Assessment of air quality in the Philadelphia, Pennsylvania subway.

BACKGROUND: Subways are popular and efficient modes of transportation in cities. However, people are exposed to high levels of particulate matter (PM) in subways. Subway air quality in the United States has been investigated in a few cities, but data is lacking on simultaneous measurement of several pollutants, especially ultrafine particles (UFP) and black carbon (BC), in combination with different size fractions of PM. OBJECTIVES: The goals of this study are to assess air quality in a belowground subway and compare it with outdoor ambient levels, to examine temporal variability of PM in the subway, and to analyze the correlation between PM and BC. METHODS: Particulate matter of varying sizes (PM1, PM2.5, PM10), UFP, and BC were measured using DustTrak, nanoparticle detector, and micro aethalometer, respectively. Measurements were made at the belowground subway platform and the aboveground street level at 15th Street subway station in Philadelphia during summer 2022. RESULTS: Belowground mean PM1, PM2.5, and PM10 were 112.2 ± 61.3 µg/m3, 120 ± 65.5 µg/m3, and 182.1 ± 132 µg/m3, respectively, which were 5.4, 5.7, and 7.6 times higher than the respective aboveground street levels. The UFP lung deposited surface area (LDSA) (59.4 ± 36.2 µm2/cm3) and BC (9.5 ± 5.4 µg/m3) belowground were 1.7 times and 10.7 times higher than the aboveground. The pollutant concentration varied from day-to-day on both the locations. A higher positive correlation was found between the belowground BC and PM2.5 (r = 0.51, p < 0.05) compared to the aboveground (r = 0.16, p < 0.05). IMPACT: This study showed high levels of particulate matter exposure at a belowground subway station in Philadelphia. Particulate matter levels were about 5 to 8 times higher at belowground subway station than the corresponding aboveground street level. Higher levels were also observed for UFP lung deposited surface area (LDSA), while black carbon levels showed the highest concentration at the belowground level by a factor of ten compared to the aboveground level. The study shows the need for air quality management at belowground subways to reduce particulate matter exposure for the commuters.

Monitoring gaseous pollutants using passive sampling in the Philadelphia region.

Air pollution can have deleterious impacts on human health and the environment. Historically, air pollution studies have focused more on cities. However, it is also important to consider the impact on large suburban populations living closer to the major cities. In this study, nitrogen oxides (nitrogen dioxide and nitric oxide), sulfur dioxide, ozone, and ammonia concentrations were measured from fifteen sites in the Greater Philadelphia area, Pennsylvania, USA using Ogawa passive samplers from September 2021 to May 2022. The fall season had the highest mean NOx concentrations (11.03 ± 4.51 ppb), and spring had the highest mean O3 concentration (18.65 ± 6.71 ppb) compared to other seasons. NOx concentrations were higher at suburban (30.43 ± 33.79 ppb) and urban sites (22.49 ± 12.54 ppb) compared to semi-rural sites (11.08 ± 9.20 ppb). SO2 was not detected in most of the measurements. The positive statistically significant correlation between NO and NH3 in urban (R2 = 0.33, p-value <0.05) and suburban sites (R2 = 0.37, p-value <0.05) during winter and spring, respectively, suggests a high attribution of traffic emissions to NH3 at urban and suburban sites. Influence of traffic emissions on air pollutant values for the study region is also supported by similar NOx concentrations between suburban and urban sites as well as decreasing NO2/NOx ratios with increased distance from expressways. This study shows that passive sampling can be effectively used for assessing spatial and seasonal variations in air pollutants within an area of diverse land use.Implications: This study presents the findings of temporal and seasonal patterns for nitrogen dioxide, nitric oxide, tropospheric ozone, and ammonia at urban, suburban, and semi-rural areas of the greater Philadelphia region. The main objective of the study is to monitor air pollution in suburban and semi-rural areas which are not monitored for air pollution. We monitored from a total of fifteen sites in three seasons to assess air pollution in suburban and semi-rural areas near the major city in the United States - Philadelphia. The findings are important to learn how air quality is affected in suburban and semi-rural areas near the major city. The study also shows the useful application of inexpensive passive sampling technique for measuring air pollution.

