Jarkko V. Niemi

Ozone and Cause-Specific Cardiorespiratory Morbidity and Mortality

Background Health effects of ozone have been observed in numerous studies. However, analyses of more cause-specific morbidity or mortality outcomes have rarely been performed. A study was undertaken to determine the short-term associations of ozone with cause-specific cardiorespiratory mortality and morbidity by age groups. Methods Daily levels of ozone were measured at a background measurement station in 1998–2004 in Helsinki, Finland. All analyses were a priori restricted to the warm season. Daily cause-specific cardiorespiratory mortality and hospital admissions were studied in elderly people (≥65 years) and adults (15–64 years) and associations between ozone and asthma emergency room visits in children (<15 years) were analysed. All models were adjusted for PM2.5 and Poisson regression was used for the analyses. Results There was a positive association between ozone and admissions for asthma-chronic obstructive pulmonary disease (COPD) in elderly people (9.6%; 95% CI 2.0% to 17.8% at 0-day lag for 25 μg/m3 increase in ozone). Consistent associations were also found between ozone and asthma emergency room visits in children (12.6%; 95% CI 0.8% to 25.1%, 0-day lag). There was a suggestion of an association between ozone and admissions for arrhythmia among elderly people (6.4%; 95% CI 0.63% to 12.5%, 1-day lag), which was slightly confounded by PM2.5. Conclusions Positive associations were found for ambient ozone with asthma visits among children and with pooled asthma/COPD admissions among elderly people. The evidence for a positive association between ozone and cardiovascular health was weaker.

Physical and Chemical Characterization of Real-World Particle Number and Mass Emissions from City Buses in Finland.

Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10(14) # (kg fuel)(-1), 6-40 g (kg fuel)(-1), 0.004-0.88 g (kg fuel)(-1), 0.004-0.56 g (kg fuel)(-1), 0.01-1.2 g (kg fuel)(-1), for particle number (EFN), nitrogen oxides (EFNOx), black carbon (EFBC), organics (EFOrg), and particle mass (EFPM1), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions.

Traffic is a major source of atmospheric nanocluster aerosol

Significance We report the significant presence of traffic-originated nanocluster aerosol (NCA) particles in a particle diameter range of 1.3–3.0 nm of urban air, determine the emission factors for the NCA, and evaluate its global importance. Our findings are important because they significantly update the current understanding of atmospheric aerosol in urban areas. They demonstrate that in urban air, extremely small particles form a significant fraction of the total particle number and are a direct result of anthropogenic emissions, that is, the emissions from road traffic. Thus, our findings also imply that in urban areas, an atmospheric nucleation process is not necessary for the formation of a large number of particles that affect population health and climate. In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)−1 in a roadside environment, 2.6·1015 (kgfuel)−1 in a street canyon, and 2.9·1015 (kgfuel)−1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)−1 to a high value of 4.3·1015 (kgfuel)−1. These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.

Size distribution, chemical composition, and hygroscopicity of fine particles emitted from an oil-fired heating plant.

Heavy fuel oil (HFO) is a commonly used fuel in industrial heating and power generation and for large marine vessels. In this study, the fine particle emissions of a 47 MW oil-fired boiler were studied at 30 MW power and with three different fuels. The studied fuels were HFO, water emulsion of HFO, and water emulsion of HFO mixed with light fuel oil (LFO). With all the fuels, the boiler emitted considerable amounts of particles smaller than 200 nm in diameter. Further, these small particles were quite hygroscopic even as fresh and, in the case of HFO+LFO emulsion, the hygroscopic growth of the particles was dependent on particle size. The use of emulsions and the addition of LFO to the fuel had a reducing effect on the hygroscopic growth of particles. The use of emulsions lowered the sulfate content of the smallest particles but did not affect significantly the sulfate content of particles larger than 42 nm and, further, the addition of LFO considerably increased the black carbon content of particulate matter. The results indicate that even the fine particles emitted from HFO based combustion can have a significant effect on cloud formation, visibility, and air quality.

Effects of long-range transported air pollution from vegetation fires on daily mortality and hospital admissions in the Helsinki metropolitan area, Finland.

