Particulate matter: Swiss Federal Commission for Air Hygiene recommends additional air quality standard to protect against harmful effects on health

Bern, 19 March 2014 - The Swiss Federal Commission for Air Hygiene has summarised and evaluated the latest research findings on adverse effects of ambient particulate matter on human health. In its report it recommends incorporating an additional ambient air quality standard for smaller particulate matter (PM2.5) into the Ordinance on Air Pollution Control (OAPC).

Seven years after its previous report on particulate matter, the Swiss Federal Commission for Air Hygiene FCAH has again examined and evaluated the situation with respect to the effects of exposure to ambient particulate matter in Switzerland. It acknowledges the notable progress Switzerland has made in reducing the level of ambient particulate matter in the past few years.

The report entitled “Particulate matter in Switzerland in 2013” takes into account the latest European health research findings, including the “Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA)”. The findings show that, even at the present-day level, air pollution causes disease and death. Evidence has also been found regarding the harmful effects on health of particles with a diameter of less than 2.5 micrometres (PM2.5), as well as of soot. Unlike in many other countries, PM2.5 is not yet regulated separately in Switzerland.

In accordance with the Swiss Federal Environmental Protection Act, ambient air quality standards have to be specified to protect the health of the population. The Federal Commission for Air Hygiene recommends the introduction of an ambient air quality standard for PM2.5 in addition to the already existing air quality standards for PM10. It is calling for the level of 10 micrograms per cubic metre of air as recommended by the World Health Organisation (WHO) to be incorporated into the Swiss Federal Ordinance on Air Pollution Control (OAPC) as an annual mean limit level. It also recommends the specification of a binding target for the reduction of carcinogenic soot by 80 percent in the next 10 years.

The proposed ambient air quality standard represents a strengthening of the existing air pollution control strategy, not a change of direction. In order to comply with the specified air quality standard, further reductions of pollutant emissions at sources will be necessary. With the introduction of the planned Euro standards for motor vehicles, emissions of particulate matter, including soot and precursor gases, will be significantly reduced again. Improvements are also necessary with respect to wood-fired stoves, which are one of the main sources of particulate matter, as well as various other sources.

Further information: Professor Dr. N. Künzli, President of the Swiss Federal Commission for Air Hygiene (phone number, 061 284 83 99 or 079 535 85 25).

Effects of particulate matter on health

Every time we breathe in, thousands of fine particles enter our respiratory system and lungs. They are deposited in the bronchi and alveoli and give rise to negative short-term or long-term health effects. The smaller the particles, the deeper they penetrate into the lungs.

The latest scientific studies clearly show the health consequences of exposure to ambient particulate matter even at the relatively low levels that are recorded in Switzerland. The greater the exposure, the higher the frequency of complaints and diseases. The range of studied health impacts is broad, and extends from increased mortality rates among infants and retarded development of the lungs among children, to respiratory and cardiovascular diseases, asthma attacks and allergies, and to a lower life expectancy due to heart and lung diseases, including lung cancer.

In Switzerland, the long-term effects of air pollution on health are being examined in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) under the leadership of Professor Nicole Probst-Henscht at the Swiss Tropical and Public Health Institute (TPH) in Basel. An evaluation of the SAPALDIA data carried out in conjunction with other long-term European studies showed that the mortality rate attributable to exposure to particulate matter (measured as PM2.5) is also higher even at low levels in the range of only 10 to 15 micrograms per cubic metre of air (mean annual levels). Fortunately, however, the results of Swiss research also indicate that health improves fairly rapidly if the concentration of pollutants in the air is reduced. This means that measures to improve air quality have a discernible positive influence on health, and thus on the national economy.

What is particulate matter?

Particulate matter (PM10 – also referred to as suspended particulates), comprises particles with a diameter of less than 10 thousandths of a millimetre, which is equivalent to around one-tenth of the diameter of a human hair. Particles with a diameter of less than 2.5 thousandths of a millimetre are referred to as PM2.5 (or PM2.5 suspended particulates). Particulate matter is directly emitted into the air, for example as the result of incomplete combustion of fuels and combustibles, from industrial processes and through the resuspension of road dust and abrasion from brakes, tyres, road surfaces and railway lines. Other particles are formed in the atmosphere from gaseous substances such as ammonia, nitrogen oxides, sulphur dioxide and organic compounds. Particles smaller than 0.1 thousandths of a millimetre are called ultrafine particles. They occur during combustion processes or are formed from gases. They increase in size through the accumulation of other particles or gases. Particulate matter is composed of a large number of chemical compounds. Extremely small carcinogenic soot particles are especially harmful components. Among the main sources of particulate matter in Switzerland are traffic and wood combustion. Large quantities of gaseous substances from which particles are formed originate from agriculture and traffic. 

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Last edition: 27.01.2022