Levels Of Traffic-related Air Pollution Research Articles

Resolving the effect of roadside vegetation barriers as a near-road air pollution mitigation strategy

A multi-regime framework adequately resolves the complex physical mechanisms of roadside barriers on near-road air quality in a computationally efficient Gaussian-based model.

Black Carbon and Particulate Matter Concentrations: Air Pollution Levels in Rio de Janeiro, Brazil

This research explores the concentration of black carbon (BC) in particulate matter (PM10 and PM2.5) from ten monitoring stations in the Metropolitan Region of Rio de Janeiro (MRRJ), Bonsucesso (BS), Botafogo (BOT), Copacabana (COP), Gavea (GAV), Gericino (GER), Lagoa (LAG), Recreio dos Bandeirantes (REC), Santa Cruz (SC), Castelo (CAS) and Urca (URC), covering a range of pollution sources (vehicular, industrial, and residential). PM samples were collected using filter units every week from January 2018 to December 2019. Results revealed high concentrations of PM10 in BS (86 ± 22 µg m-3) and PM2.5 in REC (30 ± 11 µg m-3). Likewise, both monitoring stations exceeded the international limits. In 2019, BC in PM10 decreased in the following order: BS > CAS > GER > BOT > SC > GAV. For 2018, BC in PM2.5 decreased as follows REC > LAG > SC, while 2019 REC > GAV > LAG > COP > URC. REC and BS have industrial and commercial activities and intense vehicular traffic. During the period of study, average BC concentrations in PM10 and PM2.5 were 3.3 ± 1.5 and 1.9 ± 0.70 µg m-3, respectively. These findings indicate that BC concentrations should be monitored and regulated in locations with high levels of traffic-related air pollution for offering new insights and guiding efforts to minimize emissions and enhance public health.

California’s zero-emission vehicle adoption brings air quality benefits yet equity gaps persist

Zero-emission vehicle (ZEV) adoption is a key climate mitigation tool, but its environmental justice implications remain unclear. Here, we quantify ZEV adoption at the census tract level in California from 2015 to 2020 and project it to 2035 when all new passenger vehicles sold are expected to be ZEVs. We then apply an integrated traffic model together with a dispersion model to simulate air quality changes near roads in the Greater Los Angeles. We found that per capita ZEV ownership in non-disadvantaged communities (non-DACs) as defined by the state of California is 3.8 times of that in DACs. Racial and ethnic minorities owned fewer ZEVs regardless of DAC designation. While DAC residents receive 40% more pollutant reduction than non-DACs due to intercommunity ZEV trips in 2020, they remain disproportionately exposed to higher levels of traffic-related air pollution. With more ZEVs in 2035, the exposure disparity narrows. However, to further reduce disparities, the focus must include trucks, emphasizing the need for targeted ZEV policies that address persistent pollution burdens among DAC and racial and ethnic minority residents.

Chronic Occupational Exposure to Traffic Pollution Is Associated with Increased Carotid Intima-Media Thickness in Healthy Urban Traffic Control Police.

Urban traffic officers in many low- and middle-income countries are exposed to high levels of traffic-related air pollutants (TRAP) while working vehicle control on heavily congested streets. The impact of chronic TRAP exposure on the cardiovascular health, including the carotid intima-media thickness (CIMT), of this outdoor occupational group remains unclear. This cross-sectional study compared the average mean and maximum CIMT measurements of two groups of relatively young, healthy traffic police (32 ± 7 years; 77% male) in Quito, Ecuador, who were without clinical evidence of serious cardiovascular or other disease. Previously published background data on PM10 (a TRAP surrogate) indicated that street levels of the pollutant were several orders of magnitude higher at the street intersections worked by traffic police compared to those working only in an office. Accordingly, officers permanently assigned to daily traffic control duties requiring them to stand 0-3 m from heavily trafficked street intersections were assigned to the high exposure group (n = 61). The control group (n = 54) consisted of officers from the same organization who were permanently assigned to office duties inside an administration building. Mean and maximum CIMT were measured with ultrasound. General linear models were used to compare the CIMT measurements of the high exposure and control groups, adjusting for covariates. The adjusted average mean and maximum CIMT measures of the high exposure group were increased by 11.5% and 10.3%, respectively, compared to the control group (p = 0.0001). These findings suggest that chronic occupational exposure to TRAP is associated with increased CIMT in traffic police. This is important since even small increases in arterial thickening over time may promote earlier progression to clinical disease and increased premature mortality risk.

