Air Pollution And Asthma: A Complex Relationship?

Air pollution is a pressing issue that affects the lives of millions of people worldwide. It is a complex and dynamic phenomenon that changes with the seasons and is influenced by human activity and meteorological events. The impact of air pollution on respiratory health is well-established, particularly for those with asthma.

Asthma is a chronic respiratory disease characterised by variable airflow obstruction, bronchial hyperresponsiveness, and airway inflammation. Evidence suggests that air pollution has a detrimental impact on asthma outcomes in both adult and paediatric populations. Pollutants in the air can irritate the airways, causing them to swell and tighten, leading to breathing problems. They can also increase the likelihood of upper respiratory infections, which can trigger asthma symptoms.

Outdoor air pollution, such as ground-level ozone, particle pollution, and gases like carbon monoxide, nitrogen dioxide, and sulfur dioxide, can all negatively affect lung function and trigger asthma attacks. Indoor air pollution, including second-hand smoke, heating sources, and moulds, can also worsen asthma symptoms.

Global measures to reduce exposure to air pollutants are necessary to improve asthma outcomes and management, particularly in developing and overpopulated countries, where the burden of outdoor air pollution is disproportionately high.

How does air pollution affect the respiratory system?

Air pollution can have a detrimental impact on the respiratory system, causing a range of issues from minor irritation to severe illness and even death. Here is a detailed overview of how air pollution affects the respiratory system:

Irritation and Inflammation

Air pollution can irritate the airways, causing symptoms such as coughing, wheezing, and shortness of breath. Fine particles in the air can penetrate deep into the lungs and trigger inflammation, which may damage or kill cells and compromise the integrity of the alveolar-capillary barrier. This inflammation increases the airways' responsiveness to irritants, further exacerbating respiratory issues.

Respiratory Infections

Air pollution also increases susceptibility to respiratory infections, such as colds and influenza, which can bring on or worsen asthma symptoms. This is especially true for children and those with pre-existing respiratory conditions.

Aggravation of Asthma

Air pollution is a known trigger for asthma attacks and can aggravate asthma symptoms. It can make the lungs more sensitive to allergens and irritants, leading to flare-ups.

Lung Function Impairment

Long-term exposure to air pollution can cause a decrease in lung function and growth, especially in children and older adults. This can result in conditions such as bronchitis and chronic obstructive pulmonary disease (COPD).

Cardiovascular Issues

In addition to respiratory problems, air pollution can also contribute to cardiovascular issues, including heart attacks and strokes.

Cancer Risk

Exposure to air pollution has been linked to an increased risk of lung cancer, with certain pollutants known to be carcinogenic.

Other Health Effects

Air pollution has also been associated with a range of other health issues, including metabolic disorders, impaired cognitive functioning, and adverse effects on pregnancy and fetal development.

It is important to note that certain groups, such as children, older adults, pregnant individuals, and people with pre-existing respiratory or cardiovascular conditions, are more vulnerable to the harmful effects of air pollution. Taking steps to reduce exposure to air pollution, such as improving indoor air quality and advocating for policy changes, can help mitigate these health risks.

What are the effects of air pollution on children with asthma?

Air pollution can have a detrimental effect on children with asthma. Pollutants in the air can irritate the airways, causing them to swell and tighten, which leads to breathing problems. Poor air quality can also trigger flare-ups in children with asthma, so it is important to take precautions.

Children with asthma are especially vulnerable to air pollution, and studies have shown a link between exposure to air pollution and the development of asthma in children. For example, a study by the US EPA found that African American adolescents are more vulnerable to air pollution than other children. The study reported that low levels of outdoor ozone were associated with respiratory changes and other outcomes in African American children with asthma, even when they were using inhalers to manage their symptoms.

Another study, conducted by researchers from Johns Hopkins University, found that children exposed to outdoor coarse particulate matter were more likely to develop asthma and require emergency room treatment. Coarse particulate matter can come from roadway particles such as brake and tire wear and can deposit into the airways, causing respiratory issues.

In addition to outdoor air pollution, indoor air pollution can also affect children with asthma. Tobacco smoke, for instance, is a well-known modifiable risk factor for symptom control and exacerbation. Exposure to second-hand smoke has been linked to an increased risk of developing asthma and experiencing more severe symptoms.

Overall, air pollution can have significant effects on children with asthma, including triggering flare-ups, increasing the risk of developing asthma, and causing respiratory issues. It is important for parents and caregivers of children with asthma to be aware of the potential impacts of air pollution and take steps to reduce their child's exposure.

How does air pollution affect asthma in adults?

Air pollution can make asthma symptoms worse and trigger asthma attacks in adults. The pollutants in the air can irritate the airways, making them swell and tighten up, and cause breathing problems. Pollutants can also make people more likely to catch upper respiratory infections (like colds), which can bring on asthma symptoms. If allergens in the air are an asthma trigger, pollutants can make the lungs even more sensitive to them.

The effects of air pollution on asthma can be modified by other individual factors like obesity. A large cross-sectional study found that the effect of NO2 and SO2 on asthma was significantly greater in overweight or obese children. Similarly, the exposure to O3 is associated with a poorer lung function for obese adults when compared to people with a normal weight.

Active tobacco smoking is associated with poorer asthma control, more frequent exacerbations/hospitalizations, accelerated decline of lung function, and a lower response to CS. Exposure to SHS increases the risk of asthma exacerbations, respiratory symptoms, healthcare utilization, and poor lung function.

What are the effects of second-hand smoke on asthma?

Second-hand smoke is a common trigger for asthma attacks, especially in children

What are the effects of outdoor air pollution on asthma?

Outdoor air pollution can have a significant impact on people with asthma, affecting their quality of life and even causing premature death. The effects of outdoor air pollution on asthma include:

• Irritation of the airways: Pollutants can irritate the airways, causing them to swell and tighten, leading to breathing problems.
• Increased susceptibility to infections: Pollutants can make individuals more likely to develop upper respiratory infections, such as colds, which can trigger asthma symptoms.
• Lung function decline: Exposure to pollutants, particularly ground-level ozone, has been linked to a decrease in lung function, even at low levels.
• Asthma exacerbations: Outdoor air pollution can induce asthma symptoms, exacerbations, and hospitalisations.
• Increased medication use: People with asthma may need to increase their medication during periods of high air pollution.
• Development of asthma: There is evidence to suggest that exposure to outdoor air pollution can contribute to the development of asthma, particularly in children.
• Impact on specific populations: Certain populations, such as African American children, may be more vulnerable to the effects of outdoor air pollution on asthma.

Frequently asked questions