The Dangers of PM 2.5 in Pets

The Dangers of PM 2.5 in Pets

By Associate Professor Dr. Sompoch Veerakul (Professor Kaew)

We have talked a lot about fine particulate matter (PM 2.5), which has a diameter of 2.5 microns or less. Its danger lies in its size, as it can enter the bronchial tubes, alveoli, and ultimately the bloodstream. However, its harmful effects are still being studied and discovered increasingly. This article does not delve into any specific animal species, as that has been discussed before, but rather aims to give a general understanding of the potential risks to all animals.

It has been found that PM 2.5 can absorb various harmful substances from the environment, including heavy metals, toxic gases, hydrocarbons, viruses, small bacteria, and chemicals. In addition to the dust itself, which causes inflammatory reactions in the body, it also increases the risk of toxic exposure and infection.

Current studies show that fine dust particles can trigger inflammation through various mechanisms. A commonly understood mechanism is the onset of hypersensitivity type I, which results in the activation of mast cells, eosinophils, T cells, and potentially systemic inflammatory responses. This inflammation can be exaggerated (hyperresponsiveness), affecting not just the skin, respiratory system, heart, and circulatory system but the whole body. In humans, this has led to higher rates of illness and death, with reports showing an increase in asthma-related deaths, correlating with air pollution. More than 2 million people die annually due to fine particulate matter worldwide (The United Nations Environment Program, 2012).

In animals, the same mechanisms could occur. When an animal inhales harmful dust particles, it not only causes problems on its own but also carries allergens and pathogens into the respiratory system, spreading them into the bloodstream, affecting the entire body. This leads to an increased incidence of respiratory diseases, ranging from allergic reactions to a higher risk of asthma and infections during periods of intense PM 2.5 exposure. Like humans, it has been observed that this pollution also affects unborn fetuses, increasing the risk of asthma after birth.

Moreover, this can lead to non-specific inflammation and acute respiratory diseases, such as bronchitis, potentially damaging the lung structure. The increase of alveolar macrophages helps to protect and eliminate foreign particles that enter the respiratory system. Cytokines involved in inflammation are also increased. Reports in mice have shown that exposure to PM 2.5 leads to bronchitis, with inflammatory cells and increased mucus production. Eosinophils and inflammatory cells related to asthma have been observed, similar to what happens in humans.

An additional concern is the increased production of free radicals from PM 2.5, which further stimulates inflammation. These free radicals increase mucus production and expulsion. PM 2.5 exposure also impacts the genetic changes of inflammatory cells. Furthermore, it has been noted that prolonged exposure to fine dust leads to corticosteroid resistance, making it harder to treat inflammation and allergies, requiring higher doses of anti-inflammatory medications.

Pets often visit veterinarians with symptoms linked to PM 2.5. Common symptoms include sneezing, coughing, and difficulty breathing. Some may develop fever, excessive mucus from the nose and eyes, and skin rashes due to allergic reactions. Pneumonia is also commonly diagnosed, often confirmed through clinical symptoms and X-ray imaging.

This pollution is not going anywhere and will return every year. Therefore, pet owners and veterinarians must be proactive in preventing and treating these conditions. It should not be overlooked, as the effects are severe, causing chronic symptoms and even death.