Impact of traffic-related air pollution on the blood pressure response to exercise in individuals with hypertension

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Natural Sciences and Engineering Research Council of Canada and B.C. Sports & Exercise Medicine Research Foundation. Background The epidemiologic evidence suggests that the health benefits of exercise in healthy adults outweigh the adverse effects of air pollution in all but the most extreme concentrations. However, no studies have examined the acute response to exercise in air pollution in individuals with hypertension, a subgroup particularly susceptible to the cardiovascular effects of air population. Purpose The purpose of this study was to determine the impact of traffic-related air pollution on the acute cardiovascular response to exercise in patients with hypertension. We hypothesized that exposure to higher levels of traffic-related air pollution during exercise would attenuate, but not eliminate, acute post-exercise reductions in blood pressure and arterial stiffness. Methods Fourteen patients with hypertension (62.4±6.8 years; 81% male) completed a real-world, randomized, crossover study. Two 30-minute exercise bouts at 40-59% heart rate reserve were performed: once along a commercial street (high traffic) and once in an urban plaza (low traffic). Blood pressure (BP) and arterial stiffness (i.e., carotid-femoral pulse wave velocity [cfPWV]) were examined prior to, 30 minutes after, and 2 hours following exercise. 24-hour ambulatory BP monitoring was immediately completed following each visit. Black carbon, noise, relative humidity, and temperature were measured during each exercise bout (Figure 1). Results No differences were found for baseline cardiovascular measures between high and low traffic visits. At 30 minutes and 2 hours post-exercise, systolic BP was significantly reduced relative to baseline in the low-traffic condition only; diastolic BP was not significantly reduced at any timepoint. Based on linear mixed-effects analyses, exercising at the low traffic site was associated, relative to the high traffic site, with a significant (p = 0.04) reduction in systolic BP (-4.30 mm Hg [95% CI -8.09 to -0.54]) up to 2 hours following exercise after adjusting for exercise intensity, temperature, and noise; no differences were found for diastolic BP (-1.56 mm Hg [95% CI -4.87 to 1.83], p = 0.39). Each interquartile increase in black carbon (1168 ng/m³) was significantly associated with a 2.33 mm Hg (95% CI 0.37 to 4.17) increase in systolic BP up to 2 hours following exercise. No associations were observed between traffic site and BP for any ambulatory periods (i.e., 24-hour average, daytime, nighttime, or evening). The acute cfPWV response to exercise was also similar between traffic sites (p > 0.05). Conclusion Our findings suggest that exposure to traffic-related air pollution during exercise may adversely impact the beneficial short-term BP response to exercise in patients with hypertension. While the long-term implications of these changes to the acute BP response to exercise must be further explored, patients with hypertension can employ the prudent strategy of maximizing their distance from major roadways when exercising.

Assessment of light-duty versus heavy-duty diesel on-road mobile source emissions using general additive models applied to traffic volume and air quality data and COVID-19 responses

ABSTRACT Following the outbreak of the COVID-19 pandemic, several papers have examined the effect of the pandemic response on urban air pollution worldwide. This study uses observed traffic volume and near-road air pollution data for black carbon (BC), oxides of nitrogen (NOx), and carbon monoxide (CO) to estimate the emissions contributions of light-duty and heavy-duty diesel vehicles in five cities in the continental United States. Analysis of mobile source impacts in the near-road environment has several health and environmental justice implications. Data from the initial COVID-19 response period, defined as March to May in 2020, were used with data from the same period over the previous two years to develop general additive models (GAMs) to quantify the emissions impact of each vehicle class. The model estimated that light-duty traffic contributes 4–69%, 14–65%, and 21–97% of BC, NOx, and CO near-road levels, respectively. Heavy-duty diesel traffic contributes an estimated 26–46%, 17–63%, and −7–18% of near-road levels of the three pollutants. The estimated mobile source impacts were used to calculate NOx to CO and BC to NOx emission ratios, which were between 0.21–0.32 μg m−3 NOx (μg m−3 CO)−1 and 0.013–0.018 μg m−3 BC (μg m−3 NOx)−1. These ratios can be used to assess existing emission inventories for use in determining air pollution standards. These results agree moderately well with recent National Emissions Inventory estimates and other empirically-derived estimates, showing similar trends among the pollutants. However, a limitation of this study was the recurring presence of an implausible air pollution impact estimate in 41% of the site-pollutant combinations, where a vehicle class was estimated to account for either a negative impact or an impact higher than the total estimated pollutant concentration. The variations seen in the GAM estimates are likely a result of location-specific factors, including fleet composition, external pollution sources, and traffic volumes. Implications: Drastic reductions in traffic and air pollution during the lockdowns of the COVID-19 pandemic present a unique opportunity to assess vehicle emissions. A General Additive Modeling approach is developed to relate traffic levels, observed air pollution, and meteorology to identify the amount vehicle types contribute to near-road levels of traffic-related air pollutants (TRAPs), which is important for future emission regulation and policy, given the significant health and environmental justice implications of vehicle-related pollution along major roadways. The model is used to evaluate emission inventories in the near-road environment, which can be used to refine existing estimates. By developing a locally data-driven method to readily characterize impacts and distinguish between heavy and light duty vehicle effects, local regulations can be used to target policies in major cities around the country, thus addressing local health disbenefits and disparities occurring as a result of exposure to near-road air pollution.

