A benchmark for numerical scheme validation of airborne particle exposure in street canyons

Estimating the economic value of ultrafine particle information: a contingent valuation method

Global concern regarding ultrafine particles (UFPs), which are particulate matter (PM) with a diameter of less than 100 nm, is increasing. These particles are difficult to measure using the current methods because their characteristics are different from those of other air pollutants. Therefore, a new monitoring system is required to obtain accurate UFP information, which will raise the financial burden of the government and people. In this study, we estimated the economic value of UFP information by evaluating the willingness-to-pay (WTP) for the UFP monitoring and reporting system. We used the contingent valuation method (CVM) and the one-and-one-half-bounded dichotomous choice (OOHBDC) spike model. We analyzed how the respondents' socio-economic variables, as well as their cognition level of PM, affected their WTP. Therefore, we collected WTP data of 1040 Korean respondents through an online survey. The estimated mean WTP for building a UFP monitoring and reporting system is KRW 6958.55-7222.55 (USD 6.22-6.45) per household per year. We found that people satisfied with the current air pollutant information, and generally possessing relatively greater knowledge of UFPs, have higher WTP for a UFP monitoring and reporting system. We found that people are willing to pay more than the actual installation and operating costs of current air pollution monitoring systems. If the collected UFP data is disclosed in an easily accessible manner, as is current air pollutant data, it will be possible to secure more public acceptance for expanding the UFP monitoring and reporting system nationwide.

Urban atmospheric levels of allergenic pollen: comparison of two locations in Salamanca, Central-Western Spain

In this paper, differences in the pollen levels detected in two parts of Salamanca (a city in central-western Spain) have been revealed using two volumetric samplers. One sampler was located in the city centre and the other in a semi-natural zone. The two sampling devices were separated by a distance of 1.4 km. During the two-year study period, the most abundant allergenic pollen type was Poaceae, with peak values being detected in May. Maximum values were registered between April and June. The values obtained in both zones with regard to pollen seasonality were similar during the peak day, but the abundance of pollen grains detected in the semi-urban was higher, except for Olea pollen type. The atmospheric pollen season was similar in duration, except for some types belonging to the genera Plantago and Urticaceae, which showed divergent values most probably due to the influence of climatic conditions. The meteorological parameter most significantly correlated to pollen concentration was temperature, being negative for winter species and positive for plants preferring warmer climates. In addition, rainfall showed a negative correlation in most cases due to the influence of precipitation on the behaviour of atmospheric airborne pollen.

Deep Inorganic Fraction Characterization of PM10, PM2.5, and PM1 in an Industrial Area Located in Central Italy by Means of Instrumental Neutron Activation Analysis

Atmospheric pollution is an important task in life sciences and, in particular, inorganic fraction characterization is considered as an important issue in this field. For many years, researchers have focused their attention on the particulate matter fraction below 10 μm: in this case, our attention was also focused on PM2.5 (i.e., particles with a size fraction smaller than 2.5 μm) and PM1 (below 1 μm). This paper would like to investigate whether the element accumulation in different granulometric fractions is similar, or whether there are behavior dissimilarities. Among the different analytical techniques, the instrumental neutron activation analysis, an instrumental nuclear method, was used for its peculiarity of investigating the sample without performing any chemical-physical treatment. Forty-two daily samples using the reference method were collected, 15 filters for PM10, 18 for PM2.5, and 12 for PM1; the filters, along with primary standards and appropriate standard reference materials, were irradiated at the National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) R.C.-Casaccia’s Triga MARK II reactor. The irradiations carried out in the Rabbit and Lazy Susan channels allowed for the investigation of 36 elements and the relative Pearson’s correlations between elements and PM-fractions (PM10 vs. PM2.5 was good, whereas PM10 vs. PM1 was the worst). The Enrichment Factors were studied for the three fractions to show how anthropogenic sources have affected the element content. A comparison between these data and element levels determined worldwide showed that our concentrations were lower than those determined in similar scenarios. Furthermore, a statistical approach (source discrimination, hierarchical cluster analysis, principal component analysis) has allowed us to identify similarities between the samples: the airborne filters can be divided in two main groups (i.e., one made of PM10 and PM2.5 filters and one only of PM1 filters), meaning a different element contribution to this fraction coming from other sources present at the site.

