Ten questions concerning indoor ultrafine particles

Nazaroff, William W.

doi:10.1016/j.buildenv.2023.110641

Cited by 12 publications

(6 citation statements)

References 217 publications

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“…Agreement between the CADR p calculated with our test method compared to manufacturer-reported CADR p shows that the air cleaners that claim particle removal in this study are also efficient at removing UFPsa feature that is not captured by the AHAM AC-1 test method. UFP is unique because it can efficiently penetrate deep into the lungs where they have a greater propensity to deposit and impact the bloodstream more than larger particles . As such, UFP presents a unique exposure risk compared to larger particles.…”

Section: Resultsmentioning

confidence: 99%

“…UFP is unique because it can efficiently penetrate deep into the lungs where they have a greater propensity to deposit and impact the bloodstream more than larger particles. 17 As such, UFP presents a unique exposure risk compared to larger particles. This proposed test method provides a metric for air cleaner efficiency that addresses this specific indoor air quality concern.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method

Link,

Robertson,

Claflin

et al. 2024

Environ. Sci. Technol.

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In response to the COVID-19 pandemic, air cleaning technologies were promoted as useful tools for disinfecting public spaces and combating airborne pathogen transmission. However, no standard method exists to assess the potentially harmful byproduct formation from air cleaners. Through a consensus standard development process, a draft standard test method to assess portable air cleaner performance was developed, and a suite of air cleaners employing seven different technologies was tested. The test method quantifies not only the removal efficiency of a challenge chemical suite and ultrafine particulate matter but also byproduct formation. Clean air delivery rates (CADRs) are used to quantify the chemical and particle removal efficiencies, and an emission rate framework is used to quantify the formation of formaldehyde, ozone, and other volatile organic compounds. We find that the tested photocatalytic oxidation and germicidal ultraviolet light (GUV) technologies produced the highest levels of aldehyde byproducts having emission rates of 202 and 243 μg h −1 , respectively. Additionally, GUV using two different wavelengths, 222 and 254 nm, both produced ultrafine particulate matter.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method

Link,

Robertson,

Claflin

et al. 2024

Environ. Sci. Technol.

View full text Add to dashboard Cite

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“…Homes that use gas cooking, even with stove venting, often exceed outdoor levels of NO 2 ( 29 ). Both electric and gas cooking produce PM and ultrafine particles, but their nature and abundance depend on multiple factors, including cooking method (e.g., frying versus wet cooking), pan size (smaller pans are better), oil (the best type depends on smoking temperature), cooking temperature, food type and additives, heating source surface area (smaller burners are better), and ventilation ( 39 , 40 ). Gas combustion and electrical heating generally emit smaller particles, whereas the food itself produces larger particles ( 41 ).…”

Section: Cookingmentioning

confidence: 99%

Indoor Air Sources of Outdoor Air Pollution: Health Consequences, Policy, and Recommendations: An Official American Thoracic Society Workshop Report

Nassikas,

McCormack,

Ewart

et al. 2024

Annals ATS

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Indoor sources of air pollution worsen indoor and outdoor air quality. Thus, identifying and reducing indoor pollutant sources would decrease both indoor and outdoor air pollution, benefit public health, and help address the climate crisis. As outdoor sources come under regulatory control, unregulated indoor sources become a rising percentage of the problem. This American Thoracic Society workshop was convened in 2022 to evaluate this increasing proportion of indoor contributions to outdoor air quality. The workshop was conducted by physicians and scientists, including atmospheric and aerosol scientists, environmental engineers, toxicologists, epidemiologists, regulatory policy experts, and pediatric and adult pulmonologists. Presentations and discussion sessions were centered on 1 ) the generation and migration of pollutants from indoors to outdoors, 2 ) the sources and circumstances representing the greatest threat, and 3 ) effective remedies to reduce the health burden of indoor sources of air pollution. The scope of the workshop was residential and commercial sources of indoor air pollution in the United States. Topics included wood burning, natural gas, cooking, evaporative volatile organic compounds, source apportionment, and regulatory policy. The workshop concluded that indoor sources of air pollution are significant contributors to outdoor air quality and that source control and filtration are the most effective measures to reduce indoor contributions to outdoor air. Interventions should prioritize environmental justice: Households of lower socioeconomic status have higher concentrations of indoor air pollutants from both indoor and outdoor sources. We identify research priorities, potential health benefits, and mitigation actions to consider (e.g., switching from natural gas to electric stoves and transitioning to scent-free consumer products). The workshop committee emphasizes the benefits of combustion-free homes and businesses and recommends economic, legislative, and education strategies aimed at achieving this goal.

