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No. 315: Development in air quality for 2030 in relation to National program for reducing air pollution (NAPCP) - Effects of selected initiatives in the government's climate and air play

Jensen, S.S., Christensen, J.H., Frohn, L.M., Brandt, J., Ketzel, M., Nielsen, O.-K., Plejdrup, M.S., Winther, M., Hertel, O., Ellermann, T. 2019. Udvikling i luftkvalitet for 2030 i relation til Nationalt program for reduktion af luftforurening (NAPCP) – Effekter af udvalgte initiativer i regeringens klima- og luftudspil. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 48 s. - Videnskabelig rapport nr. 315.  http://dce2.au.dk/pub/SR315.pdf

Summary

Aim and background

The aim of the project is to carry out an impact assessment for selected initiatives in the Government's Climate and Air Proposal with focus on three measures for road transport and two measures for wood stoves – hereafter climate scenario. Emissions in 2030 are estimated, and the impact on air quality and the health effects of air pollution are calculated. A previous report carried out model calculations for a base scenario and an alternative scenario with further reduction requirements for the energy sector for 2020 and 2030 (Jensen et al., 2018). Information from this report is included when comparing the climate scenario with the above scenarios.

The background for the project is due to the requirements of EU directive from 2016 on National Emission Ceilings (NEC directive). The directive requires development of national programmes for the control of air pollution named NAPCP – National Air Pollution Control Programme. Denmark is committed regularly to evaluate the development of the national emissions and their expected future development, and carry out actions to reduce emissions in order to achieve the reduction targets that have been set for Denmark in the NEC directive.

The NEC directive sets out national commitments for reductions in emissions for 2020 and 2030 for the pollutants: sulphur dioxide (SO2), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC), ammonia (NH3), and fine particles (PM2.5 - mass of particulate matter less than 2.5 microns). Emissions of these substances are included in the calculations of air quality of NO2 (nitrogen dioxide), PM2.5, PM10 (mass of particulate matter less than 10 microns), and O3 (ozone).

The study

Emissions of different scenarios

The effects of five selected initiatives in the Government's Climate and Air Proposal are estimated (Regeringen, 2018): (1) no sale of new petrol and diesel cars in 2030 and of new plug-in hybrid cars from 2035, (2) no CO2 emissions and air pollution from urban buses in cities from 2030, (3) no petrol and diesel taxis in 2030, (4) old stoves before 2000 scrapped when home ownership is changed, and (5) subsidy to scrap old stoves before 2000. These five initiatives are named the climate scenario.

The baseline scenario for Denmark originates from the baseline projection of the Danish Energy Agency. This is a forecast based on existing policy actions, also named ‘frozen policy’ and referred to as WM – With Measures.

In the alternative scenario with additional measures used for Denmark the emissions are described in details in another DCE report about the projection of emissions (Nielsen et al., 2018a). The alternative scenario only has additional measures within the energy sector and is called WAM – With Additional Measures. The energy sector includes stationary combustion (power plants, heating plants, etc.) and mobile combustion (transport and non-road mobile machinery), as well as fugitive emissions.

The starting point is 2016, and 2020 and 2030 are scenario years. For the climate scenario, calculations are only carried out for 2030.

Regional background concentrations

The regional background concentrations are calculated with the Danish Eulerian Hemispheric Model (DEHM) with a geographic resolution of 5,6 km x 5,6 km. The regional background represents the average concentration in rural areas over a larger area. The regional air pollution represents the contribution of long-range transported air pollution from emissions from abroad and from Denmark.

Background concentrations with high resolution

The development in background concentrations with high resolution is calculated with the Urban Background Model (UBM). Urban background pollution represents the average background pollution inside and outside cities calculated with a spatial resolution of 1 km x 1 km. Urban background concentrations correspond in a city to the concentration at roof top level or in a backyard/park. DEHM calculations are input in UBM. For Denmark emissions are available at a spatial resolution of 1 km x 1 km based on the SPREAD model that distributes national emissions based on various geographic variables.

Furthermore, the Average Exposure Indicator is calculated. In principle, the average exposure indicator is determined as an average over three years for PM2.5 measured at urban background locations to reflect population exposure.

In this project the exposure indicator is calculated and only for the scenario years. The Average Exposure Indicator is calculated for Copenhagen, Aarhus, Odense and Aalborg in the same geographic locations as the location of the urban background air quality monitoring stations.

Street concentrations

The development in street concentrations is calculated with Operational Street Pollution Model (OSPM) for 98 selected streets in Copenhagen. The selected streets in Copenhagen are the same as those included in the Danish Air Quality Monitoring Program. The development in vehicle emissions is based on the Danish emission model for road traffic and other mobile sources.

