Report On Effects Of Environmental Climate Change On Prevalence, Severity And Morbidity Of Asthma

Climate Change and Asthma

Human activity has created increased atmospheric carbon dioxide emissions and greenhouse gases, which has resulted in global climate change (Intergovernmental Panel on Climate Change (IPCC) 2001). There is scientific consensus that human activity has changed the Earth’s climate, with a variety of adverse reactions. Recent research has predicted that global climate change is likely to have an effect on asthma rates worldwide in the future (Beggs and Bambrick 2006). Asthma rates have increased from 7.3 percent of the population to 8.4 percent over the last decade. Other research suggests the observed increase in asthma could be due to climate change that has already occurred (D’Amato, et. al, 2010). There is substantial and concrete evidence that the prevalence of asthma and its severity have increased globally over the last thirty years. (Beggs and Bambrick, 2006). The causes of asthma are complex, and rates and patterns are different around the world, however, the recent global rise in asthma has been attributed to anthropogenic climate change (Beggs and Bambrick, 2006). The climate is becoming warmer, making plants grow faster, and creating more pollen, which is making allergies and asthma conditions worse. Asthma is a serious public health concern, affecting twenty-five million people in the U.S, and costing the U.S. economy over $20 billion a year (Hooven, 2013). The purpose of this report is to review the literature and research on climate change and its effects on asthma in humans. Climate change involves biological aerosols, aeroallergens and organic particulates. There are numerous types of asthma, this report will focus on allergic pollen-induced asthma.

Anthropogenic Climate Change

In the last fifty years, there has been a large and measurable increase in global atmospheric carbon dioxide concentrations. Before the Industrial Revolution, it had been 270-290 ppm for several thousand years (Prentice, et, al, 2001). It is much higher now. The annual mean concentration measured at the Hawaiian Mauna Loa Observatory was 373 ppm in 2002. (Kneeling and Whorf, 2003). This almost 100 ppm increase over roughly three hundred years has not been linear. In 1959, when CO2 concentrations were first recorded at Mauna Loa, it was 316 ppm. This “suggests that approximately two-thirds of the increase in atmospheric CO2 concentration since the Industrial Era has occurred over the last 50 years or so” (Beggs and Bambrick, 2006, p. 14). This increase in CO2 has been linked to global warming. Worldwide average temperature has increased by almost 1°C over the past 100 years, and the Intergovernmental Panel on Climate Change (IPCC) predicts that average global surface temperatures in 2090–2099 will be between 1.8 and 4.0°C warmer than in 1980–1999. The IPCC has stated that "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations" (IPCC, 2001).
Many of the environmental consequences of climate change are seen as being long term. However many changes have already been observed, including rising oceans, increased flooding and drought, worsening air quality, heat waves, and more intense hurricanes and storms, all which can adversely affect human health (Prentice, et. al, 2001).

Asthma is a “National Epidemic”

The EPA recently released a report calling asthma a “national epidemic" that affects one of every 12 people, or 56 million nationwide (Hooven, 2013). Bronchial asthma and other respiratory ailments are already on the rise in much of the world. The World Health Organization estimates that 300 million people globally have asthma, with 250,000 dying from the disease each year. The allergic diseases, including asthma, hay fever, rhinitis, and dermatitis, effect approximately 50 million individuals in the U.S. and are responsible for significant health care costs and diminished productivity (WHO, 2014). Respiratory illnesses in the U.S. cost $11 billion with an estimated loss of 3 million workdays and 11 million schooldays (Smith, 1997). Bronchial asthma is the second leading cause of chronic illness among children. Environmental factors do not just make asthma worse for sufferers, it can actually cause asthma, increasing the rates and the prevalence of the condition. Asthma also has an effect on society, even those who don't suffer directly, the economic costs of medical care and loss of productivity are substantial.
Asthma is etiologically complex, with numerous causes and contributing factors. Many of these factors are climate related. Climate change extends allergy season and raises pollen counts. Another factor is excess rainfall and humidity, which encourages fungi and molds. Since 1995, warmer temperatures in the U.S. have caused the ragweed pollen season to increase by 1 to 27 days. Interestingly, a 2011 study found that the ragweed season has grown longer in the northern U.S., compared to the south. The ragweed season increased one day from 1995 to 2009 in Oklahoma City. However, it jumped 16 days in Fargo, N.D., and 27 days in Saskatoon, Canada. (Ziska and Bielory, 2011). Since the northern part of the U.S. has warmed more than the south in the last fifty years, this strengthens the theory that warmer temperatures are increasing the duration of pollen seasons, and suggests that climate change has an effect on asthma. Different regions of the U.S. have higher rates of climate related warming (and asthma) than others. One study predicts that New York state will suffer higher than average effects of climate change, compared to other regions in the coming decades (Bell, et. at, 2007). Like some other northern states, New York has warmed 2.5 degrees, twice the global average, in the last forty years. (Bell, et. al, 2007).