Exploring the Spatial-temporal dynamics of travel patterns and air pollution exposure of E-scooters

Dockless mobility has been the biggest disruptive force in the shared mobility industry solving the “first-last” mile issue. With their high adoption levels combined with little to no regulation regarding their usage, these users have been driving along with motorized vehicles exposing them to major concerns. The users are exposed to high levels of traffic-related air pollution (TRAP) due to their direct exposure to vehicle exhaust. This study aims to understand the spatial and temporal dimensions of this emerging transportation mode in terms of travel behavior patterns, geographical aspects of travel, interactions between the travel route taken with the existing vehicle traffic, and resulting air pollution and exposure. The travel behavior patterns are evaluated through spatial-temporal analysis of a sample of e-scooter trip data collected in 2018 in the City of Austin and an online travel behavior survey. The analysis identified areas with peak usage, and peak ridership time. The survey results found the e-scooter user demographics to be mostly white males, in the 26–45 age range, with an undergraduate degree and working full-time. Secondly, key responded in influencing the use of an e-scooter are trip length, connectivity to transit, congestion and parking issues, and pollution reduction. Thirdly, e-scooter predominantly replaced personal vehicles and shared ridership in case of home-to-work trips and replaced walking for connecting to transit stops. The exposure to TRAP was obtained by integrating the spatial-temporal dynamics of e-scooter trips with spatial-temporal dynamics of pollutant concentrations modeled from traffic. Exposure analysis found peak exposure levels during midday and evening periods focused in the Central Austin area. This area houses the University of Texas campus and several neighborhoods with lots of shopping, restaurants, bars, and live music avenues. The findings are useful for policymakers and planners when planning for infrastructure changes air pollution control measures, incentive programs, and policies to motivate shared mobility.

Do neighbourhood traffic-related air pollution and socio-economic status moderate the associations of the neighbourhood physical environment with cognitive function? Findings from the AusDiab study

Characteristics of the neighbourhood environment, including the built and natural environment, area-level socio-economic status (SES) and air pollution, have been linked to cognitive health. However, most studies have focused on single neighbourhood characteristics and have not considered the extent to which the effects of environmental factors may interact. We examined the associations of measures of the neighbourhood built and natural environment, area-level SES and traffic-related air pollution (TRAP) with two cognitive function domains (memory and processing speed), and the extent to which area-level SES and TRAP moderated the associations.We used cross-sectional data from the AusDiab3 study, an Australian cohort study of adults (mean age: 61 years) in 2011–12 (N = 4141) for which geocoded residential addresses were available. Spatial data were used to create composite indices of built environment complexity (population density, intersection density, non-commercial land use mix, commercial land use) and natural environment (parkland and blue spaces). Area-level SES was obtained from national census indices and TRAP was based on estimates of annual average levels of nitrogen dioxide (NO2). Confounder-adjusted generalised additive mixed models were used to estimate the independent associations of the environmental measures with cognitive function and the moderating effects of area-level SES and TRAP. The positive associations between built environment complexity and memory were stronger in those living in areas with higher SES and lower NO2 concentrations. A positive association between the natural environment and memory was found only in those living in areas with lower NO2 concentrations and average or below-average SES. Built environment complexity and the natural environment were positively related to processing speed. Complex urban environments and access to nature may benefit cognitive health in ageing populations. For higher-order cognitive abilities, such as memory, these positive effects may be stronger in areas with lower levels of TRAP.

