Characterization of particle number concentrations and PM2.5 in a school: influence of outdoor air pollution on indoor air

Background, Aim and Scope The impact of air pollution on school children’s health is currently one of the key foci of international and national agencies. Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins and are deposited deeply in the respiratory tract. Materials and methods In this study, an intensive sampling campaign of indoor and outdoor airborne particulate matter was carried out in a primary school in February 2006 to investigate indoor and outdoor particle number (PN) and mass concentrations (PM2.5), and particle size distribution, and to evaluate the influence of outdoor air pollution on the indoor air. Results For outdoor PN and PM2.5, early morning and late afternoon peaks were observed on weekdays, which are consistent with traffic rush hours, indicating the predominant effect of vehicular emissions. However, the temporal variations of outdoor PM2.5 and PN concentrations occasionally showed extremely high peaks, mainly due to human activities such as cigarette smoking and the operation of mower near the sampling site. The indoor PM2.5 level was mainly affected by the outdoor PM2.5 (r = 0.68, p<0.01), whereas the indoor PN concentration had some association with outdoor PN values (r = 0.66, p<0.01) even though the indoor PN concentration was occasionally influenced by indoor sources, such as cooking, cleaning and floor polishing activities. Correlation analysis indicated that the outdoor PM2.5 was inversely correlated with the indoor to outdoor PM2.5 ratio (I/O ratio) (r = -0.49, p<0.01), while the indoor PN had a weak correlation with the I/O ratio for PN (r = 0.34, p<0.01). Discussion and Conclusions The results showed that occupancy did not cause any major changes to the modal structure of particle number and size distribution, even though the I/O ratio was different for different size classes. The I/O curves had a maximum value for particles with diameters of 100 – 400 nm under both occupied and unoccupied scenarios, whereas no significant difference in I/O ratio for PM2.5 was observed between occupied and unoccupied conditions. Inspection of the size-resolved I/O ratios in the preschool centre and the classroom suggested that the I/O ratio in the preschool centre was the highest for accumulation mode particles at 600 nm after school hours, whereas the average I/O ratios of both nucleation mode and accumulation mode particles in the classroom were much lower than those of Aitken mode particles. Recommendations and Perspectives The findings obtained in this study are useful for epidemiological studies to estimate the total personal exposure of children, and to develop appropriate control strategies for minimizing the adverse health effects on school children

Inhaled particle counts on bicycle commute routes of low and high proximity to motorised traffic

Frequent exposure to ultrafine particles (UFP) is associated with detrimental effects on cardiopulmonary function and health. UFP dose and therefore the associated health risk are a factor of exposure frequency, duration, and magnitude of (therefore also proximity to) a UFP emission source. Bicycle commuters using on-road routes during peak traffic times are sharing a microenvironment with high levels of motorised traffic, a major UFP emission source. Inhaled particle counts were measured along popular pre-identified bicycle commute route alterations of low (LOW) and high (HIGH) motorised traffic to the same inner-city destination at peak commute traffic times. During commute, real-time particle number concentration (PNC; mostly in the UFP range) and particle diameter (PD), heart and respiratory rate, geographical location, and meteorological variables were measured. To determine inhaled particle counts, ventilation rate was calculated from heart-rate-ventilation associations, produced from periodic exercise testing. Total mean PNC of LOW (compared to HIGH) was reduced (1.56 x e4 ± 0.38 x e4 versus 3.06 x e4 ± 0.53 x e4 ppcc; p = 0.012). Total estimated ventilation rate did not vary significantly between LOW and HIGH (43 ± 5 versus 46 ± 9 L•min; p = 0.136); however, due to total mean PNC, accumulated inhaled particle counts were 48% lower in LOW, compared to HIGH (7.6 x e8 ± 1.5 x e8 versus 14.6 x e8 ± 1.8 x e8; p = 0.003). For bicycle commuting at peak morning commute times, inhaled particle counts and therefore cardiopulmonary health risk may be substantially reduced by decreasing exposure to motorised traffic, which should be considered by both bicycle commuters and urban planners