Air quality calculations of regional concentrations, urban background concentrations and street concentrations are carried out for NO2, PM2.5 and PM10 for 2016, 2020 and 2030 for the baseline scenario and the alternative scenario, and for 2030 for the climate scenario.

Health impacts

Health effects of air pollution are calculated with the integrated model system EVA (Economic Valuation of Air pollution). In this project the same version of the EVA system is used as in the Danish Air Quality Monitoring Programme for 2016. The same population is assumed for all years.

Main conclusions

Development in emissions

A reduction in Danish emissions of NOx, NMVOC, NH3 and PM2.5 is seen from 2016 to 2030 in the baseline scenario. SO2 is the only pollutant expected to increase from 2016 to 2030 in the baseline scenario due to increased coal consumption. In the alternative scenario for the energy sector all pollutants are expected to have slightly lower emissions than the baseline scenario in 2030.

Foreign emissions are also reduced from 2016 to 2030. The foreign emissions are different in the Danish baseline scenario (WM) and the alternative scenario for the energy sector (WAM). The WM scenario uses the foreign countries’ baseline emissions, and the WAM scenario also uses the countries' baseline if the NEC-directive emission ceilings are met, otherwise the NEC-directive emission ceiling for that country is used. The climate scenario uses the same assumptions as the WAM scenario.

Effekt of climate scenario for road transport

The emission reduction of the three initiatives for electrification of part of the road transport sector in 2030 is shown in table 1 in relation to the baseline scenario.

The largest emission reduction is achieved for the scenario with 1 million electric cars in 2030, where NOx emissions are reduced by 13% and PM2.5-exhaust by 17% compared to the baseline in 2030. The total reduction in PM2.5 (exhaust and non-exhaust) is only 2% since PM2.5-non-exhaust is not reduced and non-exhaust constitutes a very large proportion of total PM2.5 in 2030. Non-exhaust is tire wear, road wear and brake wear.

The emission reduction for electric urban buses is around a tenth to the scenario of 1 million electric cars, and for the electric taxis it is only a twentieth. This reason is that there are far fewer urban buses and taxis compared to passenger cars.

Effect of climate scenario for wood stoves

Table 2 shows the emission reduction for the two initiatives for wood stoves.

Scrapping of old stoves before 2000 when home ownership is changed is more effective in reduction of emissions than a subsidy to scrap old wood stoves before 2000.

The emission reduction of scrapping old wood stoves when home ownership is changed leads to significant reductions for PM2.5 (11%), BaP (17%), dioxin (15%) and CH4 (17%). CH4 is a powerful greenhouse gas, which contributes to climate change.

NOx emissions are slightly increasing because modern stoves burn at a higher temperature, and thereby increases the formation of NOx.

The effect of the scrapping subsidy is very uncertain. For example, a scrapping subsidy may have a very limited effect, if it only subsidies replacements, which anyway would be have been carried out.

Samlet effekt af klimascenariet

For trafiksektoren reduceres NOx emissionen med 2.046 tons, mens den for brændeovne øges med 41 tons pga. mere moderne ovne, hvilket giver den samlede reduktion på omkring 2.000 tons. For brændeovne reduceres PM2,5 emissionen med 979 tons mens reduktionen for trafiksektoren kun er 30 tons, hvilket til sammen giver omkring 2.000 tons. Reduktionerne i NOx emissionen er således helt bestemt af reduktionerne i trafiksektoren, mens reduktionerne i PM2,5 helt er bestemt af brændeovnene.

Total impact of the climate scenario

The transport sector reduces NOx emissions by 2,046 tons, while wood stoves increase emissions by 41 tons due to more modern stoves, which gives the total reduction of approx. 2,000 tons. Wood stoves reduces PM2.5 emissions with 979 tons while the reduction of the traffic sector only is 30 tons, which in total is approx. 2,000 tons. Hence, the reductions in NOx emissions is almost entirely determined by reductions in the transport sector, while reductions in PM2.5 almost completely are determined by wood stoves.

Development in background concentrations with high resolution

The average background concentrations for the five regions in Denmark are also calculated with DEHM/UBM for baseline and the alternative scenario. In this case, the calculations are based on a geographical resolution of 1 km x 1 km.

For the baseline the background concentrations of PM2.5 for the five regions are reduced by 18-20% in 2030 compared to 2016, and for PM10 by 12-16%, and for NO2 14-31%. The interval indicates that the percentage reduction is different from region to region.

In the alternative scenario the percentage reductions in 2030 are a little larger as compared to the baseline, reflecting that the emissions are a little lower in the alternative scenario. PM2.5 will be reduced by 23-27% in 2030 in relation to 2016, and for PM10 15-20%, and for NO2 15-34%.

