An asthma attack can occur when someone with asthma is exposed to things in the environment, such as diesel exhaust, smog, house dust mites, and tobacco smoke. These are called asthma triggers. Asthma triggers cause symptoms in people who already have the underlying disease. One person’s triggers can be very different from those of another person with asthma. It is important to be aware of what your, or your child’s, triggers are.
Important asthma triggers you should be aware of:
Ozone triggers asthma attacks. People with asthma are more sensitive to ozone than other people and experience lung function changes and respiratory symptoms at lower concentrations or with greater magnitude than people without underlying lung disease. In addition, the injury, inflammation, and increased airway reactivity induced by ozone exposure may worsen a person’s underlying asthma. Source: http://www.epa.gov/apti/ozonehealth/effects.html
- Respiratory symptoms and bronchodilator use are increased when ozone concentrations are high
- Lung function is reduced on days when ozone concentrations are high
- The numbers of emergency room visits and hospital admissions for asthma are increased on days when ozone concentrations are high
- Because the prevalence of asthma in children is higher than that of adults, and because children spend more time being active outdoors than adults, they are disproportionately affected by ozone exposure
Diesel exhaust is similar to tobacco smoke in the sense that it is a mixture of tiny particles and gases with many chemical components including nitrogen compounds, sulfur compounds, PAHs, benzene, carbon monoxide, and PM2.5. Collectively these components are known as diesel exhaust particles (DEPs). Diesel exhaust is emitted by trucks, school buses, trains, ships, harbor craft, off-road vehicles, and cargo-handling and industrial equipment with diesel engines.
When inhaled, DEPs can aggravate asthma and cause lung damage as well as premature death. The World Health Organization recently affirmed that DEPs cause lung cancer. See http://press.iarc.fr/pr213_E.pdf. The EPA classifies diesel exhaust as a “likely” (but not definitive) carcinogen. Human epidemiological studies demonstrate an association between diesel exhaust exposure and increased lung cancer rates in occupational settings. Source: http://www.epa.gov/region1/eco/airtox/diesel.html
Unfortunately, many diesel emission sources such as heavily traveled roads, ports, and rail yards are concentrated near densely populated areas, which leads to higher exposures and greater health consequences for our children.
Using proximity to traffic as a proxy for diesel exhaust exposure, researchers have found that exposure to traffic emissions is associated with increased risk of adverse respiratory health outcomes, including asthma incidence, severity, and persistence among children. Source: http://www.jacionline.org/article/S0091-6749(05)00306-4/abstract
Additionally, abundant evidence suggests that components of diesel exhaust can cause biologic responses that are related to asthma. Although evidence from research indicates that exposures to diesel exhaust and DEPs are associated with the inflammatory and immune responses involved in asthma, some questions remain regarding the underlying molecular mechanisms. Source: http://www.nrdc.org/health/kids/diesel-asthma_ehp.pdf
In light of these ﬁndings, public health efforts to reduce exposures to diesel exhaust are warranted. In particular, reducing the exposure of infants and children should be a priority as part of a coordinated effort to improve the prevention and management of childhood asthma.
What Can I Do To Minimize My Risk? (From EPA)
- Avoid idling if you have a diesel vehicle. This means turn off your engine when your vehicle is not in motion.
- Keep your diesel vehicle well tuned and maintained.
- If possible, retrofit diesel engines with pollution control devices.
- If purchasing trucks or buses, consider buying those that meet EPA’s new standards ahead of schedule.
- Get involved with your child’s school system. Many school buses run on diesel engines, but retrofitting such bus fleets to reduce diesel pollution is possible. For more information, see http://www.epa.gov/cleanschoolbus/csb-overview.htm
NO2 can also form indoors when fossil fuels like wood or natural gas are burned. This means that smoke from your stove or fireplace can trigger asthma.
In people with asthma, exposure to low levels of NO2 may cause increased bronchial reactivity and make young children more susceptible to respiratory infections. Long-term exposure to high levels of NO2 can lead to chronic bronchitis. According to the EPA, current scientific evidence links short-term NO2 exposures, ranging from 30 minutes to 24 hours, with adverse respiratory effects including airway inflammation in healthy people, increased respiratory symptoms in people with asthma and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma. Source: http://www.epa.gov/asthma/no2.html
Additionally, health studies have shown a connection between breathing elevated short-term NO2 concentrations, and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma. Source: http://www.airquality.org/plans/federal/no2/
NO2exposure concentrations near roadways are of particular concern for susceptible individuals, including people with asthma, children, and the elderly.
