Study shows link between polluted air and asthma attacks in children

An American study associated two air pollutants – fine particulate matter (PM2.5) and ozone (O3) – with non-viral asthma attacks in children and adolescents. From the analyses, the researchers concluded that there is a higher incidence of airway inflammation among people in these age groups who live in low-income urban areas in the United States. The study was published on Saturday, 7, in the scientific journal The Lancet.

“The prevalence and severity of respiratory disease has increased markedly with urbanization, and children in low-income urban centers have one of the highest asthma morbidities. Outdoor air pollution has been associated with adverse respiratory effects in children and adolescents with asthma” , find scientists.

In the study, air quality indices and concentrations of atmospheric pollutants from the cities where the participants lived were used, covering the reports of asthma attacks by each participant.

We recruited 208 children between 6 and 17 years old, prone to asthma, who lived in urban areas of nine low-income cities in the United States. Of the total, 168, representing 80% of the participants, were included in the analysis.

The research also involved 419 people, between 6 and 20 years old, with persistent allergic asthma who live in urban areas of eight North American cities. At this stage, the result of the impacts of pollutants reached 189 participants, around 45%.

“We identified that increased air quality index values, driven predominantly by increased concentrations of fine particulate matter (PM2.5) and ozone (O3), were significantly associated with asthma exacerbations and decreased lung function that occurred in the absence of a triggering viral infection,” the study highlighted. That is, in these analyzed cases, the crises were triggered by pollution and not by viruses.

According to the National Institute for Space Research (Inpe), fine particulate matter involves particles of solid or liquid material suspended in the air, in the form of dust, aerosol, smoke, among others, which can remain in the air and travel long distances.

The research, funded by the National Institutes of Health and the US National Institute of Allergy and Infectious Diseases, further suggests that air pollution is an important independent risk factor for asthma exacerbations in children living in urban areas and is potentially linked to increased inflammation in the airways.

In this way, the results can help direct approaches to the prevention and treatment of respiratory disease.

What is asthma?

According to the Ministry of Health, asthma is a disease that causes difficulty breathing, as well as shortness of breath and a feeling of tightness in the chest. “The disease can be treated, and it is possible to prevent complications by avoiding exposure to dust, mites and fungi”, he adds.

Along with allergic rhinitis and chronic obstructive pulmonary disease, asthma is one of the most common chronic respiratory diseases.

Asthma has no cure, but with proper treatment, symptoms can ease and even disappear over time. Therefore, medical follow-up from the beginning is essential.

According to the Brazilian Society of Pneumology and Tisiology (SBPT), it is estimated that in Brazil there are approximately 20 million asthmatics – the disease is an important cause of absences from school and work.

What are the existing types of asthma?

Currently, there are several types of asthma. “It can be allergic asthma, non-allergic asthma, in this case it can be triggered by viruses and other factors that are irritating. That is, asthma has several phenotypes. It is important that we approach it this way, because there are different forms of treatment approaches” , advises Fábio Morato Castro, an allergist and immunology doctor from the University of São Paulo (USP) and director of Clínica Croce, specialized in allergy, vaccines and infusions.

There is also severe asthma and others that are not so serious, but the crises can be quite intense and severe.

What are the most common symptoms?

Dry cough


difficulty breathing

Quick and short breath

chest discomfort


How to diagnose?

The diagnosis is mainly clinical, obtained after medical consultation, but it is also confirmed by physical examination and pulmonary function tests (spirometry), which help to classify the severity of the disease.

How is the treatment?

The treatment aims to improve the person’s quality of life by controlling symptoms and improving lung function, according to the Ministry of Health. Drug treatment is carried out along with educational measures, which involve the control of factors that can trigger an asthma attack.

Treatment is defined based on symptoms, clinical history and functional assessment, on an individual basis. In general, medications are used to quickly relieve symptoms and maintain crisis control.

“The basis of the treatment of persistent asthma is the continued use of drugs with anti-inflammatory action, also called controllers, with inhaled corticosteroids (inhalers) being the main ones. .

It is also essential that the patient receives guidance for the early identification of symptoms, how to proceed in case of an asthma attack, control and monitoring.

“There is preventive treatment and treatment of the crisis. The person needs to breathe. You need to use a bronchodilator, as well as medications to deflate that mucosa, the tissue that lines the bronchi”, warns the allergist and immunology doctor from USP.

Why is it common in childhood?

“In small children, it is common for viral infections to trigger asthma attacks a lot, from the moment they start going to school. It is important that the doctor is always accompanying the child and instructs the parents on how to proceed in case of crisis,” says Castro.

Why do seizures happen mainly at night?

“Although crises are more common at night, from the moment the treatment is started, this tends to decrease. , seek emergency hospital care”, explains the director of Clínica Croce, specialized in allergy, vaccines and infusions.

Still according to the expert, nocturnal seizures may be more common in cities like São Paulo, where the climate changes abruptly, especially in autumn and winter. “In the middle of the night, the cold ends up triggering more important crises. But it is also important to control dust, mites and fungi so that they are not triggering”, adds Castro.

How to prevent asthma?

According to the Ministry of Health, it is possible to control crises and even prevent them from happening with some simple measures.

Keep the environment clean

Prevent accumulation of dirt, pet hair and dust in the home

Sunbathe. Vitamin D is linked to a number of diseases of the immune system, such as asthma

Avoid strong smells

Get the flu shot

Avoid contact with cigarette

Dress warmly, especially in the cold season

Practice physical activity regularly

have healthy food

Drink plenty of fluids (water)

Keep the ideal weight

What are the possible complications of asthma?

According to the Ministry of Health, asthma can trigger a series of processes that can result in complications:

Reduced ability to exercise or do other activities


Permanent changes in lung function

Persistent cough

Difficulty breathing, to the point where you need help (ventilation)

Hospitalization and hospitalization for severe asthma attacks

Side effects of medications used to control asthma


What are the risk factors?

According to the Ministry of Health, risk factors can be divided into environmental and patient-specific, such as genetic aspects, obesity and male gender (during childhood).

“Environmental factors are represented by exposure to dust, viral infections, allergens such as dust mites, pollen, cigarette smoke, chemical irritants and environmental pollution, climate change, vigorous physical exercise, emotional stress and even some types of medication”, states the folder.

For genetic factors, family history of asthma or rhinitis and obesity stand out, given that overweight people are more likely to trigger these inflammatory processes.

When there is no way to avoid exposure, the patient can follow some precautions, such as:

Avoid outdoor physical activities, especially on cold days

Avoid low humidity or exposure on days with a lot of pollution

No smoking and avoid indoors with people smoking

Know when and where pollution can be harmful:

According to the US Environmental Protection Agency, ozone is often worse on hot summer days, especially in the afternoon.

Particle pollution can be harmful at any time of the year, even in winter. It can be especially harmful when the weather is calm, allowing pollution to build up.

Particle levels can also be elevated:

Near heavily trafficked roads during peak hours and near industries

When there is smoke in the air from wood stoves, fireplaces or vegetation

How to differentiate asthma from pharyngitis and laryngitis?

Asthma – dry cough, wheezing and difficulty breathing

Pharyngitis – sore throat

Laryngitis – hoarseness