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The Puijo measurement station has produced continuous data on aerosol-cloud interactions since June 2006. The station is located on the top floor of an observation lower in a semi-urban environment near the town of Kuopio in central Finland. The top of the tower (306 m a.s.1.) has been detected to be in cloud approximately 10% of the time. We analysed continuous weather, particle size distribution and cloud droplet size distribution measurements. The effects of local pollutant sources and air mass origin on aerosol-cloud interaction were examined in detail. We were able to find clear evidence of file aerosol indirect effects at the Puijo site. There is a positive correlation between cloud droplet number concentration and particle number concentration. Higher cloud droplet concentration led to a smaller average cloud droplet size. Furthermore, the ratio of cloud droplet number concentration to accumulation mode particle number concentration is smaller when the particle number concentration is higher. Results from ore trajectory analysis indicated that at our site marine air masses had higher particle concentrations and the continental aerosols are more effective in acting as cloud condensation nuclei than marine aerosols, probably due to their larger mean size. We could also distinguish the effect of local pollutant sources. [ABSTRACT FROM AUTHOR]

We introduce a new measurement station that we established in 2005 in an observation tower at Puijo in Kuopio. At Puijo we measure several meteorological parameters, aerosol and cloud droplet size distribution, aerosol optical properties and trace gas concentrations. We summarize the research activities at the station during its three year history and present overall results. We compare the results from Puijo with those measured at the ground level in Kuopio and at the Finnish background stations. We also characterize the measured parameters according to the wind direction and air mass origins, based on trajectory analysis, for the effects of local and remote sources. Our conclusion is that the Puijo tower is a very good place to gather experimental data on cloud formation and aerosol-cloud interaction. In addition to cloud experiments, we would suggest the Puijo measurement station for studies of particle formation, which we also observed frequently. [ABSTRACT FROM AUTHOR]

Number size distributions of air ions and aerosol particles were measured at three sites in the Baltic Sea region in spring 2004. One site was on the island of Utö in the Baltic Sea and the two other sites, Hyytiälä and Tahkuse, had a more continental location not far away from the coast of the Baltic Sea. The concentrations of cluster ions (air ions with a diameter < 1.6 nm) were about three times smaller at the Utö island as compared with those at the Hyytiälä mainland site in Finland, although the particle concentrations (i.e. ion sink) were at about the same level at these two sites. Generally, the Utö island had the lowest air-ion concentration probably due to weaker sources for ions than the other two more continentally-located stations. Intermediate ion concentrations (1.6-7 nm diameter) were generally low, even though they reached several hundreds cm-3 during nucleation episodes. Charging probabilities of < 8 mn particles were found to be close to the steady state in all the three sites, suggesting that ion-induced nucleation was not playing a major role during tiffs time period. [ABSTRACT FROM AUTHOR]

During the late autumn 2004, aerosol and air ion number size distributions inside and out-side clouds and cloud droplet number size spectra were measured in Pallas, northern Finland. The concentrations of cluster ions (air ions with a diameter < 1.6 nm) were substantially lower, roughly by an order of magnitude, inside clouds as compared with cloud-free air. The observed concentration levels of cluster ions could be explained by a source rate of a few, ion pairs per second. The main sink for cluster ions was the cloud droplet population during the cloudy periods and the ion-ion recombination in cloud-free air. Very few, intermediate ions (1.6-7.4 nm diameter) were present during the cloudy periods, indicating that processes capable of generating intermediate ions were rather inactive inside clouds during the measurement campaign. [ABSTRACT FROM AUTHOR]

