A study of adults with asthma and chronic obstructive pulmonary disease (COPD) found that individuals with lower levels of some antioxidants in their blood were more vulnerable to the harmful effects of air pollution.  Particulate matter (PM) – the main pollutant measured in this study – is produced by traffic and combustion of fossil fuels. PM less than 10 micrometers in diameter, or PM10, is known to exacerbate respiratory illness and increase the risk of heart attacks and other cardiovascular disease. One way air pollutants can harm health is through oxidative stress. Harmful oxidant molecules can form when air pollutants are absorbed through the lungs. These oxidants also called free radicals damage cells. The body constantly tries to counteract oxidant molecules with protective ones (antioxidant). If not enough anti-oxidant molecules are available to cancel them out, oxidative stress  may occur.

In this study, researchers wanted to see if individual levels of antioxidants and related genetic markers would protect against harm from oxidative stress imposed by particulate air pollution. Results showed participants with low levels of vitamin C in their blood were more vulnerable to PM10. The study is important as it indicates that a healthy diet including fruits and vegetables may protect against the common health threat of air pollution.

Credits: California Academy of Sciences in San Francisco

A Natural England study on green urbanism found that people with good access to green spaces such as parks, gardens and trees at the heart of neighborhoods are 24% more likely to be physically active and hence, healthier, both physically and mentally, even after accounting for the tendency of wealthier people to live in more attractive areas. A swedish study suggests that use of green space reduced self-reported stress in the long term.

Another health benefit of green urbanism is the key improvement in air quality. It is estimated that poor air quality leads to an average life expectancy reduction of 7 – 8 months in the UK. Urban trees and green space help to absorb some of the air pollution particles.  Cities can also use green infrastructure to prepare for the challenge of climate change.  Concrete and other hard surfaces retain heat much more than trees, plants and grass, which substantially increases heat-wave health risks for urban populations. The biosphere also plays a positive role in the absorption of greenhouse gases.

Green infrastructure has also proved attractive to city planners by helping to save money at a city scale. In New York money was invested in protecting the main water catchment area instead of building a traditional filtration plant.  Although this cost the city $1.5 billion over ten years, it avoided capital costs of $6 billion for a new filtration plant and annual running costs of $300 million. Evidence contained in the studies suggests that a range of economic benefits can be gained by planning for the needs of pedestrians, cyclists and wildlife in our urban communities.