Our city is located in a temperate coniferous-mixed forest zone, with cold, wet winters, according to Köppen's climate classification. The mean temperature of the warmest month is at least +10 °C and the coldest at least -3°C, with moderate rainfall in all seasons.
Lahti’s city centre is located in a valley between ridges (Fig. A1). This induces problems (inversion) with air quality during unfavourable weather conditions. The northern location also influences air quality. Inversion occurs during winter and especially during early spring, trapping air pollutants close to the ground and inhibiting dilution. Due to cold winters, there is a need for studded tires as well as for sanding and salting roads to prevent slippery conditions. Spring is especially challenging for air quality, when sand and pulverized asphalt rise into the air.
Despite being a small city (120 000 inhabitants), Lahti monitors air quality at five stationary automatic measuring stations (Fig. A2). In addition, Lahti has had a mobile station since 2015. The mobile station is relocated yearly. In 2017, it was located in Hollola (Salpakangas) (Fig. A2). Besides automatic monitoring of NOx, O3, PM10 and PM2.5, there are passive two-week monitoring pipes, in three different locations, to monitor VOCs. The measuring stations in Saimaankatu and Vesku represent the city centre, while Laune is located on a busy road. Kisapuisto is located in a recreational area and represents urban background air quality. Satulakatu is located away from the city centre and significant emission sources. VOC measuring stations are located in industrial and business areas and are close to residential areas, except for Laune, which is in a traffic area. There is one meteorological station (Vesku) that aids in analysing the data.
Air pollution primarily originates from energy production and traffic. Of the annual mean NOx, about 55% originates from industry and 45% from traffic. For particulate matter (PM10 and PM2.5) (annual mean), about 40% originates from industry and 60% from traffic. Concentrations of PM2.5 are usually rather small in Finland. From time to time, long-range transboundary pollution caused by forest fires can be seen in the monitoring. There are a few small companies that use solvents that generate VOC emissions, along with household wood combustion in residential areas. The proportion of air pollution from long-range transport is not estimated separately.
Concentrations of hourly NO2 (120 ug/m3) levels were not exceeded in 2017; this may happen in traffic areas but, is unlikely in other areas. There were 7 occasions when the daily PM10 average concentration limit of 50 μg/m3 was exceed in March and November, in areas that were sanded.
Finland uses an air quality index based on national guidelines and limit values. The air quality index is calculated hourly. Air quality is classified as Good, Satisfactory, Tolerable, Poor or Very poor. The City of Lahti is responsible for updating and monitoring the information, based on the collected data (Fig. A2). To keep the residents informed of air quality, data is sent to a national air quality portal, where it can be followed in real-time at www.ilmanlaatu.fi.
In 2017, air quality was classified as Good 53.9%, Satisfactory 39.6%, Tolerable 4.3%, Poor 1.5% and Very poor 0.4% of the time (Fig A3). There were 182 hours of poor or very poor air quality in 30 days. The reason for this was the high amount of particulate matter concentrations.
Poor and very poor air quality index values (30 days in 2017) are nearly always caused by high PM10 concentrations. PM10 concentrations were high in March and April, due to large amounts of pulverized sand and asphalt, after the snow melt. At the Laune and Rakokivi measurement stations, the national guideline value of 70 μg/m3 (second highest daily value for a month) was exceeded in March as well as in April, in Laune.
The EU daily mean limit value of PM10 (50 μg/m3) was exceeded 18 times at the Laune station (35 allowed times). The annual mean concentrations of PM10 are below the EU limit value of 40 μg/m3 (Chart 2, Tori’s measurement station was replaced by that in Saimaankatu in 2014, which is situated close to the previous location). As usual, the EU limit value of PM2.5 (25 μg/m3) was not exceeded in 2017. The highest daily means for each month were between 5.5 μg/m3 and 17.4 μg/m3. The latter was measured in January. The annual mean concentration of PM2.5 was 3.6 μg/m3.
NO2 concentrations were low level in 2017 (long-term mean or below it throughout the year). Generally, NOx concentrations remained around aveage, throughout the year. The effect of traffic is evident, as NOx concentrations follow traffic rhythms.
Annual mean concentrations of NO2 have decreased considerably, over the past decades (Chart 1). The EU limit of 40 μg/m3 was never exceeded. In 2017, the annual mean concentrations of NO2 were as follows: Vesku 21 μg/m3, Laune 13 μg/m3 and Kisapuisto 8 μg/m3.
The NO2 EU hourly mean limit value (200 μg/m3) was never exceeded at any of the stations. The hourly mean values (second highest value per month), comparable to the national guideline value, varied at the measurement stations as follows: Vesku 39-75 μg/m3, Laune 27-90 μg/m3, Kisapuisto 23-59 μg/m3 and Hollola 15-48 μg/m3.
Requested Chart 5: There were no single hour from 2000 which would exceed the 200 µg/m3.
An Air Quality Action Plan (1997), is the basis for today’s actions and strategies. The most important measures for reducing air pollution target road traffic. Thorough monitoring ensures that immediate action is taken and residents are warned if air quality deteriorates.
As a complement to national and European Union regulations, Lahti has additional local air quality regulations. These are included in the Environmental Regulations of the City of Lahti.
The City and local businesses have signed an agreement to monitor air quality. The businesses fund the monitoring work according to the polluter pays principle.
Sanding of streets causes health hazardous dust. To minimize sand pulverization, a sand type that causes less dust is selected. When air quality worsens in the early spring, we immediately inform our street cleaning operators. Large-scale and thorough street cleaning operation are carried out to minimize the period of bad air quality (Fig. B1).
• Pedestrian city centre:
• Great cycling path network: 532 km of combined pedestrian and cycling paths .
