Low-Cost Hourly Ambient Black Carbon Measurements at Multiple Cities in Africa.

There is a notable lack of continuous monitoring of air pollutants in the Global South, especially for measuring chemical composition, due to the high cost of regulatory monitors. Using our previously developed low-cost method to quantify black carbon (BC) in fine particulate matter (PM) by analyzing reflected red light from ambient particle deposits on glass fiber filters, we estimated hourly ambient BC concentrations with filter tapes from beta attenuation monitors (BAMs). BC measurements obtained through this method were validated against a reference aethalometer between August 2 and 23, 2023 in Addis Ababa, Ethiopia, demonstrating a very strong agreement ( = 0.

Improvement of Surface PM Diurnal Variation Simulations in East Africa for the MAIA Satellite Mission.

The Multi-Angle Imager for Aerosols (MAIA), supported by NASA and the Italian Space Agency, is planned for launch into space in 2025. As part of its mission goal, outputs from a chemical transport model, the Unified Inputs for Weather Research and Forecasting Model coupled with Chemistry (UI-WRF-Chem), will be used together with satellite data and surface observations for estimating surface PM. Here, we develop a method to improve UI-WRF-Chem with surface observations at the U.

Elemental Characterization of Ambient Particulate Matter for a Globally Distributed Monitoring Network: Methodology and Implications.

Global ground-level measurements of elements in ambient particulate matter (PM) can provide valuable information to understand the distribution of dust and trace elements, assess health impacts, and investigate emission sources. We use X-ray fluorescence spectroscopy to characterize the elemental composition of PM samples collected from 27 globally distributed sites in the Surface PARTiculate mAtter Network (SPARTAN) over 2019-2023. Consistent protocols are applied to collect all samples and analyze them at one central laboratory, which facilitates comparison across different sites.

Outdoor Ultrafine Particulate Matter and Risk of Lung Cancer in Southern California.

Particulate matter ⩽2.5 μm in aerodynamic diameter (PM) is an established cause of lung cancer, but the association with ultrafine particulate matter (UFP; aerodynamic diameter < 0.1 μm) is unclear.

Two-year-long high-time-resolution apportionment of primary and secondary carbonaceous aerosols in the Los Angeles Basin using an advanced total carbon-black carbon (TC-BC(λ)) method.

In recent years, carbonaceous aerosols (CA) have been recognized as a significant contributor to the concentration of particles smaller than 2.5 μm (i.e.

Land use regression models for ultrafine particles, fine particles, and black carbon in Southern California.

Exposure models are needed to evaluate health effects of long-term exposure to ambient ultrafine particles (UFP; <0.1 μm) and to disentangle their association from other pollutants, particularly PM (<2.5 μm).

Impact of emissions from the Ports of Los Angeles and Long Beach on the oxidative potential of ambient PM measured across the Los Angeles County.

In this study, weekly samples of ambient PM (particulate matter with an aerodynamic diameter <0.25 μm) were collected in three contrasting locations, including central Los Angeles (USC), north Long Beach (NLB), and the Port of Long Beach (PRT), during June and July of 2017 to evaluate the chemical composition of ambient PM and identify the sources that contribute to the oxidative potential of ambient PM in these locations. Special focus was given in exploring the impact of emissions from the Ports of Los Angeles and Long Beach on the oxidative potential of ambient PM measured across these sites.

Spatio-temporal trends and source apportionment of fossil fuel and biomass burning black carbon (BC) in the Los Angeles Basin.

In this study, we evaluated the spatial and temporal trends of black carbon (BC) in the Los Angeles Basin between 2012-2013 and 2016-2017. BC concentrations were measured in seven wavelengths using Aethalometers (AE33) at four sites, including central Los Angeles (CELA), Anaheim, Fontana, and Riverside. Sources of BC were quantified using the equivalent black carbon (EBC) model.

Associations of Source-apportioned Fine Particles with Cause-specific Mortality in California.

Background: Exposure to ambient fine particulate matter (PM2.5) has been linked with premature mortality, but sources of PM2.5 have been less studied.

Cause-specific stillbirth and exposure to chemical constituents and sources of fine particulate matter.