Impacts of Covid-19 Lockdown on Concentration Levels of Traffic-Related Air Pollutants in Ibadan -a West African City

Trends and sources of air pollution at twenty-five traffic Intersections (TIs) before and during covid-19 lockdown were investigated in Ibadan, Nigeria. The relationships among climatic parameters, vehicular counts and ten air pollutants which includes particulate matter (PM1, PM2.5, PM10 & Total Suspended Particles-TSP) and gaseous pollutants (CO, NO2, SO2, NH3, total volatile organic compounds-TVOCs, and ground level O3) measured simultaneously at TIs were analysed. Results indicated significant decrease in mean concentrations of all pollutants studied except NO2 with 212% increase during the study period. Concentrations of gaseous pollutants CO, SO2, NH3, TVOCs and ground level O3 reduced by 7.92%, 24.80%, 1.58%, 44.08% and 4.28%, respectively while particulates concentrations of PM1, PM2.5, PM10 and TSP concentrations decreased by 49.64%, 60.79%, 81.21% and 84.17%, respectively during lockdown. An integrated source apportionment approach using Pearson’s correlation, Airflow backward trajectories arriving in the study area and Principal component analysis (PCA) identified vehicular emission as the primary source of studied air pollutants at TIs before and during lockdown in Ibadan. Emission from residences, roadside fuel combustion and local air transport of pollutants from nearby upwind areas with industries and farming activities were identified as secondary sources of air pollution affecting the study area.

Maternal exposure to air pollution during pregnancy and child's cognitive, language, and motor function: ECLIPSES study

Prenatal exposure to air pollution, even at low levels, has been associated with negative effects on a child's neuropsychological functioning. The present work aimed to investigate the associations between prenatal exposure to air pollution on a child's cognitive, language, and motor function at 40 days of age in a highly exposed area of Spain. From the ECLIPSES study population, the present work counted 473 mother-child pairs. Traffic-related air pollution levels at home addresses during the whole pregnancy were estimated including particulate matter (PM) with an aerodynamic diameter <2.5 μm (PM2.5), <10 μm (PM10) and 2.5–10 μm (PMcoarse), PM2.5absorbance, nitrogen dioxide (NO2), other nitrogen oxides (NOx), and ozone (O3) using land-use regression models developed within ESCAPE and ELAPSE projects. Children's cognitive, language, and motor functions were assessed using the Bayley Scales of Infant Development 3rd edition (BSID-III) at around 40 days of age. Linear regression models were adjusted for maternal biological, sociodemographic and lifestyle characteristics, area deprivation index, and amount of greenness around the home's address. All air pollutants assessed, except PM2.5 absorbance, were associated with lower motor function in children, while no association was observed between prenatal exposure to air pollution and cognitive and language functions. This finding highlights the need to continue raising awareness of the population-level impact that maternal exposure to air pollution even at low levels can have on the neuropsychological functions of children.

The Effects of Traffic Air Pollution in and around Schools on Executive Function and Academic Performance in Children: A Rapid Review.

This review summarises the extant literature investigating the relation between traffic-related air pollution levels in and around schools and executive functioning in primary-school-aged children. An electronic search was conducted using Web of Science, Scopus, and Education Literature Datasets databases (February 2020). Review articles were also searched, and forwards and backwards searches of identified studies were performed. Included papers were assessed for quality. We included 9 separate studies (published in 13 papers). Findings suggest that indoor and outdoor particulate matter with a diameter of 2.5 μm or less (PM2.5) negatively influences executive function and academic achievement and that indoor and outdoor nitrogen dioxide (NO2) adversely affects working memory. Evidence for the effects of particulate matter with a diameter of 10 μm or less (PM10) is limited but suggests potential wide-ranging negative effects on attention, reasoning, and academic test scores. Air pollution in and around schools influences executive function and appears to impede the developmental trajectory of working memory. Further research is required to establish the extent of these effects, reproducibility, consequences for future attainment, and place within the wider context of cognitive development.

The Community Assessment of Freeway Exposure and Health Studies: Minimising Exposure to Traffic-related Air Pollution

People who live close to busy roads and highways are exposed to high levels of traffic-related air pollution. This puts them at risk of significant health difficulties such as high blood pressure, heart attacks and cancer. The Community Assessment of Freeway Exposure and Health Studies led by Dr Doug Brugge from the University of Connecticut represent community-engaged research into the biological impact of high exposure to pollution and importantly, possible solutions to this. This work has shown that high-efficiency particulate arrestance filters are one promising intervention for minimising exposure to pollution and thus improving health.