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“…Originating directly from traffic emissions − and via in situ atmospheric oxidation processes, , ultrafine particles dominate the number distribution of urban aerosols . Exposure to ultrafine particles has been associated with respiratory and cardiovascular mortality and brain diseases. − In indoor environments, where people spend most of their time, ultrafine particle levels can be comparable, or even higher than outdoor, owing to various indoor particle generation sources. − Typical indoor ultrafine particle sources can be classified into three overlapping categories: combustion, such as cooking , and burning candles; , volatilization/nucleation/condensation, including those from electrical appliances, − heated surfaces, and painting; and oxidation, mainly referring to ozone–terpene chemistry indoors . Ultrafine particle emissions have been documented from the ozone reaction with indoor terpene-rich fragrances, , personal care products, − and cleaning agents. , A potentially strong yet understudied source of indoor ultrafine particles is ozone–human chemistry.…”

Section: Introductionmentioning

confidence: 99%

“… 8 − 10 In indoor environments, where people spend most of their time, 11 ultrafine particle levels can be comparable, or even higher than outdoor, owing to various indoor particle generation sources. 12 − 16 Typical indoor ultrafine particle sources can be classified into three overlapping categories: 9 combustion, such as cooking 17 , 18 and burning candles; 19 , 20 volatilization/nucleation/condensation, including those from electrical appliances, 21 − 23 heated surfaces, 24 and painting; 25 and oxidation, mainly referring to ozone–terpene chemistry indoors. 26 Ultrafine particle emissions have been documented from the ozone reaction with indoor terpene-rich fragrances, 27 , 28 personal care products, 29 − 31 and cleaning agents.…”

Section: Introductionmentioning

confidence: 99%

Influence of Ventilation on Formation and Growth of 1–20 nm Particles via Ozone–Human Chemistry

Yang,

Müller,

Wang

et al. 2024

Environ. Sci. Technol.

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Ozone reaction with human surfaces is an important source of ultrafine particles indoors. However, 1−20 nm particles generated from ozone−human chemistry, which mark the first step of particle formation and growth, remain understudied. Ventilation and indoor air movement could have important implications for these processes. Therefore, in a controlled-climate chamber, we measured ultrafine particles initiated from ozone−human chemistry and their dependence on the air change rate (ACR, 0.5, 1.5, and 3 h −1 ) and operation of mixing fans (on and off). Concurrently, we measured volatile organic compounds (VOCs) and explored the correlation between particles and gas-phase products. At 25−30 ppb ozone levels, humans generated 0.2−7.7 × 10 12 of 1−3 nm, 0−7.2 × 10 12 of 3−10 nm, and 0−1.3 × 10 12 of 10−20 nm particles per person per hour depending on the ACR and mixing fan operation. Size-dependent particle growth and formation rates increased with higher ACR. The operation of mixing fans suppressed the particle formation and growth, owing to enhanced surface deposition of the newly formed particles and their precursors. Correlation analyses revealed complex interactions between the particles and VOCs initiated by ozone−human chemistry. The results imply that ventilation and indoor air movement may have a more significant influence on particle dynamics and fate relative to indoor chemistry.

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Ten questions concerning indoor ultrafine particles

Cited by 12 publications

References 217 publications

Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method

Quantification of Byproduct Formation from Portable Air Cleaners Using a Proposed Standard Test Method

Indoor Air Sources of Outdoor Air Pollution: Health Consequences, Policy, and Recommendations: An Official American Thoracic Society Workshop Report

Influence of Ventilation on Formation and Growth of 1–20 nm Particles via Ozone–Human Chemistry

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