USING GREEN INFRASTRUCTURE TO IMPROVE AIR QUALITY IN ASIAN CITIES

Abstract

Roads in cities are becoming more congested with an increase in urbanization, which results in traffic-related air pollution (TRAP). In the past 6 years, air quality in a few Asian cities is generally ‘Unhealthy’, with occasional occurrences of ‘Very Unhealthy’ and ‘Hazardous’ air. Furthermore, recent studies suggested that human exposure to particulate matter (PM) near TRAP sources is of serious concern. The health effects of inhaling PM consist of cardiovascular and respiratory morbidity; and mortality. With climate change emergence, a nature-based solution is necessary to mitigate both ambient air quality and climate change.

Coniferous species has been observed to enhance the efficiency of PM deposition on its leaf surface. This enhanced efficiency is due to its smaller leaf size resulting in large Leaf Area Index (LAI). Species with high hairiness or leaf roughness also contribute to the effective PM capture. In terms of configuration, the green infrastructure should be designed high enough to intercept the full plume height. The green infrastructure should also be located close to the TRAP source. Increasing its thickness can also result in increasing filtration.

Green infrastructure would also provide biodiversity and ecosystem services, such as carbon sequestration and urban heat mitigation. However, in implementing the green infrastructure intervention policy, there are potential challenges such as inter-agency cooperation, cost constraint, practicability and prioritization. With political will and logistical support from the government, an integrated policy for green infrastructure can be formulated. This policy will improve air quality while promoting active mobility and largely bettering public health.