According to the EPA, most airborne NOx comes from combustion-related emissions sources of human origin, primarily fossil fuel combustion in electrical utilities, high-temperature operations at other industrial sources, and operation of motor vehicles. However, natural sources, like biological decay processes and lightning, also contribute to airborne NOx. Fuel-burning appliances, like home heaters and gas stoves, produce substantial amounts of NOx in indoor settings. Source: http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listByAlpha&r=188200&subtop=341
Ozone, or smog, is formed when NOx and volatile organic compounds react in the presence of heat and sunlight. Children, the elderly, people with lung diseases such as asthma, and people who work or exercise outside are at risk for adverse effects from ozone. These include reduction in lung function and increased respiratory symptoms as well as respiratory-related emergency department visits, hospital admissions, and possibly premature deaths. Source: http://www.epa.gov/air/nitrogenoxides/health.html
According to the EPA, current scientific evidence links short-term exposures to SO2, ranging from 5 minutes to 24 hours, with an array of adverse respiratory effects including bronchoconstriction and increased asthma symptoms. These effects are particularly important for asthmatics at elevated ventilation rates (e.g., while exercising or playing.) Source: http://www.epa.gov/air/sulfurdioxide/health.html
Studies also show a connection between short-term exposure and increased visits to emergency departments and hospital admissions for respiratory illnesses, particularly in at-risk populations including children, the elderly, and asthmatics. Source: http://www.epa.gov/air/sulfurdioxide/health.html
According to the American Lung Association, reducing SO2 levels are linked to an immediate gain in life expectancy, according to evidence from a study that examined the health impact of drops in sulfur dioxide. Source: http://www.lung.org/associations/states/colorado/clean-air/Sulphur-dioxide.html
Emissions that lead to high concentrations of SO2 generally also lead to the formation of other SOx. Control measures that reduce SO2 therefore can generally be expected to reduce people’s exposures to all gaseous SOx.
SOx can react with other compounds in the atmosphere to form small particles. These particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease, such as emphysema and bronchitis, and can aggravate existing heart disease, leading to increased hospital admissions and premature death. EPA’s NAAQS for particulate matter (PM) are designed to provide protection against these health effects.
The size of particles is directly linked to their potential for causing health problems. The EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs.
Particle pollution – especially fine particles – contains microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems—including aggravated asthma and decreased lung function.
EPA groups particle pollution into two categories:
- “Inhalable coarse particles,” such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
- “Fine particles,” such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.
Sources of PM emissions include: cars, trucks, power plants, fires, agriculture, dust, industrial processes. Click to view a summary of PM emissions in your state.
PM10 describes particles with a diameter of 10 micrometers or less (0.0004 inches or one-seventh the width of a human hair). PM10 includes fine particle pollution (PM2.5).
Sources of PM10 emissions include: motor vehicles, wood burning stoves and fireplaces, dust from construction, landfills, and agriculture, wildfires and brush/waste burning, industrial sources, and windblown dust from open lands.
When inhaled, PM10 particles evade the respiratory system’s natural defenses and lodge deep in the lungs. As the body reacts to these foreign particles, PM10 can increase the number and severity of asthma attacks, cause or aggravate bronchitis and other lung diseases, and reduce the body’s ability to fight infections.
Major concerns for human health from exposure to PM10 include: effects on breathing and respiratory systems, damage to lung tissue, cancer, and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma, are especially sensitive to the effects of particulate matter. Source: http://www.arb.ca.gov/html/brochure/pm10.htm
PM2.5, commonly known as fine particle pollution, describes particulate matter that is 2.5 micrometers in diameter and smaller – 1/30th the diameter of a human hair.
Fine particle pollution can be emitted directly or formed secondarily in the atmosphere. There are different types of PM2.5. Sulfates are a type of secondary particle formed from sulfur dioxide emissions from power plants and industrial facilities. Nitrates, another type of fine particle, are formed from emissions of nitrogen oxides from power plants, automobiles, and other combustion sources.
Health studies have shown a significant association between exposure to fine particles and premature death from heart or lung disease. Fine particles can aggravate heart and lung diseases and have been linked to effects such as: cardiovascular symptoms; cardiac arrhythmias; heart attacks; respiratory symptoms; asthma attacks; and bronchitis. These effects can result in increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days. Groups that may be particularly sensitive to fine particle exposure include people with heart or lung disease, older adults, and children. Source: http://www.epa.gov/pmdesignations/basicinfo.htm
EPA studies found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside homes than outside. While people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed. Source: http://www.epa.gov/iaq/voc.html
Children who sleep in bedrooms containing fumes from water-based paints and solvents are two to four times more likely to suffer allergies or asthma, according to a study at Karlstad University in Sweden.
