The campaign has ended on September 15


captorAIR is an application developed by the Universitat Politècnica de Catalunya in collaboration with Ecologistas en Acción, the Consejo Superior de Investigaciones Científicas (CSIC),, Legambiente, Zentrum für Soziale Innovation, GLOBAL 2000 and the Université Blaise Pascal Clermont-Ferrand within the framework of the European CAPTOR project. Its main objective is to inform the population about tropospheric ozone concentrations in real time. captorAIR is free software and completely free.

About the data shown in captorAIR

captorAIR use the data from CAPTOR nodes which are sensing devices designed to monitor ozone pollution in three different European regions. They are low cost sensors implemented in a citizen science approach, to increase population awareness with regard to ozone pollution. Because the low cost sensors have higher uncertainty than official reference instrumentation, the data generated by the CAPTOR nodes should only be considered informative and not be used for regulatory compliance purposes. In order to ensure their comparability with reference instruments, the CAPTOR nodes have been previously calibrated by comparison with EU reference instrumentation data from local air quality networks. CAPTOR nodes are deployed during summer periods in the houses of volunteers.

captorAIR data is given in UTC time (UTC +1 in winter and UTC+2 in summer).

Legend of captorAIR ranges

captorAIR collects and process the data from the CAPTOR nodes in order to provide understandable and useful information for citizens in terms of effects on health and legal limits of European legislation in four colors. The data generated by the CAPTOR nodes should only be considered informative and not be used for regulatory compliance purposes.

Hourly mean

Exceeds alert threshold (240 µg/m3)

Exceeds information threshold (180 µg/m3)

Intermediate situation without legal breach

Health effects not accredited

8 hour mean. Moving average*

Exceeds legal target threshold (120 µg/m3)

Exceeds WHO recommended threshold (100 µg/m3)

Intermediate situation without WHO breach

Health effects not accredited

* 8 hour mean values are provided in real time based on the calculation of last 8-hours moving averages.

Ozone (O₃) information

While stratospheric ozone (“good” ozone) blocks the sun’s ultraviolet (UV) rays and prevents them from reaching the earth’s surface, tropospheric (ground-level) ozone (O3) (“bad” ozone) is an air pollutant that damages human health, vegetation, and ecosystems.

Tropospheric ozone is a secondary pollutant, which means that it is not emitted directly into the atmosphere. Instead, it is formed from complex chemical reactions of nitrogen oxides (NOX) and volatile organic compounds (VOCs), carbon monoxide (CO) or methane (CH4), in the presence of sunlight. These gases are called ozone precursors.

In addition to respiratory disorders, it causes mucosal irritations and asthma, and facilitates the development of lung diseases. An increase of only 10μg/m3 increases by 0.4% the mortality by heart disease. It also affects the environment and agriculture, with loss of productivity that can reach up to the 39% (CIEMAT, 2009: El ozono troposférico y sus efectos en la vegetación).