A prospective panel study, in which personal exposure was monitored, was conducted among preschool children in Helsinki between October 1990 and June 1991. The aims of the study were: 1) to assess children’s personal weekly exposure to nitrogen dioxide (NO2), 2) to investigate the association of seasonal and weekly NO2 exposure with respiratory health and 3) to compare different exposure assess...

[1] The role of nitrous acid, HONO, as a precursor for hydroxyl radicals in polluted urban air has been recognized for many years. The chemical processes leading to the formation of HONO are, however, still not well understood. Laboratory studies show that HONO formation occurs primarily on surfaces and is first order in NO2. Water also plays an important role in the conversion process. While t...

The aim of this study was to determine whether outdoor nitrogen dioxide (NO2) was associated with the prevalence of asthma and respiratory symptoms. In eight nonurban communities, 843 children resident for a minimum of 2 yrs were studied. Since industrial sources of air pollution were at least 20 km away from the study communities, NO2 was considered to primarily indicate traffic-related air po...

BACKGROUND Nitrogen dioxide (NO2) is an air pollutant associated with poor respiratory health, asthma exacerbation, and an increased likelihood of inhalational allergies. NO2 is also produced endogenously in the lung during acute inflammatory responses. NO2 can function as an adjuvant, allowing for allergic sensitization to an innocuous inhaled antigen and the generation of an antigen-specific ...

The annual cycles of soil moisture and NO2 have been analysed across the climate zones of West Africa using two satellite data sets (OMI on AURA and ASCAT on MetOp-A). Exploring the sources and sinks for NO2 it is clear that the densely populated urban cities including Lagos and Abuja had the highest mean NO2 concentrations (>1.8 × 10 15 molecules cm -2 ) indicative of the anthropogenic urban e...

[1] Chemistry Transport Models (CTMs) tend to underestimate very severely NO2 concentrations in the polar lower stratosphere during the winter suggesting that either the NOx sink is overestimated or a source of NOx is missing in models. We study the night-time decay of polar NO2 because it is controlled by the reaction between NO2 and O3 which is thought to be the main NOx sink at high latitude...

[1] Nitrogen dioxide (NO2) is a key species in studying photochemical smog and formation mechanisms of nitrate in fine particles. However, the conventional commercially available chemiluminescence (CL)-based method often has uncertainties in measuring NO2 because of interferences with other reactive nitrogen species. In this study, an Aerodyne Cavity Attenuated Phase Shift Spectroscopy (CAPS) N...

It has been well documented that air pollution adversely affects health, and epidemiological pollution-health studies utilise pollution data from automatic monitors. However, these automatic monitors are small in number and hence spatially sparse, which does not allow an accurate representation of the spatial variation in pollution concentrations required for these epidemiological health studie...