Houghton Lecture — Ron Cohen (UC Berkeley) — Watching Cities from Space

“Watching cities from space: Satellite observations of chemistry in urban plumes”

Lecture 2 of 3 on Changing Air Chemistry in Cities — 

Urban air quality emerged as an interdisciplinary subject of research in the 1950’s with the discovery that smog in Los Angeles was created photochemically. This was in contrast to smog from coal burning and other human activity with emissions that were hazardous and affected visibility without any further chemistry. Decades of the interplay between science deepening our understanding of sources of photochemical air pollution, engineered solutions to reduce emissions from those sources and public policy to support and enforce investments control technologies have produced much cleaner air. Still, there are many parts of the U.S. and the world where days each year with air that exceeds health based standards number in the dozens to hundreds.

As recently as a decade ago, emissions associated with passenger vehicles including fueling, leaks and combustion byproducts were the most important aspect of urban air chemistry in the U.S. In contrast, today passenger vehicles are one among many sources, including urban forests, personal care products, and heavy duty trucking. Further, we now recognize profound inequities of exposure at neighborhood spatial scales are pervasive driving the desire for a much more fine grained picture of air within cities. This series of three lectures will offer an overview of some key emerging ideas about our understanding of urban emissions and chemistry. The first lecture will discuss technologies for studying urban air at neighborhood scale resolution using dense surface networks and some initial applications. The second, using space based remote sensing to track changes in air chemistry over more than a decade. The third will focus on the intersection of a warming planet and urban air quality, offering insights into our understanding of chemistry and temperature in cities and posing challenges for future research in the field.

Houghton Lecture Series

Supported by the Houghton Fund, Houghton Lecturers are distinguished visitors from outside MIT invited by the EAPS Program in Atmospheres, Oceans and Climate (PAOC) to spend a period of time, ranging from a week to several months, as scientists-in-residence.

Contact: kbauer@mit.edu