Soil contamination in community gardens of Philadelphia and Pittsburgh, Pennsylvania.

Community gardens have been seen sprouting up in and around urban settings such as Philadelphia and Pittsburgh over the past several decades. Due to the long histories of industrial activities and urbanization, these soils in urban regions may be at a high risk for various contaminants such as metals and metalloids. Using inductively coupled plasma mass spectrometry (ICP-MS), we measured 7 elements (lead (Pb), zinc (Zn), copper (Cu), vanadium (V), cadmium (Cd), nickel (Ni), and arsenic (As)) in soil samples collected from a total of 21 community gardens in Philadelphia City, Philadelphia suburban areas, and Pittsburgh City during September and October 2021. We found that the city areas in Philadelphia and Pittsburgh had higher elemental concentrations in community garden soils compared to the suburbs. We found that all elements except vanadium were below the Pennsylvania Department of Environmental Protection (PADEP) guidelines. When compared to more stringent Canadian Council of Ministers of the Environment (CCME) guidelines of a maximum of 140 mg/kg of lead in the soil, 36% percent of Philadelphia community gardens, 60% of Pittsburgh gardens, and 20% of the Philadelphia suburb gardens exceeded the CCME guideline. In Philadelphia city, generally, elemental concentrations exhibited a negative trend with increasing distance to historical smelter locations, although a significant correlation was observed for only zinc. We found that the soil from the raised beds had lower concentrations of lead and arsenic, but many of the samples from the raised beds had higher concentrations of zinc, copper, vanadium, and nickel. This discrepancy in raised beds is most likely attributed to these elements being actively deposited in the soil from present day sources such as vehicles on the road and active industrial sites. Understanding and recognizing such variations of these contaminants in community gardens are essential to understanding how industrial legacies and modern pollution continue to put urban communities at a disproportionate risk of health impacts.

Factors That Influence Climate Change-Related Mortality in the United States: An Integrative Review.

Global atmospheric warming leads to climate change that results in a cascade of events affecting human mortality directly and indirectly. The factors that influence climate change-related mortality within the peer-reviewed literature were examined using Whittemore and Knafl's framework for an integrative review. Ninety-eight articles were included in the review from three databases-PubMed, Web of Science, and Scopus-with literature filtered by date, country, and keywords. Articles included in the review address human mortality related to climate change. The review yielded two broad themes in the literature that addressed the factors that influence climate change-related mortality. The broad themes are environmental changes, and social and demographic factors. The meteorological impacts of climate change yield a complex cascade of environmental and weather events that affect ambient temperatures, air quality, drought, wildfires, precipitation, and vector-, food-, and water-borne pathogens. The identified social and demographic factors were related to the social determinants of health. The environmental changes from climate change amplify the existing health determinants that influence mortality within the United States. Mortality data, national weather and natural disaster data, electronic medical records, and health care provider use of International Classification of Disease (ICD) 10 codes must be linked to identify climate change events to capture the full extent of climate change upon population health.

Spatial and temporal variations in indoor radon concentrations in Pennsylvania, USA from 1988 to 2018.

Indoor radon poses one of the most significant environmental threats to public health as it is the second leading cause of lung cancer in the United States. Developing a more thorough understanding of the factors that affect radon concentrations is key for developing risk maps, identifying where testing should be a priority, and education about indoor radon exposure. The objectives of this study are to investigate seasonal and annual variation of indoor radon concentrations in Pennsylvania, USA from 1988 to 2018, to explore the hotspot areas for high indoor radon concentrations, and to analyze the association with various factors such as weather conditions, housing types, and floor levels. Based on a total of 1,808,294 radon tests conducted from 1988 to 2018, we found that 61% of the area (by zip codes), 557,869 tests conducted in the basement and 49,141 tests conducted on the ground floor in homes in Pennsylvania had higher radon levels than the U.S. EPA action level concentration of 148 Bq/m3 (equivalent to 4 pCi/L). Winter and fall had significantly higher indoor radon concentrations than summer and spring. Case studies conducted in Pittsburgh, Philadelphia, and Harrisburg showed that there was no significant correlation of daily temperature, precipitation, or relative humidity with indoor radon concentration on the day a radon test occurred.

