It can get quite warm in the country on Wednesday and Thursday with temperatures rising to above 30 degrees.

Rijkswaterstaat will therefore start the so-called heat protocol from Wednesday.

RIVM also warns against smog formation.

The air quality is bad, especially in the afternoon and evening, the RIVM says.

The institute advises people with sensitive airways to take it easy and to limit strenuous physical exertion.

People may also have to adjust their medication to be prepared for the poorer air quality.

The expected smog is so-called "summer smog", which arises in sunny weather like that of the past few days.

Due to southeast winds, waste products, such as nitrogen compounds, have been released into the air above the Netherlands.

The substances are converted into ozone by sunlight.

This is expected to create a large amount of smog in the air on Wednesday and Thursday, when tropical heat is forecast.

Road users advised to prepare well

Rijkswaterstaat announced on Tuesday that the heat protocol will be put into effect for the first time this year.

The heat protocol applies from 10:00 a.m. on Wednesday morning.

This means that road users who end up at the side of the road with a breakdown are immediately helped.

A recovery company is called in to take the stranded motorist to a safe location as quickly as possible, such as a gas station or a parking lot.

The measure applies to the provinces where, according to the KNMI, there is a great chance that temperatures will rise to 30 degrees or higher.

For the time being, these are all provinces except Groningen, Friesland and Drenthe.

Rijkswaterstaat advises road users to prepare well and to take sufficient drinking water with them.

It is also wise to put an umbrella in the car.

In the event of a breakdown, it can be used as a parasol while waiting.

See also: Weekly weather forecast: Tropical temperatures, heavy showers later in the week