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Comparative analysis of low-cost devices used to measure particulate matter concentration

The growing popularity of low-cost particulate matter sensors and a simultaneous lack of method for verifying the quality of measurement results led to joint research in this field conducted in 2017 and 2018. Two series of measurements were conducted with the use of low-cost sensors in comparison with a reference method. The measurements aimed at verifying and evaluating the reliability of available low-cost measuring instruments. The study presented below is a summary of two reports drawn up on completion of the comparative measurements. The results of the measurements have been analysed according to the methodology used while proving the equivalence to a reference method. Yet, the above-mentioned reports do not aim at proving the equivalence to a reference method. The study main objectives include:

  • Evaluation of low-cost sensors reliability,
  • Determination of their usefulness for indicating the quality of air,
  • Determination of their usefulness for information or education purposes,
  • Presentation of instructions for potential buyers.

Comparison of alert and information thresholds across the European Union

This publication compares different information and alert thresholds adopted for daily PM10 concentrations across respective EU Member States.

Despite the fact that the EU CAFE Directive (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe) introduces alert thresholds for ozone, nitrogen dioxide and sulphur dioxide, as for PM pollution Member States are given a free hand. As a result PM alert thresholds differ substantially across the EU, from 300 ug/m3 in Poland, to 50 ug/m3 in Germany. Cities and countries have adopted a different set of measures aimed at reducing PM concentration in the short term, including free public transport, restrictions on car use, ban on fireplace use, controls of what is combusted in household installations, closure of schools, to name just a few of them. They also use different strategies for informing the public and the most sensitive groups about poor air quality.

Taking effective measures in order to curb air pollution in the short term and inform the public about poor air quality is important to reduce the negative impacts on public health. Within the European Union, each year over 140 thousand people are admitted to hospitals due to exacerbation of respiratory system diseases and additional 108 thousand due to exacerbation of cardiac system diseases in EU1. Some of these admittances could be avoided by effective measures aimed at short term pollution reduction and minimization of pollution exposure.

Analysis of SO2 concentrations compared against EU limit values and WHO guidelines

This analysis compares population exposure to SO2 concentrations at three thresholds: the current EU limit values (125 µg/m3), the interim level (50 µg/m3) and the most stringent scenario, i.e. the WHO guidelines (20 µg/m3). The analysis was conducted based on the actual monitoring data and on modelling. The results from modelling show that the EU limit values are exceeded only in several municipalities. The situation is much worse when it comes to WHO guideline threshold. Over 12.7 million people are exposed to SO2 concentrations above that threshold, which accounts for one third of the country’s population. This problem is faced by nearly 800 municipalities.

This analysis confirms that need for lowering the EU limit value for SO2 concentrations. The current EU sulphur dioxide daily limit is 6-times higher than the WHO air quality guidelines. This discrepancy should be limited within the new legislation, as the current EU legislation suggests that concentrations surpassing the WHO limit are still safe for public health.

Analysis of health impacts of different information and alarm thresholds for daily PM10 concentrations

This analysis, led by ECAC, addresses the issue of new information and alert thresholds for Poland. To date Poland has the highest values for the alarm threshold (300 μg/m3) and information threshold (200 μg/m3). The Task Force on Health Impacts of Air Pollution, at the Public Health Council has prepared an analysis for setting an informative and alert threshold for daily PM10 concentrations. The analysis compares the number of hospitalizations assigned to PM10 exposure exceeding various threshold concentrations above the limit value of 50 μg/m³ during the heating period. The task force also estimated exceedances of different daily PM10 thresholds in respective regions.

The analysis used official monitoring data on concentrations of PM10 in the heating season (1st and 4th quarter) in the years 2015-2017. The data on the daily number of people hospitalized for respiratory and circulatory diseases in each municipality came from the National Health Fund.

The analysis carried out showed that the number of avoidable hospitalizations at the adoption of high threshold values is negligible on the national scale. For example, by eliminating days with a concentration of 150 μg/m³, the number of hospitalizations attributed to the exposure can be reduced by only 12%. To achieve 50% or 75% reduction, it is required that the level of 82 μg/m³ or respectively 63 μg/m³ is not exceeded. Based on the analysis, the Task Force has recommended the lowering of the current alarm and informative levels to the value of 80 μg/m³and 60 μg/m³respectively for the average daily concentration of PM10.