Mobile monitoring of air and noise pollution in Philadelphia neighborhoods during 2017.

Mobile monitoring is a useful approach for measuring intra-urban variation of air pollution in urban environments. In this study, we used a mobile monitoring approach to study the spatial-temporal variability of air and noise pollution in urban neighborhoods of Philadelphia. During summer 2017, we used portable instruments to measure PM2.5, black carbon (BC), and noise levels along 5 km paths in four residential neighborhoods (Tioga, Mill Creek, Chestnut Hill, and Northern Liberties) and one commercial district (Center City) in Philadelphia, Pennsylvania, USA. A total of 62 sets of measurements were made at three different times of day (during morning rush hour, mid-afternoon, and during afternoon rush hour) from June 5 to July 7, 2017. Spatially, there was a significant difference in PM2.5 concentrations among the four residential neighborhoods. Overall, the Chestnut Hill neighborhood had the highest PM2.5 concentrations (13.25 ±â€¯6.89 µg/m3), followed by Tioga (9.58 ±â€¯4.83 µg/m3), Northern Liberties (7.02 ±â€¯4.17 µg/m3), and Mill Creek (3.9 ±â€¯4.5 µg/m3). There was temporal variability of pollutants depending on the neighborhood; Northern Liberties demonstrated the highest temporal variability in these data. The highest PM2.5 (18.86 ±â€¯3.17 mg/m3) was measured in the Chestnut Hill neighborhood during mid-afternoon. Mean PM2.5, BC, and noise levels based on mobile measurements at Philadelphia during summer 2017 were 8.41 ±â€¯4.31 µg/m3, 0.99 ±â€¯0.44 µg C/m3, and 62.01 ±â€¯3.20 dBA, respectively. Environmental noise showed the highest temporal variation of the monitored components for 3 time periods. In general, tree cover showed a weak and inconclusive association with particulate pollution levels.

Roadside Exposure and Inflammation Biomarkers among a Cohort of Traffic Police in Kathmandu, Nepal.

Air pollution is a major environmental problem in the Kathmandu Valley. Specifically, roadside and traffic-related air pollution exposure levels were found at very high levels exceeding Nepal air quality standards for daily PM2.5. In an exposure study involving traffic police officers, we collected 78 blood samples in a highly polluted spring season (16 February 2014⁻4 April 2014) and 63 blood samples in the less polluted summer season (20 July 2014⁻22 August 2014). Fourteen biomarkers, i.e., C-reactive protein (CRP), serum amyloid A (SAA), intracellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), interferon gamma (IFN-γ), interleukins (IL1-ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13), and tumor necrosis factor (TNF-α) were analyzed in collected blood samples using proinflammatory panel 1 kits and vascular injury panel 2 kits. All the inflammatory biomarker levels were higher in the summer season than in the spring season, while particulate levels were higher in the spring season than in the summer season. We did not find significant association between 24-hour average PM2.5 or black carbon (BC) exposure levels with most of analyzed biomarkers for the traffic volunteers working and residing near busy roads in Kathmandu, Nepal, during 2014. Inflammation and vascular injury marker concentrations were generally higher in females, suggesting the important role of gender in inflammation biomarkers. Because of the small sample size of female subjects, further investigation with a larger sample size is required to confirm the role of gender in inflammation biomarkers.

Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure.

Inexpensive cloth masks are widely used in developing countries to protect from particulate pollution albeit limited data on their efficacy exists. This study examined the efficiency of four types of masks (three types of cloth masks and one type of surgical mask) commonly worn in the developing world. Five monodispersed aerosol sphere size (30, 100, and 500 nm, and 1 and 2.5 µm) and diluted whole diesel exhaust was used to assess facemask performance. Among the three cloth mask types, a cloth mask with an exhaust valve performed best with filtration efficiency of 80-90% for the measured polystyrene latex (PSL) particle sizes. Two styles of commercially available fabric masks were the least effective with a filtration efficiency of 39-65% for PSL particles, and they performed better as the particle size increased. When the cloth masks were tested against lab-generated whole diesel particles, the filtration efficiency for three particle sizes (30, 100, and 500 nm) ranged from 15% to 57%. Standard N95 mask performance was used as a control to compare the results with cloth masks, and our results suggest that cloth masks are only marginally beneficial in protecting individuals from particles<2.5 µm. Compared with cloth masks, disposable surgical masks are more effective in reducing particulate exposure.

