Status: 03/14/2023 08:55 a.m
Exposure to particulate matter can have health consequences. The WHO has therefore set stricter guidelines in 2021. According to a study, however, these are hardly ever complied with worldwide.
Fine dust pollution is still very high for people worldwide. According to a research team, the daily maximum value for particles of the size PM2.5 recommended by the World Health Organization (WHO) was exceeded on a global average on 70 percent of all days reported in the journal The Lancet Planetary Health. Only 0.001 percent of people live in places where the recommended annual maximum is not exceeded.
Fine dust particles with a diameter of less than 2.5 micrometers (0.0025 millimeters) are referred to as PM2.5. The WHO had lowered the recommended limit values for PM2.5 fine dust in 2021 – for the mean annual pollution from 10 to 5 micrograms (0.000005 grams) per cubic meter of air. According to the Federal Environment Agency (UBA), this value was exceeded in Germany in 2022 at almost all of the approximately 200 measuring stations.
Highest in Asia, lowest in Oceania
The research team led by Yuming Guo from Monash University in Melbourne determined the fine dust pollution based on measured values and computer models for the years 2000 to 2019. The global annual average of PM2.5 was 32.8 micrograms per cubic meter of air.
East Asia (including China) had the highest score at around 50, followed by South Asia at 37.2 and North Africa at 30.1. The lowest values were in Australia and New Zealand (8.5), the rest of Oceania (12.6) and South America (15.6). The daily maximum value of 15 micrograms per cubic meter of air recommended by the WHO was exceeded on more than 70 percent of all days worldwide, and on more than 90 percent of all days in East and South Asia.
Exposure decreases slightly in Europe
According to the analysis, there was a decrease in particulate matter pollution in Europe and in some regions of North America and Africa. In Europe, the recommended daily maximum was exceeded on almost 60 percent of all days in 2000, and in 2019 it was still 25 percent of all days.
In Northern Europe, the values were significantly lower than in the other regions of the continent.
Human activity is the main cause of particulate matter
According to the Federal Environment Agency (UBA), fine dust is produced, for example, in traffic, in power plants and district heating plants, furnaces and heating systems, and in metal and steel production. It can also be of natural origin, for example as a result of soil erosion. In metropolitan areas, road traffic is the dominant source.
Another important cause is agriculture. The emissions of gaseous precursors, in particular the ammonia emissions from animal husbandry, contribute to the secondary formation of particulate matter, as the UBA says.
Risk of cardiovascular disease and cancer
PM2.5 particles can sometimes penetrate into the alveoli and the bloodstream. Long-term fine dust pollution can lead to cardiovascular diseases and lung cancer. According to the WHO, around seven million people die prematurely each year as a result of air pollution.
According to data from the EU Environment Agency EEA, around 240,000 people died prematurely in the EU alone in 2020 as a result of exposure to particulate matter in the air around them.
With regard to the current study, Roland Schrödner from the Leibniz Institute for Tropospheric Research in Leipzig speaks of a promising approach that at least provides plausible data for the regions with measuring stations.
However, the researcher also points out that the PM2.5 particle size considered is only a compromise. Particles of the size PM1, i.e. with a diameter of one micrometer or less, which represent a subgroup of the category PM2.5, are mainly harmful to health.
In the future, the size categories of particulate matter could and should be recorded more precisely. The chemical composition is also important, according to Schrödner.