In the climate scenario the percentage decreases are slightly larger than in the baseline scenario, but at the same level or slightly smaller than in the alternative scenario. In the climate scenario PM2.5 is expected to be reduced for the 5 regions with 21-25% in 2030 compared to 2016, and 14-20% for PM10 and 15-34% for NO2.

Development in urban background concentrations in 4 cities

Urban background concentrations of NO2 decrease in the baseline scenario with 22-39% in 2030 compared to 2016 for the same locations as the urban background air quality monitoring stations in the four largest cities of Denmark: Copenhagen, Aarhus, Odense and Aalborg. The decrease for PM10 is 11-16% in 2030 compared to 2016. The Average Exposure Indicator for PM2.5 in the base scenario is expected to be reduced by 18-22% in 2030 compared to 2016 for the four cities.

The decrease is a result of reductions in the regional background calculated with DEHM as well as Denmark's contribution calculated with UBM. For all three pollutants there are a few percentage points further reduction in urban background concentrations in the alternative scenario, and the climate-scenario is between the baseline and the alternative scenario.

Development in street concentrations for 98 streets in Copenhagen

The development in vehicle emissions is based on DCE's national emission model for road traffic (COPERT IV). NOx emissions are expected to decrease by about 61% from 2016 to 2030. Particle exhaust emission is estimated to decrease by 81% from 2016 to 2030. In the climate scenario for road transport exhaust emissions are set to zero in the scenario of one million electric cars, and the same for electric urban buses and electric taxis.

The average NO2 concentration for the 98 streets in Copenhagen is expected to decrease from 29 µg/m3 in 2016 to 15 µg/m3 in 2030 in the baseline scenario. Only a marginal difference is seen between the baseline scenario and the alternative scenario, as background concentrations are only a little lower in the alternative scenario compared to the baseline. Hence, the reduction in street concentrations is dominated by the reduction in emissions from traffic in the specific street.

In the climate scenario the average street concentration is 1.9 µg/m3 lower than in the baseline scenario. On the other hand, the background concentrations of the climate scenario are only marginally less than the baseline scenario, an average about 0.4 µg/m3. The reduction in street concentrations is therefore dominated by the reduction in emissions from traffic.

The average PM2.5 street concentration decreases from 13 µg/m3 in 2016 to 10 µg/m3 in 2030 in the baseline scenario.

The decrease for PM10 is from 21 µg/m3 in 2016 to 18 µg/m3 in 2030 in the baseline scenario.

The percentage reduction for PM2.5 and PM10 is not as great as for NO2, since only particle exhaust emissions are reduced. Non-exhaust emissions - such as road wear, tire wear and brake wear – are unchanged and make up a far greater share than the exhaust emission.

For PM2.5 and PM10 there is also a marginal difference between the baseline scenario, the alternative scenario and the climate scenario.

In the climate scenario the average street PM2.5 concentration is 0.4 µg/m3 lower than the baseline scenario. For the background concentrations the difference is on average 0.3 µg/m3. Therefore, the lower street concentrations in the climate scenario are mainly dominated by the reduction in background concentrations and to a less degree less emissions from traffic in the streets.

The reason is that exhaust emission represents a very small part of the total emissions from traffic exhaust and non-exhaust in 2030, and electrification of parts of the road sector only reduces exhaust emissions.

PM10 shows a similar picture as PM2.5, however, even more pronounced, because traffic non-exhaust plays an even greater role for street concentrations of PM10 than PM2.5. The climate scenario has on average 0.6 µg/m3 lower street concentrations of PM10 than the baseline scenario, and the background concentrations have the same difference, on average 0.6 µg/m3. That is, the difference in background concentrations explains the difference in street concentrations between the climate scenario and the baseline scenario.

Development in health impacts

Development in morbidity and mortality is calculated with the EVA system.

There are about 3,350 premature deaths due to all air pollution from both Danish and foreign emission sources in 2016. In the baseline scenario, the number of premature deaths decreases to about 2,800 in 2030, a decrease of 16%. In the alternative scenario, the reduction is greater than in the baseline scenario with about 2,600 in 2030, a decrease of 22%. The climate scenario reduces the health effects a little more than the basic scenario but less than the WAM scenario. In climate scenario, there are about 2,700 premature deaths in 2030, which is a reduction of 19% compared to 2016.

Reductions in the number of premature deaths is primarily due to slightly lower PM2.5 concentrations, but there is also a small contribution from slightly lower ozone concentrations in 2030. The lower concentrations are due to reduction in national and international emissions.