Respiratory Effects of High Levels of Particulate Exposure in a Cohort of Traffic Police in Kathmandu, Nepal.

OBJECTIVES: To investigate the traffic-related PM2.5 and black carbon (BC) exposures and assess their health effects. METHODS: Personal exposure to PM2.5 and BC levels were monitored in a cohort of traffic police (n = 53) at six locations in Kathmandu Valley, Nepal during dry and rainy seasons in 2014. RESULTS: Mean on-road exposure levels of PM2.5 and BC ranged from 34 to 193 µg/m(3) and 12 to 28 µgC/m(3), respectively, and were associated with an acute decline in lung function. Use of N95 mask had clear benefits reducing the lung function decreases after occupational exposures when masks were worn for just half of a workweek. CONCLUSIONS: Exposure of high levels of PM2.5 was associated with reduced lung function. Increased levels of BC exposure led to reduced lung function in non-smoking traffic officers with non-normal spirometry observations.

Non-sulfate sulfur in fine aerosols across the United States: Insight for organosulfate prevalence.

We investigated the discrepancies in long-term sulfur measurements from 2000 to 2012 by two separate speciation methods, X-ray fluorescence (XRF) spectroscopy and ion chromatography (IC) across the United States (334 sites). Overall, there was a good correlation between sulfur measurements by XRF spectroscopy and IC (R ≥ 0.90 for most of the sites). However, the inorganic sulfate measured by ion chromatography was not sufficient to account for all the sulfur measured by XRF spectroscopy at many of the sites. Discrepancies were observed with the high ratios of sulfur measured by XRF spectroscopy to that by IC. Such high ratios also exhibited seasonal variation, and differed across land use types; significant differences occurred at locations classified as forest, agriculture, and mobile, but not in locations classified as commercial, desert, industrial, and residential. On average, the excess, or non-sulfate, sulfur (unmeasured organic sulfur or other inorganic species of sulfur) was variable and observed as high as ~13% of organic carbon and ~2% of PM2.5. The contribution of such assumed organosulfur was larger in the eastern region than other geographical locations in the United States. Besides the temporal and spatial trends, the additional sulfur was found to be related to other factors such as aerosol acidity and emission sources. The results suggest that these unmeasured sulfur species could have significant contribution to aerosol burden, and the understanding of these could help to control PM2.5 levels and to assess other effects of sulfur aerosols.

Investigating missing sources of sulfur at Fairbanks, Alaska.

We investigated disparities in elemental sulfur and inorganic sulfate concentrations in ambient fine particulate matter (PM2.5) data from 2005 to 2012 at a monitoring station in Fairbanks, AK. In approximately 28% of the observations from 2005 to 2012, elemental sulfur by X-ray fluorescence (XRF) spectroscopy significantly exceeded the inorganic sulfur by ion chromatography (IC), suggesting the presence of a significant quantity of unmeasured sulfur compounds. The mean ratio of sulfur by XRF to that by IC for only these cases was 1.22 ± 0.11. The largest discrepancies between elemental sulfur and sulfate were most frequently observed in the summer, although discrepancies were observed year round. Assuming the additional sulfur (other than inorganic sulfate) as the upper limit estimate, this work shows that organosulfur species (or the additional sulfur) account for 1.29% of organic carbon (OC) and 0.75% of PM2.5 in Fairbanks. An analysis of all available air quality system (AQS) data suggests that these recurring phenomena are linked to seasons, total carbon, inorganic nitrate, and elemental sources during cold periods and ozone during warm periods.

Lignin-derived phenols in Houston aerosols: implications for natural background sources.

