Researchers say asthma and allergy triggers may be commonly found at home. That means there are things you can do to reduce the cause of your family's symptoms.
Steven Pannkuk loves playing with his kids but he worries about their health. "I have some asthma and allergies in my genetics," he says. While genetics do play a role, environmental toxicologists say the bigger culprit may be in the carpet and other places that collect dust.
A new study indicates bacteria in household dust releases chemicals called endotoxins, which can inflame airways and trigger asthma.
Peter Thorne, an environmental toxicologist at the University of Iowa in Iowa City says, "If you think of a bacterium as an orange, the endotoxin is the material that makes up the peel. It's the outer layer. And this becomes shed from bacteria, and it's everywhere in the environment.
Researchers found the bedroom had fewer endotoxins, but it had a greater impact on a child's health. After all, that's where kids spend almost half their day. Plus, they have closer contact with the endotoxins. "Endotoxin in the home is related to higher rates of asthma," Thorne says.
There are things you and your family can do to lower the amount of endotoxins: wash your bed linens in hot water at least once a week, reduce clutter so you can clean better, purchase allergen-prevention pillow cases and mattress covers and don't eat in bed.
"I just try and be a little more conscious inside of what I can do so I can control my environment on the inside," Pannkuk tells DBIS. He is stuck with his seasonal allergies but is happy he can control environmental factors that affect his family.
Another cause of asthma in the home is pet dander. Cases of asthma tripled among newborns to 4-year-olds between 1980 and 2000.
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BACKGROUND: Bacteria lurking in household dust produces chemicals that may trigger asthma symptoms, whether a person suffers from asthma or allergies or not. The results, from the first nationwide study of toxins made by bacteria in households, indicate that it's not just the concentration of the bacteria-made toxin that is important. Other factors, such as how long and when a person is exposed to the bacterial toxin, as well as genetic factors, may contribute to the development of asthma.
THE STUDY: The nationwide study involved the analysis of more than 2,500 dust samples from 831 homes across the U.S. Results showed a strong association between the levels of toxins made by bacteria -- called endotoxins -- and the prevalence of diagnosed asthma, asthma symptoms and wheezing. People in households with higher endotoxin concentrations had higher instances of respiratory symptoms.
ABOUT ENDOTOXINS: Endotoxins are found in the cell wall of bacteria and are only released when the cell ruptures or disintegrates. Because bacteria can be found everywhere in the home, the likelihood of such a release is very high. Once released, endotoxins can cause inflammation of the airways and lead to asthma symptoms. Endotoxin levels can be reduced in the same way that allergy symptoms can be reduced: by removing dust, keeping the floors as clean as possible, keeping moisture low, repairing water damage, cleaning bed linens, and using a high-efficiency vacuum cleaner with a HEPA filter, among other actions.
ASTHMA OR ALLERGIES? Asthma is a chronic disease affecting the airways that carry air in and out of the lungs. The inside walls of the airways become inflamed (swollen) and narrower so less air can flow through the lung tissues. This in turn causes wheezing, coughing, tightness in the chest, and trouble breathing. Asthma is linked to allergies, although not everyone with asthma has allergies. People with allergies tend to react more strongly to the presence of allergens such as animal dander, dust mites, pollen or mold, as well as cigarette smoke and air pollution.
Tuesday, June 30, 2009
Peer Pressure Plays Major Role In Environmental Behavior
People are more likely to enroll in conservation programs if their neighbors do--a tendency that should be exploited when it comes to protecting the environment, according to results of a new study.
The research, to be published in the journal Proceedings of the National Academy of Sciences (PNAS) this week, is the first to focus on the phenomenon of social norms in the context of China's conservation efforts, said scientist Jianguo "Jack" Liu of Michigan State University (MSU).
The study focused on a mammoth government initiative called Grain-to-Green that pays Chinese farmers to convert cropland back to forest.