How Does Climate Change Decrease Air Quality?

Climate change is predicted to decrease air quality through several pathways, including production of allergens, ground level ozone, fine particles, and dust.  These pollutants can directly cause respiratory disease or intensify existing conditions in vulnerable population groups, including the elderly and young children. The simple explanation, that warmer temperatures make plants grow faster so there is more pollen, is only the beginning of the factors that may play a role in asthma. According to the IPCC (2007), pollen quantity and duration of pollination depend on environmental and meteorological variables and contribute to asthma attacks in a number of ways:
Increased surface level fine particle and ozone concentrations, which can trigger allergic and asthmatic reaction including chest pains, congestion, watery eyes, cough, throat irritation, reduced lung function and inflammation of the lungs

Increased airborne allergen distribution of pollen and mold spores

Increased precipitation in some areas leading to an increase in allergenic mold spores
Increased ozone due to higher temperatures and increased sunlight
Increased droughts, producing dust and particulate matter
Climate change might also alter the timing and duration of pollen and spore seasons and the geographic range in which they spread.

Asthma’s Effect on Children, Pregnant Women and the Elderly

The majority of asthma deaths are in at-risk populations such as young children, pregnant women and the elderly (IPCC, 2001). A 2008 Center for Disease Control (CDC) report shows that that the increasing rate of pediatric hay fever is higher than drug or food allergies, which have remained stable since 1997 (Akinbami, 2008). The CDC reported a 17% increase in pediatric asthma prevalence from 2001 through mid-2012 (Akinbami, 2008).For patients who already have asthma, climate change may be exacerbating their condition. Björkstén and Suoniemi (1981) found that exposure to more intense pollen seasons in early infancy increased the likelihood of later development of allergy. Climate change is exposing vulnerable populations to allergens more frequently, longer and with more severity.

Climate Change Effects Ragweed and Cities the Most

Climate change seems to have a greater effect on weeds than other plants (Ziska, et. al, 2011). In particular, the ubiquitous ragweed seems to be exploding. There is more of it and it is pollinating much longer. Elevated levels of CO2 encourage weeds to “produce pollen out of proportion with their growth rates — meaning you get more pollen per plant, which means more allergies” (Walsh, 2008). In fact, ragweed seems to thrive in high CO2 environments: “The wave of urbanization in America and much of the world doesn't help — the urban environment, often hotter and with more CO2 than rural areas, is ragweed heaven” (Walsh, 2008). Research shows that ragweed exposed to CO2 enrichment (600–800 ppm) on the reproductive organs of plants showed total mass increased by 31%. The increased ragweed and longer ragweed seasons have made allergy and asthma sufferer miserable throughout the U.S. (Walsh, 2008).
The research of the proliferation of asthma due to climate change has also focused on cities, where asthma are increasing at a higher rate, and on ragweed, which seems to becoming explosively pollinated in recent years. In Cities as harbingers of climate change: Common ragweed, urbanization, and public health (2003), Ziska and Gebhard examine the effect of environmental change on pollen production of ragweed. The researchers compared ragweed growth in both city and rural locations. The average daily CO2 concentration and air temperature within an urban environment were 31% and 3.6°F higher than those at a rural site. Ragweed “grew faster, flowered earlier, and produced significantly greater above-ground biomass and ragweed pollen at urban locations than at rural locations” (Ziska and Gebhard, 2003) Air temperature and atmospheric CO2, are higher in urban areas. The study concluded that urban co2 concentrations and elevated pollen levels had serious public health consequences that warranted further investigation. (Ziska and Gebhard, 2003).