Evidence suggests that residential greenness may be protective of high blood pressure, but there is scarcity of evidence on the associations between greenness around schools and blood pressure among children. We aimed to investigate this association in China. Our study included 9354 children from 62 schools in the Seven Northeastern Cities Study. Greenness around each child's school was measured by NDVI (Normalized Difference Vegetation Index) and SAVI (Soil-Adjusted Vegetation Index). Particulate matter ≤ 1 μm (PM 1) concentrations were estimated by spatiotemporal models and nitrogen dioxide (NO 2) concentrations were collected from air monitoring stations. Associations between greenness and blood pressure were determined by generalized linear and logistic mixed-effect models. Mediation by air pollution was assessed using mediation analysis. Higher greenness was consistently associated with lower blood pressure. An increase of 0.1 in NDVI corresponded to a reduction in SBP of 1.39 mmHg (95% CI: 1.86, −0.93) and lower odds of hypertension (OR = 0.76, 95% CI: 0.69, 0.82). Stronger associations were observed in children with higher BMI. Ambient PM 1 and NO 2 mediated 33.0% and 10.9% of the association between greenness and SBP, respectively. In summary, greater greenness near schools had a beneficial effect on blood pressure, particularly in overweight or obese children in China. The associations might be partially mediated by air pollution. These results might have implications for policy makers to incorporate more green space for both aesthetic and health benefits. Image 1 • Evidence on the association between greenness and blood pressure among children is scarce. • We are the first to explore this topic based on school surrounding greenness exposure. • Attending schools with higher greenness showed beneficial effects on blood pressure. • The beneficial effects were stronger in children with higher BMI levels. • Air pollution might partially mediate the effects of greenness on blood pressure. Greater greenness near schools was associated with lower blood pressure among children, which might have implications for policy makers to incorporate more green space. [ABSTRACT FROM AUTHOR]

Little information exists on interaction effects between air pollution and influenza vaccination on allergic respiratory diseases. We conducted a large population-based study to evaluate the interaction effects between influenza vaccination and long-term exposure to ambient air pollution on allergic respiratory diseases in children and adolescents. A cross-sectional study was investigated during 2012–2013 in 94 schools from Seven Northeastern Cities (SNEC) in China. Questionnaires surveys were obtained from 56 137 children and adolescents aged 2–17 years. Influenza vaccination was defined as receipt of the influenza vaccine. We estimated air pollutants exposure [nitrogen dioxide (NO 2) and particulate matter with aerodynamic diameters ≤1 μm (PM 1), ≤2.5 μm (PM 2.5) and ≤10 μm (PM 10)] using machine learning methods. We employed two-level generalized linear mix effects model to examine interactive effects between influenza vaccination and air pollution exposure on allergic respiratory diseases (asthma, asthma-related symptoms and allergic rhinitis), after controlling for important covariates. We found statistically significant interactions between influenza vaccination and air pollutants on allergic respiratory diseases and related symptoms (doctor-diagnosed asthma, current wheeze, wheeze, persistent phlegm and allergic rhinitis). The adjusted ORs for doctor-diagnosed asthma, current wheeze and allergic rhinitis among the unvaccinated group per interquartile range (IQR) increase in PM 1 and PM 2.5 were significantly higher than the corresponding ORs among the vaccinated group [For PM 1 , doctor-diagnosed asthma: OR: 1.89 (95%CI: 1.57–2.27) vs 1.65 (95%CI: 1.36–2.00); current wheeze: OR: 1.50 (95%CI: 1.22–1.85) vs 1.10 (95%CI: 0.89–1.37); allergic rhinitis: OR: 1.38 (95%CI: 1.15–1.66) vs 1.21 (95%CI: 1.00–1.46). For PM 2.5 , doctor-diagnosed asthma: OR: 1.81 (95%CI: 1.52–2.14) vs 1.57 (95%CI: 1.32–1.88); current wheeze: OR: 1.46 (95%CI: 1.21–1.76) vs 1.11 (95%CI: 0.91–1.35); allergic rhinitis: OR: 1.35 (95%CI: 1.14–1.60) vs 1.19 (95%CI: 1.00–1.42)]. The similar patterns were observed for wheeze and persistent phlegm. The corresponding p values for interactions were less than 0.05, respectively. We assessed the risks of PM 1 -related and PM 2.5 -related current wheeze were decreased by 26.67% (95%CI: 1.04%–45.66%) and 23.97% (95%CI: 0.21%–42.08%) respectively, which was attributable to influenza vaccination (both p for efficiency <0.05). Influenza vaccination may play an important role in mitigating the detrimental effects of long-term exposure to ambient air pollution on childhood allergic respiratory diseases. Policy targeted at increasing influenza vaccination may yield co-benefits in terms of reduced allergic respiratory diseases. Image 1 • Few studies on interaction between air pollution and influenza vaccine on asthma. • A large population-based study to assess these interaction effects in China. • Influenza vaccine may mitigate the detrimental effects of air pollution on asthma. • Boys seem to be more sensitive to these interaction effects than girls. [ABSTRACT FROM AUTHOR]