Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Your Environment. Your Health.



mom watching son while he uses asthma inhaler


What is asthma?

Asthma is an inflammatory disease of the lung. This inflammatory process can occur along the entire airway from the nose to the lung. Once the airway becomes swollen and inflamed, it becomes narrower, and less air gets through to the lung tissue. This causes symptoms like wheezing, coughing, chest tightness, and trouble breathing. During an asthma attack, the muscles around the airways tighten up and the asthma symptoms become even worse than usual.

Once considered a minor ailment, asthma is now the most common chronic disorder in childhood. The prevalence of asthma has progressively increased over the past 15 years. In the United States alone, nearly 40 million people — 13.3 percent of adults and 13.8 percent of children — have been diagnosed with asthma.1

Does asthma run in families?

Asthma does run in families, which suggests that genetics play an important role in the development of the disease. If one or both parents have asthma, the child is much more likely to develop the condition — this is known as genetic susceptibility. An NIEHS study of 615 Mexico City families showed that variations in two genes, ORMDL3 and GSDML, were associated with an increased risk of childhood asthma.2 These results confirm a similar study conducted among European populations.

NIH World Asthma Day 2018

Are allergies related to asthma?

Simple steps for decreasing indoor allergens:

  • Encase mattresses, pillows, and box springs in allergen-impermeable covers
  • Replace carpeting with smooth surfaces such as hardwood or vinyl
  • Steam clean carpets and floor mats every 8 weeks
  • Vacuum carpets and upholstered furniture every week
  • Wash sheets and blankets in hot water every week

Asthma can be triggered by substances in the environment called allergens. Indoor allergens from dust mites, cockroaches, dogs, cats, rodents, molds, and fungi are among the most important environmental triggers for asthma.

NIEHS scientists, along with researchers from the U.S. Department of Housing and Urban Development, conducted an extensive survey known as the National Survey of Lead Hazards and Allergens in Housing, which showed that 46 percent of the homes had dust mite allergens high enough to produce allergic reactions, while nearly 25 percent of the homes had allergen levels high enough to trigger asthma symptoms in genetically susceptible individuals. The survey also showed that nearly two-thirds of American homes have cockroach allergens.

What can I do to reduce allergens and asthma attacks?

NIEHS scientists identified several strategies that reduce indoor allergens and asthma symptoms — cockroach extermination, thorough professional cleaning, and in-home visits to educate the occupants about asthma management. Using these strategies, cockroach allergens were reduced by 84 percent, well below the threshold for producing asthma symptoms.3

Other research showed that some simple steps — washing bedding in hot water; putting allergen-impermeable covers on pillows, box springs, and mattresses; and vacuuming and steam cleaning carpets and upholstered furniture — can significantly reduce dust mite allergen levels.4

smog city
Children living within 150 meters of a freeway were more likely to be diagnosed with asthma than children who lived further away.

What about the air pollution outside? 

While much of the asthma research has focused on indoor allergens, scientists know that outdoor pollution also plays a major role. NIEHS-funded researchers at the Keck School of Medicine of the University of Southern California studied air pollution in 10 Southern California cities and found that children living within 150 meters of a freeway were more likely to be diagnosed with asthma than children who lived further away. The researchers also found that children who had higher levels of nitrogen dioxide in the air around their homes were more likely to develop asthma symptoms. Nitrogen dioxide is one of many pollutants emitted from motor vehicles.

Scientists with the Columbia Center for Children’s Environmental Health found that New York City mothers who were exposed during pregnancy to both polycyclic aromatic hydrocarbons, air pollutants from gasoline and other fossil fuels, and secondhand tobacco smoke had children who were more likely to have asthma.5

Research conducted by NIEHS-funded scientists at Yale University also suggests that asthmatic children who use medication to control asthma symptoms are particularly vulnerable to the effects of ground-level ozone, a highly reactive form of oxygen that is a primary ingredient of urban smog.6 

Impacts of Climate Change on Human Health in the United States: A Scientific Assessment

Impacts of Climate Change on Human Health in the United States: A Scientific Assessment

Climate change is affecting the health of Americans1. As the climate continues to change, the risks to human health will grow, exacerbating existing health threats and creating new public health challenges. This assessment significantly advances what we know about the impacts of climate change on public health, and the confidence with which we know it. While all Americans will be affected by climate change, the report recognizes populations of concern, such as children, the elderly, outdoor workers, and those living in disadvantaged communities, who are disproportionately vulnerable.

Read the full report online
Video: Impacts of Climate Change on Human Health in the United States: A Scientific Assessment

What is NIEHS Doing?

