ground-level O 3 pollution. Li et al. (2017b) quantitatively analyzed data from
Chinese studies on temperate and subtropical regions to determine how elevated
O 3 concentrations affect vegetation growth, biomass, and functional leaf traits of
different types of woody plants. Their results indicated that if averaged O 3 level is
equal to 116 ppb, total biomass of woody plants would decrease by 14% comparing
with O 3 levels equal to ~21 ppb. Effect of elevated O 3 concentration on biomass,
growth, leaf characteristics, photosynthetic pigments, gas exchange, chlorophyll
fluorescence, and antioxidant parameters for all kinds of trees in China are shown
in Fig. 7.11 (Li et al. 2017b).
In fact, high O 3 level is one of the most damaging pollutants that severely damage
economic and biological aspects of crop-bearing plants (Feng et al. 2011). Current
ground-level O 3 concentration significantly decreased wheat growth as well as its
quality and yield according to the meta-analysis, which are shown in Fig. 7.12
(Pleijel et al. 2018). Feng et al. (2015b) reviewed data on how elevated O 3 levels
affect food crops in China and also demonstrated significant reduction in wheat
yield. Based on exposure concentration and stomatal O 3 flux-response relationships
obtained by O 3 -FACE experimental data, they predicted that if O 3 level continues to
increase, wheat crops will produce less yield by 6.4%–14.9% and 14.8%–23.0%,
respectively. Thus, if O 3 level continues rising, food security in China might be
severely compromised. Without certain regulations, precautions, and measures,
ground-level O 3 levels will continue to rise and to damage forests and crops.
7.6 Mitigation Measures of Ozone Pollution
Ozone causes so much damage to vegetation, and finding a solution on how to
control O 3 pollution is a worldwide concern. Yet, there is no a single solution to this
issue. Below are several policy recommendations and mitigation measures, which
should help to decrease O 3 impacts and to mitigate risks associated with high O 3
levels:
1. Strict control of emissions containing potential agents participating in O 3 formation cycle
Strict laws on O 3 -related precursor (such as VOCs and NO x ) emissions are
required. Currently, majority of these chemicals are from automotive exhausts. One
solution is to impose a Euro standard V for all vehicle exhaust gases throughout China
by no later than 2020. Another solution is to decrease personal use of cars and to
encourage usage of public transportation in major and overpopulated areas. One way
to regulate this is to increase gasoline price and parking fees (Feng et al. 2015a, b).
7 Contribution of Atmospheric Reactive Nitrogen to Ozone Pollution in China
149
Chinese studies on temperate and subtropical regions to determine how elevated
O 3 concentrations affect vegetation growth, biomass, and functional leaf traits of
different types of woody plants. Their results indicated that if averaged O 3 level is
equal to 116 ppb, total biomass of woody plants would decrease by 14% comparing
with O 3 levels equal to ~21 ppb. Effect of elevated O 3 concentration on biomass,
growth, leaf characteristics, photosynthetic pigments, gas exchange, chlorophyll
fluorescence, and antioxidant parameters for all kinds of trees in China are shown
in Fig. 7.11 (Li et al. 2017b).
In fact, high O 3 level is one of the most damaging pollutants that severely damage
economic and biological aspects of crop-bearing plants (Feng et al. 2011). Current
ground-level O 3 concentration significantly decreased wheat growth as well as its
quality and yield according to the meta-analysis, which are shown in Fig. 7.12
(Pleijel et al. 2018). Feng et al. (2015b) reviewed data on how elevated O 3 levels
affect food crops in China and also demonstrated significant reduction in wheat
yield. Based on exposure concentration and stomatal O 3 flux-response relationships
obtained by O 3 -FACE experimental data, they predicted that if O 3 level continues to
increase, wheat crops will produce less yield by 6.4%–14.9% and 14.8%–23.0%,
respectively. Thus, if O 3 level continues rising, food security in China might be
severely compromised. Without certain regulations, precautions, and measures,
ground-level O 3 levels will continue to rise and to damage forests and crops.
7.6 Mitigation Measures of Ozone Pollution
Ozone causes so much damage to vegetation, and finding a solution on how to
control O 3 pollution is a worldwide concern. Yet, there is no a single solution to this
issue. Below are several policy recommendations and mitigation measures, which
should help to decrease O 3 impacts and to mitigate risks associated with high O 3
levels:
1. Strict control of emissions containing potential agents participating in O 3 formation cycle
Strict laws on O 3 -related precursor (such as VOCs and NO x ) emissions are
required. Currently, majority of these chemicals are from automotive exhausts. One
solution is to impose a Euro standard V for all vehicle exhaust gases throughout China
by no later than 2020. Another solution is to decrease personal use of cars and to
encourage usage of public transportation in major and overpopulated areas. One way
to regulate this is to increase gasoline price and parking fees (Feng et al. 2015a, b).
7 Contribution of Atmospheric Reactive Nitrogen to Ozone Pollution in China
149