Air Pollution And Runny Nose: Is There A Link?

Air pollution has been linked to chronic inflammation of nasal and sinus tissues, and it is suggested that it may be a direct cause of year-round runny noses. While human population studies have established this link, direct biological and molecular evidence has been lacking. However, recent experiments on mice have provided evidence of the direct biological effect of air pollution on the upper respiratory system. This has significant implications for people living in large cities and industrial areas with polluted air, especially in developing countries.

Air pollution and its effect on the upper respiratory tract

The nose is the first organ to encounter inhaled air and its associated pollutants. Pollutants are deposited in the nose during inspiration and accumulate on mucus, becoming absorbed in the nasal mucosa. This can lead to a range of adverse effects on the body.

Irritation and inflammation

The irritation of the nose and sinuses from pollutants results in direct contact with the nasal mucosa, causing inflammation, edema, swelling, and blocked sinuses. This can lead to acute and chronic sinusitis.

Allergic reactions

The absorption of pollutants into the body can affect the immune system, leading to dramatic changes in allergic responses. The T-suppressor cell, the most sensitive cell of the immune system, is the first to be affected by chemical pollutants. The diminution of suppressor activity and the relative increase in helper activity result in heightened immunoglobulin production and the manifestation of allergy symptoms.

Social implications

Chronic sinonasal disease, including sinusitis, has been linked to significant social implications such as depression, lost productivity, and chronic fatigue.

Specific pollutants

Two types of pollutants, nitrogen oxide and PM 2.5, have been associated with worse rhinitis symptoms. Nitrogen oxide, a byproduct of fossil fuel combustion, contributes to smog, while PM 2.5 includes solid particles and liquid droplets smaller than 2.5 micrometers, such as dust, dirt, soot, and smoke.

Treatment and prevention

Treatment options for chronic sinusitis include balloon sinuplasty, which expands the airways and removes fluids from the sinus cavities. Preventative measures include staying indoors, using air purifiers, and reducing traffic fumes by opting for public transportation.

Allergies and viral infections

Viral infections, such as the common cold, flu, and COVID-19, can also cause a runny nose. When you have a viral infection, your body produces more mucus to trap and flush out the virus. This mucus can be thicker and may change colour, becoming white, yellow, or even green.

In addition to allergies and viral infections, other factors can contribute to a runny nose. Nonallergic rhinitis, for example, occurs without an allergic reaction and is triggered by factors such as air pollutants, strong smells, and cold or dry air.

Air pollution, in particular, has been linked to an increased risk of developing a runny nose. Studies have shown that exposure to air pollution can cause chronic inflammation of nasal and sinus tissues, leading to a higher risk of sinus problems. Fine particulate matter, nitrogen oxide, and other pollutants found in traffic fumes have been associated with worse rhinitis symptoms, including congestion, nasal irritation, and sneezing.

Sinus infections

Sinusitis, or inflammation of the sinuses, can be caused by exposure to air pollution. This condition is characterised by congestion, a runny nose, mucus dripping down the throat, headaches, loss of smell or taste, and snoring. Sufferers of chronic sinusitis experience these symptoms for 12 weeks or more.

A 2021 study by Johns Hopkins University found that long-term exposure to air pollution increases the likelihood of developing chronic rhinosinusitis (CRS). The study examined 6,102 patients aged 18 and over, including 2,034 who had been diagnosed with CRS within the last five years. The research team found that those exposed to higher concentrations of pollutants for longer periods were more likely to have CRS. Exposure to higher levels of pollution was associated with a 50% increase in the likelihood of developing the condition.

The study also found that exposure to higher levels of pollution over a 60-month period was associated with a nearly fivefold increase in the risk of developing pansinusitis, or inflammation in all four sinuses.

The lead author of the study, Dr Murugappan "Murray" Ramanathan, stated that this was the first study to report that long-term exposure to fine particulate matter air pollution increases the odds of developing CRS, particularly in its most severe form.

A 2018 study by Johns Hopkins Medicine also found that exposure to polluted air can lead to inflammation of the nasal and sinus tissues in mice, mimicking human chronic sinusitis. The study exposed 38 eight-week-old male mice to either filtered air or concentrated polluted air for six hours a day, five days a week for 16 weeks. The researchers found that the mice exposed to polluted air had significantly more white blood cells signalling inflammation in their noses and sinuses compared to those that breathed filtered air.

These findings suggest that people living in areas with high levels of air pollution, such as large cities and industrial areas, may be at a higher risk of developing chronic sinus problems.

Air pollution and asthma

Air pollution is a major trigger for asthma symptoms. When people with asthma are exposed to air pollution, they may experience an increase in the frequency and severity of their asthma symptoms, including coughing, wheezing, and difficulty breathing.

Air pollution can irritate the airways and lungs, leading to inflammation and narrowing of the airways, which can trigger asthma attacks. Certain pollutants, such as nitrogen dioxide and particulate matter (PM 2.5), are particularly harmful to people with asthma. Nitrogen dioxide is a byproduct of fossil fuel combustion, while PM 2.5 refers to a mixture of solid particles and liquid droplets smaller than 2.5 micrometers in diameter, which can include dust, dirt, soot, and smoke.

People living in areas with high levels of air pollution, such as large cities and industrial areas, are at a greater risk of experiencing asthma symptoms. This is especially true for individuals living in developing countries, where regulations may not be as stringent as in other parts of the world. For example, in cities like New Delhi, Cairo, or Beijing, the use of wood-burning stoves and the release of pollutants from factories contribute to poor air quality, which can exacerbate asthma symptoms.

Additionally, indoor air pollution can also trigger asthma symptoms. Sources of indoor air pollution include tobacco smoke, strong odours, and even cooking fumes. Using air purifiers can help improve indoor air quality and reduce the risk of asthma attacks.

It is important for individuals with asthma to monitor air quality alerts and plan their activities accordingly. Avoiding outdoor activities during peak pollution times or staying indoors when air quality is poor can help reduce exposure to harmful pollutants. Seeking medical advice and adhering to prescribed treatments are also crucial in managing asthma effectively.

While air pollution can trigger asthma symptoms, it is important to note that it does not cause asthma. However, long-term exposure to air pollution can worsen existing asthma and make it more challenging to manage. Therefore, it is essential to take steps to reduce air pollution, both indoors and outdoors, to protect the health and well-being of people with asthma.

The social implications of chronic sinonasal disease

Air pollution has been linked to chronic inflammation of nasal and sinus tissues, which can lead to conditions such as rhinitis and sinusitis. These conditions can have significant social implications, including depression, loss of productivity, and chronic fatigue.

Chronic sinonasal disease can have a substantial impact on an individual's quality of life and their ability to function in society. For example, symptoms such as congestion, sneezing, and nasal irritation can cause discomfort and disrupt daily activities. In severe cases, individuals may experience pain and pressure in the face, as well as a constant drippy nose, which can be socially stigmatizing and embarrassing.

Furthermore, the economic burden of chronic sinonasal disease can be significant. The condition often requires ongoing medical care and treatment, including medications, surgery, and regular doctor's visits. The financial strain of managing the disease can be a source of stress and anxiety for individuals and their families.

Additionally, chronic sinonasal disease has been associated with an increased risk of developing mental health issues, such as depression and anxiety. The constant discomfort and social isolation that may result from the condition can contribute to negative thoughts and emotions, further exacerbating the impact on an individual's overall well-being.

Overall, the social implications of chronic sinonasal disease are far-reaching and can affect various aspects of an individual's life, including their physical health, mental health, social interactions, and economic stability. It is important to recognize and address these implications to improve the quality of life for people living with these conditions.

Frequently asked questions