An official website of the United States government
Science for Society Buildings account for a significant fraction of the land area in cities and actively exchange air with their proximate outdoor environments via mechanical ventilation systems. However, the direct impact of buildings on urban air pollution remains poorly characterized. Due to reductions in traffic-associated emissions of volatile organic compounds (VOCs), volatile chemical products, which are widely used inside buildings, have become a major VOC source in urban areas. Indoor-generated VOCs are likely to be an important contributor to the VOC burden of the urban atmosphere, and ventilation systems provide a pathway for VOCs to be released outdoors. Here, we show how modern buildings act as significant emission sources of VOCs for the outdoor environment. Our results demonstrate that future air quality monitoring efforts in cities need to account for direct VOC discharge from buildings in order to capture emerging sources of environmental pollution that can impact the climate and human health. Summary Urban air undergoes transformations as it is actively circulated throughout buildings via ventilation systems. However, the influence of air exchange between outdoor and indoor atmospheres on urban air pollution is not well understood. Here, we quantify how buildings behave as a dynamic source and sink for urban air pollutants via high-resolution online mass spectrometry measurements. During our field campaign in a high-performance office building, we observed that the building continually released volatile organic compounds (VOCs) into the urban air and removed outdoor ozone and fine particulate matter. VOC emissions from people, their activities, and surface reservoirs result in significant VOC discharge from the building to the outdoors. Per unit area, building emissions of VOCs are comparable to traffic, industrial, and biogenic emissions. The building source-sink behavior changed dynamically with occupancy and ventilation conditions. Our results demonstrate that buildings can directly influence urban air quality due to substantial outdoor-indoor air exchange.
more »
« less
Advancements in miniaturized infrared spectroscopic-based volatile organic compound sensors: A systematic review
The global trends of urbanization and industrialization have given rise to critical environmental and air pollution issues that often receive insufficient attention. Among the myriad pollution sources, volatile organic compounds (VOCs) stand out as a primary cluster, posing a significant threat to human society. Addressing VOCs emissions requires an effective mitigation action plan, placing technological development, especially in detection, at the forefront. Photonic sensing technologies rooted in the infrared (IR) light and matter interaction mechanism offer nondestructive, fast-response, sensitive, and selective chemical measurements, making them a promising solution for VOC detection. Recent strides in nanofabrication processes have facilitated the development of miniaturized photonic devices and thus sparked growing interest in the creation of low-cost, highly selective, sensitive, and fast-response IR optical sensors for VOC detection. This review work thus serves a timely need to provide the community a comprehensive understanding of the state of the art in this field and illuminate the path forward in addressing the pressing issue of VOC pollution.
more »
« less
- Award ID(s):
- 2340060
- PAR ID:
- 10559361
- Publisher / Repository:
- Applied Physics Review
- Date Published:
- Journal Name:
- Applied Physics Reviews
- Volume:
- 11
- Issue:
- 3
- ISSN:
- 1931-9401
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Outdoor air pollution, particularly volatile organic compounds (VOCs), significantly contributes to the global health burden. Previous analyses of VOC exposure have typically focused on regional and national scales, thereby limiting global health burden assessments. In this study, we utilized a global chemistry-climate model to simulate VOC distributions and estimate related cancer risks from 2000 to 2019. Our findings indicated a 10.2% rise in global VOC emissions during this period, with substantial increases in Sub-Saharan Africa, the Rest of Asia, and China, but decreases in the U.S. and Europe due to reductions in the transportation and residential sectors. Carcinogenic VOCs such as benzene, formaldehyde, and acetaldehyde contributed to a lifetime cancer burden affecting 0.60 [95% confidence interval (95CI): 0.40–0.81] to 0.85 [95CI: 0.56–1.14] million individuals globally. We projected that between 36.4% and 39.7% of the global population was exposed to harmful VOC levels, with the highest exposure rates found in China (82.8–84.3%) and considerably lower exposure in Europe (1.7–5.8%). Open agricultural burning in less-developed regions amplified VOC-induced cancer burdens. Significant disparities in cancer burdens between high-income and low-to-middle-income countries were identified throughout the study period, primarily due to unequal population growth and VOC emissions. These findings underscore health disparities among different income nations and emphasize the persistent need to address the environmental injustice related to air pollution exposure.more » « less
-
