Modern coal plants produce more ultra-fine dust particles and can modify and redistribute rain patterns, according to a new 15-year international study.
The study suggests that filtration systems of modern coal power plants are the largest source of ultrafine particles and can have significant impacts on the climate in several ways.
In urban areas, road traffic has long been considered a major source of emission of small particles that have the potential to negatively affect health and the environment.
However, long-term measurements carried out by two scientists, Professor Wolfgang Junckner of Karlsruhe Technological Institute (KIT) in Germany and Professor Jörger Hacker of the aviation research Australia, associated with Flinders University, discovered a source that particularly affects the regional climate: modern coal plants.
In Bulletin of the American Meteorological Society, researchers say coal power plants clearly emit large amounts of ultra-fine particles (UFP) through the technology of filtering exhaust gases. The key findings from the long-term study are:
- Modern coal plants are releasing more UFP than city traffic
- UFP can harm people's health
- UFP can affect the distribution of rain at local to regional levels by increasing the number of condensation nuclei
- UFP can be transported in layers with high concentrations of hundreds of kilometers and then lead to localized "particle events" (dramatic increases in short-term particulate concentrations) away from their source.
The survey also showed that UFP concentrations are steadily increasing, as modern coal plants have been commissioned in many locations around the world.
For the measurement flights in Europe, Australia, and even in Mexico and Inner Mongolia, the research team used two rather unusual small research aircraft, the most comprehensively engineered bikers in Australia, and a "trick" developed in Germany – thought to be the smallest exploration aircraft whole world.
Flying laboratories are equipped with highly sensitive instruments and sensors for measuring dust particles, trace gases, temperature, humidity, wind and energy balances.
"Our two research planes are particularly suitable for tracking holes in the hundreds of miles of holes and are studying their behavior in detail," says Professor Hucker, located in Australia's Air Research Area (ARA) in South Australia.
Scientists then linked these data with meteorological observations and used dispersive and transport models to find their origin.
"In this way, we found that for many years, fossil power plants have become the strongest individual sources of ultrafine particles around the world. They have a massive effect on meteorological processes and can cause extreme weather events, including intense rains.
"With the redistribution of rainy events, this can lead to more than usual conditions in some places and to unusually heavy and persistent strong rains elsewhere," says Professor Hacker.
With a diameter of less than 100 nm, UFP has a huge impact on environmental processes that can affect the properties of clouds and precipitation, the newspaper said.
"UFP offers surfaces for chemical reactions in the atmosphere or can affect the properties of clouds and precipitation," says Professor Junkermann.
Outdoors, forest fires, storms of dust or volcanic eruptions create fine particles, but usually not in the nanometric range.
In order to study UFP's existing and distribution and transport processes, researchers not only flown their instruments near or through the wind of coal but also in remote regions where very low UFP concentrations were measured in the past at the country level.
Specifically, in regions with visible precipitation trends, such as western Australia and Queensland, researchers have found that UFP concentrations are increasing steadily and can be linked to emissions from coal and refrigeration plants.
"The exhaust gas cleaning takes place under conditions that are optimal for a new formation of particles. Ammonia is added to the exhaust gases in order to convert nitrogen oxides into safe water and nitrogen," said Professor Junckern.
At the same time, ammonia is available in an appropriate mixing ratio for particulate formation, resulting in increased concentrations in the exhaust gas. After emission of 200-300 meters of smoke from the smoke, many small particles usually spread to several hundred kilometers depending on the weather and climatic conditions in the atmosphere, researchers found.
Power plants produce more turning dust from traffic
Wolfgang Juncker et al. Ultra-sweet particles in the lower troposphere: main sources, invisible clouds and meteorological transport processes, Bulletin of the American Meteorological Society (2018). DOI: 10.1175 / BAMS-D-18-0075.1