"Much of the marginal cropland in rural communities has been converted from agriculture to forests through the Grain-to-Green Program, one of the largest 'payment for ecosystem services' programs in the world," said Alan Tessier, program director in the National Science Foundation (NSF)'s Division of Environmental Biology.
"Results of this study show that a community's social norms have substantial impacts on the sustainability of these conservation investments."
Liu's research was funded through NSF's Coupled Natural and Human Systems (CNH) Program. CNH is co-funded by three NSF Directorates: Biological Sciences; Geosciences; and Social, Economic & Behavioral Sciences.
While money is a key factor in whether people sign up for the voluntary program, peer pressure also plays a surprisingly large role, Liu said.
"That's the power of social norms," he said. "It's like recycling. If you see your neighbors doing it, you're more likely to do it."
A representative survey of households in China's Wolong Nature Reserve for giant pandas found that both government payments and social norms had "significant impacts" on citizens' intentions of re-enrolling in the Grain to Green program.
"In other words, people's re-enrollment intentions can be affected by the re-enrollment decisions of their neighbors and tend to conform to the majority," says Liu.
Xiaodong Chen, a doctoral student at MSU and lead author of the paper, said government officials should leverage these social norms along with economic and demographic trends when deciding how to support conversation programs such as Grain to Green.
"We found that, without considering the social norm factor, conservation payments may not be used efficiently," Chen said.
"But if the government considers social norms as it decides where to invest money, it could obtain more environmental benefits in communities that are supportive of these programs than in those that aren't."
Added co-author and MSU scientist Frank Lupi: "Simply by taking account of the social norms, more conservation can be obtained from limited conservation budgets."
Also contributing to the study was doctoral student Guangming He.
Funding also was provided by NASA, the National Institutes of Health, MSU's Environmental Research Initiative and the Michigan Agricultural Experiment Station.
The research, to be published in the journal Proceedings of the National Academy of Sciences (PNAS) this week, is the first to focus on the phenomenon of social norms in the context of China's conservation efforts, said scientist Jianguo "Jack" Liu of Michigan State University (MSU).
The study focused on a mammoth government initiative called Grain-to-Green that pays Chinese farmers to convert cropland back to forest.
"Much of the marginal cropland in rural communities has been converted from agriculture to forests through the Grain-to-Green Program, one of the largest 'payment for ecosystem services' programs in the world," said Alan Tessier, program director in the National Science Foundation (NSF)'s Division of Environmental Biology.
"Results of this study show that a community's social norms have substantial impacts on the sustainability of these conservation investments."
Liu's research was funded through NSF's Coupled Natural and Human Systems (CNH) Program. CNH is co-funded by three NSF Directorates: Biological Sciences; Geosciences; and Social, Economic & Behavioral Sciences.
While money is a key factor in whether people sign up for the voluntary program, peer pressure also plays a surprisingly large role, Liu said.
"That's the power of social norms," he said. "It's like recycling. If you see your neighbors doing it, you're more likely to do it."
A representative survey of households in China's Wolong Nature Reserve for giant pandas found that both government payments and social norms had "significant impacts" on citizens' intentions of re-enrolling in the Grain to Green program.
"In other words, people's re-enrollment intentions can be affected by the re-enrollment decisions of their neighbors and tend to conform to the majority," says Liu.
Xiaodong Chen, a doctoral student at MSU and lead author of the paper, said government officials should leverage these social norms along with economic and demographic trends when deciding how to support conversation programs such as Grain to Green.
"We found that, without considering the social norm factor, conservation payments may not be used efficiently," Chen said.
"But if the government considers social norms as it decides where to invest money, it could obtain more environmental benefits in communities that are supportive of these programs than in those that aren't."
Added co-author and MSU scientist Frank Lupi: "Simply by taking account of the social norms, more conservation can be obtained from limited conservation budgets."
Also contributing to the study was doctoral student Guangming He.
Funding also was provided by NASA, the National Institutes of Health, MSU's Environmental Research Initiative and the Michigan Agricultural Experiment Station.
