Do local urban emissions influence ambient meteorology?

<p>The WRF-Chem model was used to analyze three different 14-day periods during 2016–2017 in Prague, Czech Republic. Specifically a summertime high-level ozone episode, a summertime convective episode and a wintertime episode with high concentrations of aerosol pollutants have been analyzed in great detail. Simulations were run on a 2 km grid domain covering the center of the Czech Republic with the capital Prague, which was nested into a 10 km domain covering Central Europe. For the analysis of the meteorological impact of the reduction of urban induced emissions, two model simulations were performed for each episode; one simulation with full anthropogenic emissions and a second idealized simulation where emissions over the Prague urban area were reduced to the background level. In this presentation we discuss the differences and similarities between these simulations for chemical species (gas and particle pollutants) but also meteorological variables (e.g., downward solar radiation, temperature, boundary layer height).</p>

Spatial distribution and temporal trend of ozone pollution in China observed with the OMI satellite instrument, 2005–2017

We use data from the new China Ministry of Ecology and Environment (MEE) network to show that OMI satellite observations of tropospheric ozone can successfully map the distribution of surface ozone pollution in China and the frequency of high-ozone episodes. After subtracting the Pacific background, OMI ozone enhancements over China can quantify mean summer afternoon surface ozone with a precision of 10.7 ppb and a spatial correlation coefficient R=0.73. Day-to-day correlations between OMI and the MEE ozone data are statistically significant but limited by noise in the individual OMI retrievals. OMI shows significantly higher values on surface ozone episode days (>82 ppb). An extreme value model can successfully predict the probability of surface ozone episodes from the daily OMI data. The 2005–2017 OMI record shows a 0.67 ppb a−1 increase in mean summer afternoon ozone in eastern China and an increasing frequency of ozone pollution episodes particularly in the north.