Sahba Maani at his office Photo: Wang Shan/GT

The weather has started turning warmer but the shift in seasons comes with a new round of haze. According to weather forecasts, from today until March 22, the capital will experience the "longest-lasting spell of smog" since the year started, with March 17 and 18 expected to see especially heavy air pollution. Despite the government's efforts to decrease pollution, the public remains concerned about how air pollution, and in particular PM 2.5 (particulate matter with a diameter of less than 2.5 micrometers), affects lung health. The Global Times (GT) recently brought these questions to Sahba Maani, MD, FCCP, specializing in Pulmonary & Intensive Care at Beijing United Family Hospital and Clinics, with the aim of understanding more about the health risks.

GT: Is there a direct link between smog and lung cancer?

Maani: There have been numerous studies showing that the risk of air pollution is even greater than we once thought. Earlier studies mostly concentrated on showing the link between exposure to air pollution and increased rates of respiratory disease, cardiovascular disease, stroke and even diabetes and obesity. More recently, in 2013, there were a number of studies in the American medical and scientific journals showing direct links between air pollution in general, as well as PM 2.5 and 10 in particular, to lung cancer. The most important study was the one released by the World Health Organization's cancer agency International Agency for Research on Cancer in 2013. This reviewed over 1,000 scientific studies from five different continents and came to the conclusion that air pollution and particulate matter were both linked to lung cancer, and should be classified as carcinogenic.

GT: What can we do to protect ourselves? How can we help raise awareness of air pollution?

Maani: The most important thing is for the government as well as the medical establishment to first recognize that air pollution is in fact a carcinogen, something that can cause lung cancer in humans. This will then hopefully lead to more education for the public, more needed research and maybe government sponsored events such as "clean air awareness days." Once people are educated about these health risks, they will become more aware of the importance of avoiding air pollution by wearing N95 masks (a rating for masks approved by health professionals) and having high efficiency particulate air (HEPA) filters in their homes.

GT: How should we change our diets?

Maani: I believe proper nutrition and lifestyle modification are both very important in helping decrease the negative effects air pollution can have on us. When we inhale PM 2.5 particles, they not only enter our lungs, but because of their very small size these particles can also enter our bloodstream. Once they enter our bloodstreams, they cause inflammation in our bodies that can lead to further damage, and over time lead to chronic diseases, such as diabetes, heart disease, asthma and cancer. Whatever we can do to decrease inflammation, or "heat," in our bodies will in turn help counteract the effects of pollution. So I would recommend an anti-inflammatory diet, such as a plant-based diet, and taking dietary supplements like vitamin C, vitamin E and fish oil. Hopefully, these measures can help decrease the impact of air pollution. Meanwhile, the more vegetables in your diet, the better. 

GT: How does air pollution affect foreigners who come from countries with cleaner air?

Maani: In my practice, I generally see people with lung disease. So I see a lot of patients coming in with asthma, coughs, pneumonia and lung infections. Those with a previous history of allergies or a previous history of asthma find that the pollution does increase their symptoms. If they are otherwise healthy, they usually don't have too many problems, except maybe the usual cough and congestion on high pollution days.