INTRODUCTION Fine particulate matter (PM2.5) emissions from vegetation fires can be transported over long distances and may cause significant air pollution episodes far from the fires. However, epidemiological evidence on health effects of vegetation-fire originated air pollution is limited, particularly for mortality and cardiovascular outcomes. OBJECTIVE We examined association between short-term exposure to long-range transported PM2.5 from vegetation fires and daily mortality due to non-accidental, cardiovascular, and respiratory causes and daily hospital admissions due to cardiovascular and respiratory causes in the Helsinki metropolitan area, Finland. METHODS Days significantly affected by smoke from vegetation fires between 2001 and 2010 were identified using air quality measurements at an urban background and a regional background monitoring station, and modelled data on surface concentrations of vegetation-fire smoke. Associations between daily PM2.5 concentration and health outcomes on i) smoke-affected days and ii) all other days (i.e. non-smoke days) were analysed using Poisson time series regression. All statistical models were adjusted for daily temperature and relative humidity, influenza, pollen, and public holidays. RESULTS On smoke-affected days, 10µg/m3 increase in PM2.5 was associated with a borderline statistically significant increase in cardiovascular mortality among total population at a lag of three days (12.4%, 95% CI -0.2% to 26.5%), and among the elderly (≥65 years) following same-day exposure (13.8%, 95% CI -0.6% to 30.4%) and at a lag of three days (11.8%, 95% CI -2.2% to 27.7%). Smoke day PM2.5 was not associated with non-accidental mortality or hospital admissions due to cardiovascular causes. However, there was an indication of a positive association with hospital admissions due to respiratory causes among the elderly, and admissions due to chronic obstructive pulmonary disease or asthma among the total population. In contrast, on non-smoke days PM2.5 was generally not associated with the health outcomes, apart from suggestive small positive effects on non-accidental mortality at a lag of one day among the elderly and hospital admissions due to all respiratory causes following same-day exposure among the total population. CONCLUSIONS Our research provides suggestive evidence for an association of exposure to long-range transported PM2.5 from vegetation fires with increased cardiovascular mortality, and to a lesser extent with increased hospital admissions due to respiratory causes. Hence, vegetation-fire originated air pollution may have adverse effects on public health over a distance of hundreds to thousands of kilometres from the fires.

Investigating the chemical species in submicron particles emitted by city buses

ABSTRACT Detailed chemical characterization of exhaust particles from 23 individual city buses was performed in Helsinki, Finland. Investigated buses represented different technologies in terms of engines, exhaust after-treatment systems (e.g., diesel particulate filter, selective catalytic reduction, and three-way catalyst) and fuels (diesel, diesel-electric (hybrid), ethanol, and compressed natural gas). Regarding emission standards, the buses operated at EURO III, EURO IV, and EEV (enhanced environmentally friendly vehicle) emission levels. The chemical composition of exhaust particles was determined by using a soot particle aerosol mass spectrometer (SP-AMS). Based on the SP-AMS results, the bus emission particles were dominated by organics and refractory black carbon (rBC). The mass spectra of organics consisted mostly of hydrocarbon fragments (54–86% of total organics), the pattern of hydrocarbon fragments being rather similar regardless of the bus type. Regarding oxygenated organic fragments, ethanol-fueled buses had unique mass-to-charge ratios (m/z) of 45, 73, 87, and 89 (mass fragments of C2H5O+, C3H5O2+, C4H7O2+, and C4H9O2+, respectively) that were not detected for the other bus types at the same level. For rBC, there was a small difference in the ratio of C4+ and C5+ to C3+ for different bus types but also for the individual buses of the same type. In addition to organics and rBC, the presence of trace metals in the bus emission particles was investigated. Copyright

Fatty acids on continental sulfate aerosol particles: FATTY ACID SURFACTANTS

Published 2005 American Geophysical Union. Reproduced by permission of American Geophysical Union.

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.

Money talks: Customer-initiated price negotiation in business-to-business sales interaction

This article provides an in-depth analysis of a conversational exchange initiated by a customer’s price question in real-life business-to-business (B2B) sales encounters. The analysis focusses on when the customer requests a price, what that implies as well as how the price discussion is conducted. Marketing literature usually considers product/service price to be an obstacle that the salesperson needs to overcome; we demonstrate that the price question is a positive signal for the salesperson. By requesting the price, the customer claims sufficient understanding of the offer, recognition of the service value and a readiness to move to the next phase in the meeting. The salesperson initiates an insert expansion to tailor the price to her or his customer and then informs the price in an expanded clausal response to build customer value. The conversation analytic study was based on a dataset of 13 video-recorded B2B sales meetings in Finland.