Page 93 - Materials Chemistry, Second Edition

80 Part 2a: Guide

Main choices and guidelines

Method status Characterisation method/factor Table in Part 2b
baseline 4.3.8.1
alternative 1 4.3.8.2
alternative 2 4.3.8.3
alternative 3 4.3.8.4
alternative 4 4.3.8.5
additional — —
variant see Part 3 -
Example (for baseline)

impact category marine sediment ecotoxicity
LCI results emissions of toxic substances to air, water and soil (in kg)
characterisation model USES 2.0 model developed at RIVM, describing fate, exposure
and effects of toxic substances, adapted to LCA
category indicator predicted environmental concentration/predicted no-effect
concentration
characterisation factor marine sediment ecotoxicity potential (MSETP) for each
emission of a toxic substance to air, water and/or soil (in kg 1 ,4­
dichlorobenzene equivalents/kg emission)
unit of indicator result kg (1,4-dichlorobenzene eq)

4.3.3.9 Photo-oxidant formation

Topic

Photo-oxidant formation is the formation of reactive chemical compounds such as ozone by
the action of sunlight on certain primary air pollutants. These reactive compounds may be
injurious to human health and ecosystems and may also damage crops. The relevant areas
of protection are human health, the man-made environment, the natural environment and
natural resources.

Photo-oxidants may be formed in the troposphere under the influence of ultraviolet light,
through photochemical oxidation of Volatile Organic Compounds (VOCs) and carbon
monoxide (CO) in the presence of nitrogen oxides Ozone is considered the most
important of these oxidising compounds, along with peroxyacetylnitrate (PAN). Photo-
oxidant formation, also known as summer smog, Los Angeles smog or secondary air
pollution, contrasts with winter smog, or London smog, which is characterised by high levels
of inorganic compounds, mainly particles, carbon monoxide and sulphur compounds. This
latter type of smog causes bronchial irritation, coughing, etc. Winter smog, as far as
considered in this Guide, is part of human toxicity.