Volatile organic compounds (VOCs) that evaporate under standard atmospheric conditions are of growing concern. This is because it is well established that VOCs represent major contamination risks since release of these compounds into the atmosphere can contribute to global warming, and thus, can also be detrimental to the overall health of worldwide populations including plants, animals, and humans. Consequently, the detection, discrimination, and quantification of VOCs have become highly relevant areas of research over the past few decades. One method that has been and continues to be creatively developed for analyses of VOCs is the Quartz Crystal Microbalance (QCM). In this review, we summarize and analyze applications of QCM devices for the development of sensor arrays aimed at the detection of environmentally relevant VOCs. Herein, we also summarize applications of a variety of coatings, e.g., polymers, macrocycles, and ionic liquids that have been used and reported in the literature for surface modification in order to enhance sensing and selective detection of VOCs using quartz crystal resonators (QCRs) and thus QCM. In this review, we also summarize novel electronic systems that have been developed for improved QCM measurements.more » « less
-
The ocean is a vast reservoir of bioavailable dissolved organic compounds (DOCs). Phytoplankton and bacterioplankton are the primary producers and consumers of these organic compounds, respectively, driving DOCs turnover on timescales of minutes to days. Volatile organic compounds (VOCs) make up about a third of DOCs, and their diffusivity and reactivity cause them to be important contributors to plankton carbon cycling and atmospheric chemistry. This research sought to describe plankton interactions mediated by VOCs. A model diatom, Phaeodactylum tricornutum, and five bacterial species known to be associated with the P. tricornutum phycosphere were studied in monocultures and co-cultures. Investigations evaluated the VOCs produced and consumed, temporal dynamics of VOC production and their roles in diatom metabolism, and physiological strategies of bacterial VOC consumers. P. tricornutum produced 78 VOCs during exponential growth. About 60% of these VOCs were hydrocarbons. In co-cultures with P. tricornutum, bacteria consumed different ranges of VOCs. The VOC specialists, Marinobacter and Roseibium, consumed the most, had hydrocarbon oxidation genes, and showed motility and physical attachment to the diatom. Rhodobacter and Stappia consumed fewer VOCs and were non-motile, while Yoonia consumed only acetaldehyde. Diatom gross carbon fixation was 29% higher in the presence of VOC specialists, suggesting rapid VOC consumption in the phycosphere impacts global gross carbon production. Temporal VOC production in P. tricornutum was monitored over a diel cycle. All VOCs were produced in higher concentrations during the day compared to night. Regression spline functions revealed six unique temporal production patterns associated with diel shifts in metabolism and the cell cycle. Physiological strategies for VOC uptake were studied in the VOC specialist Marinobacter. Marinobacter consumed some benzenoids at concentrations ranging from pM to μM and most increased cell densities compared to no VOC added controls and were not chemoattractants. Other VOCs that did not stimulate higher cell densities were strong chemoattractants. Thus, some VOCs are chemoattractants that guide motile cells toward co-emitted growth substrates. VOC discrimination may optimize spatial and temporal positioning in the phycosphere and enhance VOC uptake, sustaining the extremely low VOC concentrations in the surface ocean. This research revealed phytoplankton and ii bacterioplankton physiological processes that underlie the biological cycling of surface ocean VOCs and their potential for air-sea flux. This dissertation on microbiology in the phycosphere provided a foundation for exploring elements of science art that promote audience engagement through an exhibition that used scientific findings from the dissertation. Original art and audience surveys were used iteratively to increase science accessibility to general audiences.more » « less
-
Abstract We investigated how various sources contributed to observations of over 40 trace gas and particulate species in a typical Fairbanks residential neighborhood during the Alaskan Layered Pollution and Chemical Analysis campaign in January–February 2022. Aromatic volatile organic compounds (VOCs) accounted for ∼50% of measured VOCs (molar ratio), while methanol and ethanol accounted for ∼34%. The total wintertime VOC burden and contribution from aromatics were much higher than other US urban areas. Based on diel cycles and positive matrix factorization (PMF) analyses, we find traffic was the largest source of NO, CO, black carbon, and aromatic VOCs. Formic and acetic acid, hydroxyacetone, furanoids, and other VOCs were primarily attributed to residential wood combustion (RWC). Formaldehyde was one of several VOCs featuring significant contributions from multiple sources: RWC (∼35%), aging (∼30%), traffic (∼21%), and heating oil combustion (HO, ∼14%). PMF solutions assigned primary fine particulate matter to RWC (10%–30%), traffic (25%–40%), and HO (30%–60%), the latter likely reflecting high sulfur emissions from older furnaces and fast secondary chemistry. Despite cold and dark conditions, secondary processes impacted many trace gas and particle species' budget by ±10%–20% and more in some cases. Transport of O3‐rich regional air into Fairbanks contributed to aging, specifically NO3radical formation. This work highlights a long‐term trend observed in Fairbanks: increasing traffic and decreasing RWC relative contributions as total pollution decreases. Fairbanks exports a relatively fresh pollutant mixture to the regional arctic, the fate of which warrants future study.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0197236
