The World Health Organization (WHO) is committed to urging governments around the world to improve the quality of the air in cities, in order to protect people's health. The request comes with the presentation of the new WHO Air Quality Guidelines, which propose dramatically lower standards on pollutant levels. The WHO believes that, by reducing the level of a particular type of pollutant (known as PM10), it could reduce mortality in polluted cities by 15% per year. The Guidelines also significantly lower the recommended limits for ozone and sulfur dioxide.
The Air Quality Guidelines, for the first time, apply to all countries in the world and provide uniform targets that are much more stringent than the national standards in place in many parts of the world, and in some cities would mean a reduction of more than three times the current level of pollution.
It has been estimated that air pollution causes about 2 million premature deaths worldwide every year. More than half of these deaths occur in developing countries. In many cities, the annual average levels of PM10 (which comes mainly from the combustion of fossil materials and other types of fuels) exceed 70 micrograms per cubic meter.
Reducing the particulate from 70 to 20 micrograms per cubic meter, as established in the new Guidelines, could lead to a reduction in mortality of 15%. By reducing pollution levels, there would be a decrease in the incidence of diseases due to respiratory infections, heart disease and lung cancer. Furthermore, actions to reduce air pollution would contribute to a drop in emissions of gases that affect climate change, thus providing other health benefits.
Considering the evident and growing impact that atmospheric pollution has on health, WHO has revised the already existing Air Quality Guidelines for Europe (AQGs) and has expanded them to produce the first indications applicable to world level. These, which was attended by more than 80 scientists, are based on the latest scientific literature available and define objectives to protect the health of the majority of people from the effects of pollution. The WHO hopes that the new air quality directives will become part of national laws.
Many countries do not yet have regulation on air pollution, which makes it almost impossible to control this important risk factor for health. The existing national standards vary significantly and do not guarantee sufficient guarantees. Whilst the WHO understands the need for individual governments to establish national standards based on their particular circumstances, these Guidelines provide indications on the levels of pollution at which the risk to health is minimal and give the different countries the basis for defining the own policies based on sound scientific evidence.
Air pollution, in the form of particulates of sulfur dioxide, ozone and nitrogen dioxide, has a major impact on health. For example, in the European Union, only the finest particulate matter (PM 2.5) causes a loss of life expectancy of around 8.6 months. Although particulate matter is considered the main risk factor for air pollution for human health, the new Guidelines recommend a lower daily limit for ozone, from 120 to 100 micrograms per cubic meter. The achievement of these levels will be a challenge for many countries, especially for developing countries, and in particular those with many sunny days, when ozone concentrations reach maximum values, causing respiratory problems and asthma attacks.
For sulfur dioxide, the Guidelines lower the level from 125 to 20 micrograms per cubic meter: experience has shown that even simple actions can quickly decrease levels, with immediate consequences on the mortality and infantile morbidity rate. The levels of nitrogen dioxide, on the other hand, remain unchanged. However, respecting these limits is especially important in those areas where traffic is intense.
The WHO Guidelines propose progressive objectives and represent a milestone in achieving better air quality.