The stillbirth rate in the United States is relatively high, but limited evidence is available linking stillbirth with fine particulate matter (PM), its chemical constituents and sources. In this study, we explored associations between cause-specific stillbirth and prenatal exposures to those pollutants with using live birth and stillbirth records from eight California locations during 2002-2009. ICD-10 codes were used to identify cause of stillbirth from stillbirth records.

Source apportionment of fine particulate matter and risk of term low birth weight in California: Exploring modification by region and maternal characteristics.

Previous studies have demonstrated associations between fine particulate matter (PM) and risk of term low birth weight (TLBW; birth weight<2500g and gestational weeks≥37weeks). However, it remains unclear which PM sources mainly contribute to these associations, and which subgroups (e.g.

Associations of Source-Specific Fine Particulate Matter With Emergency Department Visits in California.

While many studies have investigated the health effects associated with acute exposure to fine particulate matter (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5)), very few have considered the risks of specific sources of PM2.

Associations between microvascular function and short-term exposure to traffic-related air pollution and particulate matter oxidative potential.

Background: Short-term exposure to ambient air pollution has been associated with acute increases in cardiovascular hospitalization and mortality. However, causative chemical components and underlying pathophysiological mechanisms remain to be clarified. We hypothesized that endothelial dysfunction would be associated with mobile-source (traffic) air pollution and that pollutant components with higher oxidative potential to generate reactive oxygen species (ROS) would have stronger associations.

Associations of oxidative stress and inflammatory biomarkers with chemically-characterized air pollutant exposures in an elderly cohort.

Background: Exposure to air pollution has been associated with cardiorespiratory morbidity and mortality. However, the chemical constituents and pollution sources underlying these associations remain unclear.

Method: We conducted a cohort panel study involving 97 elderly subjects living in the Los Angeles metropolitan area.

The relative importance of tailpipe and non-tailpipe emissions on the oxidative potential of ambient particles in Los Angeles, CA.

This study examines the associations between the oxidative potential of ambient PM2.5 and PM0.18, measured by means of the dithiothreitol (DTT) assay, and their chemical constituents and modeled sources.

Urban traffic-derived nanoparticulate matter reduces neurite outgrowth via TNFα in vitro.

Background: The basis for air pollution-associated neurodegenerative changes in humans is being studied in rodent models. We and others find that the ultrafine particulate matter (PM) derived from vehicular exhaust can induce synaptic dysfunction and inflammatory responses in vivo and in vitro. In particular, a nano-sized subfraction of particulate matter (nPM, PM0.

Oxidative potential of coarse particulate matter (PM(10-2.5)) and its relation to water solubility and sources of trace elements and metals in the Los Angeles Basin.

In this study, potential sources of water-soluble (WS) and water-insoluble (WI) fractions of metals and trace elements in coarse particulate matter (CPM) (PM(10-2.5), 2.5 < dp < 10 μm) were identified and their association with the redox properties of CPM, measured by means of reactive oxygen species (ROS), was explored.

Fine and ultrafine particulate organic carbon in the Los Angeles basin: Trends in sources and composition.

In this study, PM2.5 and PM0.18 (particles with dp<2.

Long-term source apportionment of ambient fine particulate matter (PM2.5) in the Los Angeles Basin: a focus on emissions reduction from vehicular sources.

Positive Matrix Factorization (PMF) was utilized to quantify sources of ambient PM2.5 in central Los Angeles (LA) and Rubidoux, using the Speciation Trends Network data, collected between 2002 and 2013. Vehicular emissions (including gasoline and diesel vehicles) were the second major contributor to PM2.

Chemical characterization and source apportionment of indoor and outdoor fine particulate matter (PM(2.5)) in retirement communities of the Los Angeles Basin.

Concurrent indoor and outdoor measurements of fine particulate matter (PM2.5) were conducted at three retirement homes in the Los Angeles Basin during two separate phases (cold and warm) between 2005 and 2006. Indoor-to-outdoor relationships of PM2.

Diurnal and seasonal trends in the apparent density of ambient fine and coarse particles in Los Angeles.

Diurnal and seasonal variations in the apparent density of ambient fine and coarse particulate matter (PM2.5 and CPM [PM2.5-10], respectively) were investigated in a location near downtown Los Angeles.