Solvent-extractable monomeric methoxyphenols in aerosol samples conventionally have been used to indicate the influence of biomass combustion. In addition, the presence of lignin oxidation products (LOP), derived from the CuO oxidation of vascular plant organic matter, can help trace the source and inputs of primary biological particles in aerosols. Ambient aerosols (coarse and fine) collected in Houston during summer 2010 were analyzed by gas chromatography-mass spectrometry to characterize monomeric and polymeric sources of LOPs. This is the first time polymeric forms of the LOPs have been characterized in ambient aerosols. The absence or small concentrations of solvent-extractable monomeric LOPs and levoglucosan isomers point to the limited influence of biomass burning during the sampling period. The trace levels of anhydrosugar concentrations most likely result from long-range transport. This observation is supported by the absence of co-occurring lignin monomers that undergo photochemical degradation during transport. The larger concentration (142 ng m(-3)) of lignin polymers in coarse aerosols shows the relative importance of primary biological aerosol particles, even in the urban atmosphere. The LOP parameters suggest a predominant influence from woody tissue of angiosperms, with minor influence from soft tissues, gymnosperms, and soil organic matter.

Secondary organic aerosol from photooxidation of polycyclic aromatic hydrocarbons.

Secondary organic aerosol (SOA) formation from the photooxidation of five polycyclic aromatic hydrocarbons (PAHs, naphthalene, 1- and 2-methylnaphthalene, acenaphthylene, and acenaphthene) was investigated in a 9-m(3) chamber in the presence of nitrogen oxides and the absence of seed aerosols. Aerosol size distributions and PAH decay were monitored by a scanning mobility particle sizer and a gas chromatograph with a flame ionization detector. Over a wide range of conditions, the aerosol yields for the investigated PAHs were observed to be in the range of 2-22%. The observed evolution of aerosol and PAH decay indicate that light and oxidant sources influence the time required to form aerosol and the required threshold reacted concentration of the PAHs. The SOA yields also were related to this induction period and the hydroxyl radical concentrations, particularly for smaller aerosol loadings (<∼6 µg m(-3)). Estimation of SOA production from oxidation of PAHs emitted from mobile sources in Houston shows that PAHs could account for more than 10% of the SOA formed from emissions from mobile sources in this region.

Chemically catalyzed uptake of 2,4,6-trinitrotoluene by Vetiveria zizanioides.

The efficiency of vetiver grass (Vetiveria zizanioides) in removing 2,4,6-trinitrotoluene (TNT) from aqueous media was explored in the presence of a common agrochemical, urea, used as a chaotropic agent. Chaotropic agents disrupt water structure, increasing solubilization of hydrophobic compounds (TNT), thus, enhancing plant TNT uptake. The primary objectives of this study were to: (i) characterize TNT absorption by vetiver in hydroponic media, and (ii) determine the effect of urea on chemically catalyzing TNT uptake by vetiver grass in hydroponic media. Results showed that vetiver exhibited a high TNT uptake capacity (1.026 mgg(-1)), but kinetics were slow. Uptake was considerably enhanced in the presence of urea, which significantly (p<0.001) increased the 2nd-order reaction rate constant over that of the untreated (no urea) control. Three major TNT metabolites were detected in the roots, but not in the shoot, namely 1,3,5-trinitrobenzene, 4-amino 2,6-dinitrotoluene, and 2-amino 4,6-dinitrotoluene, indicating TNT degradation by vetiver grass.

High uptake of 2,4,6-trinitrotoluene by vetiver grass--potential for phytoremediation?

2,4,6-Trinitrotoluene (TNT) is a potent mutagen, and a Group C human carcinogen that has been widely used to produce munitions and explosives. Vast areas that have been previously used as ranges, munition burning, and open detonation sites are heavily contaminated with TNT. Conventional remediation activities in such sites are expensive and damaging to the ecosystem. Phytoremediation offers a cost-effective, environment-friendly solution, utilizing plants to extract TNT from contaminated soil. We investigated the potential use of vetiver grass (Vetiveria zizanioides) to effectively remove TNT from contaminated solutions. Vetiver grass plants were grown in hydroponic systems containing 40 mg TNTL(-1) for 8d. Aqueous concentrations of TNT reached the method detection limit ( approximately 1 microg L(-1)) within the 8-d period, demonstrating high affinity of vetiver for TNT, without any visible toxic effects. Results from this preliminary hydroponic study are encouraging, but in need of verification using TNT-contaminated soils.