• During the winter, main cycling network are highly maintenaned to promote winter biking.
• 2014 public transportation network reform:
• Lahti’s Master Plan is concentrates on consolidating land use and ensuring a population density of at least 15 inhab./ha enabling a good public transportation and cycling path network.
• 2016 a transportation hub was built uniting train and bus transportation, parking houses for bicycles and cars. Investment 18 M€.
• To enhance smart mobility, i.e. commuting, we financed companies to execute smart mobility plans for their employees.
• Lahti City consortium owns 8 electric cars, 35 biogas vehicles and a few electric bicycles and traditional bicycles for use by city employees.
• The city arranged an electric bicycle test-ride in 2016.
• Campaigns to support the use of public transport: On the World Car Free Day bus tickets on reduced price.
• City has ambitious SUMP targets (Fig. B3).
* These are not comparable to 2010 &2016 numbers due to differences in the research methods and period.
2010-2016 Consumers Energy Advisory in the Päijät-Häme project: energy counselling targeted residents and housing cooperatives in the Lahti region. Budgeted 77 000 € during 2014-2015 and then 25 000 € annually for 2016-2020.
2015-2016 the “Eco-efficient Energy Solutions” project developed an e-service for property owners and residents to assist in comparing different sustainable energy solutions. Investment 190 000 €.
Lahti Energy Ltd. (part of the Lahti City Group) invested in energy efficient and sustainable district heating. The district heating network is extensive; over 90% of the population and 99% of municipal buildings uses district heating. Over 95% of district heating is produced efficiently in the Kymijärvi CHP-plant I-II.
Lahti Energy Ltd.:
• Supports schools with educational kits on energy saving.
• Advises residents on solar power, delivers ready-made solar power packages to households.
• Electric charging points, charging is free for registered users.
• Air quality can be followed in real-time at www.ilmanlaatu.fi.
• SMS warning service: message sent if air quality reaches a harmful level (Fig. B4).
• Our website offers air quality reports from 2006-2017.
• A Facebook posting is immediately set (on the Urban Environment Facebook page) if air quality reaches unhealthy levels.
• Media releases are given to local media, when air quality deteriorates, and forecasts are compiled so that vulnerable groups may plan their actions and outings.
Air quality has improved over the past few decades (Fig. B5).
Our vision is: “Lahti – Bold Environmental City”. Environmental protection is at the heart of this strategy and taking care of the environment is one of the five promises. Lahti will invest in a circular economy and in developing a carbon neutral and sustainable resource managed city. We are committed to increasing the use of public transportation, walking and cycling.
We aim to achieve easy walking and cycling in the city. To promote sustainable transportation modes and lessen the negative effects of car traffic (e.g. pollution), three strategic goals have been set:
1) Changing attitudes.
2) Urban structure.
3) Infrastructure (Fig. C1).
The city is planning to launch a bicycle borrowing system (long-term goal). A preliminary long-term decision has been reached, whereby public transportation buses will be changed with electric buses and biogas will be enhanced in other logistics.
The street network will undergo a change (Fig. C2). Vapaudenkatu Street is developed primarily for public transportation. Vapaudenkatu’s two-way, high-quality cycling paths will be increased westward. Rautatienkatu Street (not highlighted on the map) will be further developed as a pedestrian zone. Most car traffic will be directed to an outer “circle” around the city centre, lessening traffic inside the circle (see also Fig. A1). This enables additional cycling paths (e.g. along Vesijärvenkatu Street) to be constructed.
Construction of a bypass road will start in 2018. The bypass road will allow lorry transports to be directed away from the centre and enable the city centre to be developed into a pedestrian zone. Air pollution will reduce in the centre and on Mannerheiminkatu Road (currently main road no. 12, red line) can be developed into a normal city street.
Although the new bypass will not reduce total city traffic volume, it creates smoother traffic and promotes walking and cycling in the city centre, as well as reduces air pollutants in more people-dense ares.
The Sustainable Energy Action Plan (SEAP) includes measures for more sustainable heating and electricity production, energy efficiency, traffic and traffic planning, and increasing environmental awareness.
At least six new charging points will be installed by the Lahti City Group organizations.
In 2015-2018, Lahti Energy Ltd. invests 20 M€ in wind power, mainly on Finland’s west coast.
Lahti Energy Ltd. and the City Council have decided that a new biofuel power plant, Kymijärvi III, will be built in Lahti and operational by 2020. In 2017, 40.53% of district heating was generated from renewable sources and, with the new biofuel power plant, it will increase to 80%. The investment will cost 150 M€. The old coal-operated power plant, Kymijärvi I, will be phased out, which will improve air quality by reducing emissions (SO₂, NO/NOₓ, PM).
Together with local businesses, we have decided to start monitoring benzopyrene B(a)P during certain periods in winter 2017-2018. Since benzopyrene comes from traffic and burning wood, it will be measured in an older residential area.
Lahti has joined the Smart & Clean Foundation. The Smart & Clean Foundation is setting up a comprehensive, city-wide, air quality system test bed in the Helsinki Region, which could also be set up in Lahti. This kind of air quality system would produce open data and enable targeted measures to prevent and lower air pollution and its consequences.
In 2017, the Lahti City Group’s expenditures on air and climate protection amounted to 5 M€, investments were 3.4 M€. We will continue to invest in keeping our streets clean, reducing pollution from power plants and reducing traffic.
There is a plan to put a mobile application (free of charge for users) into use where residents can access information on current air quality.
The National Air Quality Portal will be integrated into the national Finnish Meteorological Institute web pages at www.fmi.fi. It may improve visibility for inhabitants, as people tend to use the Finnish Meteorological Institute web pages to check the weather forecast. The new air quality service will replace the Air Quality Portal, by the end of 2017.