Climate, air emissions and air quality

5.13.1 Climate

The climate in Finland has features of both marine and continental climates.

The weather conditions are dependent on the direction of the air flows and the relation of low and high-pressure areas.

Finland is located in the middle latitudes, in the west wind zone at the boundary of tropical and polar air masses where weather types change quickly particular-ly in the winter. Usualparticular-ly, air flows to Fin-land from the southwest. (Ilmasto-opas 2018a)

Most of the Uusimaa region belongs in the southern boreal climatic zone. Be-cause of the Gulf of Finland, the Uusimaa climate is strongly marked by the ma-rine conditions, but their effects reduce towards the inland from the southwest.

The ground elevations from the coast towards the inland affects the rain and snow conditions. (Ilmasto-opas 2018a)

The capital region is located in South-ern Finland on the coast of the Gulf of Finland and it includes the cities of Hel-sinki, Espoo, Vantaa and Kauniainen. The long-term (1981–2010) average tempera-ture in Kaisaniemi, Helsinki was –3.5°C in winter (December–February) and 16.2°C in summer (June–August). The long-term average rainfall exceeded 650 mm per year; rainfall is at its lowest in spring. On average, the capital region gets its snow cover in late December, and it lasts until

late March. Occasionally, the region ex-periences wet winters with little snow.

The prevailing wind blows from the southwest. (HSY 2016a)

In the Baltic Sea area, the average air temperature is estimated to increase by 3–5°C by the end of the century. The tem-perature rises in the eastern and northern parts of the Baltic Sea in winter and in the southern parts in summer, which will likely increase the water surface temper-ature by 2–4°C.  (Ilmasto-opas 2018b;

BACC Author Team 2008)

5.13.2 Air emissions and air quality In the Gulf of Finland, emissions into the air are generated in the combustion of fuel in marine traffic. Ships’ combus-tion processes generate nitrogen ox-ides (NO_x), sulfur dioxides (SO₂), particle emissions and carbon dioxide (CO₂).

The emissions into the air from ship traffic in the Baltic Sea in 2012 are pre-sented in the adjancent table (Table 5-7) (Jalkanen et al. 2013). The table also in-cludes the emissions into the air from Finnish water traffic in the Finnish eco-nomic area in 2011 (international and national traffic). Out of total traffic emis-sions in Finland, water transportation accounts for the largest share of sulfur dioxide emissions (94% of total sulfur di-oxide emissions) and the second largest share of other compounds (49% of nitro-gen oxides, 36% of particles and 18% of carbon emissions out of total traffic emis-sions). Freight ships cause clearly higher

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sulfur dioxide and nitrogen dioxide emis-sions than passenger ships. (VTT 2012) Emissions from ship traffic are limited globally with the MARPOL convention.

The total emissions in 2016 were as follows: nitrogen oxides 11,724 tonnes, particles 490 tonnes, sulfur dioxide 4,610 tonnes, carbon monoxide 11,973 and volatile organic compounds 1,612 tonnes. In 2016, sulfur dioxide emissions grew by approx. 13%, particle emissions grew by approx. 9% and nitrogen oxide emissions declined approx. 3% year on year. In the long term, the air pollutant emissions in the capital region have re-duced significantly. However, in the past ten years, their reduction rate has been slower. (HSY 2016a) In 2017, the total greenhouse gas emissions in the capital region were 4,954,000 tonnes of carbon dioxide equivalents. The change in the emissions was –3% year on year.