Traffic-related air pollution associated pulmonary pathophysiologic changes and cardiac injury in elderly patients with COPD

Traffic-related air pollution (TRAP) has shown enormous environmental toxicity, but its cardiorespiratory health impact on chronic obstructive pulmonary disease (COPD) has been less studied. We followed a panel of 45 COPD patients with 4 repeated clinical visits across 14 months in a traffic-predominated urban area of Beijing, China, with concurrent measurements of TRAP metrics (fine particulate matter, black carbon, oxides of nitrogen and carbon monoxide). Linear mixed-effect models were performed to evaluate the associations and potential pathways linking traffic pollution to indicators of spirometry, cardiac injury, inflammation and oxidative stress. We observed that interquartile range increases in moving averages of TRAP exposures at prior up to 7 days were associated with significant reductions in large and small airway functions, namely decreases in forced vital capacity of 3.1–9.3% and forced expiratory flow 25–75% of 5.9–16.4%. Higher TRAP levels were also associated with worsening of biomarkers relevant to lung injury (hepatocyte growth factor and surfactant protein D) and cardiac injury (high-sensitivity cardiac troponin I, B-type natriuretic peptide and soluble ST2), as well as enhanced airway/systemic inflammation and oxidative stress. Mediation analyses showed that TRAP exposures may prompt cardiac injury, possibly via worsening pulmonary pathophysiology. These findings highlight the importance of traffic pollution control priority in urban areas.

Understanding the environmental factors related to the decrease in Pediatric Emergency Department referrals for acute asthma during the SARS-CoV-2 pandemic.

BackgroundLockdown measures during the SARS‐CoV‐2 pandemic determined radical changes to behavioral and social habits, that were reflected by a reduction in the transmission of respiratory pathogens and in anthropogenic atmospheric emissions.ObjectiveThis ecological study aims to provide a descriptive evaluation on how restrictive measures during the SARS‐CoV‐2 pandemic impacted Pediatric Emergency Department (PED) referrals for asthma exacerbations, and their potentially associated environmental triggers in Bologna, a densely populated urban area in Northern Italy.MethodsFiles of children evaluated for acute asthma during 2015 to 2020 at the PED of Sant'Orsola University Hospital of Bologna were retrospectively reviewed. Historical daily concentration records of particulate (PM2.5, PM10) and gaseous (NO2, C6H6) air pollutants, and pollen were concurrently evaluated, including specific PM chemical tracers for traffic‐related air pollution (TRAP).ResultsIn 2020, asthma‐related PED referrals decreased compared to referral rates of the previous 5 years (p < 0.01). This effect was particularly marked during the first lockdown period (March to May), when the drastic drop in PED referrals was associated with a reduction of high‐priority cases up to 85% and by 54%, on average. A concomitant reduction in the concentrations of traffic‐related air pollutants was observed in the range of 40%–60% (p < 0.01).ConclusionsThe lower rate of asthma exacerbations in childhood was in this study paralleled with reduced TRAP levels during the pandemic. Synergic interactions of the multiple consequences of lockdowns likely contributed to the reduced exacerbations, including decreased exposure to ambient pollutants and fewer respiratory infections, identified as the most important factor in the literature.

Particulate matter pollution at traffic hotspots of Accra: levels, exposure experiences of street traders, and associated respiratory and cardiovascular symptoms

