The more I practice medicine, the more I see how important air pollution is to my patients’ health. It can be hard to help people understand the impact of pollution or how to decrease their risk. We can advise someone not to smoke, but it’s hard to even know what pollution is like at your individual home or work site or school. It sometimes seems that we take a look at a whole county and say that the air pollution level there might be safe “on average,” but that feels to me like measuring tobacco smoke in the air and declaring an area “safe,” when we know that there may be homes in that area with kids breathing breathing very unhealthy air in a home with someone who smokes while another child lives in a home with very clean air, and that such widespread data may not be helpful.
This has also struck Dr. Vivek Shandas, who is a Professor of Climate Adaptation and Founder and Director of the Sustaining Urban Places Research Lab at Portland State University. Dr.Shandas studies the effects of urban development patterns and processes on environmental health and justice, with specific attention to the assumptions that guide the growth of human settlements. He has published over 100 articles, three books, and his research has been featured in the NYTimes, National Geographic, The Guardian, Scientific American, and dozens of other national and local media. Dr.Shandas serves as Chair of the City of Portland’s Urban Forestry Commission and on several local and national advisory boards.
One study of his we talked about was regarding the impact of trees on NO2. NO2 is associated with a range of health effects- I worry most about it’s impact on asthma. The EPA sets a level at 53ppb for an annual mean exposure, and the WHO sets it at an average exposure of around 20 ppb (40 μg/m3), though multiple studies have found increased risk of asthma at lower levels, particularly in children (see references). For example, this study in Detroit found a linear association w/ asthma exacerbations in children starting at a level of around 10ppb. As in all things air pollution, I increasingly think our current “safe” levels are set far too high- just as we used to think second-hand smoke couldn’t be harfmul.
Dr. Shandas and his group made a map of current land use and tree cover in my hometown and surrounding area, and then placed NO2 monitors across the city, taking measurements in summer and winter.
They were then able to analyze the amount that different forms of land cover and trees had in reducing NO2, and what an increase in tree canopy or other forms of development and urban use might do.
They used data from the EPA BenMap resource on estimating health effects from air pollution, and evaluated the benefit of trees, shrubs and open spaces in reducing asthma health effects in the area. They looked at the potential impact in a variety of interventions to reduce NO2, and found that a 5-10% increase in tree canopy in the worst areas of NO2 would reduce asthma exacerbations in kids by 6-11%! On the podcast, we also discuss efforts to estimate the economic benefit that trees and increased greenery would provide in terms of avoided healthcare costs.
One very tragic element of asthma is that children growing up in historically red-lined areas have less tree canopy benefit, increased air pollution and NO2 exposure, and suffer more from asthma. We also discussed this on the podcast today, including his research on pollution and redlining. I was recently testifying for our state legislature about the importance of understanding the impact of air pollution at a more local level, and ensuring we have developed a process so that we do not risk the health of people living in dense areas or areas with high levels of construction. While I was doing so, from my window, I could see Tubman middle school right by the freeway, where we know there are very high levels of pollution compared to the closest DEQ sensor. I was also speaking from a hospital based in the historically red-lined district highlighted in the image below. These decisions from years ago are still impacting lives today, and we have to be intentional about ensuring that we monitor and address air pollution to not continue to affect future generations.
To Do
1- Plant a tree! In the Pacific Northwest, consider volunteering or donating to Friends of Trees!
2- Plant a tree when you search! Use Ecosia when you search on-line!
3- Air quality is local- advocate for cleaner construction standards. Donate to Neighbors for Clean Air.
4- Learn about the history of red-lining and how it impacts health now- see the Mapping Inequality project for more. Good books include the Color of Law and A Terrible Thing to Waste.
5- Listen to podcast episode “Tubman’s Air Troubles” to learn more from an atmospheric chemist about air pollution.
Twitchy Airways Club Members
1- Commute on lower pollution routes if you can, avoid busy roads, peak traffic times, etc
2- Advocate for cleaner air for you and your community!
3- Look for green spaces, and encourage more trees in your community. Check out Imperial College London Air App- helps a Londoner find the safest commute for air pollution. They also found that walking and biking, especially a low-traffic route, can lower your exposure! Let me know if your city has one, too!
