Early pregnancy particulate matter exposure, pre-pregnancy adiposity and risk of gestational diabetes mellitus in Finnish primiparous women: An observational cohort study.

AIMS: To evaluate the association between the exposure of particulate matter with an aerodynamic diameter of ≤ 2.5µm (PM2.5) and with an aerodynamic diameter of ≤ 10µm (PM10) over the first trimester and the risk of gestational diabetes mellitus (GDM), and to assess whether maternal pre-pregnancy body mass index (BMI) modified the GDM risk. METHODS: All Finnish primiparous women without previously diagnosed diabetes who delivered between 2009 and 2015 in the city of Vantaa, Finland, composed the study cohort (N = 6189). Diagnosis of GDM was based on a standard 75 g 2-hour oral glucose tolerance test. The average daily concentration of PM2.5 and PM10 over the first trimester was calculated individually for each woman. The relationship between exposure of PM2.5 and PM10 and GDM was analyzed with logistic models. RESULTS: No association was observed between the average daily concentrations of PM2.5 and PM10 over the first trimester and the GDM risk. When simultaneously taking BMI and PM10 into account both mean daily PM10 concentration (p = 0.047) and pre-pregnancy BMI (p = 0.016) increased GDM risk independently and an interaction (p = 0.013) was observed between PM10 concentration and pre-pregnancy BMI. CONCLUSIONS: Even globally low PM10 exposure level together with elevated maternal pre-pregnancy BMI seems to increase the GDM risk.

Size distribution and chemical composition of airborne particles in south-eastern Finland during different seasons and wildfire episodes in 2006.

The inorganic main elements, trace elements and PAHs were determined from selected PM(1), PM(2.5) and PM(10) samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 microm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM(10) were actually in PM(2.5). For PAHs and trace elements, it is more beneficial to analyse the PM(2.5) or even the PM(1) fraction instead of PM(10), because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 microm, as well as those of submicron particles, increased, and also the ratio PM(1)/PM(10) increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 microm. PAH concentrations rose even to the same level as in winter.

Airborne sulfur and nitrogen in Finland-trends and exposure in relation to air transport sector.

We present the concentration trends and the atmospheric exposure of sulfur and nitrogen compounds in different transport sectors during the period 1981-2000, based on the air quality data of the Finnish Meteorological Institute. Sulfur and nitrogen concentrations in air and precipitation were assessed from background stations covering the whole country. A significant decrease of more than 60% was observed in the concentrations of all sulfur compounds throughout the country during 1981-2000. In the 1990's, significant trends were detected in all sulfur time series, with the exception of sulfate in precipitation at the northernmost stations. On the other hand, the concentrations of oxidized nitrogen compounds in air and precipitation have declined only slightly or not at all, especially in the 1990's. This is attributed to the fairly small domestic and European NO(x) emission reductions after 1981. The ammonium concentration in precipitation has declined by more than 50% during 1981-2000. The atmospheric sulfur exposure was found to be dominated by transport from the West and South-West sectors during summer, whereas in winter all the southward sectors were important. The largest decline in the sectoral sulfur concentrations has taken place already before 1991, with a more pronounced reduction during winter than during summer. The atmospheric nitrogen exposure was mainly dominated by transport from the sectors between west and south, but in the latter half of the study period there seems to have been a slight shift towards increased transport from the eastern and northern sectors.