Factors affecting air quality
Air quality is usually good in Helsinki compared with the large cities of Europe, but occasionally air pollution increases to hazardous levels in the city. Most frequently, the worsening of the city’s air quality is caused by vehicular traffic, as its emissions are released at the street level and directly to air.
Transport affects the Helsinki air quality the most
The most hazardous exhaust gas emissions of transport are fine particles and nitrogen oxide. In springtime, air quality is worsened particularly by road and street dust generated by traffic when road surfaces dry out. Exhaust gases are poorly diluted especially on winter days with no or little wind, and air quality may worsen markedly in busy traffic and transport environments.
The most challenging places in Helsinki in terms of air quality are areas on busy roads and streets as well as busy streets flanked by tall buildings in the inner city. Here the concentrations of nitrogen oxide and particle pollution in the air occasionally exceed the limits set by the EU for these emissions.
Sensitive groups of people, including those suffering from asthma, elderly people suffering from the cardiovascular disease or emphysema and children may be adversely affected when air quality worsens. At times of poor air quality, they may alleviate symptoms by moving indoors and by avoiding strenuous outdoor physical activity.
In spring and summer, ozone is generated in sunny weather and can be transported from other areas to the Helsinki region in fairly high concentrations. Smoke transported from forest fires and clearing of land by burning beyond the national borders can occasionally worsen air quality in spring and summer. Wind and rain help to clean the air and, as a result, air quality is often the best in autumn.
Burning of wood occasionally worsens air quality in housing areas
Smoke produced from the burning of wood in fireplaces results in high concentrations of particle pollution in the air during cold weather when there is no or little wind. The effect can be severe especially in densely built areas of detached and semi-detached housing. According to the environmental regulations, only dry and clean wood can be burned in fireplaces. It is forbidden to burn twigs and waste at properties.
The limits for air pollution are occasionally exceeded in busy traffic and transport environments.
Clean burning of wood causes no smoke hazards in the vicinity
Everybody can markedly affect the emissions of their fireplaces. Appropriately stored, dry wood and good burning techniques help significantly to cut down emissions caused by the burning of wood. Chimney sweeps distribute a guidebook on wood burning published by Helsinki Region Environmental Services Authority (HSY) and otherwise guide house owners and tenants in the Helsinki Metropolitan Area on the proper use and maintenance of fireplaces.