Observation, modeling, and analysis of air quality at the urban regional interface
Creators: name: Christiansen, Megan Brittany
Publisher: name: University of Iowa
Year: 2022
Subjects: coastal air quality
Lake Michigan
particle size distribution
public abstract
Ozone

description: Air pollutants such as ozone, particulate matter, and nitrogen oxides negatively affect human health and impact the climate. Long term exposure to ozone increases the effects of asthma, heart disease, respiratory illnesses, and for at-risk groups of the population. Particles can deposit in the airways and lungs and are a cause of concern for the human population sensitive to respiratory illnesses.
description: Ozone pollution remains a challenge in coastal environments due, in part, to the unique meteorology induced by the presence of large bodies of water, or the lake-land breeze. The Lake Michigan Ozone Study 2017 was an intensive summer field campaign with the overall objective to better understand the formation and transport ozone and ozone precursors in the region. Three ozone periods occurred during the campaign: June 2-4, June 9-12, and June 14-16. The majority of the ozone events occurred on lake breeze days, but some did not. LMOS was the first field campaign to measure particles in the 1-3 nm range, with an average number concentration of 1.80x104 cm-3. Ultrafine particle number concentrations increased 47 % (significant by t-test) within a few minutes of the lake breeze arrival. The Photochemical Grid Model WRF-Chem reproduced the ozone variability well, but did underpredict peak ozone with a bias of -4.4 ppb for the coastal west sites. A decrease in NOx and VOCs emissions (~25 % and ~28 %, respectively) resulted in a 5-7 ppb decrease in ozone concentrations in rural areas and over the lake, but a 3-4 ppb increase in large urban areas during the daytime of the high ozone periods.
description: Globally, an estimated 1.5 million deaths in 2020 were attributed to tuberculosis (TB) and Vietnam is one of the 30 high TB burden countries. Few studies have focused on additional preventative measures despite poor adherence to lengthy prophylactic therapy. Identifying and assessing the impact of environmental factors (such as air pollution) on the early stages of TB infection is critical to developing additional preventative measures. Hanoi experiences poor air quality with 91 days exceeding the 24 hr Vietnamese standard for PM2.5 in 2018. The seasonal variability has been well-established with winter being the most polluted in general. However, the spatial variability is still highly uncertain. Using the two long-term measurements and sensors install during a tuberculosis study, there is a clear spatial variation over downtown Hanoi. Two global reanalysis products (MERRA-2 and CAMS) were compared to the average of the long-term measurement sites PM2.5. CAMS was better correlated (R = 0.721) with observations, but overestimated by a factor 2.8, on average. MERRA-2 captured the cleaner summer months, but underpredicted the winter months resulting in a lower correlation, R = 0.248, when compared to observations. Future research will be to develop a high resolution spatial map of air pollutants for use in health exposure models.