Evaluation of the Submicron Particles Distribution Between Mountain and Urban Site: Contribution of the Transportation for Defining Environmental and Human Health Issues

Transportation is one of the main causes of atmospheric pollution, especially in downtown big cities. Researchers usually point their attention to gaseous and/or particulate matter pollutants. This paper investigated the role of submicron particles, particularly the fraction ranging between 5–560 nm, in aerosol chemistry for identifying the contribution of autovehicular traffic and investigating the doses deposited in the human respiratory tract. Measurements carried out by two Fast Mobility Particle Sizer (FMPS, TSI) analyzers were simultaneously performed at two different sampling sites (an urban and a mountain site) during workdays and weekends in July. The total particle number (2–2.5 times higher in the urban site), the aerosol size distribution (different modes during the day), and the ultrafine/non-ultrafine particle ratios (ranging between 2–4 times between two sites) were investigated and discussed in relationship to the high autovehicular traffic in Rome and the almost null anthropogenic emissions at the mountain site, as well as the differing contributions of both to the “fresh nucleation” and to “aged aerosol”. Furthermore, the regional cumulative number doses deposited in the human respiratory tract were studied for both sites: The difference between the urban/mountain site was very high (up to 15 fold), confirming the pollutant role of transportation.

A novel approach to evaluate the lung cancer risk of airborne particles emitted in a city

Air quality still represents a main threat to human health in cities. Even in developed countries, decades of air pollution control not yet allowed to reduce pollutant concentrations in urban areas adequately. Indeed, high airborne particle concentrations are measured in several European cities; this is a main issue since particles represent a carrier for carcinogenic compounds. Numerous researches measuring the exposure to the different aerosol metrics in urban areas were recently performed, nonetheless, few data on the lung cancer risk in such environments are available. In the present paper a novel approach to evaluate the lung cancer risk related to the airborne particles emitted by the different sources located in a city is proposed and applied to a pilot case-study (i.e. an Italian city). In particular, an existing lung cancer risk model was modified and applied to assess the particle-related lung cancer "emitted" by the different sources of the city using pollutant emission factors provided by accredited emission inventory databases. Therefore, the average toxicity of the particles emitted by the city (i.e. lung cancer slope factor) and the lung cancer risk globally emitted by the city, expressed as new cases of lung cancer, were evaluated. The proposed emission inventory also allowed to identify and localize the main contributors to the overall risk emitted in a city. As an example, for the city under investigation, the research revealed that the main contributor, amongst the sources considered, is the vehicular traffic which is characterized by a lower mass fraction of carcinogenic compounds but a much higher sub-micron particle emission with respect to the other sources.

Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon

The vertical profiles of lung deposited surface area (LDSA) concentration were measured in an urban street canyon in Helsinki, Finland, by using an unmanned aerial system (UAS) as a moving measurement platform. The street canyon can be classified as an avenue canyon with an aspect ratio of 0.45 and the UAS was a multirotor drone especially modified for emission measurements. In the experiments of this study, the drone was equipped with a small diffusion charge sensor capable of measuring the alveolar LDSA concentration of particles. The drone measurements were conducted during two days on the same spatial location at the kerbside of the street canyon by flying vertically from the ground level up to an altitude of 50 m clearly above the rooftop level (19 m) of the nearest buildings. The drone data were supported by simultaneous measurements and by a two-week period of measurements at nearby locations with various instruments. The results showed that the averaged LDSA concentrations decreased approximately from 60 μm²/cm³ measured close to the ground level to 36-40 μm²/cm³ measured close to the rooftop level of the street canyon, and further to 16-26 μm²/cm³ measured at 50 m. The high-resolution measurement data enabled an accurate analysis of the functional form of vertical profiles both in the street canyon and above the rooftop level. In both of these regions, exponential fits were used and the parameters obtained from the fits were thoroughly compared to the values found in literature. The results of this study indicated that the role of turbulent mixing caused by traffic was emphasized compared to the street canyon vortex as a driving force of the dispersion. In addition, the vertical profiles above the rooftop level showed a similar exponential decay compared to the profiles measured inside the street canyon.