The most significant sources of emis-sions in the capital region are road traf-fic, combustion of wood and energy production. Contaminants enter Finland also from abroad as “long-range trans-boundary air pollution”. Air quality is particularly affected by vehicle traffic and small-scale combustion of wood as these emissions are released at a low al-titude. The air quality in the capital region is usually quite good. However, at times, particle and nitrogen dioxide concentra-tions reach harmful levels especially near busy streets and roads. (HSY 2016b)

The Helsinki Region Environmental Services Authority HSY constantly mon-itors air quality in the capital region with 7 permanent and 4 mobile measurement stations. 2016 was a quite good year in terms of air quality. The air quality was deemed good or satisfactory more than 90% of the time. The air quality was poor or very poor no more than 1.5% of the year. (HSY 2016a)

In 2016, the average yearly concen-trations of inhalable particulate matter at the permanent measurement stations in the capital region varied between 13–21 μg/m³ and thereby remained below the annual limit of 40 μg/m³. Particulate con-centrations were clearly below the annu-al limit of 25 µg/m³. On the other hand, at times, nitrogen dioxide and particle concentrations reached harmful levels especially near busy streets and roads.

The most problematic areas include busy street canyons with poor ventila-tion, where the annual nitrogen oxide limit is still exceeded and the particle

concentrations are high due to exhaust gas emissions and steet dust from traffic.

(HSY 2016a)

In high concentrations, contaminants have harmful impacts on health, comfort and the environment and, therefore, they have specific limit, guidance, threshold and target values and critical levels. (HSY 2016a) The adjacent table presents the EC air quality limit values (Table 5-8).

Table 5-7. Emissions into the air from Baltic Sea ship traffic and Finnish water traffic (tonnes per year) (VTT 2016, Jalkanen et al. 2013)

Nitrogen

ox-ides (NOx) Sulfur dioxide

(SO₂) Particles Carbon dioxide (CO)

t t t t

Baltic Sea (year

2012) 370,000 84,000 23,000 19,000,000

Finnish exclusive economic zone

(year 2016) 45,000 8,000 1,000 3,000,000

161 Table 5-8. EC air quality limit values issued with the Government Decree on Air Quality in 2017 (Government Decree

79/2017).

Compound Time Limit value,

μg/m³ Allowed tolerance

Inhalable particulate matter year 40

-day 50 35 days/year

Particulates, PM_2.5 year 25

-Nitrogen oxide year 40

-hour 200 18 h/year

Sulphur dioxide day 125 3 days/year

hour 350 24 h/year

Carbon monoxide 8 hours 10 mg/m³

-Benzene year 5

-Lead year 0.5

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ment takes into account the impacts of construction and decommissioning. The potential cumulative effects of the ject with other existing or planned pro-jects in the area are assessed. The im-pacts of the zero alternative (project not implemented) are also assessed.

The environmental impact assess-ment procedure assesses the environ-mental impacts of activities in the project area and those that extend outside of the area. Traffic related to construction and operation is an example of activities ex-tending outside of the project area.

In order to support the existing docu-mentation, the following separate studies will be performed as part of the assess-ment:

– Underwater archaeology surveys – Diving surveys of the marine

envi-ronment

– Fish stock and fishery surveys – Hunting surveys

– Soil quality studies and probing, both on land and at sea

– Seabed fauna studies

– Continued bird fauna studies – Surveying of historic unexploded

ordnances in the sea area – Water quality and flow models – Noise modelling: observing both

above-ground and underwater noise

– Illustrations of the artificial island (excluding detailed depictions of the buildings)

– Traffic estimates by modelling

As regards the above studies, the underwater archaeology surveys, div-ing surveys of the marine environment, seabed quality studies and probing, sea-bed fauna studies and bird fauna stud-ies have mainly been completed in the summer and autumn of 2018. The aim has been to perform the studies across a sufficiently large area in order to avoid new requirements in relation to the wa-ter permit stage following the EIA report stage. However, further studies related to the permit stage are not ruled out for the open water season of 2019, since the authorities will only officially comment on the separate studies in the statement and justified conclusion of the EIA pro-gramme and the EIA re-port.

The following chapters describe the methods used for environmental impact assessment, the related assumptions and the studies to be performed.

6.1.2 Limiting the examined and affected areas

An environmental impact assessment examines the environmental impacts of the activities in the project area and the related activities extending out of the project area during construction, oper-ation and decommissioning. Activities extending outside of the project area in-clude, for example, the development of traffic and infrastructure near the stations and the artificial island, made possible by the railway tunnel.

In this context, the examined area means the area determined for each

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