Waste water plus bugs make hydrogen
Bacteria that feed on vinegar and waste water zapped with a shot of electricity could produce a clean hydrogen fuel to power vehicles that now run on petrol, researchers report.These so-called microbial fuel cells can turn almost any biodegradable organic material into zero-emission hydrogen gas fuel, says Professor Bruce Logan of Penn State University.This would be an environmental advantage over the current generation of hydrogen-powered cars, where the hydrogen is most commonly made from fossil fuels.Even though the cars themselves emit no greenhouse gases, the manufacture of their fuel does."This is a method of using renewable organic matter, using anything that's biodegradable and being able to generate hydrogen from that material," Logan says.In research published today in the Proceedings of the National Academy of Sciences, Logan and colleague Dr Shaoan Cheng used naturally-occurring bacteria in an electrolysis cell with acetic acid, the acid found in vinegar.The bacteria slurp up the acetic acid and release electrons and protons creating up to 0.3 volts of electricity. When a bit more electricity is added from an outside source, hydrogen gas bubbles up from the liquid.Water is the only emissionThis is far more efficient than water hydrolysis, where an electric charge is run through water to break it down into its constituent parts of oxygen and hydrogen."It uses about a 10th as much energy as water electrolysis," Logan says.That is because the bacteria do most of the work, breaking the organic material into subatomic particles, so all the electricity does is juice these particles to form hydrogen.The resulting fuel is a gas, not a liquid, but could still be used to power vehicles
This process could be used with cellulose, glucose, acetate or other volatile acids, Logan says. The only emission is water.Although it sounds futuristic, microbial fuel cell technology is available now. The researchers have filed for a patent on this work.These cells are too large to be put into cars, so the gaseous hydrogen fuel they produce must be made in a factory."You could put one of these reactors at a food processing plant and take the waste water and make hydrogen out of it," Logan says."Or you could go to a farm, where there's lot of cellulose or ... agricultural cellulosic residues, take that and make hydrogen there."This would be unlikely to work in big cities but might well be effective in rural areas."The first step is just to start using locations where we have waste waters that were spending money on treating, and turning those water treatment plants into hydrogen production plants," Logan says.
This process could be used with cellulose, glucose, acetate or other volatile acids, Logan says. The only emission is water.Although it sounds futuristic, microbial fuel cell technology is available now. The researchers have filed for a patent on this work.These cells are too large to be put into cars, so the gaseous hydrogen fuel they produce must be made in a factory."You could put one of these reactors at a food processing plant and take the waste water and make hydrogen out of it," Logan says."Or you could go to a farm, where there's lot of cellulose or ... agricultural cellulosic residues, take that and make hydrogen there."This would be unlikely to work in big cities but might well be effective in rural areas."The first step is just to start using locations where we have waste waters that were spending money on treating, and turning those water treatment plants into hydrogen production plants," Logan says.
Liquid coal for cars 'dirtier' than petrol
Some alternative vehicle fuels such as liquid coal can cause more harmful greenhouse gas emissions than petrol or diesel, scientists warn."Liquid coal, for example, can produce 80% more global warming pollution than [petrol]," says the US non-profit environmental group, the Union of Concerned Scientists.Some people have billed liquid coal, the name for petrol or diesel derived from coal, as a potential replacement to the oil on which countries rely heavily to fuel vehicles.Likewise another alternative fuel, petrol from tar sands, is estimated to have 14% more global warming potential compared with standard petrol, says the union in its latest report Biofuels: an important part of a low-carbon diet."Corn ethanol, conversely, could be either more polluting or less than [petrol], depending on how the corn is grown and the ethanol is produced," the report says.The analysis is based on replacing a fifth of all petrol used in the US with alternative fuels by 2030.If most of these alternatives consist of liquid coal, the change could pump pollution into the atmosphere equivalent to 34 million more cars on the road, the report says.But favouring cleaner "advanced biofuels" could cut harmful gases by a similar amount.The cleanest alternative, the report says, is cellulosic ethanol, made from grass or wood chips. It could cut greenhouse emissions compared with petrol by more than 85%."We need to wean ourselves off oil, but we should replace it with the cleanest alternatives possible," says study author Patricia Monahan."Let's not trade one bad habit for another."
