Healthy living How air pollution increases the risk of cardiovascular diseases

Air pollution essentially means that substances (pollutants) have altered the natural composition of air. Examples of pollutants include smoke, soot, dust, gases, aerosols, vapors and odorants.

Numerous air pollutants can be harmful to human and animal health if their concentrations in the air we breathe exceed certain levels. The main air pollutants that have been shown to pose health risks include particulate matter, ozone, nitrogen dioxide and sulfur dioxide.

These air pollutants are largely caused by human activities. Harmful substances are released into the air through energy generation and consumption, traffic, agriculture and especially industrial production. There are also natural causes such as forest fires.

Of the air pollutants mentioned, particulate matter in particular can contribute to changes in the walls of the arteries (arteriosclerosis) and, in turn, cardiovascular diseases.

Particulate matter is created by a wide range of both natural and man-made sources:

These include, in particular:

• exhaust gases produced by internal combustion engines
• abrasion from car tires, brakes and road surfaces
• emissions from heating systems and power plants
• the burning of waste and wood
• gases from agriculture and livestock production that contribute to the formation of particulate matter
• sources of particulate matter in indoor air, such as cigarette smoke, cooking, candles and fireplaces 

Particulate matter is one type of airborne particle. Airborne particles are particles that remain suspended in the air for a certain period of time, rather than falling to the ground immediately. Specifically, the term refers to all airborne particles with a diameter of 10 micrometers or less. These particles are about the size of a red blood cell and are invisible to the naked eye. Finer particles with a diameter of 2.5 micrometers or less are known as “fine fraction” particulate matter. It gets even smaller than this: There are also “ultrafine particles”, which have a diameter of less than 0.1 micrometers (less than one tenth of a micrometer). A micrometer is one millionth of a meter. 

Particulate matter, especially ultrafine particles are considered to be particularly harmful to health compared to other air pollutants. This is because they can penetrate very deeply into the airways with the result that they remain in the body rather than being exhaled like other air pollutants.

The respiratory system and cardiovascular system are connected by means of the pulmonary alveoli (air sacs). The alveoli are located at the end of the airways, deep inside the lungs. Tiny blood vessels called capillaries surround the alveoli. This is where gas exchange happens during the breathing process. Oxygen in the inhaled air passes from the alveoli into the blood in the capillaries, while carbon dioxide in the blood passes from the capillaries into the alveoli. Inhaled particulate matter can penetrate the pulmonary alveoli and enter the bloodstream via the capillaries.

The processes that happen next have not yet been researched in detail. However, experts believe that particulate matter triggers inflammation in the walls of the blood vessels. Laboratory experiments and clinical studies have demonstrated that particulate matter can damage blood vessel walls, affect blood clotting, induce inflammatory responses and increase blood pressure. These factors increase the risk of arteriosclerosis – a vascular disease commonly known as “hardening of the arteries”.

Arteriosclerosis is associated with progressive damage to the arterial blood vessels: the vessel walls harden and deposits form in them, constricting the blood vessels.

Due to these vascular changes, arteriosclerosis can cause a number of cardiovascular diseases.

These include:

• coronary heart disease (ischemic heart disease)
• stroke
• heart attack
• high blood pressure

To reduce the health effects of particulate matter, the following limit values for particulate matter apply in Germany and Europe as a whole:

• The annual mean value must not exceed 40 micrograms per cubic meter of air.
• The daily mean value must not exceed 50 micrograms per cubic meter of air on more than 35 days per calendar year.

Although levels of particulate matter in the air in Germany have been significantly reduced since 1990, levels in many places are still frequently high enough to be harmful to health, particularly in urban areas.

The National Air Pollution Control Programme, established in 2019, aims to further improve air quality in Germany by 2030. For example, it sets emission limits for various industrial sectors. The main objective of the program is to significantly reduce levels of particulate matter as well as the emission of substances such as ammonia that contribute to its formation.

The European Union’s revised Ambient Air Quality Directive entered into force in 2024. It sets new limits that will apply from 2030, including an annual mean value of 10 micrograms per cubic meter for fine fraction particulate matter. 

The latest information about air quality in your region and Germany as a whole can be found on the website of the Federal Environment Agency (Umweltbundesamt).