Lung cancer risk assessment due to traffic-generated particles exposure in urban street canyons: A numerical modelling approach

Combustion-generated nanoparticles are responsible for negative health effects due to their ability to penetrate in the lungs, carrying toxic compounds with them. In urban areas, the coexistence of nanoparticle sources and particular street-building configurations can lead to very high particle exposure levels. In the present paper, an innovative approach for the evaluation of lung cancer incidence in street canyon due to exposure to traffic-generated particles was proposed. To this end, the literature-available values of particulate matter, PAHs and heavy metals emitted from different kind of vehicles were used to calculate the Excess Lifetime Cancer Risk (ELCR) at the tailpipe. The estimated ELCR was then used as input data in a numerical CFD (Computational Fluid Dynamics) model that solves the mass, momentum, turbulence and species transport equations, in order to evaluate the cancer risk in every point of interest inside the street canyon. Thus, the influence of wind speed and street canyon geometry (H/W, height of building, H and width of the street, W) on the ELCR at street level was evaluated by means of a CFD simulation. It was found that the ELCR calculated on the leeward and windward sides of the street canyon at a breathable height of 1.5 m, for people exposed 15 min per day for 20 years, is equal to 1.5 × 10^-5 and 4.8 × 10^-6, respectively, for wind speed of 1 m/s and H/W equal to 1. The ELCR at street level results higher on the leeward side for aspect ratios equal to 1 and 3, while for aspect ratio equal to 2 it is higher on the windward side. In addition, the simulations showed that with the increasing of wind speed the ELCR becomes lower everywhere in the street canyon, due to the increased in dispersion.

Temporal evolution of ultrafine particles and of alveolar deposited surface area from main indoor combustion and non-combustion sources in a model room

Aerosol number size distributions, PM mass concentrations, alveolar deposited surface areas (ADSAs) and VOC concentrations were measured in a model room when aerosol was emitted by sources frequently encountered in indoor environments. Both combustion and non-combustion sources were considered. The most intense aerosol emission occurred when combustion sources were active (as high as 4.1×10⁷particlescm^-3 for two meat grilling sessions; the first with exhaust ventilation, the second without). An intense spike generation of nucleation particles occurred when appliances equipped with brush electric motors were operating (as high as 10⁶particlescm^-3 on switching on an electric drill). Average UFP increments over the background value were highest for electric appliances (5-12%) and lowest for combustion sources (as low as -24% for tobacco cigarette smoke). In contrast, average increments in ADSA were highest for combustion sources (as high as 3.2×10³μm²cm^-3 for meat grilling without exhaust ventilation) and lowest for electric appliances (20-90μm²cm^-3). The health relevance of such particles is associated to their ability to penetrate cellular structures and elicit inflammatory effects mediated through oxidative stress in a way dependent on their surface area. The highest VOC concentrations were measured (PID probe) for cigarette smoke (8ppm) and spray air freshener (10ppm). The highest PM mass concentration (PM₁) was measured for citronella candle burning (as high as 7.6mgm^-3).

Determination of the vertical profile of particle number concentration adjacent to a motorway using an unmanned aerial vehicle

A quantitative assessment of the vertical profile of traffic pollution, specifically particle number concentration (PNC), in an open space adjacent to a motorway was possible for the first time, to the knowledge of the authors, using an Unmanned Aerial Vehicle (UAV) system. Until now, traffic pollution has only been measured at ground level while the vertical distribution, is limited to studies conducted from buildings or fixed towers and balloons. This new UAV system demonstrated that the PNC sampled during the period form 10 a.m. to 4 p.m., outside the rush hours with a constant traffic flow, increased from a concentration of 2 × 10⁴ p/cm³ near the ground up to 10 m, and then sharply decreased attaining a steady value of 4 × 10³ p/cm³ beyond a height of about 40 m. While more comprehensive investigations would be warranted under different conditions, such as topography and vehicle and fuel type, this finding is of great significance, given that it demonstrates the impact of traffic emissions on human exposure, but less so to pollution within the upper part of the boundary layer.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR.