Green Revolution in India
The introduction of high-yielding varieties of seeds after 1965 and the increased use of fertilizers and irrigation are known collectively as the Green Revolution, which provided the increase in production needed to make India self-sufficient in food grains, thus improving agriculture in India. Famine in India, once accepted as inevitable, has not returned since the introduction of Green Revolution crops.
Initiation
The program was started with the help of the United States-based Rockefeller Foundation and was based on high-yielding varieties of wheat, rice, and other grains that had been developed in Mexico and in the Philippines. Of the high-yielding seeds, wheat produced the best results. Production of coarse grains- the staple diet of the poor and pulses the main source of protein- lagged behind, resulting in reduced per capita availability.
Results
The major benefits of the Green Revolution were experienced mainly in northern and northwestern India between 1965 and the early 1980s; the program resulted in a substantial increase in the production of food grains, mainly wheat and rice. Food-grain yields continued to increase throughout the 1980s, but the dramatic changes in the years between 1965 and 1980 were not duplicated. By FY 1980, almost 75 percent of the total cropped area under wheat was sown with high-yielding varieties. For rice the comparable figure was 45 percent. In the 1980s, the area under high-yielding varieties continued to increase, but the rate of growth overall was slower. The eighth plan aimed at making high-yielding varieties available to the whole country and developing more productive strains of other crops.
The Green Revolution created wide regional and interstate disparities. The plan was implemented only in areas with assured supplies of water and the means to control it, large inputs of fertilizers, and adequate farm credit. These inputs were easily available in at least parts of the states of Punjab, Haryana, and western Uttar Pradesh; thus, yields increased most in these states. In other states, such as Andhra Pradesh and Tamil Nadu, in areas where these inputs were not assured, the results were limited or negligible, leading to considerable variation in crop yields within these states. The Green Revolution also increased income disparities: higher income growth and reduced incidence of poverty were found in the states where yields increased the most and lower income growth and little change in the incidence of poverty in other states.
The Green Revolution has also been criticized as unsustainable. It requires immense amounts of capital each year to purchase equipment and fertilizers. This may lead to a cycle of debt if a farmer is unable to pay off the loans required each year. Addtionally, the crops require so much water that water tables in some regions of India have dropped dramatically. If this drop continues, it is possible that the process of desertification may take place. Already, the low water is starting the process of salinization. If continued, this would leave the land infertile, spelling disaster for India
Initiation
The program was started with the help of the United States-based Rockefeller Foundation and was based on high-yielding varieties of wheat, rice, and other grains that had been developed in Mexico and in the Philippines. Of the high-yielding seeds, wheat produced the best results. Production of coarse grains- the staple diet of the poor and pulses the main source of protein- lagged behind, resulting in reduced per capita availability.
Results
The major benefits of the Green Revolution were experienced mainly in northern and northwestern India between 1965 and the early 1980s; the program resulted in a substantial increase in the production of food grains, mainly wheat and rice. Food-grain yields continued to increase throughout the 1980s, but the dramatic changes in the years between 1965 and 1980 were not duplicated. By FY 1980, almost 75 percent of the total cropped area under wheat was sown with high-yielding varieties. For rice the comparable figure was 45 percent. In the 1980s, the area under high-yielding varieties continued to increase, but the rate of growth overall was slower. The eighth plan aimed at making high-yielding varieties available to the whole country and developing more productive strains of other crops.
The Green Revolution created wide regional and interstate disparities. The plan was implemented only in areas with assured supplies of water and the means to control it, large inputs of fertilizers, and adequate farm credit. These inputs were easily available in at least parts of the states of Punjab, Haryana, and western Uttar Pradesh; thus, yields increased most in these states. In other states, such as Andhra Pradesh and Tamil Nadu, in areas where these inputs were not assured, the results were limited or negligible, leading to considerable variation in crop yields within these states. The Green Revolution also increased income disparities: higher income growth and reduced incidence of poverty were found in the states where yields increased the most and lower income growth and little change in the incidence of poverty in other states.
