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The object of this study was to investigate the different modal behavior of ultrafine aerosol particles collected at the Gruvebadet observatory located in Ny-Ålesund (Svalbard Islands, 78°55′N, 11°56′E). Aerosol particle size distribution was measured in the size range from 10 to 470 nm typically from the beginning of spring to the beginning of fall during four (non-consecutive) years (2010, 2011, 2013 and 2014). The median concentration for the whole period taken into account was 214 particles cm−3, oscillating between the median maximum in July with a concentration of 257 particles cm−3and a median minimum in April with 197 particles cm−3. The median total number concentration did not present a well-defined seasonal behavior, as shown by contrast looking at the sub/modal number concentration, where distinct trends appeared in the predominant accumulation concentration recorded during April/May and the preponderant concentration of Aitken particles during the summer months. Lastly, the short side-by-side spring 2013 campaign performed at the Zeppelin observatory with a differential mobility particle sizer was characterized by an aerosol concentration mean steady difference between the two instruments of around 14 %, thereby supporting the reliability of the device located at Gruvebadet.

AbstractResidential wood combustion (RWC) is responsible for 33% of the total carbon mass emitted in Europe. With the new European targets to increase the use of renewable energy, there is a growing concern that the population exposure to woodsmoke will also increase. This study investigates observed and simulated light-absorbing carbon mass (MLAC) concentrations in a residential neighborhood (Lycksele, Sweden) where RWC is a major air pollution source during winter. The measurement analysis included descriptive statistics, correlation coefficient, coefficient of divergence, linear regression, concentration roses, diurnal pattern, and weekend versus weekday concentration ratios. Hourly RWC and road traffic contributions to MLACwere simulated with a Gaussian dispersion model to assess whether the model was able to mimic the observations. Hourly mean and standard deviation concentrations measured at six sites ranged from 0.58 to 0.74 µg m-3and from 0.59 to 0.79 µg m-3, respectively. The temporal and spatial variability decreased with increasing averaging time. Low-wind periods with relatively high MLACconcentrations correlated more strongly than high-wind periods with low concentrations. On average, the model overestimated the observations by 3- to 5-fold and explained less than 10% of the measured hourly variability at all sites. Large residual concentrations were associated with weak winds and relatively high MLACloadings. The explanation of the observed variability increased to 31–45% when daily mean concentrations were compared. When the contribution from the boilers within the neighborhood was excluded from the simulations, the model overestimation decreased to 16–71%. When assessing the exposure to light-absorbing carbon particles using this type of model, the authors suggest using a longer averaging period (i.e., daily concentrations) in a larger area with an updated and very detailed emission inventory.

AbstractIn this paper we derive typical emission factors for coarse particulate matter (PM10), oxides of nitrogen (NOx), black carbon (BC), and number particle size distributions based on a combination of measurements and air quality dispersion modeling. The advantage of this approach is that the emission factors represent integrated emissions from several vehicle types and different types of wood stoves. Normally it is very difficult to estimate the total emissions in cities on the basis of laboratory measurements on single vehicles or stoves because of the large variability in conditions. The measurements were made in Temuco, Chile, between April 18 and June 15, 2005 at two sites. The first one was located in a residential area relatively far from major roads. The second site was located in a busy street in downtown Temuco where wood consumption is low. The measurements support the assumption that the monitoring sites represent the impact of different emission sources, namely traffic and residential wood combustion (RWC). Fitting model results to the available measurements, emission factors were obtained for PM10(RWC = 2160 ± 100 mg/kg; traffic = 610 ± 51 mg/vehkm), NOx(RWC = 800 ± 100 mg/kg; traffic = 4400 ± 100 mg/veh-km), BC (RWC = 74 ± 6 mg/kg; traffic = 60 ± 3 mg/veh-km) and particle number (N) with size distribution between 25 and 600 nm (N25–600) (RWC = 8.9 ± 1 × 1014pt/kg; traffic = 6.7 ± 0.5 × 1014pt/veh-km). The obtained emission factors are comparable to results reported in the literature. The size distribution of the N emission factors for traffic was shown to be different than for RWC. The main difference is that although traffic emissions show a bimodal size distribution with a main mode below 30 nm and a secondary one around 100 nm, RWC emissions show the main mode slightly below 100 nm and a smaller nucleation mode below 50 nm.

Oceanic dimethyl sulfide (DMS) emissions have been recognized as a biological regulator of climate by contributing to cloud formation. Despite decades of research, the climatic role of DMS remains ambiguous largely because of limited observational evidence for DMS‐induced cloud condensation nuclei (CCN) enhancement. Here, we report concurrent measurement of DMS, physiochemical properties of aerosol particles, and CCN in the Arctic atmosphere during the phytoplankton bloom period of 2010. We encountered multiple episodes of new particle formation (NPF) and particle growth when DMS mixing ratios were both low and high. The growth of particles to sizes at which they can act as CCN accelerated in response to an increase in atmospheric DMS. Explicitly, the sequential increase in all relevant parameters (including the source rate of condensable vapor, the growth rate of particles, Aitken mode particles, hygroscopicity, and CCN) was pronounced at the DMS‐derived NPF and particle growth events. This field study unequivocally demonstrates the previously unconfirmed roles of DMS in the growth of particles into climate‐relevant size and eventual CCN activation. Marine phytoplankton can produce gaseous dimethyl sulfide (DMS), which is the most abundant form of sulfur released into the atmosphere through sea‐air gas exchange. The polar oceans are known to be the most productive ocean in terms of DMS due to the high abundance of DMS‐producing phytoplankton. The oceanic emission of DMS into the marine atmosphere has received substantial attention during the last 30 years because of its contribution to cloud formation and its subsequent impact on climate. However, the climate feedback role of DMS remains uncertain due to insufficient evidence supporting DMS‐derived formation of aerosol particles and their subsequent activation into cloud condensation nuclei (CCN), in turn affecting the Earth's radiation budget. In this study, we analyzed atmospheric DMS mixing ratios, and concentrations of aerosol particles and CCN in the Arctic atmosphere during the phytoplankton bloom period. Our results show that atmospheric DMS affects the formation and growth of aerosol particles and significantly contributes to CCN populations. Dimethyl sulfide (DMS), aerosol particle numbers, and cloud condensation nuclei (CCN) were measured in the Arctic atmosphereMultiple episodes of new particle formation and particle growth with both high and low DMS mixing ratios were observedAn increase in CCN was observed when the formation and growth of aerosol particles derived from DMS occurred Dimethyl sulfide (DMS), aerosol particle numbers, and cloud condensation nuclei (CCN) were measured in the Arctic atmosphere Multiple episodes of new particle formation and particle growth with both high and low DMS mixing ratios were observed An increase in CCN was observed when the formation and growth of aerosol particles derived from DMS occurred