The paper provides the results of the inventory of greenhouse gases (GHGs) from road transport in Poland over the period

This article presents results of the inventory of pollutant emission from motor vehicles in Poland. To determine emission from motor vehicles in Poland COPERT 5 software was used for the first time. In addition, a comparison of the national emission from motor vehi-cles in 2016 and in 2015 was included. Pollutants harmful to health were considered primarily: carbon monoxide, organic compounds, nitrogen oxides and particulate matter. Emission of substances contributing to the intensification of the greenhouse effect were also examined: carbon dioxide, ammonia and nitrous oxide. It was found that the relative increase in volume of emission of carbon monoxide and non-methane volatile organic compounds is less than 10%, and nitrogen oxides and particulate matter less than 15%. The relative increase in carbon dioxide emission is approximately 14%, which corresponds to a relative increase in fuel consumption. The relative increase of volume of heavy metal emission is similar. The assessment of the energy emission factor (emission of pollution related to energy equal to used fuel) proves that – amongst pollutants harmful to health – for carbon monoxide and non-methane volatile organic compounds there is a relative reduction by approximately 5% in 2016, and for nitrogen oxides and particulate matter – increase by approximately (3–4)%.

The article presents the results of studies on the influence of the thermal state of vehicle combustion engines on pollutant emissions. This influence was analyzed based on data from Poland’s inventory of pollutant emissions for the years 1990–2017. The results show that during engine warm-up, carbon monoxide emission constitutes the largest share (up to 50%) in the national annual total emission. Volatile organic compounds are next in the ranking, whereas the share of nitrogen oxides is the lowest (less than 5%). Under the model traffic conditions, close to those in Poland’s cities in winter, simulation tests regarding additional pollutant emissions from passenger cars during engine warm-up were also carried out. As a result of the cold-start emissive behavior of internal combustion engines, emissions of carbon monoxide and volatile organic compounds showed a considerably greater impact on national pollutant emission, as compared to carbon dioxide, nitrogen oxides and particulate matter. This is particularly evident for the results of the inventory of pollutant emissions from road transport.

The paper provides the results of the inventory of pollutants hazardous to the health of living organisms, emitted by road transport in Poland between 1990 and 2017. For estimating pollutant emissions from road transport, a standardized methodology was applied, consistent with the guidance of EEA/EMEP Emission Inventory Guidebook 2019 and the COPERT 5 software. The following substances were analyzed: carbon monoxide (CO), non-methane volatile organic compounds (NMVOC), nitrogen oxides (NOx) and particulate matter size fractions (total suspended particles—TSP, PM10, PM2.5). For the pollutants, emission values averaged over the distance travelled by the road fleet (average specific distance emission) were determined. The results obtained indicated that between 1990 and 2017 the annual pollutant emissions from road vehicles in Poland had an increasing trend concerning TSP (74%), PM10 (64%), PM2.5 (52%) and NOx (25%), while the corresponding emissions had a decreasing trend for CO (−117%) and NMVOC (−85%). However, a clear downward trend was found for the average specific distance emissions of all substances throughout the subsequent inventory years: TSP (−28%), PM10 (−100%), PM2.5 (−91%), NOx (−84%), CO (−208%) and NMVOC (−173%), which is due to the dynamic progress in the technological advancement of road vehicles.

The road transport sector is a significant source of air pollutants' and greenhouse gases' emissions. These emissions, considered as the masses of particular substances released into the air, can be split into two groups: those that are regulated under EU road transport legislation and those that presently are not [8]. The 'regulated' pollutants include among others: hydrocarbons (HCs). The legislation on emissions regulates total hydrocarbons (THC/HCs) emissions, with no distinction between methane (CH 4 ) and non-methane volatile organic compounds (NMVOCs) [7].According to the data presented in the EU's report [8], HCs belong to a larger group of chemicals known as volatile organic compounds (VOCs). HCs are compounds that chemically consist of hydrogen and carbon only, while VOCs may also contain another element, such as sulfur. NMVOCs also cover the homologous series such as aromatic compounds, aldehydes, alkenes, alkynes, ketones, and alkanes. They are produced by incomplete combustion of hydrocarbon fuels, and also by their evaporation. Due to the fact that there are many hundreds of different compounds, HCs and VOCs are groups of various chemical compounds displaying a wide range of proper-ties. Some of them, such as benzene, are carcinogenic; some are toxic, while others harmless to health [4,8].Hydrocarbons emitted by vehicles are products of either incomplete, or partial combustion, which are also toxic to human health [4]. HCs, and particularly the VOCs, contribute to the formation of ground-level ozone and photochemical ('Los Angeles' type) smog in the atmosphere, while methane (CH 4 ) is regarded as a greenhouse gas [8].The vast majority of the HCs emissions come from vehicle exhaust systems. Cold-start emissions, defined as the total mass of a particular