The Green Revolution has also been criticized as unsustainable. It requires immense amounts of capital each year to purchase equipment and fertilizers. This may lead to a cycle of debt if a farmer is unable to pay off the loans required each year. Addtionally, the crops require so much water that water tables in some regions of India have dropped dramatically. If this drop continues, it is possible that the process of desertification may take place. Already, the low water is starting the process of salinization. If continued, this would leave the land infertile, spelling disaster for India
Global Warming Leads to 150,000 Deaths Every Year
Global warming is not only a threat to our future health, it already contributes to more than 150,000 deaths and 5 million illnesses annually, according to a team of health and climate scientists at the World Health Organization and the University of Wisconsin at Madison—and those numbers could double by 2030.
Research data published in the journal Nature show that global warming may affect human health in a surprising number of ways: speeding the spread of infectious diseases such as malaria and dengue fever; creating conditions that lead to potentially fatal malnutrition and diarrhea; and increasing the likelihood of heat waves and floods.
Health Effects of Global Warming Hardest on Poor NationsAccording to the scientists, who have mapped the growing health impacts of global warming, the data show that global warming affects different regions in very different ways. Global warming is particularly hard on people in poor countries, which is ironic, because the places that have contributed the least to global warming are most vulnerable to the death and disease higher temperatures can bring.
"Those least able to cope and least responsible for the greenhouse gases that cause global warming are most affected," said lead author Jonathan Patz, a professor at UW-Madison's Gaylord Nelson Institute for Environmental Studies. "Herein lies an enormous global ethical challenge."
Global Regions at Highest Risk from Global WarmingAccording to the Nature report, regions at highest risk for enduring the health effects of climate change include coastlines along the Pacific and Indian oceans and sub-Saharan Africa. Large sprawling cities, with their urban "heat island" effect, are also prone to temperature-related health problems. Africa has some of the lowest per-capita emissions of greenhouse gases. Yet, regions of the continent are gravely at risk for diseases related to global warming.
"Many of the most important diseases in poor countries, from malaria to diarrhea and malnutrition, are highly sensitive to climate," said co-author Diarmid Campbell-Lendrum of WHO. "The health sector is already struggling to control these diseases and climate change threatens to undermine these efforts."
"Recent extreme climatic events have underscored the risks to human health and survival," added Tony McMichael, director of the National Centre for Epidemiology and Population Health at the Australian National University. "This synthesizing paper points the way to strategic research that better assesses the risks to health from global climate change."
Global Responsibilities of Developed and Developing NationsThe United States, which currently emits more greenhouse gases than any other nation, has refused to ratify the Kyoto Protocol, choosing instead to initiate a separate multinational effort with less ambitious goals. Patz and his colleagues say their work demonstrates the moral obligation of countries with high per-capita emissions, such as the United States and European nations, to take the lead in reducing the health threats of global warming. Their work also highlights the need for large, fast-growing economies, such as China and India, to develop sustainable energy policies.
"The political resolve of policymakers will play a big role in harnessing the man-made forces of climate change," said Patz, who also holds a joint appointment with the UW-Madison department of Population Health Sciences.
Global Warming is Getting WorseScientists believe that greenhouse gases will increase the global average temperature by approximately 6 degrees Fahrenheit by the end of the century. Extreme floods, droughts and heat waves, such as Europe's 2003 heat wave, are likely to strike with increasing frequency. Other factors such as irrigation and deforestation can also affect local temperatures and humidity.
According to the UW-Madison and WHO team, other model-based forecasts of health risks from global climate change project that:
Climate-related disease risks of the various health outcomes assessed by WHO will more than double by 2030.
Flooding as a result of coastal storm surges will affect the lives of up to 200 million people by the 2080s.
Heat related deaths in California could more than double by 2100.