NIEHS Research Efforts

  • A Human Health Perspective on Climate Change (Full Report) (4MB) - A Report Outlining the Research Needs on the Human Health Effects of Climate Change.
  • Caffeine - Caffeine, a natural alkaloid found in tea, coffee, cocoa, and cola, was tested for its effects on reproduction and fertility in Swiss CD-1 mice.
  • Cell Biology Group - Work performed by members of the Cell Biology Group has led to the discovery of a number of novel transcriptional regulators: several orphan nuclear receptors, nuclear receptor-associated proteins (Project I), and the GLIS proteins (Project II). Subsequent studies revealed that these proteins play critical roles in the regulation of many physiological processes (development, immunity, metabolism), are implicated in several major human pathologies (e.g., asthma, fibrosis, autoimmune disease, diabetes, autism, cancer, metabolic syndrome, cystic kidney disease), provide a link between environment and genome, and offer therapeutic potential to intervene in these illnesses.
  • Chromatin & Gene Expression Group - The group studies chromatin remodeling complexes, epigenetics, and embryonic stem cell pluripotency.
  • Controlling Allergens in Your Home - In this podcast, we take a look at some common indoor allergens and offer tips on improving the air quality in your home.
  • Environmental Cardiopulmonary Disease Group - The group conducts basic and clinical/translational research to better understand the role of the environment in the etiology and pathogenesis of respiratory and cardiovascular diseases such as allergy, asthma, adult respiratory distress syndrome, pulmonary fibrosis, atherosclerosis, hypertension, ischemic heart disease, and stroke.
  • Genetics, Environment & Respiratory Disease Group - The Genetics, Environment & Respiratory Disease Group focuses on environmental, genetic, and epigenetic factors, and their interactions, in relation to respiratory health and illness across the life-course. Outcomes of interest include asthma, allergies, pulmonary function and chronic obstructive pulmonary disease.
  • Global Alliance for Clean Cookstoves - NIEHS has invested over $9 million in research related to cookstoves and their health effects, primarily in community-based intervention studies in Guatemala, Ecuador, Nepal, Pakistan, Ghana, and the U.S. with study endpoints including lower respiratory infection (LRI) and tuberculosis in children, low birth weight, COPD, and other respiratory conditions in adult women.
  • Immunogenetics Group - The Immunogenetics Group uses genetic approaches to understand the molecular and cellular mechanisms that lead to either immunogenic or tolerogenic responses to inhaled allergens.
  • Impact of Traffic-Related Particles on Asthma for Students in an Urban School District - The research aimed to uncover and reduce the impact of air pollution from idling school buses and other vehicles on childhood asthma.
  • Molecular Endocrinology Group - The group studies steroid hormones, which regulate tissue-specific gene expression in animals via receptor dependent intracellular signal transduction pathways.
  • NHALES (Natural History of Asthma with Longitudinal Environmental Sampling) - The goal of NHALES is to help scientists understand how bacteria and other factors in the environment affect people who have moderate to severe asthma.
  • NIEHS Cross-Divisional Inflammation Faculty - The cross-divisional inflammation faculty is a trans-NIEHS collaboration on cutting-edge research related to Inflammation.
  • Nuclear Magnetic Resonance Group - The Nuclear Magnetic Resonance (NMR) Group performs fundamental research on biological systems aimed at providing insight into the molecular mechanisms that underlie problems of environmental concern.
  • Partnerships for Environmental Public Health (PEPH) - PEPH is a network of scientists, community members, educators, healthcare providers, public health officials, and policymakers who share the goal of increasing the impact of environmental public health research at the local, regional, and national level.
  • Programs and Initiatives: Climate Change and Human Health - The federal government has called for efforts to support adaptation and mitigation of climate change to create healthier, more sustainable communities. The goals of the NIEHS Climate Change and Human Health Program align with these efforts.
  • The Interagency Working Group on Climate Change and Health (1MB) - The report identifies relevant federal research and science needs, including research on mitigation and adaptation strategies.

Further Reading

Stories from the Environmental Factor (NIEHS Newsletter)

Additional Resources

  • CDC: Asthma - The CDC has compiled a list of resources about triggers if Asthma, FactStats for asthma, healthcare links, and information children and adults about the disease.
  • CDC Tips from Former Smokers Campaign (Tips) - A national campaign to help people quit smoking.
  • Economic Benefits of Improving Air Quality and Protecting Children’s Health - In this Partnerships for Environmental Public Health (PEPH) podcast, we explore how the physical, psychological, and economic stress of chronic diseases can be taken into account when considering air quality. Plus, we learn about the many social and economic benefits of preventing early exposures and protecting children's health.
  • Environmental Wellness Toolkit - What surrounds you each day in your home, work, or neighborhood and the resources available to you can affect your health. You can’t always choose what’s in the environments you live, work, or play in. But taking small steps to make your environments safer and limiting your exposure to potentially harmful substances can help keep you healthier.
  • EPA's Asthma Program - The EPA has created program for raising awareness about asthma and its indoor triggers. They provide links to information about Asthma, Outreach, Resource links, and Basic facts about the condition.
  • Healthy People 2020 - Healthy People provides science-based, 10-year national objectives for improving the health of all Americans.
  • Household Products Database: Health Effects - This database links over 16,000 consumer brands to health effects from Safety Data Sheets (formerly Material Safety Data Sheets), provided by manufacturers and allows scientists and consumers to research products based on chemical ingredients.
Content courtesy of the Centers for Disease Control and Prevention (CDC)

Related Health Topics

For Educators

  1. $footnote_asmresult
  2. $footnote_asmresult
  3. $footnote_asmresult
  4. $footnote_asmresult
  5. $footnote_asmresult
  6. $footnote_asmresult
  7. $footnote_asmresult

This Content is available to use on your website.

Please visit NIEHS Syndication to get started.
to Top