In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 18, No. 5 ( 2018-03-12), p. 3563-3587
Abstract:
Abstract. Exposure to nitrogen dioxide (NO2) is associated with
negative human health effects, both for short-term “peak” concentrations and
from long-term exposure to a wider range of NO2 concentrations. For the
latter, the European Union has established an air quality limit value of 40 µg m−3 as an annual average. However, factors such as proximity
and strength of local emissions, atmospheric chemistry, and meteorological
conditions mean that there is substantial variation in the hourly NO2
concentrations contributing to an annual average concentration. The aim of
this analysis was to quantify the nature of this variation at thousands of
monitoring sites across Europe through the calculation of a standard set of
“chemical climatology” statistics. Specifically, at each monitoring site that
satisfied data capture criteria for inclusion in this analysis, annual
NO2 concentrations, as well as the percentage contribution from each
month, hour of the day, and hourly NO2 concentrations divided into 5 µg m−3 bins were calculated. Across Europe, 2010–2014 average annual NO2 concentrations (NO2AA)
exceeded the annual NO2 limit value at 8 % of 〉 2500 monitoring sites. The application of this “chemical climatology” approach
showed that sites with distinct monthly, hour of day, and hourly NO2
concentration bin contributions to NO2AA were not grouped into specific
regions of Europe, furthermore, within relatively small geographic regions there were
sites with similar NO2AA, but with differences in these contributions.
Specifically, at sites with highest NO2AA, there were generally similar
contributions from across the year, but there were also differences in the
contribution of peak vs. moderate hourly NO2 concentrations to
NO2AA, and from different hours across the day. Trends between 2000 and
2014 for 259 sites indicate that, in general, the contribution to NO2AA
from winter months has increased, as has the contribution from the rush-hour
periods of the day, while the contribution from peak hourly NO2
concentrations has decreased. The variety of monthly, hour of day and hourly
NO2 concentration bin contributions to NO2AA, across cities,
countries and regions of Europe indicate that within relatively small
geographic areas different interactions between emissions, atmospheric
chemistry and meteorology produce variation in NO2AA and the conditions
that produce it. Therefore, measures implemented to reduce NO2AA in one
location may not be as effective in others. The development of strategies to
reduce NO2AA for an area should therefore consider (i) the variation in monthly,
hour of day, and hourly NO2 concentration bin contributions to
NO2AA within that area; and (ii) how specific mitigation actions will
affect variability in hourly NO2 concentrations.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-18-3563-2018
DOI:
10.5194/acp-18-3563-2018-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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