The analysis of the results of long-term air quality monitoring in Riga is presented, which shows that in city centre throughout the measurement time (2004-2014) according to the guidelines defined by the European Union directives and Latvian laws the limits of small particles PM10 and nitrogen dioxide (NO2) are exceeded. From the nature of appearance of pollution and from the research of morphology and composition of fine dust particles it was concluded that in the city centre where the monitoring was performed the main air pollutants are caused by internal combustion engine vehicles. The measures to reduce air pollution performed by two Action Programs (2004-2009; 2011-2015) of the City Council showed that there were only two possible ways to improve air quality in urban environment ‒ to decrease the number of traffic units and/or to decrease exhaust emissions from vehicles.
From the analysis of energy consumption and resources used for it the conclusion was drawn that Latvia is dependent on fossil fuel import, especially in traffic sector (99 %). A new trend has been observed in Latvia ‒ the type of cars is changing: the number of gasoline cars rapidly decreases and number of diesel cars is growing. Both fuels in exhaust gases of second-hand cars are giving high emissions of fine particles (soot) and nitrogen oxides as compared with new cars; 72 % of cars on the roads of Latvia are more than 13 years old. The switch to bio-diesel can improve Latvian statistics according to CO2 reduction target for 2020 but not the concentration of PM10 and NO2 on streets with dense traffic.
Therefore, to improve air quality in urban environment and simultaneously reduce the dependence of Latvia from fossil fuel import, a scenario is proposed for the changeover to zero-carbon technologies in transport and energy production. Hydrogen is analyzed from the point of view of availability of resources and commercialized technologies. The research of the public opinion was done because there is little awareness in society about hydrogen as energy carrier and simultaneously as fuel.