A historic region

Mainz and surrounding area

A medium-sized city with a strong historical culture

Mainz on the Rhine is a city of 220,000 inhabitants, similar in size to Rennes, which is also featured on this site.

Birthplace of Johannes Gutenberg, Mainz is the headquarters of several German media; it is home to the famous “Johannes Gutenberg” University and is mainly home to metal processing industries. Situated 60 km west of Frankfurt, its environment is relatively protected.

A well-monitored environment

A network of 6 official sensors and at least 28 citizen sensors monitors air quality in the city of Mainz and its suburbs, including neighboring Wiesbaden.

Three official sensors (shown in blue on the map) are located on either side of the two communities. They are located mainly in populated and frequented areas of the communities, and not in the immediate vicinity of major roads.

Most of Mainz’s population and activity seems to be concentrated on the left bank of the Rhine, while Wiesbaden spreads out on the right bank downstream.

Citizen sensors are therefore mainly located on the right bank of the Rhine. Sensors in Wiesbaden are relatively far from the city center, and two of them (ID15155 and ID25133 on the “eastern” side) are apparently faulty (very low values, not credible).

The sensor network in and around Mainz

Very similar measurements from official sensors

Measurements from official sensors are public and can therefore be exploited at will; the values are reported in the attached graphs without correction, as no other credible reference is available.

These sensors can provide measurements of a range of pollutants, including NO2 and fine particulates; the analysis presented covers only fine particulates in order to make a comparison with citizen sensors limited solely to these components.

PM10 measurements in September 2024
PM2.5 measurements in September 2024

The six sensors give similar signatures for the different particle sizes, with some peaks mainly for the sensors located in the center of Mainz.

Concentrations were higher than the acceptable WHO limit (blue dotted line), mainly in PM2.5, with a disturbed period at the beginning of the month and a very disturbed period between the 18th and 24th. On the other hand, two relatively quiet periods were observed between these two phases of activity. What were the particular events that led to this rise in concentration during the two phases observed: specific events in the communes or external events; the occurrence being similar in the two communes, the influence of external pollution/disturbance seems more credible.

Overview of measurement results for the Mainz region in September 2024

After processing the various sensors providing operational values, and using the full month’s readings, a measurement map can be drawn up for each type of concentration.

The figures shown give the average concentration of the particulate type concerned over the month in micrograms per m3 (please refer to the information on the home page for the color code).

PM 10

Mainz and surroundings

PM 2.5

Overall balance

The official sensors give slightly higher values than the citizens’ sensors; this can be explained by a more protected situation at the citizens’ level, as the sensors are in a private outdoor location, but not directly on the sensitive points of urban activities.

We note that the center of Mainz (DERP010) is subject to strong disturbance in terms of both PM10 and PM2.5; the official DERP009 sensor seems to give underestimated PM2.5 values (partial acquisition?).

The Rhine crossing north of Mainz (between DERP007 and DEHE022) reveals a disturbed/polluted zone due to heavy traffic on the transit bridge (the DERP007 sensor gives no PM2.5 measurement).

Urban areas measured by citizen sensors show an acceptable average PM10 level (below 15) but a more worrying PM2.5 level (above 5).

Detailed measurements

Measurements from the various sensors show similar dynamics, with concentration peaks more or less accentuated depending on sensor location.

Periods of high concentration are globally confirmed by all sensors. The study of sensors located at a great distance from Mainz would enable us to determine whether the disturbance is local to the city and its surroundings, or global over a wide region.

PM10 measurements
PM2.5 measurements
Temperature trends

Temperature curves are recorded because citizen sensors are sensitive to low temperatures in particular: but this is not a concern at this time of year.

However, we can see that periods of high concentrations are concomitant with periods of high temperatures. This could be correlated with atmospheric disturbances (winds….) bringing warm air masses with their flow of particles (a simple hypothesis…).

Dynamic presentation of measurement points

To better interpret the measurement curves and their evolution at each location, a dynamic presentation of the air quality measurement over the study area is better suited to showing the evolution of particle pollution both geographically and over time.

PM10 concentration trends in the Mainz region

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Visualization

PM10 and PM2.5 in Mainz

The two videos opposite show the environment considered over the period September 1 to September 30, 2024. The accelerated speed corresponds to approximately 4 hours every second.

All valid measurement points (official sensors and citizen sensors) are taken into account in these simulations.

 

PM2.5 concentration trends in the Mainz region

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