BACKGROUND AND AIM: There is limited studies on health effects of street trading in spite of common knowledge that individuals engaged in the trade are exposed to high levels of traffic-related air pollution per their mode of operation, and also the fact that the venture is a dominant occupation in cities of Sub-Saharan Africa and other developing regions. We characterized particulate matter (PM) pollution levels at traffic hotspots of Accra, Ghana during the dry and wet seasons, and assessed exposure experiences of street traders. METHODS: A cross-sectional study was conducted among 236 street traders operating along six selected traffic routes of Accra and a comparison group of 186 office workers. PurpleAir PA-II monitors was used to measure PM levels at the selected traffic routes. We estimated annual PM exposure of street traders using assigned seasonal PM2.5 and PM10 levels, and information collected in a structured questionnaire on activity patterns of the street traders. RESULTS:PM levels at Accra traffic hotspots were high in both seasons. 1ug/m3 increase in PM2.5 exposure increased respiratory, cardiovascular and overall symptoms by a score of 0.0001 (95% CI: 0.00004, 0.0002), 0.00008 (95% CI: 0.00002, 0.0001) and 0.0002 (95% CI: 0.00008, 0.0003), respectively. Compared to office workers, high PM2.5 exposure among street traders was statistically associated with increased odds of coughing, catarrh, sneezing, rapid heart beating, sharp chest pains, irregular heartbeat, fainting spells, headaches and dizziness. Low and medium PM2.5 exposure was also statistically associated with increased odds of dermatitis and rapid heart beating, and sharp chest pains, respectively. CONCLUSIONS:We found consistent evidence that PM2.5 exposure among street traders increases occurrence of self-reported respiratory and cardiovascular symptoms. We also provide indicative measurements of PM levels at traffic hotspots of a rapidly growing SSA city with heavy vehicular traffic and yet, limited air quality monitoring capacity. KEYWORDS: Street trader, Traffic-related air pollution, Particulate matter, Respiratory symptoms, Cardiovascular symptoms

The effects of traffic-related air pollutants on chronic obstructive pulmonary disease in the community-based general population

BackgroundPrevious studies have shown inconsistent results regarding the impact of traffic pollution on the prevalence of chronic obstructive pulmonary disease (COPD). Therefore, using frequency matching and propensity scores, we explored the association between traffic pollution and COPD in a cohort of 8284 residents in a major agricultural county in Taiwan.MethodsAll subjects completed a structured questionnaire interview and health checkups. Subjects with COPD were identified using Taiwan National Health Insurance Research Databases. A hybrid kriging/LUR model was used to identify levels of traffic-related air pollutants (PM2.5 and O3). Multiple logistic regression models were used to calculate the prevalence ratios (PRs) of COPD and evaluate the role played by traffic-related indices between air pollutants and COPD. The distributed lag nonlinear model was applied in the analysis; we excluded current or ever smokers to perform the sensitivity analysis.ResultsIncreased PRs of COPD per SD increment of PM2.5 were 1.10 (95% CI 1.05–1.15) and 1.25 (95% CI 1.13–1.40) in the population with age and sex matching as well as propensity-score matching, respectively. The results of the sensitivity analysis were similar between the single and two pollutant models. PM2.5 concentrations were significantly associated with traffic flow including sedans, buses, and trucks (p < 0.01). The higher road area and the higher PM2.5 concentrations near the subject’s residence correlated with a greater risk of developing COPD (p for interaction < 0.01).ConclusionsOur results suggest that long-term exposure to traffic-related air pollution may be positively associated with the prevalence of COPD.Graphical abstract

A randomized crossover trial of HEPA air filtration to reduce cardiovascular risk for near highway residents: Methods and approach

BackgroundNear highway residents are exposed to elevated levels of traffic-related air pollution (TRAP), including ultrafine particles, which are associated with adverse health effects. The efficacy of using in-home air filtration units that reduce exposure and potentially yield health benefits has not been tested in a randomized controlled trial. MethodsWe will conduct a randomized double-blind crossover trial of portable air filtration units for 200 adults 30 years and older who live in near-highway homes in Somerville, MA, USA. We will recruit participants from 172 households. The intervention periods will be one month of true or sham filtration, followed by a one-month wash out period and then a month of the alternate intervention. The primary health outcome will be systolic blood pressure (BP); secondary outcome measures will include diastolic and central BP, C-Reactive Protein (CRP) and D-dimer. Reasons for success or failure of the intervention will be evaluated in a subset of homes using indoor/outdoor monitoring for particulate pollution, personal monitoring, size and composition of particulate pollution, tracking of time spent in the room with the filter, and interviews for qualitative feedback. ResultsThis trial has begun recruitment and is expected to take 2–3 years to be completed. Recruitment has been particularly challenging because of additional precautions required by the COVID-19 pandemic. DiscussionThis study has the potential to shed light on the value of using portable air filtration in homes close to highways to reduce exposure to TRAP and whether doing so has benefits for cardiovascular health.

Particulate matter pollution at traffic hotspots of Accra, Ghana: levels, exposure experiences of street traders, and associated respiratory and cardiovascular symptoms.

