A Life of Science: A Series by New Scientists
If scientists can come to a consensus as to how particles change clouds and vice versa, they can better understand how those changes affect sunlight management and rainfall production globally.
Something about the balmy ocean breeze soothes me. Perhaps it is because I grew up so close to the sea, even while living in the highly urbanized metropolis of Metro Manila. One day when my niece Iya was still a baby, she cried so hard we did not know what to do. As a last resort, we brought her to the oceanside to catch the famous Manila Bay sunset. There, the Asian summer southwest monsoon was blowing steadily. Wondrously, the embrace of the strong ocean breeze finally stopped her crying.
Photo by Genie Lorenzo Pearson.
Manila Bay still hosts ships from all over the world but, rather than wind energy, these ships now run predominantly on fossil fuels. Ship exhaust forms clouds that trace the ships’ paths over water. They are visible from satellites above the earth in some areas of the world as white and fluffy intertwined veins. Clouds form when water vapor condenses on particles in the air. The particles on which clouds form, such as sea salt or emissions from volcanoes and wildfires, are called cloud condensation nuclei, or CCN. CCN must be small and attracted enough to water for clouds to form on them. The increasing numbers of ships, cities, and wildfires in and around the Philippines and indeed around the world are adding particles to the air and “man-made seeds” on which clouds can “grow,” increasing or decreasing certain cloud types depending on particle size and composition. These changes affect total absorbed and reflected sunlight as well as how much rainfall is produced in the Philippines and other similarly polluted marine regions around the world.
According to the Intergovernmental Panel on Climate Change, how particles contribute to warming or cooling the atmosphere is the greatest source of uncertainty in our understanding of climate change. More observations are needed at ground and cloud levels, and especially over the oceans, to help reduce this uncertainty. If scientists can come to a consensus as to how particles change clouds and vice versa (called aerosol-cloud interactions), they can better understand how those changes affect sunlight management and rainfall production globally. This is the motivation for my research as a Ph.D. student in Atmospheric Sciences at the University of Arizona.
Photo by Vidal Salazar, courtesy NASA.
Early results from CAMP2Ex suggest that, during the southwest monsoon, a combination of particles in the region originating from wildfires and emissions from cities and ships are acting as CCN and making clouds grow taller. Yet, how this affects global temperatures, the monsoons, and rainfall is something we still need to tease out. As students, our research examines the properties of the particles collected by these aircrafts. It is a once-in-a-lifetime opportunity to participate in a NASA mission, especially for someone like me from a developing country. My focus is on how the observed particles attract water and can become CCN, impacting solar radiation and the formation of clouds. It seems providential that I can help in this international effort which was based only a few hours away from my hometown and the comforting Manila Bay.
Photo courtesy Manila Observatory.
I was in high school when I was introduced to the air pollution situation in Metro Manila. A layer of sticky, black particles would coat my face after a ten-mile cramped stop-and-go bus ride to school, worsening my acne flare-ups. After college, I went to work at the Manila Observatory as a research assistant and learned about the technical components of air quality, such as particulate matter and black carbon from the incomplete combustion of carbon-containing fuels, the ubiquitous black particles (also called soot) that aggravated my acne in high school. I did not enjoy the constant exposure to Metro Manila’s poor air quality as I set up air samplers for my work. However, I also recognized that the particles affected not only my skin but also the respiratory health of the entire population. Black carbon also affects the global climate because these particles absorb light, warming the atmosphere. Additionally, black carbon hinders cloud growth due to their aversion to water. My research motivation thus grew beyond my own discomfort, and I was inspired by the mission of the Manila Observatory to work with communities and their environmental realities through science.
Through our work in the observatory, I also became aware of the complex social impact of air pollution, issue such as poverty that may seem more pressing than air pollution. For example, it took almost a decade after stakeholder discussions began for motorized tricycle operators to come to the table and agree to shift from two-stroke to four-stroke engines. This is understandable, because their livelihood was threatened and there was inadequate transitional support for them. But environmental issues and poverty are interlinked. Unemployment, population increase, an underdeveloped agricultural sector, and risks due to conflicts and environmental disasters all affect the economy of the Philippines. Air pollution’s wide-reaching effects, from people’s health to global climate, make it an urgent environmental crisis that we must address together.
Photo by Obie Cambaliza.
Years before CAMP2Ex, observatory and government researchers had already made an alarming discovery that air filters exposed for 24 hours to roadside Metro Manila air became black as soot. We had to recheck our lab procedures to make sure we had analyzed the filter samples properly. We found out that Metro Manila traffic produces some of the greatest levels of black carbon in the world. This awareness has led to improved implementation of emissions standards that have significantly improved air quality in Metro Manila.
At elevations greater than one kilometer from the ground, when particles from traffic become more mixed with the surrounding air, the sun photometer senses air that is still relatively clean. Winds over bodies of water around the Philippines dilute the particles from the city. Air pollution can also travel into the Philippines from East Asia, which is the region’s largest industrial air pollution source. These winds cause the transported particles, mostly sulfate particles that cool the atmosphere (unlike black carbon), to aggravate Metro Manila air quality. Smoke particles from massive wildfires in Borneo (in the Maritime Continent), a mixture of black and organic carbon, have also been detected in filter samples at the Manila Observatory.
Over the past five years, I have been working in the University of Arizona in Tucson, far away from the Southeast Asian southwest monsoon. These days, I am in the field less often and work mostly on my computer to analyze the data from the CAMP2Ex campaign for my doctoral research. I was shocked by the prevalence of smoke from the maritime continent wildfires that we found throughout southern Southeast Asia during the southwest monsoon and the potential they have to affect clouds. These smoke particles are not as water-loving as particles that clouds have typically formed on in the past. This changing particle profile influences the amount of solar radiation reflected or absorbed by particles and cloud formation over the region in ways that need more research to be fully understood. Yet their impacts on global climate, and the total and type of rain that makes its way to the Philippines and Southeast Asia, are already underway, affecting agriculture and human safety. This is concerning because more wildfires are projected with climate change and changing rainfall has already been observed in the Philippines during the southwest monsoon.
Image courtesy Melliza Templonuevo Cruz, et al.
Image courtesy NASA.
Header photo of sunrise over Metro Manila and Manila Bay by hintsvisuals, courtesy Shutterstock.