RIVM has investigated, at the request of the province of North Holland, whether the monitoring networks in this province are still suitable for current questions, for example, whether they measure the right substances in the right places. Various stakeholders, such as municipalities, the province, and local residents were also asked what they expect from the monitoring networks.
Monitoring networks suitable for monitoring and testing against threshold values
The monitoring networks prove to be suitable for tracking (monitoring) air quality over the years. It can also be tested whether the concentrations of certain substances remain below the Dutch threshold values or the advisory values of the World Health Organization (WHO World Health Organization (World Health Organization)) for air quality.
Advice to share information more actively
The monitoring networks provide a lot of information to answer questions from stakeholders about air quality. However, these parties need explanations for the bare measurement results to better understand what they mean. Furthermore, residents indicate that they do not always know where to find the measurement results. RIVM therefore advises the province of North Holland to share the measurement results and knowledge about air quality more actively with them. It is up to the province how best to do this.
Measuring and calculating for a good picture of air quality
A monitoring network is not suitable for formally testing whether a company complies with the permitted emissions of pollutants into the air. Air quality is determined by much more than the presence of a company. However, the measurements of a monitoring network, combined with calculations, can help to gain insight into how much a company contributes to air quality. For these calculations, data from the company about emissions is used, among other things. If the difference between measurements and calculations is large, this may prompt the competent authority to discuss this with the respective company.
Some residents want more local measurements. Measurements and model calculations together now provide a good picture of air quality in a region. More measurement points do not always provide more information. RIVM also advises against relocating monitoring points that have existed for a long time. Fixed monitoring points are important to accurately map developments over time.
Ultrafine particles
RIVM recommends that the province consider expanding existing measurement locations in the IJmond and Haarlemmermeer monitoring networks with measurements of ultrafine particles. These measurements provide more insight into the concentrations of ultrafine particles in the region. They also help determine how much ultrafine particles the Dutch population inhales through the air. This knowledge is important to gain more insight into potential health effects of ultrafine particles.