There are limited studies on the health effects of street trading in spite of common knowledge that individuals engaged in the trade are exposed to high levels of traffic-related air pollution per their mode of operation, and also the fact that the venture is a dominant occupation in cities of Sub-Saharan Africa (SSA) and other developing regions. We characterized particulate matter (PM) pollution levels at traffic hotspots of Accra, Ghana during the dry and wet seasons, and assessed exposure experiences of street traders. A cross-sectional study was conducted among 236 street traders operating along six selected traffic routes of Accra and a comparison group of 186 office workers. PurpleAir PA-II monitors were used to measure PM levels at the selected traffic routes. We estimated annual PM2.5 exposure of street traders using assigned seasonal PM2.5 levels, and information collected in a structured questionnaire on their activity patterns. Outcomes investigated were self-reported respiratory and cardiovascular symptoms. PM levels at Accra traffic hotspots were high in both seasons. 1 ug/m3 increase in PM2.5 exposure increased respiratory, cardiovascular, and overall symptoms by a factor of 0.00027 (95% CI: 0.00012, 0.00041), 0.00022 (95% CI: 0.00007, 0.00036), and 0.00048 (95% CI: 0.00023, 0.00073), respectively. Compared to office workers, high PM2.5 exposure among street traders was associated with increased odds of coughing, catarrh (postnasal drip), sneezing, rapid heart beating, irregular heartbeat, sharp chest pains, fainting spells, headaches, and dizziness. Low and medium PM2.5 exposure was associated with increased odds of dermatitis, rapid heart beating, and irregular heartbeat, and sharp chest pains, respectively. We found consistent evidence that PM2.5 exposure among street traders increases the occurrence of respiratory and cardiovascular symptoms. We also provide indicative measurements of PM levels at traffic hotspots of a rapidly growing SSA city with heavy vehicular traffic and yet, limited air quality monitoring capacity.

Impact of the COVID-19 lockdown on roadside traffic-related air pollution in Shanghai, China

The outbreak of COVID-19 has significantly inhibited global economic growth and impacted the environment. Some evidence suggests that lockdown strategies have significantly reduced traffic-related air pollution (TRAP) in regions across the world. However, the impact of COVID-19 on TRAP on roadside is still not clearly understood. In this study, we assessed the influence of the COVID-19 lockdown on the levels of traffic-related air pollutants in Shanghai. The pollution data from two types of monitoring stations—roadside stations and non-roadside stations were compared and evaluated. The results show that NO2, PM2.5, PM10, and SO2 had reduced by ~30–40% at each station during the COVID-19 pandemic in contrast to 2018–2019. CO showed a moderate decline of 28.8% at roadside stations and 16.4% at non-roadside stations. In contrast, O3 concentrations increased by 30.2% at roadside stations and 5.7% at non-roadside stations. This result could be resulted from the declined NOx emissions from vehicles, which lowered O3 titration. Full lockdown measures resulted in the highest reduction of primary pollutants by 34–48% in roadside stations and 18–50% in non-roadside stations. The increase in O3 levels was also the most significant during full lockdown by 64% in roadside stations and 33% in non-roadside stations due to the largest decrease in NO2 precursors, which promote O3 formation. Additionally, Spearman's rank correlation coefficients between NO2 and other pollutants significantly decreased, while the values between NO2 and O3 increased at roadside stations.

Childhood exposure to polluted neighborhood environments and intergenerational income mobility, teenage birth, and incarceration in the USA

This paper joins a growing body of research linking measures of the physical environment to population well-being, with a focus on neighborhood toxins. Extending a national database on the social mobility of American children growing up in over 70,000 Census tracts, we explore the association between childhood exposure to two forms of pollutants and three socioeconomic outcomes for African Americans, whites, and Latinos. We find that children who grew up in Census tracts with higher levels of traffic-related air pollution and housing-derived lead risk experienced lower adult incomes on average relative to their parents and higher likelihoods of being incarcerated as an adult or having children as teenagers, after controlling for standard socio-demographic characteristics and metropolitan-level effects. The spatial distribution of these two pollutants is surprisingly different, however, with air pollution varying mostly between regions of the country while lead risk varies dramatically between neighborhoods within the same city. Yet, each pollutant predicts the three aspects of social mobility similarly, and we show important disparities in exposure by race. Differential exposure to environmental toxins in childhood may be a contributor to racial inequality in socioeconomic outcomes among adults.