Impact of Residential Real-World Wood Stove Operation on Air Quality concerning PM2.5 Immission

In Germany, the number of small wood-burning combustion plants was around 11 million in 2020. The PM2.5 immissions caused by the operation of these combustion plants are already about as high as those from traffic exhaust gases. Thus, particulate matter immissions occur not only on busy roads but also in residential areas. Since there are few official measuring stations for PM2.5 in residential areas and suburbs, this study determined PM2.5 concentrations from November 2020 to June 2021 at three stations (urban, suburban, and residential) in the Karlsruhe area. Simultaneous measurements of PM2.5 at the three locations have been implemented to determine short-term (peaks), medium-term, and long-term particulate matter levels and to assign them to sources by observation, considering wind direction. Illustratively, PM2.5 immission levels in January and May 2021 were compared in this paper. The comparison of the particulate matter immissions measured in the urban and residential area in January revealed that PM2.5 concentration peaks of up to 60 μg/m3 occurred for short periods in the residential area, especially on Fridays and in the evenings, which could be assigned towood stove operation. In the urban and suburban areas, the number of the immission peaks was lower by 70–80%, and the peak concentrations were also lower by an average of 13–18%. However, the high short-term peaks have no significant impact when calculating the PM2.5 annual average according to the current limit value regulation (39. BImSchV)

Long-term effects of mitigation measures and meteorological conditions on aerosol characteristics in Beijing, China

The aim of this dissertation was to study the characteristics and development of Beijing aerosol pollution and to evaluate the effects of governmental mitigation measures thereon, while considering meteorological conditions. Based on a decade of aerosol measurements, chemical elements, black carbon (BC), particulate mercury (HgP) and size distribution of aerosol particles were studied to quantify the effects of these measures. Gallium was recommended as a tracer for coal combustion

Atmospheric particulate measurements in Norfolk, Virginia

Characterization of atmospheric particulates was conducted at a site near the center of Norfolk, Virginia. Air quality was measured in terms of atmospheric mass loading, particle size distribution, and particulate elemental composition for a period of 2 weeks. The objectives of this study were (1) to establish a mean level of air quality and deviations about this mean, (2) to ascertain diurnal changes or special events in air quality, and (3) to evaluate instrumentation and sampling schedules. Simultaneous measurements were made with the following instruments: a quartz crystal microbalance particulate monitor, a light-scattering multirange particle counter, a high-volume air sampler, and polycarbonate membrane filters. To assess the impact of meteorological conditions on air quality variations, continuous data on temperature, relative humidity, wind speed, and wind direction were recorded. Particulate elemental composition was obtained from neutron activation and scanning electron microscopy analyses of polycarbonate membrane filter samples. The measured average mass loading agrees reasonably well with the mass loadings determined by the Virginia State Air Pollution Control Board. There are consistent diurnal increases in atmospheric mass loading in the early morning and a sample time resolution of 1/2 hour seems necessary to detect most of the significant events

