Green the environment
You tackle the following challenges:
That's how you do it
It is predicted that by 2050 at least 70% of the world's population will live in urban areas. As a result, cities will increasingly be confronted with air pollution and the heat island effect. Governments have many options for limiting the consequences of this:
- create (mini) parks,
- plant native trees,
- lay out green, car-free walking and cycling routes,
- enlarge the tree mirrors and take care of underplanting,
- put perennials around parking lots,
- create green schoolyards,
- create wadis or water squares,
- provide facade planting,
- build green/blue roofs,
- go for softening or water-permeable paving,
- construction nature including,
Tips
- Plants or trees can hinder air circulation and prevent polluted air from getting out. This must be taken into account especially in so-called street canyons (narrow streets with high buildings).
- Research shows that people who live in a green environment are generally more sociable and feel calmer, happier and healthier
Knowing more
Green can influence the air quality in cities in 3 ways :
- direct influence on air concentrations through deposition
- influence of air currents
- indirect reduction of emissions, because a green environment encourages alternatives to the car, such as walking or cycling. Moreover, where a lot of space is made for greenery, less space is left for motorized traffic.
Trees filter the polluted air because dust particles stick to the outer wax layer of a leaf (di adsorption) and gases (including NO 2 ) are retained in the leaf via the stomata (ie absorption). Coniferous trees are better suited for the adsorption of particulate matter, while deciduous trees are better for the absorption of NO 2 . A large leaf area is beneficial for both. Permanently green trees obviously have a greater effect than trees that lose their leaves in winter. However, the positive effect of trees on air quality is limited compared to the traffic emissions emitted by traffic. More information can be found in the document "Creating healthy living environments: focus on air quality" of the Environment Department.
Trees not only filter the air but also have a major impact on air circulation. They lower the wind speed, which prevents the discharge of polluted air. Their negative impact on air circulation is unfortunately much greater than their air-purifying effect.
More information
- Brochure green roofs for air quality and climate . (Wageningen University, Netherlands)
- Greenery and air quality in an urban environment (research Academic workplace GGD Amsterdam, the Netherlands )
- Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies (Nature)
