Good clinical management is essential for saving and improving the lives of children with asthma. Yet even children with the best clinically-managed asthma suffer if they’re continuously exposed to environmental triggers. In order to truly help children with asthma, we need to focus on prevention. While scientists continue to explore what causes asthma, it is clear that environmental pollution plays a role in developing and aggravating asthma and can lead to serious health consequences such as emergency room visits and even death. Additionally, we know that a number of environmental factors, including air pollutants, environmental tobacco smoke, mold, animal hair, and dust mites, can trigger asthma attacks in children who already have asthma.
Poor indoor and outdoor air quality caused by chemicals and biological agents, such as mold, affect the severity and onset of asthma. In addition, outdoor air pollution from a variety of sources, including diesel engines, emit a complex mixture of air pollutants causing a serious problem in most urban and many rural areas. The presence of such uncontrolled environmental triggers causes irritation to the lungs and can lead to the development and exacerbation of asthma as well as allergies and other health-threatening conditions.
Outdoor Air Pollution
Outdoor air pollution is a serious problem in most urban areas as well as in many rural areas of the United States and California. Today, nearly all Californians (about 99 percent) live in areas that fail to meet the State health-based ozone and/or particulate matter standards.1 However, the problem affects low-income and minority communities disproportionately because these groups tend to live in the areas where air pollution is worst. Air pollution can have long-term effects on our health and can contribute to the development of asthma, respiratory tract infections, and lung cancer. Each year ozone and fine particulate matter (PM2.5) at levels above federal air quality standards in the San Joaquin Valley and South Coast Air Basin (including Los Angeles, San Bernardino, Riverside, and Orange Counties) cost California an estimated $28 billion due to adverse health effects such as premature deaths, hospital admissions, respiratory illnesses and school or work absences.2 Despite gains in air quality in the past decade, the associated costs remain high, and many vulnerable populations are not adequately protected. This is especially true for children whose developing lungs are more sensitive to the harmful effects of outdoor air pollution.
Diesel engines emit a complex mixture of air pollutants. In California, diesel particulate matter (PM) contributes to an estimated 3,500 premature deaths each year as well as thousands of hospital admissions, asthma attacks and other respiratory symptoms, and lost workdays. Many diesel emission sources such as heavily traveled roadways, ports, and rail yards are concentrated near densely populated areas, which leads to higher exposures and greater health consequences for our children. Additionally, diesel pollution has been observed on every school bus tested in California regardless of the age of the bus.
- Diesel exhaust is emitted by trucks, school buses, trains, ships, harbor craft, off-road vehicles, and cargo-handling and industrial equipment with engines running on diesel fuel.
- Diesel engines emit a complex mixture of air pollutants, composed of gaseous and solid materials.The visible emissions in diesel exhaust are known as diesel exhaust particulates (DEP) or soot. Diesel exhaust also contains a variety of harmful gases and over 40 other cancer-causing substances. In addition, diesel exhaust contributes to the formation of ozone.
- Diesel exhaust has costly implications: The cost of premature deaths resulting from exposure to diesel PM is estimated to be $16 billion per year in California. Furthermore, an annual cost of over $3.5 billion is associated with hospitalizations, treatment of illnesses, and lost workdays each year.4
On average, California adults and children spend nearly 90% of their time during the week indoors and the majority of this time in the home. Children can be exposed to many asthma triggers in their homes. The presence of uncontrolled environmental triggers causes irritation to the lungs and can lead to the development and exacerbation of asthma as well as allergies and other health-threatening conditions.
The major environmental triggers found in homes and the outdoors and how they impact childhood asthma:
Indoor Air Pollutants
Exposure to indoor air pollutants is linked with asthma exacerbations, decreased lung function, and other respiratory symptoms. Sources of indoor pollutants related to asthma include tobacco smoke, gas stoves, and space heaters. There is also growing concern about the chemical emissions from common consumer products including household cleaning products and air purifiers.