The transport of PM10 over Cape Town during high pollution episodes

PM10 is a notorious air pollutant that often degrades the air quality in Cape Town. Previous studies have attributed high concentrations of PM10 over Cape Town to local sources, neglecting the influence of remote sources. The present study investigates the influence of remote and local pollution sources to PM10 episodes over the city. The study analysed observations from Cape Town’s air quality monitoring stations and simulations from the Weather Research and Forecasting model with Chemistry (WRFChem). The observation data were used to identify PM10 episodes over the city between 2008 and 2014 and WRF-Chem was applied to simulate the atmospheric conditions and PM10 transport over southern Africa a few days before, during, and after each episode. To examine the sensitivity of the simulations to chemistry parameterisation, two chemistry parameterisation schemes were used in the study. The two schemes are RADM2 chemistry scheme coupled with the MADE/SORGAM aerosol module (RMS) and RADM2 coupled with the GOCART aerosol module (RGC). While RMS accounts for aerosol feedbacks, RGC does not. The capability of the model (with each scheme) to reproduce the PM10 concentration and wind over Cape Town was quantified by comparing the simulations with the station observation data. To identify the paths of air parcels that arrived in Cape Town during each episode, the study employed back trajectory simulations from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and from the WRF-Chem output. A third WRFChem simulation (KAYE) was performed in order to investigate the influence of idealized local emissions from Khayelitsha (one of the largest local sources of the pollutant in Cape Town) on the spatial distribution of PM10 concentration over the city. The results show that all the WRF-Chem simulations reproduce well the observed wind speed and direction over Cape Town during the episodes but struggle to reproduce the observed PM10. The simulations under-estimate the observed PM10 concentration over the city and, in most cases, reproduce peaks in PM10 concentration days earlier or later than the observations. However, the simulations agree with the HYSPLIT back-trajectory simulations that most of the air parcels over Cape Town during the episodes came from central southern Africa or the Namibian coast and travelled over the Kalahari, Namib, or both deserts before reaching Cape Town. The RMS simulations link the peaks in PM10 concentration over Cape Town with the transport of the pollutant from the north-west coast of southern Africa, featuring a coastal trough and a plume of PM10 along the coast. The study reveals that northwesterly flows provides a conducive condition for the long-range transport of PM10 to Cape Town, while south-easterly winds favour the transport of PM10 from Khayelitsha emissions to the city

An annual assessment of air quality with the CALIOPE modeling system over Spain

The CALIOPE project, funded by the Spanish Ministry of the Environment, aims at establishing an air quality forecasting system for Spain. With this goal, CALIOPE modeling system was developed and applied with high resolution (4 km × 4 km, 1 h) using the HERMES emission model (including emissions of resuspended particles from paved roads) specifically built up for Spain. The present study provides an evaluation and the assessment of the modeling system, coupling WRF-ARW/HERMES/CMAQ/BSC-DREAM8b for a full-year simulation in 2004 over Spain. The evaluation focuses on the capability of the model to reproduce the temporal and spatial distribution of gas phase species (NO2, O3, and SO2) and particulate matter (PM10) against ground-based measurements from the Spanish air quality monitoring network. The evaluation of the modeling results on an hourly basis shows a strong dependency of the performance of the model on the type of environment (urban, suburban and rural) and the dominant emission sources (traffic, industrial, and background). The O3 chemistry is best represented in summer, when mean hourly variability and high peaks are generally well reproduced. The mean normalized error and bias meet the recommendations proposed by the United States Environmental Protection Agency (US-EPA) and the European regulations. Modeled O3 shows higher performance for urban than for rural stations, especially at traffic stations in large cities, since stations influenced by traffic emissions (i.e., high-NOx environments) are better characterized with a more pronounced daily variability. NOx/O3 chemistry is better represented under non-limited-NO2 regimes. SO2 is mainly produced from isolated point sources (power generation and transformation industries) which generate large plumes of high SO2 concentration affecting the air quality on a local to national scale where the meteorological pattern is crucial. The contribution of mineral dust from the Sahara desert through the BSC-DREAM8b model helps to satisfactorily reproduce episodic high PM10 concentration peaks at background stations. The model assessment indicates that one of the main air quality-related problems in Spain is the high level of O3. A quarter of the Iberian Peninsula shows more than 30 days exceeding the value 120 μg m−3 for the maximum 8-h O3 concentration as a consequence of the transport of O3 precursors downwind to/from the Madrid and Barcelona metropolitan areas, and industrial areas and cities in the Mediterranean coast

