By Nena Rokx
Last summer I visited Bangkok, where I noticed many people wear mouth caps. I wondered why and downloaded the application AirVisual to check the United-States Air Quality Index (AQI). The AQI value was 137 at that moment and marked as orange and unhealthy for sensitive groups. This value was more than twice as high as the highest value in the Netherlands, which was 63 in Amsterdam. This value was marked as yellow and moderate. In some other cities around the world, the AQI value was marked green and good, red and unhealthy or even purple and very unhealthy. Because of this, I wondered what the health consequences of air pollution are.
During the rest of my holiday, I checked the air quality regularly and I saw that the AQI differed a lot each day and during the day. To understand why this happens, it is important to know what air pollution and the AQI exactly are. To protect public health, the U.S. Environmental Protection Agency (EPA) has established national air quality standards for five major air pollutants; ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide, from which particle pollution is the most toxic. Each day, thousands of monitors continuously record the concentrations of these five major pollutants worldwide. A separate AQI for each pollutant is calculated by formulas and the highest of these AQI values is reported as the AQI value of that moment. The concentration of these pollutants is dependent on the weather, agriculture, traffic, industrial pollution, and sometimes an (inevitable) natural course like sandstorms . These conditions differ per day and during the day, and therefore the AQI differs too. As mentioned before, the higher the AQI, the higher the health concern. Particle pollution has been held responsible for the majority of health effects and is the silent killer of the five major pollutants with 7 million deaths a year worldwide . For comparison, there are 8.2 million deaths per year due to cancer .
Particle pollution consists of a mixture of solids and liquid droplets in different sizes . Particles smaller than 10 mm (PM10) and especially those smaller than 2.5 mm, called PM2.5 or fine particles, can penetrate into the lungs . In this way, it enters the circulation and leads to tissue damage and inflammation. Because of this, particle pollution can be a substantial contribution to the risk of cardiovascular and cardiopulmonary diseases . As many as a quarter of the cardiac deaths and nearly one-third of the lung cancer deaths are caused by polluted air . In general, the life expectancy of Europeans is reduced by about 8.6 months owing to PM2.5 pollution . In addition, particle pollution also adversely affects the quality of life of many people, this is for example the case for people who suffer from COPD or asthma, or for people who developed cardiovascular and cardiopulmonary diseases due to particle pollution .
To reduce these health effects, the World Health Organization has established guidelines for particle pollution; an annual average of 20 μg/m3 for PM10 and 10 μg/m3 for PM2.5 . These values are equal to an AQI of 19 for PM10 and 9 for PM2.5 . In general, almost everywhere in the world, these values are significantly exceeded, not rarely five times .
With this knowledge, it is shocking that an increase of 10 μg/m3 in PM10 is associated with a 53% increase in relative risk of mouth and throat cancer. This increase of 10 μg/m3 is also associated with a higher relative risk of prostate cancer, breast cancer and non-melanoma skin cancer . If PM2.5 concentrations would be reduced to the WHO guidelines for air quality, the average life expectancy in the most polluted cities can be increased with approximately 22 months .
Studies state that air pollution has become the main environmental cause of premature death. With almost the same amount of deaths a year as cancer, and even a contribution in the incidence of some cancers, air pollution should be seen as a big problem. Although there is a lot of attention and research for cancer, this is not the case for (particle) air pollution. Try to contribute as much as possible in the reduction of (particle) air pollution by for example taking your bike instead of the car. This is better for your own health but also for the health of millions of people because you will not contribute to the emission of harmful air pollutants. However, an important thing if you want to limit your exposure to air pollution while biking is to avoid busy roads because the concentration of air pollutants is very high there . Therefore, the best solution to be exposed as little as possible is moving away from the city and busy roads.
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