Environmental tobacco smoke, or secondhand or passive smoke, is produced when individuals use tobacco products inside the home or too close to open doors and windows. Environmental tobacco smoke has been identified by the California Air Resources Board as a toxic air contaminant. Exposure to tobacco smoke has consistently been shown to increase both allergic sensitization and subsequent asthma attacks.
Gas Stoves and Space Heaters
Space heaters, furnaces, and gas stoves can emit nitrogen dioxide (NO2), a common outdoor air pollutant. Exposure to NO2 indoors increases the likelihood, frequency and severity of asthma symptoms.
Volatile organic compounds (VOCs) are chemicals commonly found in household cleaning products, paints, and fuels. They can also be emitted from building materials, new furniture, or carpet. There is recent evidence suggesting an association between exposure to VOCs and exacerbation of asthma.
Exposure to indoor allergens is associated with exacerbation of asthma for sensitized individuals. Common indoor allergens include mold, dust mites, cockroaches, cats, and dogs.
Mold spores and bacteria, found in the air, in settled dust, on surfaces, or behind walls have been significantly associated with increased prevalence of respiratory symptoms and decreased lung function among children with asthma. There is also emerging evidence of a relationship between exposure to mold and the development of asthma in children. Mold and bacteria problems are worse in certain conditions, such as when there is moisture damage or higher indoor humidity.
Dust mites have been consistently associated with both allergic sensitization and increased asthma symptom prevalence and severity, especially when there is inadequate ventilation and higher humidity. There is conflicting evidence regarding the role of exposure to dust mites in the development of asthma. Intervention studies have shown that dust mite allergen levels are reduced by polyurethane-coated covers on mattresses, quilts, and pillows, removal of carpets and rugs, and improved ventilation to reduce humidity.
Cockroaches and Rodents
Cockroach and rodent (mouse, rat) allergens in kitchens and bedrooms have been linked to increased asthma symptom prevalence and severity. Intervention studies have demonstrated that professional cleaning, professional extermination, or integrated pest management, and air filtration reduced measured levels of these pest allergens or allergic responses to them, including asthma.
Cats and Dogs
Allergens from dogs and cats can collect in dust on smooth floors, upholstered furniture, and especially on carpets or rugs. Findings regarding the relationship between pet allergens and asthma have been inconsistent. Some studies found exposure to cats was related to an increased risk of allergic sensitization, but other studies found a decreased risk. Studies examining dog exposure suggest no effect or a protective effect. However, there is consistent evidence that both cat and dog exposure is related to asthma exacerbations among sensitized individuals. Intervention studies have reported that some air filtration devices and the removal of carpet or rugs reduced levels of pet allergens in the home.
What RAMP is doing
RAMP works with both regional and state partners to reduce multiple asthma triggers in our daily environment, particularly in disproportionately impacted communities. Current activities focus on improving outdoor air quality through emissions reductions and improved land-use decisions and addressing issues of substandard housing. Some of environmental efforts that RAMP is leading or supporting include:
- Reducing regional diesel emissions associated with idling and freight transportation through participation in the Ditching Dirty Diesel Collaborative
- Supporting the creation and enforcement of diesel emission regulations established by the California Air Resources Board
- Ensuring public health “co-benefits” of state (AB 32) and regional (SB 375) climate change policies
- Advocating for asthma-friendly land-use planning, transportation investments, and redevelopment policies
- Developing and disseminating a guide to aid health workers in navigating landlord-tenant issues
- Building partnerships with housing organizations and agencies to develop effective policies that achieve Healthy Housing
- Engaging tenants to be stronger advocates and spokespersons for indoor air quality improvement policies and tenant rights.
- Pursuing local and state policies that improve housing conditions that:
- Reduce children’s exposure to environmental tobacco smoke
o Establish indoor air quality guidelines for housing authority agencies and housing code inspectors, and improve inspection and remediation practices.
o Create clean indoor air programs and policies for private and public landlords and tenants.
o Remove or reduce indoor exposures by promoting the use of building materials, consumer products and appliances that emit little or no air pollutants.