Air Pollution Meteorology

Although air pollution is usually linked with human activities, natural processes may also lead to major concentrations of hazardous substances in the low atmosphere. Pollutant levels may be reduced when emissions can be controlled. However, the impact of meteorological variables on the concentrations measured may be noticeable, and these variables cannot be controlled. This book is devoted to the influence of meteorological processes on the pollutant concentrations recorded in the low atmosphere. Measurements, cycles, statistical procedures, as well as specific variables such as the synoptic pattern, temperature inversion, or the calculation of back-trajectories, are considered in the studies included in this book to highlight the relationship between air pollution and meteorological variables. In addition, the state of the art of this subject following meteorological scales, from micro to macro-scale, is presented. Consequently, this book focuses on applied science and seeks to further current knowledge of what contribution meteorological processes make to the concentrations measured in order to achieve greater control over air pollution

Urban air pollution and emergency room admissions for respiratory symptoms: a case-crossover study in Palermo, Italy

<p>Abstract</p> <p>Background</p> <p>Air pollution from vehicular traffic has been associated with respiratory diseases. In Palermo, the largest metropolitan area in Sicily, urban air pollution is mainly addressed to traffic-related pollution because of lack of industrial settlements, and the presence of a temperate climate that contribute to the limited use of domestic heating plants. This study aimed to investigate the association between traffic-related air pollution and emergency room admissions for acute respiratory symptoms.</p> <p>Methods</p> <p>From January 2004 through December 2007, air pollutant concentrations and emergency room visits were collected for a case-crossover study conducted in Palermo, Sicily. Risk estimates of short-term exposures to particulate matter and gaseous ambient pollutants including carbon monoxide, nitrogen dioxide, and sulfur dioxide were calculated by using a conditional logistic regression analysis.</p> <p>Results</p> <p>Emergency departments provided data on 48,519 visits for respiratory symptoms. Adjusted case-crossover analyses revealed stronger effects in the warm season for the most part of the pollutants considered, with a positive association for PM₁₀(odds ratio = 1.039, 95% confidence interval: 1.020 - 1.059), SO₂(OR = 1.068, 95% CI: 1.014 - 1.126), nitrogen dioxide (NO₂: OR = 1.043, 95% CI: 1.021 - 1.065), and CO (OR = 1.128, 95% CI: 1.074 - 1.184), especially among females (according to an increase of 10 μg/m³in PM₁₀, NO₂, SO₂, and 1 mg/m³in CO exposure). A positive association was observed either in warm or in cold season only for PM₁₀.</p> <p>Conclusions</p> <p>Our findings suggest that, in our setting, exposure to ambient levels of air pollution is an important determinant of emergency room (ER) visits for acute respiratory symptoms, particularly during the warm season. ER admittance may be considered a good proxy to evaluate the adverse effects of air pollution on respiratory health.</p

Ambient Air Quality Assessment in the Grand Casablanca Area (Morocco): Impact of Road Traffic Emissions for the 2013-2016 Period

Air Pollution is a serious hazard worldwide especially in urban areas. Road traffic is the main cause of pollution in agglomerations that are confronted to an excess of pollutants due to traffic intensity and the dominance of diesel cars. This paper presents the assessment of road traffic pollution in the Grand Casablanca area. Data used are the result of simultaneous measurements at thirteen sites located in the Grand Casablanca. Available data cover 4 years period (2013-2016). Traffic-related air pollutants are reviewed in order to assess their impact on the local air quality. It include nitrogen dioxide (NO2), particulate matter (PM10), carbon monoxide (CO) and Benzene (C6H6). Annual evolutions are presented and compared to national air quality standards; NO2 annual trends are also evaluated. The [NO]/[NO2] emissions ratio calculation allows then to characterize the measurement sites against road traffic. The paper focuses on determining the contribution of road traffic emissions on air quality modifying; we found spatial variability in traffic pollutants. The results pointed out that road traffic and conditions are the main causes of air pollution in the area and the analysis provide a quick view of the relatively critical areas that need more action to reduce this pollution