease Control, at least half of 112 households showed “visible mold growth” and 17% suffered from “heavy mold coverage.” Upon further inspection and study, some of these molds have the capacity to induce allergies. Other studies in the area also revealed that there were higher mold spore counts from October to November 2005 in the area, developing in flooded areas. As a result of these developments, hospitals around the state reported increasing numbers of patients with allergies due to mold and dust. Coughing also became a problem in many patients in New Orleans, giving it the name “Katrina cough” due to the concentration of spore and allergen content in the area. At least 18% of New Orleans’ child population have developed asthma and this number is said to be potentially higher for the minority sector living in other areas affected by Katrina. Although some scientists would stress that Hurricane Katrina did not just develop due to climate change, it is important – experts pointed out – to consider that stronger precipitation in the future can trigger similar occurrences .
With the persistence of allergy and asthma cases worldwide due to the influence of climate change, several adaptation and mitigation strategies must be done to combat these increasing rates. According to the Interagency Working Group on Climate Change and Health (2010), additional research efforts must be done in order to determine how climate-sensitive diseases can be prevented. Although mitigation and adaptation strategies are currently available for the public to use, such as the reduction of ozone emissions through carpooling and alternative transportation, it is not enough to stop the impact of exposure to the public. Other sectors may contribute to the increase in allergen and pollutants, rendering short-term mitigation strategies ineffective. Adaptive measures can also render attempts for mitigation moot because some adaptive methods like using air conditioning can also generate emissions dangerous for health.
Additional research must start with the development – and creation - of real-time remote sensing modules and monitoring techniques which would enable experts and the public to determine air quality and allergen concentrations. Having these sensing and monitoring techniques and modules would assist in understanding the nature of allergens and how climate change affects its severity and impact . Some countries have already begun developing monitoring stations and research centers to combat allergies and asthma in their territories. The US, for example, currently has 78 counting stations in the mainland, 2 stations in Canada and 2 stations in Argentina under the Aeroallergen network and National Allergy Bureau to monitor allergen concentrations and air quality index in the continent. The European Union had also opened up their own European Aeroallergen Network which assists in researching allergen quantification and mitigation efforts. Satellite imagery and remote sensing are also used by some countries to determine ground level coverage of certain pollen as airborne pollen data is not as comprehensive in determining ground-level pollen ratio .
Governments and healthcare organizations must also start determining high-risk areas prone to climate-related respiratory diseases and provide early warning systems and health care support. Having a clear map of high-risk populations and which regions to concentrate on will allow the government and health care sector determine the common factors as to why climate-related health risks such as allergy and asthma persist in the area. Early warning systems would use these data in understanding how the state and local government can apply mitigation strategies to contain the asthma and allergy content . Early warning systems may also assist local and state governments in determining when allergen or pollen concentrations are high and base pre-emptive action from there. Increasing forecasting ability of governments would also help in managing the adverse impacts of allergy and asthma for other regions. Healthcare and medication must also be given in these high-risk areas and easily accessible for other areas because this would ensure that immediate treatment would be given to patients.
It is also necessary to introduce new planting practices and policies as this would help regulate plants known to develop high concentrations of allergens, especially if exposed to CO2 emissions and warmer temperature. Some countries, especially those from warmer territories, can use plant management systems to reduce certain species in their territory. In Europe, for example, ragweed plants are carefully destroyed by governments in order to reduce instances of ragweed allergies. Plant management systems and policies can also assist urban areas because there are species of plants that can be used to reduce allergen concentrations and at the same time, assist in boosting urban reforestation. Experts argue that introducing green spaces in rooftops, streets, and sidewalks would assist in reducing greenhouse emissions and increase sustainability in the area. Families can even convert their existing gardens to host low allergen plants which would promote pollination. If these new planting strategies are properly observed, experts stress that it would assist in removing ambient pollen concentrations that often causes allergic or asthmatic symptoms in the process.
The government must also reintroduce new urban planning and building design frameworks which would assist in reducing the possibility of allergen or spore development. Contractors and planners must be aware of the factors that would trigger indoor and outdoor exposure before they construct in an area. These considerations must be put on top of the planning stage of any construction project, especially in flood prone area. The plan must also take into consideration overall health of inhabitants and must possess areas with green spaces to minimize allergen content in the environment. Urban planners must also consider areas where physical activity is supported because asthma and allergies can become severe if a person has type II diabetes and overweight. Building design must also consider proper heating, ventilation and air-conditioning before it is constructed because indoor allergens are a possibility if these factors are not considered. A building must be able to foster natural air filtration capabilities, and at the same time, reduce possibilities of outdoor pollen from entering the area.
Finally, education must also be improved when it comes to how the public can prevent the impacts of higher allergen exposure to their health, especially for patients or those at risk to both diseases. Specialized lessons discussing allergen concentrations and its sources must be given to students, teachers and communities alike to prepare them for immediate action. Education would also help these people determine signs of early pollen seasons, assisting mitigation efforts in reducing allergy and asthma cases. Allergy and asthmatic patients can use this knowledge in avoiding areas where their symptoms can worsen, while others can use their knowledge in helping their love ones. Education would also help in ensuring that the public can take necessary steps in their homes on how they can reduce allergy and asthma cases in their family .
As the world continues to fight against climate change, there is a high risk that illnesses and diseases would change to match the current environment. Asthma and allergy cases are not exempted from this change and studies clearly show that climate change affects its prevalence. Higher CO2 emissions and warmer temperatures induces high pollen production and distribution, with severe weather patterns further increasing exposure risks to the public. It is important that the international community – through governments and health care sectors – to begin the application of key mitigation and adaptation strategies to reduce allergy and asthma attacks. If nothing is to be done, more people would suffer from these diseases especially children who cannot fight back easily against these diseases.
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Appendix
Appendix A: The Prevalence of asthma symptoms among 13-14 year olds. This figure shows the ISAAC estimate of the prevalence of asthma symptoms among 13 to 14 year olds worldwide .
Appendix B: The burden of disease per age group. The figure shows the impact of asthma to certain age groups and sex as noted by the IHME .
Appendix C. Economic Burden of Allergies from 2005 to 2007. This figure shows the economic losses brought by allergies and asthma to several regions worldwide .