Traffic aerosol lobar doses deposited in the human respiratory system

Aerosol pollution in urban environments has been recognized to be responsible for important pathologies of the cardiovascular and respiratory systems. In this perspective, great attention has been addressed to Ultra Fine Particles (UFPs < 100 nm), because they efficiently penetrate into the respiratory system and are capable of translocating from the airways into the blood circulation. This paper describes the aerosol regional doses deposited in the human respiratory system in a high-traffic urban area. The aerosol measurements were carried out on a curbside in downtown Rome, on a street characterized by a high density of autovehicular traffic. Aerosol number-size distributions were measured by means of a Fast Mobility Particle Sizer in the range from 5.6 to 560 nm with a 1 s time resolution. Dosimetry estimates were performed with the Multiple-Path Particle Dosimetry model by means of the stochastic lung model. The exposure scenario close to traffic is represented by a sequence of short-term peak exposures: about 6.6 × 10¹⁰ particles are deposited hourly into the respiratory system. After 1 h of exposure in proximity of traffic, 1.29 × 10¹⁰, 1.88 × 10¹⁰, and 3.45 × 10¹⁰ particles are deposited in the head, tracheobronchial, and alveolar regions. More than 95 % of such doses are represented by UFPs. Finally, according to the greater dose estimated, the right lung lobes are expected to be more susceptible to respiratory pathologies than the left lobes.

Dynamic of submicrometer particles in urban environment

Many studies show that particle toxicity increases with decreasing their size, emphasizing the role of submicrometric particles, in particular of ultrafine particles (<100 nm). In fact, particles greater than 2.5 μm are quickly removed through dry and wet deposition on the timescale of hours whereas submicrometer particles may reside in atmosphere for weeks, penetrate in indoor environment, and be long-range transported. High aerosol size resolution measurements are important for a correct assessment of the deposition efficiency in the human respiratory system, and time resolution is another important requisite. Starting from such considerations, time-resolved aerosol particle number size distributions have been measured in downtown Rome. Fast Mobility Particle Sizer (FMPS) and Scanning Mobility Particle Sizer (SMPS) measurements have been carried out at the INAIL's Pilot Station, located in downtown Rome, in an area characterized by high density of autovehicular traffic. The two instruments have allowed to investigate deeply the urban aerosol in the range of 5.6-560 and 3.5-117 nm, respectively. In particular, the FMPS measurements have confirmed the interpretation about the transition phenomena in the time interval of few seconds, timescale typically associated with the emission of gasoline and diesel engines. In downtown Rome, the hourly average size distribution is bimodal or trimodal with maxima at about 5-15, 20-30, and 70-100 nm. Particle formation in the nucleation mode was associated to freshly emitted autovehicular exhaust.

Pedestrians in Traffic Environments: Ultrafine Particle Respiratory Doses

Particulate matter has recently received more attention than other pollutants. PM10 and PM2.5 have been primarily monitored, whereas scientists are focusing their studies on finer granulometric sizes due both to their high number concentration and their high penetration efficiency into the respiratory system. The purpose of this study is to investigate the population exposure to UltraFine Particles (UFP, submicrons in general) in outdoor environments. The particle number doses deposited into the respiratory system have been compared between healthy individuals and persons affected by Chronic Obstructive Pulmonary Disease (COPD). Measurements were performed by means of Dust Track and Nanoscan analyzers. Forty minute walking trails through areas with different traffic densities in downtown Rome have been considered. Furthermore, particle respiratory doses have been estimated for persons waiting at a bus stop, near a traffic light, or along a high-traffic road, as currently occurs in a big city. Large differences have been observed between workdays and weekdays: on workdays, UFP number concentrations are much higher due to the strong contribution of vehicular exhausts. COPD-affected individuals receive greater doses than healthy individuals due to their higher respiratory rate.