Hazardous ozone pollution days in the Eastern U.S. could increase 60 percent by 2050. Individual People Can Make a DifferenceAside from research and the needed support of policymakers worldwide, Patz says individuals can also play an important role in curbing the health consequences of global warming.
"Our consumptive lifestyles are having lethal impacts on other people around the world, especially the poor," Patz said. "There are options now for leading more energy-efficient lives that should enable people to make better personal choices."
Research data published in the journal Nature show that global warming may affect human health in a surprising number of ways: speeding the spread of infectious diseases such as malaria and dengue fever; creating conditions that lead to potentially fatal malnutrition and diarrhea; and increasing the likelihood of heat waves and floods.
Health Effects of Global Warming Hardest on Poor NationsAccording to the scientists, who have mapped the growing health impacts of global warming, the data show that global warming affects different regions in very different ways. Global warming is particularly hard on people in poor countries, which is ironic, because the places that have contributed the least to global warming are most vulnerable to the death and disease higher temperatures can bring.
"Those least able to cope and least responsible for the greenhouse gases that cause global warming are most affected," said lead author Jonathan Patz, a professor at UW-Madison's Gaylord Nelson Institute for Environmental Studies. "Herein lies an enormous global ethical challenge."
Global Regions at Highest Risk from Global WarmingAccording to the Nature report, regions at highest risk for enduring the health effects of climate change include coastlines along the Pacific and Indian oceans and sub-Saharan Africa. Large sprawling cities, with their urban "heat island" effect, are also prone to temperature-related health problems. Africa has some of the lowest per-capita emissions of greenhouse gases. Yet, regions of the continent are gravely at risk for diseases related to global warming.
"Many of the most important diseases in poor countries, from malaria to diarrhea and malnutrition, are highly sensitive to climate," said co-author Diarmid Campbell-Lendrum of WHO. "The health sector is already struggling to control these diseases and climate change threatens to undermine these efforts."
"Recent extreme climatic events have underscored the risks to human health and survival," added Tony McMichael, director of the National Centre for Epidemiology and Population Health at the Australian National University. "This synthesizing paper points the way to strategic research that better assesses the risks to health from global climate change."
Global Responsibilities of Developed and Developing NationsThe United States, which currently emits more greenhouse gases than any other nation, has refused to ratify the Kyoto Protocol, choosing instead to initiate a separate multinational effort with less ambitious goals. Patz and his colleagues say their work demonstrates the moral obligation of countries with high per-capita emissions, such as the United States and European nations, to take the lead in reducing the health threats of global warming. Their work also highlights the need for large, fast-growing economies, such as China and India, to develop sustainable energy policies.
"The political resolve of policymakers will play a big role in harnessing the man-made forces of climate change," said Patz, who also holds a joint appointment with the UW-Madison department of Population Health Sciences.
Global Warming is Getting WorseScientists believe that greenhouse gases will increase the global average temperature by approximately 6 degrees Fahrenheit by the end of the century. Extreme floods, droughts and heat waves, such as Europe's 2003 heat wave, are likely to strike with increasing frequency. Other factors such as irrigation and deforestation can also affect local temperatures and humidity.
According to the UW-Madison and WHO team, other model-based forecasts of health risks from global climate change project that:
Climate-related disease risks of the various health outcomes assessed by WHO will more than double by 2030.
Flooding as a result of coastal storm surges will affect the lives of up to 200 million people by the 2080s.
Heat related deaths in California could more than double by 2100.
Hazardous ozone pollution days in the Eastern U.S. could increase 60 percent by 2050. Individual People Can Make a DifferenceAside from research and the needed support of policymakers worldwide, Patz says individuals can also play an important role in curbing the health consequences of global warming.
"Our consumptive lifestyles are having lethal impacts on other people around the world, especially the poor," Patz said. "There are options now for leading more energy-efficient lives that should enable people to make better personal choices."