Regional Climate Abnormalities and “Thunderstorm Asthma”

Regionally, pollen and asthma rates are highly dependent on a variety of factors, including plant life, urban vs. rural populations, and geographic location. Temperate areas seem to see a higher level of warming, pollen counts, and asthma. Longer growing seasons in a warmer world may further worsen allergies. A study in the Journal of Allergy and Clinical Immunology reported data showing that from 1982 to 2001, increasingly early pollination the olive crop in Spain led to much higher overall pollen counts, similar to those found in much warmer parts of the Mediterranean region. The study concluded that “comparable outcomes can be expected in other temperate parts of the world as climate change kicks in” (Cecchi, et. al, 2003). Similar research has predicted that northern climates, as far north as Scandinavia, may soon see warmer temperatures, higher pollen counts and allergies and asthma (D’amato, et. al, 2007).
Climate change has also been attributed to other abnormalities including “thunderstorm asthma”, which was first recorded and discussed in the UK in the mid-1980’s. characterized by asthma outbreaks possibly caused by the dispersion of pollution, molds, spores and other allergenic particles by “osmotic rupture” (D’Amato, et. al, 2010). Since the first reports of thunderstorm related asthma attacks in the United Kingdom in 1985, multiple thunderstorm episodes have been characterized by reported increases in emergency room visits for asthma around the world (D’Amato, et. al, 2010). According to Bell & Goldberg (2007), there will be increased frequency and intensity an of heavy thunderstorms over the next few decades, which can be expected to increase the number and severity of asthma attacks both in adults and in children. The mechanics of thunderstorm asthma is not fully understood, but researchers hypothesize that “heavy thunderstorm winds create updrafts that lift pollen and mold particles from the ground. Beating rain saturates and bursts the particles into tiny pieces. A downdraft then spreads those small particles into the environment and the air we breathe” (Levingston, 2014)
Some researchers believe the electrical charge of the storm make particulates more likely to “stick in the lungs” when inhaled (Suphioglu 1998). The particulates are primarily grains of grass weed pollen, and mold spores, primarily Alternaria and Cladosporium. These two molds are associated with asthma in medical studies (Levingston, 2014). Rain and humidity induces hydration and breakage and fragmentation of pollen grains, which releases “allergenic biological aerosols into the atmosphere” (Suphioglu, 1998, p. 253). During a thunderstorm, asthmatic individuals may inhale a high concentration of biological aerosols and dispersed particulates, which can induce severe asthmatic reactions.

Asthma and Climate Change in the Future

It is clear that human activities have led to increases in atmospheric carbon dioxide concentration and consequent changes in climate (IPCC 2001). There is also a clear correlation between effects of climate change and increased rates of asthma. Both research and evidence from patients and emergency rooms have shown that that aeroallergens have enormous clinical and public health significance (Beggs and Bambrick). While there are many factors associated with asthma, climate change provides an additional explanation for both increasing asthma susceptibility, prevalence and the increasing severity for patients around the world. (McMichael, Woodruff & Hales, 2006). Some reasons asthma has become more widespread may be because of increased levels of pollen due to longer growing seasons. Dust, mold and other particulates from both droughts and increased rain have also contributed to a more toxic environment for asthma sufferers to live in. A number of populations are particularly at risk for problems associated with climate exacerbated asthma: Children, pregnant women, and the elderly. For these groups and all asthma sufferers, further research is important to determine the safety risks associated with pollen levels, abnormal weather events that can cause conditions like thunderstorm asthma, and the factors that cause asthma onset in young children. Climate change will be a challenge in the 21st century, and the health related consequences are only beginning to be investigated and understood. Research on the health effects of climate change can help countries and international agencies develop national and international policies to protect public health, and further justify environmental regulations and emphasize the importance of decreasing greenhouse gas emissions.