Urban and Transport Planning Related Exposures and Mortality: A Health Impact Assessment for Cities

BACKGROUND

By 2050, nearly 70% of the global population is projected to live in urban areas. Because the environments we inhabit affect our health, urban and transport designs that promote healthy living are needed.

OBJECTIVE

We estimated the number of premature deaths preventable under compliance with international exposure recommendations for physical activity (PA), air pollution, noise, heat, and access to green spaces.

METHODS

We developed and applied the Urban and TranspOrt Planning Health Impact Assessment (UTOPHIA) tool to Barcelona, Spain. Exposure estimates and mortality data were available for 1,357,361 residents. We compared recommended with current exposure levels. We quantified the associations between exposures and mortality and calculated population attributable fractions to estimate the number of premature deaths preventable. We also modeled life-expectancy and economic impacts.

RESULTS

We estimated that annually, nearly 20% of mortality could be prevented if international recommendations for performance of PA; exposure to air pollution, noise, and heat; and access to green space were followed. Estimations showed that the greatest portion of preventable deaths was attributable to increases in PA, followed by reductions of exposure to air pollution, traffic noise, and heat. Access to green spaces had smaller effects on mortality. Compliance was estimated to increase the average life expectancy by 360 (95% CI: 219, 493) days and result in economic savings of 9.3 (95% CI: 4.9, 13.2) billion EUR/year.

CONCLUSIONS

PA factors and environmental exposures can be modified by changes in urban and transport planning. We emphasize the need for a) the reduction of motorized traffic through the promotion of active and public transport and b) the provision of green infrastructure, both of which are suggested to provide opportunities for PA and for mitigation of air pollution, noise, and heat. Citation: Mueller N, Rojas-Rueda D, Basagaña X, Cirach M, Cole-Hunter T, Dadvand P, Donaire-Gonzalez D, Foraster M, Gascon M, Martinez D, Tonne C, Triguero-Mas M, Valentín A, Nieuwenhuijsen M. 2017. Urban and transport planning related exposures and mortality: a health impact assessment for cities. Environ Health Perspect 125:89-96; http://dx.doi.org/10.1289/EHP220.

Variability of airborne particle metrics in an urban area

In the present study a mobile monitoring approach (i.e. bike with onboard instruments) was proposed and applied to investigate the spatial variability of all the key airborne particle metrics in an Italian urban area from a statistical point of view. Particle number, alveolar-deposited surface area, and PM₁₀ concentrations were measured through hand-held monitors and compared to simultaneous background concentrations by means of non-parametric tests and further post-hoc tests (Kruskal-Wallis test). Streets characterized by exposure levels statistically higher than the background levels for all the particle metrics were identified for different seasons in a pilot urban area (Cassino, Italy). A higher number of hot spots was detected for metrics affected by ultrafine particles (i.e. number and alveolar-deposited surface area concentrations) with respect to PM₁₀. The effect of metrological requirements of the instrumentation on the proposed method was also discussed.

Benchmark study on fine-mode aerosol in a big urban area and relevant doses deposited in the human respiratory tract

It is well-known that the health effects of PM increase as particle size decreases: particularly, great concern has risen on the role of UltraFine Particles (UFPs). Starting from the knowledge that the main fraction of atmospheric aerosol in Rome is characterized by significant levels of PM2.5 (almost 75% of PM10 fraction is PM2.5), the paper is focused on submicron particles in such great urban area. The daytime/nighttime, work-/weekdays and cold/hot seasonal trends of submicron particles will be investigated and discussed along with NOx and total PAH drifts demonstrating the primary origin of UFPs from combustion processes. Furthermore, moving from these data, the total dose of submicron particles deposited in the respiratory system (i.e., head, tracheobronchial and alveolar regions in different lung lobes) has been estimated. Dosimeter estimates were performed with the Multiple-Path Particle Dosimetry model (MPPD v.2.1). The paper discusses the aerosol doses deposited in the respiratory system of individuals exposed in proximity of traffic. During traffic peak hours, about 6.6 × 10(10) particles are deposited into the respiratory system. Such dose is almost entirely made of UFPs. According to the greater dose estimated, right lung lobes are expected to be more susceptible to respiratory pathologies than left lobes.