Low-cost NO2 measurements at an urban high traffic site

<p class="western"><span lang="en-GB">A network of low-cost air quality sensors for monitoring NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB">- and O</span>_{<span lang="en-GB">3</span>}<span lang="en-GB">-concentrations has been installed at an urban high traffic site in the city of Munich (Bavaria, South Germany). NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB">-measurements conducted over a period of several seasons are used to analyse the effectiveness of novel air filtering systems that have been installed alongside the street section.</span></p> <p class="western"><span lang="en-GB">Estimates of hourly mean NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB">-concentrations at the network sites are determined by applying several calibration methods (linear and non-linear models) that were fitted, validated and compared based on data gathered during two periods where all sensors were co-located at an on site official reference station.</span></p> <p class="western"><span lang="en-GB">Resulting NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB">-estimates at the low-cost network sites are further analysed with respect to spatiotemporal variations in NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB">-concentrations. Thereby the effects of local scale variations in the urban environment, varying traffic loads, changing synoptic weather types and different operating conditions of the air filtering systems are considered.</span></p> <p class="western"><span lang="en-GB">The contribution presents </span><span lang="en-GB">and discusses different approaches for the calibration of the low-cost NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB"> measurements and shows preliminary results of the analyses of spatiotemporal NO</span>_{<span lang="en-GB">2</span>}<span lang="en-GB"> variations in a high traffic urban environment under special consideration of the effectiveness of novel air filtering systems.</span></p>