Members of this class of compounds have been identified as exhibiting toxic and hazardous properties, and for this reason the EPA has included 16 PAH on its list of priority pollutants to be monitored in water and wastes. Source: http://toxics.usgs.gov/definitions/pah.html
In addition to anthropogenic sources, PAH are also formed from natural sources, including: forest fires, volcanic eruptions, and decomposition.
Exposure to PAH as a result of ambient air pollution has been associated with increased symptoms among asthmatics. Prenatal exposure to PAH from air pollution has also been linked to increases in cough and wheeze.
In addition to being proportionately more heavily exposed to pesticides than adults, infants and children are biologically more vulnerable to them.
Places where children may be exposed to pesticides:
- Day-care centers
- Parks and gardens
According to an article about pesticides and inner-city children, approximately 90% of American households use pesticides, and homeowners accounted for the purchase of an estimated 74 million pounds of the pesticides used in the United States in 1995, representing a nearly $2 billion industry. Diet, including drinking water, is a second important source of children’s pesticide exposure. Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1566233/pdf/envhper00520-0047.pdf
Pesticide exposure can both cause and trigger asthma.
How do pesticides cause asthma? According to the advocacy organization Beyond Pesticides:
- Numerous studies have found compelling evidence that exposure to pesticides is correlated with higher rates of asthma. One research focus has been on farmers and pesticide applicators (adults), groups typically exposed to higher levels of pesticides than the average population. Many studies have shown that this population has higher rates of asthma and other respiratory problems due to their use of pesticides. Yet occupational pesticide exposure is only one piece of the puzzle—household and community exposure to pesticides (where children are more prone) can also lead to respiratory problems. An early study done in the 1960s in Hawaii found that frequent household use of insecticides is correlated with an increased prevalence of respiratory disorders, including asthma and chronic bronchitis. The majority of the pesticides used were bug sprays for mosquitoes, ﬂies, and cockroaches.
- In children without previous respiratory problems, pesticides overwhelm the cells’ ability to detoxify chemicals, or cause immune and muscular effects, all of which can lead to respiratory problems.
- Timing is crucial–The of over 4000 school-aged children studied in California, researchers discovered that children exposed to herbicides during their ﬁrst year of life are four and a half times more likely to be diagnosed with asthma before the age of ﬁve; toddlers exposed to insecticides are more than twice as likely to get asthma.
How do pesticides trigger asthma? According to the advocacy organization Beyond Pesticides:
- People with asthma are especially sensitive to pesticides and at risk of attacks when exposed to even small amounts. Most pesticides are small molecules that can exacerbate or aggravate asthma symptoms. Pesticides can trigger asthma attacks by increasing airway hyper-reactivity, which makes the airway very sensitive to any allergen or stimulus. Hypersensitive lungs are a trademark feature of asthmatics. Subsequent exposure to a stimulus can cause an extreme reaction in a hyper-reactive airway. In these situations, researchers at Johns Hopkins University believe that pesticides alter the nerve function controlling the smooth muscle lining of the airway, causing the airway to contract and restrain airﬂow, which is exactly what occurs during an asthma attack. Pesticides can also trigger asthma attacks by damaging lung epithelial cells directly.
While not all pesticides are associated with asthma, many are.
27 out of 30 commonly used lawn pesticides are sensitizers or irritants, and therefore have the potential to trigger asthma attacks, exacerbate asthma, or lead to a higher risk of developing asthma. Similarly, 39 of the 48 pesticides commonly used in schools are sensitizers or irritants. Many insecticides, herbicides and fungicides are linked to respiratory problems—click here for more info. Source: http://www.beyondpesticides.org/infoservices/pesticidesandyou/Summer%2005/asthma%20article.pdf
In a 2004 study, it was found that, among inner city children, cockroach exposure and sensitivity were predominate in the Northeast and cockroach allergen appears to have a greater effect on asthma morbidity than dust mite or pet allergen in these children.
While cockroaches pose a threat, you should not use toxic pesticides to kill the roaches—this may only make conditions worse for someone suffering from asthma.
Here are some tips from Beyond Pesticides for preventing cockroaches and asthma safely:
- Remove all food waste and keep food in airtight containers.
- Limit the spread of food around the house.
- Eliminate potential water sources, such as leaky faucets and pipes.
- Caulk and seal all cracks and crevices.
- Vacuum frequently and intensively.
- Monitor populations using sticky-traps.
- In the event of infestation, use boric acid bait stations.
Disclaimer: this is meant to be used as a reference only, not a medical guide. Please consult your physician for any serious medical questions.
Click here for a list of asthma-related MCAF blog posts.