References

Akinbami, L. J. (2006). The state of childhood asthma, United States. CDC Advanced Data and Vital Statistics. smith, DH, et al., am J respir crit care med, 1997. 156(3 Pt 1): p. 787-93, Weiss, KB, et al., N engl J med, 1992.
Asher MI, Keil U, Anderson HR, Beasley R, Crane J, Martinez F, et al. International study of asthma and allergies in childhood (ISAAC): rationale and methods. Eur Respir J 1995; 8:483-91.    
Bell, M. L., Goldberg, R., Hogrefe, C., Kinney, P. L., Knowlton, K., Lynn, B., & Patz, J. A. (2007). Climate change, ambient ozone, and health in 50 US cities.Climatic Change, 82(1-2), 61-76.
Beggs, P. J., & Bambrick, H. J. (2006). Is the global rise of asthma an early impact of anthropogenic climate change?. Ciência & Saúde Coletiva, 11(3), 745-752.
Björkstén F, Suoniemi I. 1981. Time and intensity of first pollen contacts and risk of subsequent pollen allergies. Acta Med Scand 1981; 209:299-303.
Cecchi, L., d’Amato, G., Ayres, J. G., Galan, C., Forastiere, F., Forsberg, B., & Annesi‐Maesano, I. (2010). Projections of the effects of climate change on allergic asthma: the contribution of aerobiology. Allergy, 65(9), 1073-1081.
"D’amato, G., Cecchi, L., Bonini, S., Nunes, C., Annesi‐Maesano, I., Behrendt, H., & Van Cauwenberge, P. (2007). Allergenic pollen and pollen allergy in Europe. Allergy, 62(9), 976-990.
D'amato, G., Cecchi, L., D'amato, M., & Liccardi, G. (2010). Urban air pollution and climate change as environmental risk factors of respiratory allergy: an update. Journal of Investigational Allergology and Clinical Immunology, 20(2), 95-102.
Hooven, Molly. "Nearly 26 Million Americans Continue to Live with Asthma, EPA." Environmental Protection Agency. N.p., 05 July 2013. Web.
IPCC. Climate Change 2001: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change (McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS, eds). Cambridge, UK: Cambridge University Press; 2001. 
IPCC. Climate change 2007: the physical science basis. In: SolomonS, QinD, 
ManningM, ChenZ, MarquisM, AverytKB, TignorM,MillerHL, (2007). editors. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press: 996 pp.
Keeling, CD & Whorf, TP. 2007. Atmospheric Carbon Dioxide Record from Mauna Loa.
Carbon Dioxide Information Analysis Center. Trends: A Compendium of Data on
Global Change. Oak Ridge, TN: Carbon Dioxide Information Analysis Center,
Oak Ridge National Laboratory.
Levingston, Suzanne. "You Thought Rain Washed Away Pollen. It Does, but a Heavy Storm Can Also Worsen Allergies and Asthma." Washington Post. The Washington Post, n.d. Web. 11 Feb. 2014.
McMichael, A. J., Woodruff, R. E., & Hales, S. (2006). Climate change and human health: present and future risks. The Lancet, 367(9513), 859-869.
Prentice IC, Farquhar GD, Fasham MJR, Goulden ML, Heimann M, Jaramillo VJ, et al. The carbon cycle and atmospheric carbon dioxide. In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (Houghton JT, Ding Y, Griggs DJ, Noguer M, van der Linden PJ, Dai X, et al., eds). Cambridge, UK: Cambridge University Press; 2001; p. 183-237.
Smith, D. H., Malone, D. C., Lawson, K. A., Okamoto, L. J., Battista, C., & Saunders, W. B. (1997). A national estimate of the economic costs of asthma.American Journal of Respiratory and Critical Care Medicine, 156(3), 787-793.
Suphioglu, C. (1998). Thunderstorm asthma due to grass pollen. International archives of allergy and immunology, 116(4), 253-260.
Walsh, Bryan. "Allergies Getting Worse? Blame Global Warming." Time. Time Inc., 15
Sept. 2008. Web. 11 Feb. 2015.
World Health Organization, 2014. "Climate Change and Health." WHO. N.p., n.d. Web. 11 Feb. 2015.
Ziska, L., Knowlton, K., Rogers, C., Dalan, D., Tierney, N., Elder, M. A., & Frenz, D. (2011). Recent warming by latitude associated with increased length of ragweed pollen season in central North America. Proceedings of the National Academy of Sciences, 108(10), 4248-4251.
Ziska, L. H., Gebhard, D. E., Frenz, D. A., Faulkner, S., Singer, B. D., & Straka, J. G. (2003). Cities as harbingers of climate change: common ragweed, urbanization, and public health. Journal of Allergy and Clinical Immunology,111(2), 290-295