How It Affects Your Health
It's a fair bet that global warming is going to lead to a rise in human sickness and death. But what form they will take is difficult to say. We can be pretty sure that as average temperatures climb, there will be more frequent and longer heat waves of the sort that contributed to the death of at least 20,000 Europeans in August 2003. Other predictions are more tenuous. For example, rising temperatures could--if rainfall and other conditions are right--result in larger mosquito populations at higher elevations in the tropics, which could in turn contribute to the spread of malaria, dengue and other insect-borne infections. Early indications are not encouraging. The World Health Organization (WHO) believes that even the modest increases in average temperature that have occurred since the 1970s have begun to take a toll. Climate change is responsible for at least 150,000 extra deaths a year--a figure that will double by 2030, according to WHO's conservative estimate. As with so many public-health issues, a disproportionate part of the burden appears to be falling on the poorest of the poor. That doesn't mean, however, that the comparatively wealthy--who account for more than their share of greenhouse-gas emissions--will escape harm.
A look at three key factors affected by warming offers a hint of things to come.
AIR We're used to thinking of industrial and traffic pollution as having a detrimental effect on air quality. But all other things being equal, rising temperature by itself increases the amount of ground-level ozone, a major constituent of smog. So many studies have linked higher ozone levels to death rates from heart and lung ailments that many cities issue smog alerts to warn those at risk to stay indoors. You can expect more and longer alerts.
It gets worse. Higher levels of carbon dioxide favor the growth of ragweed and other pollen producers over other plants, according to Dr. Paul Epstein at Harvard's Center for Health and the Global Environment. In addition, ragweed churns out more pollen as CO2 levels rise. Scientists have tied local spikes in asthma and allergy attacks to increases in molds and emissions from diesel engines. Apparently, the molds attach themselves to diesel particles, which deliver them more efficiently deep into the lungs. Add a plentiful helping of dust storms (from, for instance, the desertification of Mongolia or northern Africa) and a rise in drought-driven brushfires, and you have a made- to-order recipe for increasing respiratory distress worldwide.
WATER Residents of the U.S. Gulf Coast don't have to be reminded that water can be a killer. You can usually evacuate people ahead of a major storm, but you can't evacuate infrastructure. "Thirteen of the 20 largest cities in the world happen to be located at sea level," says Dr. Cindy Parker of the Johns Hopkins School of Public Health in Baltimore, Md. That means that where people are most at risk from floods, so are hospitals and water-treatment plants. As we have seen in New Orleans, the health effects of losing those facilities persist long after the water has receded.
A look at three key factors affected by warming offers a hint of things to come.
AIR We're used to thinking of industrial and traffic pollution as having a detrimental effect on air quality. But all other things being equal, rising temperature by itself increases the amount of ground-level ozone, a major constituent of smog. So many studies have linked higher ozone levels to death rates from heart and lung ailments that many cities issue smog alerts to warn those at risk to stay indoors. You can expect more and longer alerts.
It gets worse. Higher levels of carbon dioxide favor the growth of ragweed and other pollen producers over other plants, according to Dr. Paul Epstein at Harvard's Center for Health and the Global Environment. In addition, ragweed churns out more pollen as CO2 levels rise. Scientists have tied local spikes in asthma and allergy attacks to increases in molds and emissions from diesel engines. Apparently, the molds attach themselves to diesel particles, which deliver them more efficiently deep into the lungs. Add a plentiful helping of dust storms (from, for instance, the desertification of Mongolia or northern Africa) and a rise in drought-driven brushfires, and you have a made- to-order recipe for increasing respiratory distress worldwide.
WATER Residents of the U.S. Gulf Coast don't have to be reminded that water can be a killer. You can usually evacuate people ahead of a major storm, but you can't evacuate infrastructure. "Thirteen of the 20 largest cities in the world happen to be located at sea level," says Dr. Cindy Parker of the Johns Hopkins School of Public Health in Baltimore, Md. That means that where people are most at risk from floods, so are hospitals and water-treatment plants. As we have seen in New Orleans, the health effects of losing those facilities persist long after the water has receded.
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