Spring has started again and that means – if all goes well – warmer weather and less rain showers. But what do these changes in weather conditions actually mean for the quality of our air?
RIVM recently published new figures on Dutch air quality. Last year’s lockdown made it painfully clear how much impact traffic has on the quality of our air. Air pollution decreased the fastest in large cities in particular.
In addition to traffic, industrial areas and farms also have a bad influence. Polluted air is bad for our health and can lead to heart and lung problems, cardiovascular diseases and respiratory problems, among other things. How much we suffer from that polluted air also depends on the weather.
“It depends on the weather situation how much polluted air you breathe”
Michiel van Weele, KNMI researcher
Rain washes the air clean
So says Guus Velders, researcher at RIVM and professor of air quality and climate interactions at Utrecht University. “When it rains, the air is flushed clean, as it were. Clean air blows along with a westerly wind, the opposite is the case when the wind blows from the Ruhr area.”
So it depends on the weather picture how much polluted air you breathe. “Two factors are important here,” says Michiel van Weele, researcher at KNMI. “The thickness of the bottom layer of air and the wind speed.” If the bottom layer of air is very thin – this is mainly the case in winter – then pollutants such as particulate matter will linger nearby, Van Weele explains. “You see the same when there is little or no wind.” Next spring is a period with extra pollen in the air. Hay fever patients experience the differences in weather conditions every day.
“It is important to reduce human emissions as much as possible”
Guus Velders, professor
It always seems to be blowing
We live in a country where it is never dry for very long and where the wind always seems to blow. This means that we often experience little trouble ourselves from the pollutants that end up in the atmosphere through our own actions. “They blow out of our country very quickly”, says Van Weele. “But polluted air from Germany and Poland also blows back into our country just as quickly with a strong easterly wind.” If the weather forecast is unfavorable for the blown away of polluted air, RIVM will send a heating alert, which will relieve residential areas even more. At a heating alert you are asked not to burn wood in or around the house that day.
So no country has full control over its own air quality. “That is why it is so important to make good agreements in Europe,” says Velders. The professor also wants to emphasize the importance of reducing human emissions as much as possible and taking measures to combat air pollution. After all, it doesn’t matter how strong the wind force is, the air is clean in any case. “This can be done, for example, by removing traffic as much as possible from the city and making public transport more sustainable and stimulating its use. The increasing popularity of electric cars is also a good development in this regard.”
What if we go back to the office later?
It is difficult to say how long the positive effects of the lockdown on our air quality will continue. Will people continue to work from home, or will we be back to the office in a minute? It is clear that, even after a year of less traffic, we have breathed a lot cleaner air, but we still do not meet all the requirements of the World Health Organization. The figures from Statistics Netherlands show how, despite political promises and the corona crisis, emissions are still 0.5 percent too high.
So we can be disappointed when the umpteenth rain shower falls on us or when we are almost blown off our bike again. The often turbulent weather regularly works in our favor. Hay fever patients know this from their own experience.